- Free-Radical Halogenations. 5. Reaction of Chlorosulfonyl Isocyanate with Alkanes
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The free-radical chain reactions of chlorosulfonyl isocyanate with alkanes can be initiated with either light or thermal initiators.The major products in these reactions are chlorides, with low yields of isocyanates and sulfonyl chlorides.On the basis of tertiary to primary hydrogen selectivity of about 120:1 and the relative reactivities of various substrates toward the abstracting radical from chlorosulfonyl isocyanate, the hydrogen-abstracting radical is suggested to be the NCO radical.
- Mosher, Melvyn W.
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- POLYMERIZATION, OXYGENATION AND ISOMERIZATION OF ISOCYANIDES UNDER IRRADIATION
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Irradiation in the presence of triplet oxygen polymerized both 2,4-dimethoxyphenyl and cyclohexyl isocyanide and photoautoxidized each into the corresponding isocyanate.The aryl, but not the alicyclic, isocyanide also photoisomerized into a cyanide.The consumption of an isocyanide was enhanced in the presence of certain aromatic hydrocarbons, e. g., naphthalene and phenanthrene, but was diminished in the presence of pyrene.Two bisisocyanides were unaffected by the presence of oxygen during irradiation.
- Boyer, Joseph H.,Ramakrishnan, V. T.,Srinivasan, K. G.,Spak, A. J.
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Read Online
- Synthesis and biological evaluation of novel 4-(4-formamidophenylamino)-N-methylpicolinamide derivatives as potential antitumor agents
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A novel series of 4-(4-formamidophenylamino)-N-methylpicolinamide derivatives were synthesized and evaluated against different tumor cell lines. Experiments in vitro showed that these derivatives could inhibit the proliferation of two kinds of human cancer cell lines (HepG2, HCT116) at low micromolar concentrations and the most potent analog 5q possessed broad-spectrum antiproliferative activity. Experiments in vivo demonstrated that 5q could effectively prolong the longevity of colon carcinoma-burdened mice and slow down the progression of cancer cells by suppression of angiogenesis and the induction of apoptosis and necrosis.
- Hu, Min,Meng, Nana,Xia, Yong,Xu, Youzhi,Yu, Luoting,Zeng, Xiuxiu,Zhou, Shuyan
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- Production process of cyclohexyl isocyanate
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The invention discloses a production process of cyclohexyl isocyanate, which comprises the following steps: desorbing phosgenation byproduct hydrochloric acid through a desorption tower, removing water, introducing the generated hydrogen chloride gas into
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Paragraph 0013; 0028; 0029; 0030; 0031; 0032; 0033; 0034
(2021/03/11)
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- Supporting-Electrolyte-Free Anodic Oxidation of Oxamic Acids into Isocyanates: An Expedient Way to Access Ureas, Carbamates, and Thiocarbamates
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We report a new electrochemical supporting-electrolyte-free method for synthesizing ureas, carbamates, and thiocarbamates via the oxidation of oxamic acids. This simple, practical, and phosgene-free route includes the generation of an isocyanate intermediate in situ via anodic decarboxylation of an oxamic acid in the presence of an organic base, followed by the one-pot addition of suitable nucleophiles to afford the corresponding ureas, carbamates, and thiocarbamates. This procedure is applicable to different amines, alcohols, and thiols. Furthermore, when single-pass continuous electrochemical flow conditions were used and this reaction was run in a carbon graphite Cgr/Cgr flow cell, urea compounds could be obtained in high yields within a residence time of 6 min, unlocking access to substrates that were inaccessible under batch conditions while being easily scalable.
- Petti, Alessia,Fagnan, Corentin,van Melis, Carlo G. W.,Tanbouza, Nour,Garcia, Anthony D.,Mastrodonato, Andrea,Leech, Matthew C.,Goodall, Iain C. A.,Dobbs, Adrian P.,Ollevier, Thierry,Lam, Kevin
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supporting information
p. 2614 - 2621
(2021/06/27)
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- Dehydrogenative Synthesis of Carbamates from Formamides and Alcohols Using a Pincer-Supported Iron Catalyst
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We report that the pincer-ligated iron complex (iPrPNP)Fe(H)(CO) [1, iPrPNP- = N(CH2CH2PiPr2)2-] is an active catalyst for the dehydrogenative synthesis of N-alkyl- and N-aryl-substituted carbamates from formamides and alcohols. The reaction is compatible with industrially relevant N-alkyl formamides, as well as N-aryl formamides, and 1°, 2°, and benzylic alcohols. Mechanistic studies indicate that the first step in the reaction is the dehydrogenation of the formamide to a transient isocyanate by 1. The isocyanate then reacts with the alcohol to generate the carbamate. However, in a competing reaction, the isocyanate undergoes a reversible cycloaddition with 1 to generate an off-cycle species, which is the resting state in catalysis. Stoichiometric experiments indicate that high temperatures are required in catalysis to facilitate the release of the isocyanate from the cycloaddition product. We also identified several other off-cycle processes that occur in catalysis, such as the 1,2-addition of the formamide or alcohol substrate across the Fe-N bond of 1. It has already been demonstrated that the transient isocyanate generated from dehydrogenation of the formamide can be trapped with amines to form ureas and, in principle, the isocyanate could also be trapped with thiols to form thiocarbamates. Competition experiments indicate that trapping of the transient isocyanate with amines to produce ureas is faster than trapping with an alcohol to produce carbamates and thus ureas can be formed selectively in the presence of alcohols. In contrast, thiols bind irreversibly to the iron catalyst through 1,2 addition across the Fe-N bond of 1, and it is not possible to produce thiocarbamates. Overall, our mechanistic studies provide general guidelines for facilitating dehydrogenative coupling reactions using 1 and related catalysts.
