- A novel procedure for the formation of isatins via carbonylation of lithiated N'-aryl-N,N-dimethylureas
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Isatin and substituted isatins can be formed in very good yields from the appropriate N'(2-bromoaryl)-N,N-dimethylureas via bromine-lithium exchange followed by treatment with carbon monoxide.
- Smith, Keith,El-Hiti, Gamal A.,Hawes, Anthony C.
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- On the Reaction of Bis(dimethylamino)acetonitrile with Phenylisocyanate
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Bis(dimethylamino)acetonitrile (1) reacts with phenylisocyanate to yiield the imidazolidinedione 2, as confirmed by X-ray structure analysis.The mechanism of formation of 2 is discussed.
- Seckinger, Karl
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- Selenium-catalyzed reductive carbonylation of nitrobenzene with amines as coreagents to give unsymmetric phenylureas
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The reductive carbonylation of nitrobenzene catalyzed by selenium to yield unsymmetric phenylureas has been studied. When secondary amines were used as coreagents, a single product, PhNHCONR2, was formed; when primary amines were chosen as coreagents, mixed products, including RNHCONHR, RNHCONHPh and PhNHCONHPh, were obtained.
- Yang, Ying,Lu, Shiwei
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- New synthetic strategy for urea herbicides
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This work describes an effective and a safe procedure for the preparation of commercially applicable trisubstituted ureas derived from their thio analogues which result from the thiuram disulfides in quantitative yields.
- Ramadas,Janarthanan
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- Kinetics of the alkaline hydrolysis of fenuron in aqueous and micellar media
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The kinetics of the hydrolysis of fenuron in sodium hydroxide has been investigated spectrometrically in an aqueous medium and in cationic micelles of cetyltrimethylammonium bromide (CTAB) medium. The reaction follows first-order kinetics with respect to [fenuron] in both the aqueous and micellar media. The rate of hydrolysis increases with the increase in [NaOH] in the lower concentration range but shows a leveling behavior at higher concentrations. The reaction followed the rate equation, 1/kobs = 1/k + 1/(kK|OH -]), where kobs is the observed rate constant, k is rate constant in aqueous medium, and K is the equilibrium constant for the formation of hydroxide addition product. The cationic CTAB micelles enhanced the rate of hydrolytic reaction. In both aqueous and micellar pseudophases, the hydrolysis of fenuron presumably occurs via an addition-elimination mechanism in which an intermediate hydroxide addition complex is formed. The added salts decrease the rate of reaction.
- Gangwar,Rafiquee
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- Merging C-H activation and alkene difunctionalization at room temperature: A palladium-catalyzed divergent synthesis of indoles and indolines
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A palladium-catalyzed 1,2-carboamination through C-H activation at room temperature is reported for the synthesis of 2-arylindoles, and indolines from readily available, inexpensive aryl ureas and vinyl arenes. The reaction initiates with a urea-directed electrophilic ortho palladation, alkene insertion, and ?2-hydride elimination sequences to provide the Fujiwara-Moritani arylation product. Subsequently, aza-Wacker cyclization, and ?2-hydride elimination provide the 2-arylindoles in high yields. Intercepting the common -alkyl-Pd intermediate, corresponding indolines are also achieved. The indoline formation is attributed to the generation of stabilized, cationic -benzyl-Pd species to suppress ?2-hydride elimination.
- Manna, Manash Kumar,Hossian, Asik,Jana, Ranjan
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- Distinct reactivity of Pd(OTs)2: The intermolecular Pd(II)-catalyzed 1,2-carboamination of dienes
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A Pd-catalyzed intermolecular 1,2-carboamination route to indolines from N-aryl ureas and 1,3-dienes that proceeds under mild conditions in relatively nonacidic media, is presented. The in situ generation, or preformation, of a palladium tosylate emerges as a key parameter in gaining the requisite reactivity for the C-H insertion/carbopalladation/nucleophilic displacement process. Copyright
- Houlden, Chris E.,Bailey, Chris D.,Ford, J. Gair,Gagne, Michel R.,Lloyd-Jones, Guy C.,Booker-Milburn, Kevin I.
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- Hydroamination of carbodiimides, isocyanates, and isothiocyanates by a bis(phosphinoselenoic amide) supported titanium(IV) complex
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The hydroamination of heterocumulenes such as carbodiimides, isocyanates, and isothiocyanates by a bis(phosphinoselenoic amide) supported titanium(iv) complex as a precatalyst is reported here. The titanium(iv) complex [{Ph2P(Se)NCH2CH2NPPh2(Se)}Ti(NMe2)2] (1) was synthesised by the reaction of tetrakis-(dimethylamido)titanium(iv) [Ti(NMe2)4] with [{Ph2P(Se)NHCH2CH2NHPPh2(Se)}] in toluene at ambient temperature. Titanium complex 1 proved to be a competent pre-catalyst for the addition of an amine N-H bond to carbodiimides, isocyanates, and isothiocyanates. The reaction scope was expanded to reactions of aliphatic and aromatic amines with phenylisocyanates and phenylisothiocyanates in toluene solvents proceeding rapidly at room temperature with 5 mol% catalyst loadings to yield the corresponding urea and thio-urea derivatives up to 99%. However, ambient temperature was needed for hydroamination of 1,3-dicyclohexylcarbodiimide. The amine addition reactions with isocyanates showed first order kinetics with respect to catalyst 1 as well as substrates. The most plausible mechanism for the hydroamination reaction was established by isolating 1,1-dimethylphenyl urea as a side product.
- Bhattacharjee, Jayeeta,Das, Suman,Kottalanka, Ravi K.,Panda, Tarun K.
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- Improved method for the preparation of 1,1-dimethyl-3-arylureas using chlorocarbonylsulfenyl chloride
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A convenient procedure for preparing some arylureas having herbicidal properties is reported. The method has two steps: (1) reaction of arylamine with chlorocarbonylsulfenyl chloride in the presence of nonpolar solvent to produce aryl carbonylsulfenyl chloride and (2) reaction with dimethylamine in a two-phase reaction catalysed by phase-transfer catalyst to produce the corresponding aryl ureas. Taylor & Francis Group, LLC.
- Adeppa,Rupainwar,Misra, Krishna
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- Facile dehalogenation of halogenated anilines and their derivatives using Al-Ni alloy in alkaline aqueous solution
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This article describes the simple hydrodehalogenation of halogenated anilines and their derivatives by the action of Raney aluminium-nickel alloy in aqueous alkaline solution at room temperature. The reaction course was monitored by means of 1H nuclear magnetic resonance (NMR) spectroscopy and GC-MS spectra. The effect of Al and Ni and the nature and quantity of the base for effective hydrodehalogenation were studied. The possibility of lowering Al content more than 500 times and Ni content more than 10 times in the filtered mother liquor by a dehalogenation procedure was tested using precipitation. The reduction method described was satisfactorily proved for dehalogenation of polyhalogenated anilines in the multiphase dimethoxymethane/aqueous NaOH/Al-Ni reaction mixture. Dehalogenation under multi-phase conditions was demonstrated for the preparation of ortho-alkylated anilines from simply available 2-substituted-4-chloroanilines. Versita Sp. z o.o.
- Weidlich, Tomas,Prokes, Lubomir
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- A Facile and High-yielding Preparation of 1-Aryl-3,3-dialkylureas
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A convenient procedure for the preparation of 1-aryl-3,3-dialkylureas using bis(trichoromethyl) carbonate ('triphosgene') is described.
- Xian, Ming,Lu, Jianming,Zhu, Xiaoqing,Mu, Linjing,Cheng, Jin-Pei
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- Photochemical transformation of aqueous para-halogenophenylureas: Evidence for the intermediary formation of carbenes
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N-Substituted 4-iminocyclohexa-2,5-dienylidenes (λ(max) = 300 and 405 nm) are detected at pulse end upon laser flash photolysis of aqueous monuron and metobromuron. In oxygenated medium these carbenes are converted into N-substituted iminoquinone-O-oxides
- Boukhram,Richard
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- Stabilization of Azapeptides by Namide···H-NamideHydrogen Bonds
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An unusual Namide···H-Namide hydrogen bond (HB) was previously proposed to stabilize the azapeptide β-Turns. Herein we provide experimental evidence for the Namide···H-Namide HB and show that this HB endows a stabilization of 1-3 kcal·mol-1 and enforces the trans-cis-Trans (t-c-T) and cis-cis-Trans (c-c-T) amide bond conformations in azapeptides and N-methyl-Azapeptides, respectively. Our results indicate that these Namide···H-Namide HBs can have stabilizing contributions even in short azapeptides that cannot fold to form β-Turns.