- Bernskoetter, Wesley H.,Hazari, Nilay,Mercado, Brandon Q.,Townsend, Tanya M.
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p. 10614 - 10624
(2021/09/02)
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- Practical one-pot amidation of N -Alloc-, N -Boc-, and N -Cbz protected amines under mild conditions
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A facile one-pot synthesis of amides from N-Alloc-, N-Boc-, and N-Cbz-protected amines has been described. The reactions involve the use of isocyanate intermediates, which are generated in situ in the presence of 2-chloropyridine and trifluoromethanesulfonyl anhydride, to react with Grignard reagents to produce the corresponding amides. Using this reaction protocol, a variety of N-Alloc-, N-Boc-, and N-Cbz-protected aliphatic amines and aryl amines were efficiently converted to amides with high yields. This method is highly effective for the synthesis of amides and offers a promising approach for facile amidation.
- Hong, Wan Pyo,Tran, Van Hieu,Kim, Hee-Kwon
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p. 15890 - 15895
(2021/05/19)
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- Preparation method of cyclohexyl isocyanate
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The invention relates to a preparation method of cyclohexyl isocyanate, which is characterized by comprising the following steps: S1: putting raw materials of cyclohexylamine and sufficient toluene solvent into a reaction kettle, and controlling the heating temperature of the reaction kettle to be 80-95 DEG C; S2, adding liquid hydrochloric acid into the reaction kettle in the step S1, controllingthe dropwise adding time to be 2.5-3 hours, and controlling the pH value to be 3-7; S3, after the hydrochloric acid is dropwise added in the S2, and performing heating distillation and dehydration; S4, transferring the product salt in S3 and a toluene solvent into an esterification kettle, then slowly adding triphosgene, and controlling the temperature to be 95-115 DEG C when triphosgene is added; s5, after triphosgene is added in the step S4, carrying out heat preservation reaction for 0.5 h, and meanwhile purging the reactor with nitrogen for 0.5-2.5 h; and S6, after the reaction in the step S5 is finished, carrying out reduced pressure distillation to recover the toluene solvent, and carrying out cyclic utilization to produce the cyclohexyl isocyanate.
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Paragraph 0012-0018
(2020/08/27)
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- Method for preparing cyclohexyl isocyanate from solid phosgene
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The invention provides a method for preparing cyclohexyl isocyanate from solid phosgene. The method comprises the following steps: S1, dissolving the solid phosgene in a solvent; S2, slowly adding thesolid phosgene solution into cyclohexylamine hydrochloride, heating, and carrying out a phosgenation reaction to obtain a crude product of cyclohexyl isocyanate; and S3, separating and purifying to obtain the cyclohexyl isocyanate. According to the method provided by the invention, the cyclohexyl isocyanate is prepared through the reaction of the solid phosgene and the cyclohexylamine hydrochloride, so that the yield of the cyclohexyl isocyanate is guaranteed, the chemical property of the solid phosgene is relatively stable, no obvious toxicity exists, and the method has the advantages of improving the safety and reducing the safety production cost.
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Paragraph 0043-0066
(2020/09/23)
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- Palladium-Mediated CO2 Extrusion Followed by Insertion of Isocyanates for the Synthesis of Benzamides: Translating Fundamental Mechanistic Studies to Develop a Catalytic Protocol
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Mechanistic studies of a stoichiometric palladium-mediated ExIn (ExIn = extrusion-insertion) decarboxylative amidation of aromatic carboxylic acids are presented, providing gas-phase and condensed-phase spectroscopic data, as well as theoretical computational evidence for intermediates in a proposed stepwise process. The understanding gained from these mechanistic studies directed the development of a palladium-catalyzed procedure in which benzamides are obtained in good to high yields in a one-pot 30 min microwave irradiation assisted protocol. A combination of experimental data and DFT calculations reveals that certain ligand additives favor the selective formation of benzamides rather than the undesired protodecarboxylation side product.
- Canty, Allan J.,Donnelly, Paul S.,McKay, Alasdair I.,O'Hair, Richard A. J.,Yang, Yang
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- Design, synthesis, and biological evaluation of 2,4-imidazolinedione derivatives as hdac6 isoform-selective inhibitors
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Histone deacetylase 6 (HDAC6) has emerged as a promising drug target for various human diseases, including diverse neurodegenerative diseases and cancer. Herein, we reported a series of 2,4-imidazolinedione derivatives as novel HDAC6 isoform-selective inhibitors based on structure-based drug design. Most target compounds exhibit good profiles in a preliminary screening concerning HDAC6 inhibitory activities. Moreover, the most active compound 10c increases the acetylation level of α-tubulin with little effect on the acetylation of histone H3. Further biological evaluation suggested that potent compound 10c, which possesses good antiproliferative activity, could induce apoptosis in HL-60 cell by activating caspase 3.