- Baruah, Kalpita,Sahariah, Biswajit,Sakpal, Sushil S.,Deka, Jugal Kishore Rai,Bar, Arun Kumar,Bagchi, Sayan,Sarma, Bani Kanta
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supporting information
p. 4949 - 4954
(2021/06/28)
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- Hydroamination and Hydrophosphination of Isocyanates/Isothiocyanates under Catalyst-Free Conditions
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Symmetrical and unsymmetrical N,N’-disubstituted as well as trisubstituted ureas/thioureas by the hydroamination of isocyanates/isothiocyanates, and various phosphathioureas by the hydrophosphination of isothiocyanates have been synthesized in good to excellent yields under catalyst-free and mild conditions. This protocol is also applicable for the efficient synthesis of chiral ureas and thioureas and common herbicides, such as fenuron and monuron.
- Zhu, Xiancui,Xu, Mengchen,Sun, Jinrong,Guo, Dianjun,Zhang, Yiwei,Zhou, Shuangliu,Wang, Shaowu
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p. 5213 - 5218
(2021/10/19)
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- A Fe3O4?SiO2/Schiff Base/Pd Complex as an Efficient Heterogeneous and Recyclable Nanocatalyst for One-Pot Domino Synthesis of Carbamates and Unsymmetrical Ureas
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A palladium-catalyzed domino method for the direct synthesis of carbamates and ureas has been developed by using readily available and economical starting materials (aryl halide, carbon monoxide, sodium azide, amines and alcohols) in a one-pot approach. The domino process underwent carbonylation, Curtius rearrangement, and nucleophilic addition. This protocol provides a step-economical and highly efficient reaction to access the wide range of valuable carbamates, symmetrical and unsymmetrical ureas with high yields under remarkable mild reaction conditions that are important factors in pharmaceutical science, biochemistry and agricultural industries. Furthermore, the magnetically recoverable nanocatalyst (Fe3O4?SiO2/Pd(II)) can be conveniently and swiftly recycled using external magnet and reused at least for seven times without noticeable loss of its catalytic activity.
- Inaloo, Iman Dindarloo,Majnooni, Sahar
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p. 6359 - 6368
(2019/11/05)
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- Reaction of N-methylazomethine ylide with aroyl azides: Synthesis of imidazolidin-4-ones
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Aryl isocyanates generated in situ from aroyl azides react with N-methylazomethine ylide generated in situ from N-methylspiroanthraceneoxazolidine at 210 °C in a microwave reactor to form 3-arylimidazolidin-4-ones in 30–81% yield.
- Buev, Evgeny M.,Moshkin, Vladimir S.,Sosnovskikh, Vyacheslav Y.
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p. 773 - 776
(2019/02/13)
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- Sulfonium Salts as Alkylating Agents for Palladium-Catalyzed Direct Ortho Alkylation of Anilides and Aromatic Ureas
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A novel method for the ortho alkylation of acetanilide and aromatic urea derivatives via C-H activation was developed. Alkyl dibenzothiophenium salts are considered to be new reagents for the palladium-catalyzed C-H activation reaction, which enables the transfer of methyl and other alkyl groups from the sulfonium salt to the aniline derivatives under mild catalytic conditions.
- Simkó, Dániel Cs.,Elekes, Péter,Pázmándi, Vivien,Novák, Zoltán
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supporting information
p. 676 - 679
(2018/02/09)
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- Cu(II)-Catalyzed Ortho-C-H Nitration of Aryl Ureas by C-H Functionalization
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A novel protocol for the aromatic ortho C-H nitration of aryl ureas with Fe(NO3)3·9H2O is developed. The reaction utilizes CuCl2·2H2O as catalyst and p-TSA as additive, showing good functional group tolerance and furnishing the desired products in moderate to excellent yields.
- Wang, Chun-Meng,Tang, Kai-Xiang,Gao, Tian-Hong,Chen, Lin,Sun, Li-Ping
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p. 8315 - 8321
(2018/07/15)
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- One-pot synthesis of 2,3-difunctionalized indoles: Via Rh(III)-catalyzed carbenoid insertion C-H activation/cyclization
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Reported herein is the first Rh(iii)-catalyzed carbenoid insertion C-H activation/cyclization of N-arylureas and α-diazo β-keto esters. The redox-neutral reaction has the following features: good to excellent yields, broad substrate/functional group tolerance, exclusive regioselectivity, and no need for additional oxidants or additives, which render this methodology as a more efficient and versatile alternative to the existing methods for the synthesis of 2,3-difunctionalized indoles.
- Lv, Honggui,Shi, Jingjing,Wu, Bo,Guo, Yujuan,Huang, Junjun,Yi, Wei
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supporting information
p. 8054 - 8058
(2017/10/13)
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- Cationic Pd(II)-catalyzed C-H activation/cross-coupling reactions at room temperature: Synthetic and mechanistic studies
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Cationic palladium(II) complexes have been found to be highly reactive towards aromatic C-H activation of arylureas at room temperature. A commercially available catalyst [Pd(MeCN)4](BF4)2 or a nitrile-free cationic palladium(II) complex generated in situ from the reaction of Pd(OAc)2 and HBF4, effectively catalyzes C-H activation/cross-coupling reactions between aryl iodides, arylboronic acids and acrylates under milder conditions than those previously reported. The nature of the directing group was found to be critical for achieving room temperature conditions, with the urea moiety the most effective in promoting facile coupling reactions at an ortho C-H position. This methodology has been utilized in a streamlined and efficient synthesis of boscalid, an agent produced on the kiloton scale annually and used to control a range of plant pathogens in broadacre and horticultural crops. Mechanistic investigations led to a proposed catalytic cycle involving three steps: (1) C-H activation to generate a cationic palladacycle; (2) reaction of the cationic palladacycle with an aryl iodide, arylboronic acid or acrylate, and (3) regeneration of the active cationic palladium catalyst. The reaction between a cationic palladium(II) complex and arylurea allowed the formation and isolation of the corresponding palladacycle intermediate, characterized by X-ray analysis. Roles of various additives in the stepwise process have also been studied.
- Nishikata, Takashi,Abela, Alexander R.,Huang, Shenlin,Lipshutz, Bruce H.
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supporting information
p. 1040 - 1064
(2016/07/06)
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- Synthesis method of phenylurea herbicide or deuteration-labeled phenylurea herbicide
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The invention relates to a synthesis method of a phenylurea herbicide or a deuteration-labeled phenylurea herbicide (a compound of a formula (I)). The compound of the formula (I) is obtained by reacting a compound of a formula (II) with a dimethylamine salt or D6-dimethylamine salt in the presence of an organic base. According to the synthesis method, the side reaction of substituted phenyl isocyanate and water or alcohol is avoided, the leakage of dimethylamine or dimethylamine-D6 is reduced, and the synthesis method has the advantages of simple operation, low requirements for equipment, low cost, high yield, and fewer by-products. The formula I is shown in the description.
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Paragraph 0114; 0115; 0116
(2017/02/17)
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- Comparative Catalytic Activity of Group 9 [CpMIII] Complexes: Cobalt-Catalyzed C-H Amidation of Arenes with Dioxazolones as Amidating Reagents
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A procedure for the [CpCoIII]-catalyzed direct C-H amidation of arenes with dioxazolone has been developed. This reaction proceeds under straightforward and mild conditions with a broad range of substrates, including anilides. A comparative study on the catalytic activity of Group 9 [{CpMCl2}2] complexes revealed the unique efficiency of the cobalt catalyst. Pick of the bunch: A variety of arenes, including anilides, underwent direct C-H amidation with dioxazolones in the presence of a cobalt catalyst with a Cp? ligand under mild and straightforward reaction conditions (see scheme; Piv=pivaloyl). A comparative study of Group 9 [CpMIII] complexes revealed the unique ability of the cobalt catalyst to promote this transformation efficiently.
- Park, Juhyeon,Chang, Sukbok
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supporting information
p. 14103 - 14107
(2016/01/25)
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- Synthesis of unsymmetrical phenylurea derivatives via oxidative cross coupling of aryl formamides with amines under metal-free conditions
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A new synthetic approach for phenylurea derivatives involving the cross coupling of N-aryl formamides with amines through the formation of isocyanate intermediates in the presence of hypervalent iodine reagents is described.
- Reddy, Nagireddy Veera,Kumar, Pailla Santhosh,Reddy, Peddi Sudhir,Kantam, Mannepalli Lakshmi,Reddy, Kallu Rajender
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p. 805 - 809
(2015/02/19)
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- Rhodium(iii)-catalysed aerobic synthesis of highly functionalized indoles from N-arylurea under mild conditions through C-H activation
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A Rh(iii) catalysed amino arylation of alkynes using copper as the terminal oxidant for regeneration of the catalytically active species under aerobic conditions is described. This novel C-H activation reaction was applied to the synthesis of a wide range of substituted indoles from N-arylureas.