- Liang, Tao,Hou, Xuben,Zhou, Yi,Yang, Xinying,Fang, Hao
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supporting information
p. 1122 - 1127
(2019/08/27)
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- Method for preparing isocyanate by using amine and carbonyl fluoride
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The invention discloses an efficient synthesis method for preparing corresponding isocyanate by enabling carbonyl fluoride to directly react with amine. The efficient synthesis method mainly comprises the following two steps: carrying out acylation reaction on the amine and the carbonyl fluoride according to a preferable proportion in an anhydrous inertial organic solvent under a sealed environment and a proper reaction condition, thus generating an intermediate-carbamyl fluoride; (2) carrying out dehydrofluorination on the intermediate-carbamyl fluoride under normal pressure and the proper reaction condition, thus obtaining the target isocyanate. During a reaction process, addition of a catalyst is not needed, the reaction conditions are mild, excessive carbonyl fluoride and a used solvent during the reaction process can be efficiently recycled and reused, and a by-product HF can be commercially sold after being collected and refined.
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Paragraph 0113-0114
(2017/07/07)
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- An investigation on practical synthesis of carboxylic acid derivatives using p-toluenesulfonyl chloride
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Carboxylic acid derivatives are well recognized as important class of reagents frequently used in the preparation of a variety of fine or special chemicals such as amides, esters, peptides, drugs, and dyes. Although several methods were developed for the preparation of these compounds, many of them present difficulties, including low yield, high reaction temperature, harsh reaction conditions, tedious work-up, and incompatibility with scale-up. Methods: The synthesis of carboxylic anhydrides is developed through the reaction of carboxylic acids with TsCl in the presence of K2CO3 and acetonitrile as a solvent under ultrasound irradiation and conventional conditions. In addition, one-pot synthesis of acyl azides was carried out in the presence of produced carboxylic anhydrides and the addition of sodium azide under identical condition. Results: A series of carboxylic anhydrides and acyl azides were synthesized using TsCl under ultrasound irradiation and conventional stirring with simple procedure, mild reaction conditions, high yields, and scale-up ability without any restriction. In most cases, the reaction under ultrasound irradiation was better in both yields and the reaction times compared to the conventional method. Conclusion: A convenient method has been developed for the preparation of carboxylic anhydrides and acyl azides under ultrasound irradiation and conventional stirring. The present method is practical and a highly effective alternative for previous reports. The major advantages of this method are: (i) simplicity of the procedure (ii) high yields and high purity of product (iii) scale-up capacity without considerable limitation in conventional system. Under ultrasound irradiation short reaction times as compared to conventional method are observed; yields are comparable to or better than conventional method.
- Eskandari, Parvin,Kazemi, Foad
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p. 431 - 439
(2017/07/24)
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- Alkyl Isocyanates via Manganese-Catalyzed C-H Activation for the Preparation of Substituted Ureas
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Organic isocyanates are versatile intermediates that provide access to a wide range of functionalities. In this work, we have developed the first synthetic method for preparing aliphatic isocyanates via direct C-H activation. This method proceeds efficiently at room temperature and can be applied to functionalize secondary, tertiary, and benzylic C-H bonds with good yields and functional group compatibility. Moreover, the isocyanate products can be readily converted to substituted ureas without isolation, demonstrating the synthetic potential of the method. To study the reaction mechanism, we have synthesized and characterized a rare MnIV-NCO intermediate and demonstrated its ability to transfer the isocyanate moiety to alkyl radicals. Using EPR spectroscopy, we have directly observed a MnIV intermediate under catalytic conditions. Isocyanation of celestolide with a chiral manganese salen catalyst followed by trapping with aniline afforded the urea product in 51% enantiomeric excess. This represents the only example of an asymmetric synthesis of an organic urea via C-H activation. When combined with our DFT calculations, these results clearly demonstrate that the C-NCO bond was formed through capture of a substrate radical by a MnIV-NCO intermediate.
- Huang, Xiongyi,Zhuang, Thompson,Kates, Patrick A.,Gao, Hongxin,Chen, Xinyi,Groves, John T.
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supporting information
p. 15407 - 15413
(2017/11/06)
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- With anti-tumor effect of a quinazoline-urea derivative and its application (by machine translation)
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The present invention relates to a of the general formula (II) anti-tumor function of said quinazoline-urea derivative and its application. The definition of the substituent in the general formula (II) in the specification. This invention, in order to SUO draw non-Buddhist nun and Geftinat compounds as the precursor, retention of SUO draw non-Buddhist nun the pharmocology-carbamido; at the same time, such as in reserved [...] EGFR-TKIs Geftinat, synthesis, and obtain a series of quinazoline-urea derivatives, by the in vitro activity tests, some compounds exhibit excellent anti-tumor activity, such derivatives have high research and utility value. (II). (by machine translation)
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Paragraph 0139-0142; 0178
(2016/11/02)
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- One-pot synthesis of carbamates and thiocarbamates from Boc-protected amines
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A highly efficient one-pot procedure for the synthesis of carbamates and thiocarbamates has been described. In the presence of 2-chloropyridine and trifluoromethanesulfonyl anhydride, the isocyanate intermediates were generated in situ for further reactions with alcohols and thiols to afford the desired carbamates and thiocarbamates in high yields.
- Kim, Hee-Kwon,Lee, Anna
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supporting information
p. 4890 - 4892
(2016/10/21)
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- Selective N-methylation of aliphatic amines with CO2 and hydrosilanes using nickel-phosphine catalysts
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A method using CO2 and PhSiH3 for the methylation of primary and secondary aliphatic amines catalyzed by Ni (0) complexes was developed, selectively producing the monomethylated products in moderate to good yields. For that purpose, two catalysts were used: [(dippe)Ni(μ-H)]2 and the commercially available Ni(COD)2/dcype, both of which were rather efficient in this process. With a slight experimental modification, the reaction allowed the production of monomethylated ureas in good yields by using low amounts of PhSiH3. On the basis of the experimental results, we propose a possible reaction mechanism for the formation of the new C-N bond.