- Kathiravan, Subban,Nicholls, Ian A.
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supporting information
p. 14964 - 14967
(2014/12/11)
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- A highly efficient Pd-catalyzed decarboxylative ortho-arylation of amides with aryl acylperoxides
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An efficient Pd-catalyzed decarboxylative ortho-arylation of amides with aryl acylperoxides was developed. A variety of anilides reacted with aryl acylperoxides to afford the corresponding ortho-arylation products, and N-methoxyarylamides generated phenanthridinones. This journal is
- Li, Dengke,Xu, Ning,Zhang, Yicheng,Wang, Lei
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supporting information
p. 14862 - 14865
(2014/12/11)
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- Rhenium-catalyzed synthesis of 3-imino-1-isoindolinones by C-H bond activation: Application to the synthesis of polyimide derivatives
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Polyimide solution: Synthesis of the title compounds from aromatic imidates and isocyanates in good to excellent yields by a rhenium-catalyzed C-H bond transformation is described. The reaction also proceeded in high yield on gram scale and could be applied to the synthesis of polyimide derivatives (see figure), which are highly soluble in organic solvents. Copyright
- Sueki, Shunsuke,Guo, Yuanfang,Kanai, Motomu,Kuninobu, Yoichiro
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p. 11879 - 11883
(2013/11/19)
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- Copper-catalysed oxidative C-H/N-H cross-coupling between formamides and amides through chelation-assisted N-H activation
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A copper-catalysed oxidative C-H/N-H cross-coupling between formamides and amides through chelation-assisted N-H activation has been developed for the preparation of various multi-substituted ureas.
- Li, Xiaoyu,Li, Bijin,You, Jingsong,Lan, Jingbo
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p. 1925 - 1928
(2013/05/21)
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- Orthoamides and iminium salts LXXIV [1]. Reactions of N,N,N',N'- Tetramethyl-chloroformamidiniumChloride with metals
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N,N,N',N'-Tetramethyl-formamidinium chloride (2a) reacts with elemental sodium in various solvents to give N,N,N',N',N'',N''-hexamethyl-guanidinium chloride (4a). The reaction of 2a with potassium affords N,N,N',N',N'',N'',N''', N'''-octamethyl-oxamidinium dichloride (3a). From the reaction of 2a with magnesium in different solvents in general result mixtures of the salts 4a, 3a and N,N,N',N'-tetramethyl-formamidinium chloride (10a). The composition of these mixtures depends on the solvent and the reaction temperature. Similar results are obtained, when a zinc'copper couple is used instead of magnesium. Very likely from 2a and magnesium or zinc, respectively, organometallic intermediates 11, 12 are formed which could be trapped by aromatic aldehydes and phenylisocyanate. The salt 2a can be reductively coupled by a low-valent titanium reagent to give the oxamidinium salt 3a.
- Kantlehner, Willi,Aichholz, Reiner,Karl, Martin
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experimental part
p. 305 - 319
(2012/07/13)
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- Synthesis and application of isocyanates radiolabeled with carbon-11
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Carbon-11 labeled isocyanates are efficiently prepared by dehydration of [11C]carbamate salts, which in turn are easily formed from cyclotron-produced [11C]CO2 and amines in the presence of a CO2 fixation agent. The [11C]isocyanates are useful radiosynthons for the synthesis of a variety of [carbonyl-11C]- labeled asymmetrical ureas and carbamate esters. The method is well suited to incorporate any isotope of carbon, and is especially useful for positron emission tomography (PET) radiotracers for in vivo imaging. This is demonstrated by using the method to make [carbonyl-11C]-6-hydroxy-[1,1′- biphenyl]-3-yl cyclohexylcarbamate which is a novel radiotracer for PET imaging of fatty acid amide hydrolase.
- Wilson, Alan A.,Garcia, Armando,Houle, Sylvain,Sadovski, Oleg,Vasdev, Neil
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supporting information; experimental part
p. 259 - 264
(2011/03/19)
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- The vinyl moiety as a handle for regiocontrol in the preparation of unsymmetrical 2,3-aliphatic-substituted indoles and pyrroles
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Rho-Rho-Rho your boat: A rhodium catalyst effects the regioselective oxidative coupling of enynes with N-aryl ureas (X=NR2) and N-vinylacetamides (X=C(O)Me), affording the corresponding 2-alkenylindoles and 2-alkenylpyrroles in good yield. Simple hydrogenation delivers the C2/C3-aliphatic-substituted indole or pyrrole (see scheme).