- Gonzlez-Sebastin, Lucero,Flores-Alamo, Marcos,Garca, Juventino J.
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p. 763 - 769
(2015/05/12)
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- COMPOUNDS, COMPOSITIONS, AND METHODS FOR THE TREATMENT OF CANCERS
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The present teachings relate to compounds and compositions for treatment of cancers. In some embodiments, the composition comprises a platinum (IV) complex having at least one carboxylate or carbamate ligand.
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Paragraph 00184
(2014/07/08)
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- One-pot synthesis of ureas from Boc-protected amines
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A practical one-pot synthesis of ureas is described. Boc-protected amines can be transformed into nonsymmetrical and symmetrical disubstituted and trisubstituted ureas utilizing 2-chloropyridine and trifluoromethanesulfonyl anhydride for the in situ generation of an isocyanate, which reacts with an amine. A variety of amines can be employed successfully, leading to high yields of isolated ureas.
- Spyropoulos, Constantinos,Kokotos, Christoforos G.
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p. 4477 - 4483
(2014/06/09)
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- Structure-activity relationship studies of pyrazolo[3,4-d]pyrimidine derivatives leading to the discovery of a novel multikinase inhibitor that potently inhibits FLT3 and VEGFR2 and evaluation of its activity against acute myeloid leukemia in vitro and in vivo
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We describe the structural optimization of a hit compound, 1-(4-(1H-pyrazolo[3,4-d]pyrimidin-4-ylamino)phenyl)-3-(3-methoxyphenyl)urea (1), which exhibits inhibitory activity but low potency against FLT3 and VEGFR2. A series of pyrazolo[3,4-d]pyrimidine derivatives were synthesized, and structure-activity relationship analysis using cell- and transgenic-zebrafish- based assays led to the discovery of a number of compounds that exhibited both high potency against FLT3-driven human acute myeloid leukemia (AML) MV4-11 cells and a considerable antiangiogenic effect in transgenic-zebrafish-based assays. The compound 1-(4-(1H-pyrazolo[3,4-d]pyrimidin -4-yloxy)phenyl)-3-(4-chloro-3- (trifluoromethyl)phenyl)urea (33), which exhibited the highest activity in preliminary in vivo anti-AML assays, was chosen for further anti-AML studies. The results demonstrated that compound 33 is a multikinase inhibitor that potently inhibits FLT3 and VEGFR2. In an MV4-11 xenograft mouse model, a once-daily dose of compound 33 at 10 mg/kg for 18 days led to complete tumor regression without obvious toxicity. Western blot and immunohistochemical analyses were performed to determine the mechanism of action of compound 33.
- Yang, Ling-Ling,Li, Guo-Bo,Ma, Shuang,Zou, Chan,Zhou, Shu,Sun, Qi-Zheng,Cheng, Chuan,Chen, Xin,Wang, Li-Jiao,Feng, Shan,Li, Lin-Li,Yang, Sheng-Yong
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supporting information
p. 1641 - 1655
(2013/04/10)
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- N-methylimidazole-catalyzed synthesis of carbamates from hydroxamic acids via the lossen rearrangement
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An efficient, one-pot, N-methylimidazole (NMI) accelerated synthesis of aromatic and aliphatic carbamates via the Lossen rearrangement is reported. NMI is a catalyst for the conversion of isocyanate intermediates to the carbamates. Moreover, the utility of arylsulfonyl chloride in combination with NMI minimizes the formation of often-observed hydroxamate-isocyanate dimers during the sequence. Under the present conditions, lowering of temperatures is also possible, enabling a mild protocol.
- Yoganathan, Sabesan,Miller, Scott J.
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p. 602 - 605
(2013/04/11)
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- (Tosylimino)phenyl-λ3-iodane as a reagent for the synthesis of methyl carbamates via hofmann rearrangement of aromatic and aliphatic carboxamides
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A new, mild procedure for the Hofmann rearrangement of aromatic and aliphatic carboxamides using (tosylimino)phenyl-λ3-iodane, PhINTs, as a reagent is reported. Because of the mild reaction conditions, this method is particularly useful for the Hofmann rearrangement of substituted benzamides, which usually afford complex reaction mixtures with other hypervalent iodine oxidants. The mild reaction conditions and high selectivity in the reaction of carboxamides with PhINTs allow the isolation of the initially formed labile isocyanates or their subsequent conversion to stable carbamates by treatment with alcohols.
- Yoshimura, Akira,Luedtke, Matthew W.,Zhdankin, Viktor V.
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experimental part
p. 2087 - 2091
(2012/05/05)
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- Novel tetrahydropyrido[1,2-a]isoindolone derivatives (valmerins): Potent cyclin-dependent kinase/glycogen synthase kinase 3 inhibitors with antiproliferative activities and antitumor effects in human tumor xenografts
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The development of CDK and GSK3 inhibitors has been regarded as a potential therapeutic approach, and a substantial number of diverse structures have been reported to inhibit CDKs and GSK-3β in recent years. Only a few molecules have gone through or are currently undergoing clinical trials as CDK and GSK inhibitors. In this paper, we prepared valmerins, a new family containing the tetrahydropyrido[1,2-a]isoindone core. The fused heterocycle was prepared with a straightforward synthesis that was functionalized by a (het)arylurea. Twelve valmerins inhibited the CDK5 and GSK3 with an IC50 100 nM. A semiquantitative kinase scoring was realized, and a cellular screening was done. At the end of our study, we investigated the in vivo potency of one valmerin. Mice exhibited good tolerance to our lead, which proved its efficacy and clearly blocked tumor growth. Valmerins appear also as good candidates for further development as anticancer agents.
- Boulahjar, Rajaa,Ouach, Aziz,Matteo, Chiurato,Bourg, Stephane,Ravache, Myriam,Guével, Rémy Le,Marionneau, Séverine,Oullier, Thibauld,Lozach, Olivier,Meijer, Laurent,Guguen-Guillouzo, Christiane,Lazar, Sa?d,Akssira, Mohamed,Troin, Yves,Guillaumet, Gérald,Routier, Sylvain
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p. 9589 - 9606
(2013/01/16)
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- Design, synthesis and biological evaluation of novel amino acid ureido derivatives as aminopeptidase N/CD13 inhibitors
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A series of amino acid ureido derivatives as aminopeptidase N (APN/CD13) inhibitors were synthesized and evaluated for their APN inhibitory activities and anti-cancer effects. The results showed that most of these amino acid ureido derivatives exhibited good inhibition against APN, several of which were better than Bestatin. The most active compound 12j (IC50 = 1.1 μM, compared with Bestatin IC50 = 8.1 μM) not only possessed much better APN inhibitory activity and anti-proliferation effect on cancer cells, but also exhibited significant block effect of human cancer cell invasion compared with the positive control, Bestatin. These amino acid ureido derivatives could be possibly developed as new APN inhibitors for cancer chemotherapy in the future.
- Su, Li,Jia, Yuping,Zhang, Lei,Xu, Yingying,Fang, Hao,Xu, Wenfang
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experimental part
p. 3807 - 3815
(2012/08/27)
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- Trifluoroacetic anhydride-catalyzed oxidation of isonitriles by DMSO: A rapid, convenient synthesis of isocyanates
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A smooth and efficient oxidation of isonitriles to isocyanates by sulfoxides is catalyzed by trifluoroacetic anhydride. With use of DMSO as the oxidant and 5 mol·% TFAA (dichloromethane, -60 to 0 °C), the process is complete in a few minutes, forming dimethyl sulfide as the only byproduct. The newly formed isocyanates may be used directly or isolated in high purity by solvent evaporation.
- Le, Hoang V.,Ganem, Bruce
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supporting information; experimental part
p. 2584 - 2585
(2011/06/25)
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- Organocatalyzed synthesis of ureas from amines and ethylene carbonate
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A new solventless method for the synthesis of symmetrical and unsymmetrical ureas, starting from ethylene carbonate and amines, is reported. 1,5,7-Triazabicyclo[4.4.0]dec-5-ene(TBD) and thioureas have been found to be efficient organocatalysts for this reaction.
- Saliu, Francesco,Rindone, Bruno
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body text
p. 6301 - 6304
(2011/01/04)
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- Triphenylphosphine/2,3-dichloro-5,6-dicyanobenzoquinone (DDQ)/[n-Bu4N]OCN as a useful system for the efficient conversion of tetrahydropyranyl (THP) ethers to the corresponding alkyl isocyanates
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Triphenylphosphine/2,3-dichloro-5,6-dicyanobenzoquinone/tetrabutylammonium cyanate was used as an efficient system for the conversion of tetrahydropyranyl ethers to the corresponding alkyl isocyanates. Taylor & Francis Group, LLC.
- Akhlaghinia, Batool,Samiei, Sima
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experimental part
p. 2525 - 2529
(2010/03/31)
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- Synthesis and evaluation of structurally constrained imidazolidin derivatives as potent dipeptidyl peptidase IV inhibitors
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To find potent and selective inhibitors of dipeptidyl peptidase IV (DPP-IV), we synthesized a series of 2-cyanopyrrolidine derivatives with constrained imidazolidin ring and tested their activities against DPP-IV. Most of them exhibited submicromolar inhibitory activities against DPP-IV. The most potent compound among these is (S)-1-(2-(2-(3-(3,4-dimethoxyphenyl)-2-oxoimidazolidin-1-yl)ethyl-amino)acetyl)pyrrolidine-2-carbonitrile (6n), which is a 2 nM DPP-IV inhibitor.
- Wang, Liutang,Zhang, Bin,Ji, Jianxin,Li, Bogang,Yan, Jufang,Zhang, Weiyu,Wu, Yong,Wang, Xuechao
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experimental part
p. 3318 - 3322
(2009/12/01)
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- Discovering potent small molecule inhibitors of cyclophilin A using de novo drug design approach
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This work describes an integrated approach of de novo drug design, chemical synthesis, and bioassay for quick identification of a series of novel small molecule cyclophilin A (CypA) inhibitors (1-3). The activities of the two most potent CypA inhibitors (3h and 3i) are 2.59 and 1.52 nM, respectively, which are about 16 and 27 times more potent than that of cyclosporin A. This study clearly demonstrates the power of our de novo drug design strategy and the related program LigBuilder 2.0 in drug discovery.
- Ni, Shuaishuai,Yuan, Yaxia,Huang, Jin,Mao, Xiaona,Lv, Maosheng,Zhu, Jin,Shen, Xu,Pei, Jianfeng,Lai, Luhua,Jiang, Hualiang,Li, Jian
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supporting information; experimental part
p. 5295 - 5298
(2010/02/28)
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- Carbonyldiimidazole-mediated lossen rearrangement
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[Chemical Equation Presented] Carbonyldiimidazole (CDI) was found to mediate the Lossen rearrangement of various hydroxamic acids to isocyanates. This process is experimentally simple and mild, with imidazole and CO 2 being the sole stoichiometric byproduct. Significant for large-scale application, the method avoids the use of hazardous reagents and thus represents a green alternative to standard processing conditions for the Curtius and Hofmann rearrangements.
- Dube, Pascal,Fine Nathel, Noah F.,Vetelino, Michael,Couturier, Michel,Aboussafy, Claude Larrivee,Pichette, Simon,Jorgensen, Matthew L.,Hardink, Mark
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supporting information; experimental part
p. 5622 - 5625
(2010/03/02)
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- One-pot, three-step preparation of alkyl and aryl alkylcarbamates from S-methyl N-alkylthiocarbamates
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A general procedure for the synthesis of alkyl and aryl alkylcarbamates starting from the corresponding 5-methyl N-alkylthiocarbamates is described. This procedure consists of three steps that are carried out in a one-pot fashion, without isolating the intermediate N-alkylcarbamoyl chlorides or alkyl isocyanates. All the target products were obtained in high yields (16 examples, average yield 91%). To be noted is the recovery of a co-product of industrial interest, dimethyl disulfide, in a half mole amount for each mole of thiocarbamate, with complete exploitation of the reagent. The alkyl isocyanates, if required, can also be isolated in high yields. Georg Thieme Verlag Stuttgart.
- Artuso, Emma,Degani, Iacopo,Fochi, Rita,Magistris, Claudio
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experimental part
p. 1612 - 1618
(2009/04/03)
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- Synthesis and structure of N-alkyl(aryl)aminocarbonyl-1,4-benzoquinone imines
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New N-alkyl(aryl)aminocarbonyl-1,4-benzoquinone imines were synthesized by reaction of isocyanates with the corresponding substituted 4-aminophenols, and their structure was determined on the basis of 1H and 13C NMR spectra and X-ray diffraction data.
- Avdeenko,Konovalova,Sergeeva,Zubatyuk,Palamarchuk,Shishkin
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experimental part
p. 1765 - 1772
(2009/09/05)
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- Organosilicon synthesis of isocyanates: II. Synthesis of aliphatic, carbocyclic, and fatty-aromatic isocyanates
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Silylation of a series of aliphatic, carbocyclic, and fatty-aromatic amines gave the corresponding silyl derivatives whose yield depended on the electronic and steric structure of the substrate and the nature of the silylating agent. The yield of isocyanates obtained by phosgenation of the silyl derivatives under mild conditions decreased in going from aliphatic amines to benzylamines and rose as the length of the alkyl chain in fatty-aromatic amines extended. The most convenient procedure for the synthesis of low-boiling alkyl isocyanates was found to be based on the transformation of amines or ammonium salts into silyl or silyl silyl-carabamates, followed by pyrolysis of the latter in the presence of trichloro(phenyl)silane. Pleiades Publishing, Inc., 2006.
- Lebedev,Lebedeva,Sheludyakov,Ovcharuk,Kovaleva,Ustinova
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p. 469 - 477
(2008/02/07)
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- A new and convenient method of generating alkyl isocyanates from alcohols, thiols and trimethylsilyl ethers using triphenylphosphine/2,3-dichloro-5,6- dicyanobenzoquinone/Bu4NOCN
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Alkyl isocyanates are prepared in good to excellent yields by treatment of alcohols, thiols and trimethylsilyl ethers with triphenylphosphine/2,3-dichloro- 5,6-dicyanobenzoquinone/ Bu4NOCN in acetonitrile. This method is highly selective for conversion of primary alcohols to alkyl isocyanates in the presence of secondary and tertiary alcohols, thiols and trimethysilyl ethers. Georg Thieme Verlag Stuttgart.
- Akhlaghinia, Batool
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p. 1955 - 1958
(2007/10/03)
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- Development of tyrosinase labile protecting groups for amines
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(Chemical Equation Presented) The development of two novel protecting groups for amines is described. Thus, a range of amines have been converted to ureas, and the deprotection of these upon exposure to mushroom tyrosinase (E.C. 1.14.18.1) has been demonstrated.
- Osborn, Helen M. I.,Williams, Nana Aba O.
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p. 3111 - 3113
(2007/10/03)
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- Method for producing monoisocyanates and oligoisocyanates
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The present invention relates to a process for the preparation of aliphatic, cycloaliphatic, araliphatic and aromatic mono- and oligoisocyanates by phosgenation of the corresponding primary amines at atmospheric pressure, which comprises a) introducing a catalytic amount of a monoisocyanate (isocyanate a) into an inert solvent together with phosgene; b) adding the primary amine, and c) reacting the resulting reaction mixture with phosgene.
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Page column 7
(2010/02/05)
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- Alkanethioimidoyl Radicals: Evaluation of β-Scission Rates and of Cyclization onto S-Alkenyl Substituents
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Thioimidoyl radicals were generated by addition of alkylsulfanyl radicals to alkyl isonitriles and were characterized by electron paramagnetic resonance (EPR) spectroscopy. The β-scissions of their C·S-C bonds were studied by variable-temperature EPR spectroscopy and the fragmentation rate constants and activation energies were calculated. The scission rates depend on the stability of the released alkyl radicals but in any case, at room temperature, the processes were fast. Data collected on similar oxyimidoyls showed that their fragmentations are slightly slower compared to those of analogous thioimidoyls. The scission rates of selenoimidoyls could not be studied by EPR and were evaluated by theoretical calculations. EPR experiments also enabled both β-scission and 5-exo ring closure rate constants of two S-but-3-enyl-substituted imidoyl radicals to be determined, showing that cyclization prevails only at low temperatures. Density functional theory (DFT) theoretical calculations predicted that the fragmentation process preferentially occurs from the s-cis rotamers (X-C bond) of the imidoyl radicals. Thio- and seleno-imidoyls (but not oxyimidoyls) prefer s-trans conformations so that their fragmentations involve prior rotation about the X-C bond.
- Minozzi, Matteo,Nanni, Daniele,Walton, John C.
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p. 2056 - 2069
(2007/10/03)
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- A new and efficient catalytic method for synthesizing isocyanates from carbamates
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Operationally simple, recyclable and environmentally friendly montmorillonite efficiently catalyses dealcoholysis of a wide range of mono- and dicarbamates to isocyanates.
- Uriz, Pedro,Serra, Marc,Salagre, Pilar,Castillon, Sergio,Claver, Carmen,Fernandez, Elena
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p. 1673 - 1676
(2007/10/03)
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- Heterocyclic compounds having MMP and TNF inhibitory activity
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Compounds of formula (I) are useful as therapeutic agents, by virtue of having MMP and TNF inhibitory activity.
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- Di-tert-butyl dicarbonate and 4-(dimethylamino)pyridine revisited. Their reactions with amines and alcohols
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The reaction of BOC2O in the presence and absence of DMAP was examined with some amines, alcohols, diols, amino alcohols, and aminothiols. Often, unusual products were observed depending on the ratio of reagents, reaction time, polarity of solvent, pK(a) of alcohols, or type of amine (primary or secondary). In reactions of aliphatic alcohols with BOC2O/DMAP, we isolated for the first time carbonic-carbonic anhydride intermediates; this helps explain the formation of symmetrical carbonates in addition to the O-BOC products. In the case of secondary amines, we succeeded to isolate unstable carbamic-carbonic anhydride intermediates that in the presence of DMAP led to the final N-BOC product. The effect of N-methylimidazole in place of DMAP was also examined.
- Basel, Yochai,Hassner, Alfred
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p. 6368 - 6380
(2007/10/03)
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- Elevation of HDL cholesterol by 2-[(aminothioxomethyl)-hydrazono]-2-arylethyl carbamates
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This invention relates to the treatment of atherosclerosis via raising the level of HDL cholesterol by administration of a compound of the formula STR1 wherein: R1, R2, and R3 are independently hydrogen, C1 -C6 alkyl or --(CH2)0-6 Ph where Ph is phenyl optionally substituted by halogen, cyano, nitro, C1 -C6 alkyl, C1 -C6 alkoxy, trifluoromethyl, C1 -C6 alkoxycarbonyl, --CO2 H or OH; R4 and R5 are independently hydrogen, C1 -C6 alkyl, C3 -C8 cycloalkyl, or --(CH2)0-6 Ar1 where Ar1 is phenyl, naphthyl, furanyl, pyridinyl or thienyl and Ar1 can be optionally substituted by halogen, cyano, nitro, C1 -C6 alkyl, phenyl, C1 -C6 alkoxy, phenoxy, trifluoromethyl, C1 -C6 alkoxycarbonyl, --CO2 H or OH; and Ar is phenyl, naphthyl, furanyl, pyridinyl or thienyl or Ar is optionally substituted by halogen, cyano, nitro, C1 -C6 alkyl, C3 -C6 cycloalkyl, phenyl, C1 -C6 alkoxy, phenoxy, trifluoromethyl, C1 -C6 alkoxycarbonyl, --CO2 H or OH.
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- Preparation of isocyanates from primary amines and carbon dioxide using Mitsunobu chemistry
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Primary alkylamines 1 and hindered arylamines 1 give high yields of isocyanates 5 when reacted with carbon dioxide and the Mitsunobu zwitterions 4 generated from dialkyl azodicarboxylates and Bu3P in dichloromethane at - 78°C. Use of Ph3P still gave high yields of isocyanates from reactions of primary alkylamines, but only low yields were obtained from reactions of aromatic amines. Reactions which failed to give high yields of isocyanates gave either carbamoylhydrazines 6 and/or dicarbamoylhydrazines 10 and/or triazolinones 7. The triazolinones were shown to arise from reactions of reactive aryl isocyanates with the Mitsunobu zwitterion. The carbamoylhydrazines were shown not to arise from reaction of isocyanate with reduced dialkyl azodicarboxylates, and a mechanism for their formation is proposed. Single-crystal X-ray analyses confirmed the structures of 6, 7, and 10.
- Saylik, Dilek,Horvath, Michael J.,Elmes, Patricia S.,Jackson, W. Roy,Lovel, Craig G.,Moody, Keith
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p. 3940 - 3946
(2007/10/03)
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- A Mitsunobu-based procedure for the preparation of alkyl and hindered aryl isocyanates from primary amines and carbon dioxide under mild conditions
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A Mitsunobu-based procedure for the preparation of alkyl and hindered aryl isocyanates in excellent yields from primary amines and carbon dioxide under very mild conditions is described.
- Horvath,Saylik,Elmes,Jackson,Lovel,Moody
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p. 363 - 366
(2007/10/03)
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- Novel carbamates as potent histamine H3 receptor antagonists with high in vitro and oral in vivo activity
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The known histamine H3 receptor antagonists burimamide, thioperamide, clobenpropit, and a related homohistamine thioamide derivative were taken as templates in search for new leads. Novel histamine H3 receptor antagonists structurally described as carbamate derivatives of 3-(1H-imidazol-4- yl)propanol were prepared in high yields by treatment of the alcohol with corresponding isocyanates or carbamoyl chlorides and investigated for their H3 receptor antagonist activity. Different chain lengths and various substituents possessing different electronic and steric parameters were introduced and structure-activity relationships established. In different functional tests, the new antagonists showed high H3 receptor antagonist potencies in vitro (-log K(i) values of 6.4-8.4) at synaptosomes of rat cerebral cortex and low activities at histamine H1 and H2 receptor subtypes. They were also screened for their central in vivo activity in mice after peroral administration. The most promising compounds (2, 16, 19) showed ED50 values of about 1-2 mg/kg and thus are potential drugs for the therapy of H3 receptor dependent diseases. Some of the novel carbamate derivatives are H3 receptor selective compounds with high in vitro and in vivo activity.
- Stark, Holger,Purand, Katja,Ligneau, Xavier,Rouleau, Agnès,Arrang, Jean-Michel,Garbarg, Monique,Schwartz, Jean-Charles,Schunack, Walter
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p. 1157 - 1163
(2007/10/03)
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- Reactivity of Carbamoyl Radicals. A New, General, Convenient Free-Radical Synthesis of Isocyanates from Monoamides of Oxalic Acid
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A new, general, simple synthesis of isocyanates was developed by oxidation of monoamides of oxalix acid with peroxydisulfate catalyzed by Ag and Cu salts.The reaction was carried out in a two-phase system (water and an organic solvent), and it is suitable also for practical applications, due to the simple experimental conditions and the inexpensive as well as nontoxic reagents.The first example of homolytic intramolecular aromatic carbamoylation is also reported.
- Minisci, Francesco,Fontana, Francesca,Coppa, Fausta,Yan, Yong Ming
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p. 5430 - 5433
(2007/10/02)
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- A Convenient and High Yielding Procedure for the Preparation of Isoselenocyanates. Synthesis and Reactivity of O-Alkylselenocarbamates.
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A high yielding one pot procedure for the preparation of isoselenocyanate from the corresponding formamide is reported.Various aromatic and aliphatic primary amines were employed in order to prepare the isoselenocyanates to establish the generality of the procedure.O-Alkylselenocarbamates of various primary, secondary and tertiary alcohols were synthesized and their stability and comparative reactivity were studied.Radical deoxygenation of the selenocarbamate of a secondary and a tertiary alcohol was accomplished under various conditions.
- Barton, Derek H. R.,Parekh, Shyamal I.,Tajbakhsh, Mahmoud,Theodorakis, Emmanouil A.,Tse, Chi-Lam
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p. 639 - 654
(2007/10/02)
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- Isocyanates From Primary Amines and Carbon Dioxide: 'Dehydration' of Carbamate Anions
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Carbamate anions, derived from primary amines CO2 and an added base (e.g.NEt3), undergo rapid reaction with electrophilic 'dehydrating agents' (e.g.POCl3, P4O10) to give the corresponding isocyanates in excellent yields.
- Waldman, Thomas E.,McGhee, William D.
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p. 957 - 958
(2007/10/02)
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- Reactivity of Carbamoyl Radicals: the First General and Convenient Free-radical Synthesis of Isocyanates
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The first free-radical synthesis of isocyanates was performed by oxidation of oxalic acid monoamides by S2O82-, catalysed by silver(I) and copper(II) salts, in a two-phase system.
- Minisci, Francesco,Coppa, Fausta,Fontana, Francesca
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p. 679 - 680
(2007/10/02)
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- Process for preparing isocyanates using phosphazine catalysts
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A process for preparing isocyanates comprising (a) contacting carbon dioxide and a primary amine in the presence of an aprotic organic solvent and a phosphazene compound or a mixture of a phosphazene compound and an organic, nitrogenous base selected from the group consisting of guanidine compounds, amidine compounds, tertiary amines, pyridine and mixtures thereof to produce the corresponding ammonium carbamate salt, and (b) reacting the ammonium carbamate salt with an electrophilic or oxophilic dehydrating agent to produce the corresponding isocyanate. A second embodiment comprises recovering the ammonium carbamate salt of step (a) prior to reacting the ammonium carbamate salt with an electrophilic or oxophilic dehydrating agent in the presence of an aprotic organic solvent and a phosphazene compound or a mixture of a phosphazene compound and an organic, nitrogenous base selected from the group consisting of guanidine compounds, amidine compounds, tertiary amines, pyridine and mixtures thereof.
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- Process for preparing isocyanates
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A process for preparing isocyanates comprising (a) contacting carbon dioxide and a primary amine in the presence of an aprotic organic solvent and an organic, nitrogenous base to produce the corresponding ammonium carbamate salt, and (b) reacting the ammonium carbamate salt with an electrophilic or oxophilic dehydrating agent to produce the corresponding isocyanate. A second embodiment comprises recovering the ammonium carbamate salt of step (a) prior to reacting the ammonium carbamate salt with an electrophilic or oxophilic dehydrating agent in the presence of an aprotic organic solvent and an organic, nitrogenous base.
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- Synthesis of isocyanates from carboxylic acids using diphenylphosphoryl azide and 1,8-bis(dimethylamino)naphthalene
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A simple phosgene-free method for the synthesis of high-purity isocyanates from carboxylic acids was developed using diphenylphosphoryl azide and 1,8-bis(dimethylamino)naphthalene. Yields for evaluated monoisocyanates ranged from 60.0% to 81.5%.
- Gilman,Otonari
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p. 335 - 341
(2007/10/02)
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