- Huestis, Malcolm P.,Chan, Lina,Stuart, David R.,Fagnou, Keith
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supporting information; experimental part
p. 1338 - 1341
(2011/04/21)
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- Intramolecular hydrogen bonding in medicinal chemistry
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The formation of intramolecular hydrogen bonds has a very pronounced effect on molecular structure and properties. We study both aspects in detail with the aim of enabling a more rational use of this class of interactions in medicinal chemistry. On the basis of exhaustive searches in crystal structure databases, we derive propensities for intramolecular hydrogen bond formation of five- to eight-membered ring systems of relevance in drug discovery. A number of motifs, several of which are clearly underutilized in drug discovery, are analyzed in more detail by comparing small molecule and protein-ligand X-ray structures. To investigate effects on physicochemical properties, sets of closely related structures with and without the ability to form intramolecular hydrogen bonds were designed, synthesized, and characterized with respect to membrane permeability, water solubility, and lipophilicity. We find that changes in these properties depend on a subtle balance between the strength of the hydrogen bond interaction, geometry of the newly formed ring system, and the relative energies of the open and closed conformations in polar and unpolar environments. A number of general guidelines for medicinal chemists emerge from this study
- Kuhn, Bernd,Mohr, Peter,Stahl, Martin
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supporting information; experimental part
p. 2601 - 2611
(2010/08/05)
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- Accelerating effects of N-aryl-N′,N′-dialkyl ureas on epoxy-dicyandiamide curing system
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This report focuses on epoxy-dicyandiamide (DICY) curing system accelerated by N-aryl-N′,N′-dialkyl urea, aiming at clarifying the accelerating mechanism and the relationship between accelerating effect and molecular structure of the accelerators. Nine N-aryl-N′,N′-dialkyl ureas were synthesized and investigated with measurements of differential scanning calorimetry, thermo gravimetric/differential thermal analysis and NMR spectroscopy. The results revealed that the ureas released the corresponding secondary amines by the thermal dissociation in the presence of epoxide, which led to the formation of tertiary amines that catalyze the addition reaction of DICY to epoxide. Moreover, a tendency that the ureas able to release more compact amines exhibited higher acceleration effects was discovered.
- Liu, Xiang Dong,Kimura, Mika,Sudo, Atsushi,Endo, Takeshi
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experimental part
p. 5298 - 5305
(2011/06/21)
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- Preparation of N,N-Dimethyl-N′-arylureas using S,S-dimethyl dithio-carbonate as a carbonylating reagent
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A new, general method for the preparation of N,N-di-methyl-N′- arylureas using S,S-dimethyl dithiocarbonate as a phosgene substitute is reported. The method has been set up according to four procedures, all including three steps: (1) reaction of S,S-di- methyl dithiocarbonate with dimethylamine to give S-methyl N,N-dimethylthiocarbamate; (2) halogenation with various halogenating reagents (chlorine, methanesulfenyl chloride, bromine, and meth-anesulfenyl bromide) to give N,N-dimethylcarbamoyl chloride or bromide; (3) in situ reaction with primary arylamines. All the target products were obtained in high yields (85-98%; 16 reactions, average yield 93%) and with high purity. Also noteworthy is the recovery of byproducts of industrial interest, namely methanethiol and dimethyl disulfide, with complete exploitation of the reagent S,S- dimethyl dithiocarbonate. Georg Thieme Verlag Stuttgart.
- Degani, Iacopo,Fochi, Rita,Magistris, Claudio,Migliaccio, Mara
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experimental part
p. 801 - 808
(2009/08/07)
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- Comparative catalytic C-H vs. C-Si activation of arenes with Pd complexes directed by urea or amide groups
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Analysis of regiocontrol in Pd-catalysed C-H activation leads to observations of aryltrimethylsilyl activation and to superior results with urea-based substrates.
- Rauf, Waqar,Thompson, Amber L.,Brown, John M.
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supporting information; experimental part
p. 3874 - 3876
(2010/01/06)
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- Catalytic amide-mediated methyl transfer from silanes to alkenes in Fujiwara-Moritani oxidative coupling
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(Chemical Equation Presented) Intramolecular assistance: Carbon-bound trimethylsilyl groups are activated intramolecularly by a carbonyl group and can participate in Heck reactions under oxidative conditions. Good stereoselectivities are obtained for a range of di-and trisubstituted alkenes (see example).
- Rauf, Waqar,Brown, John M.
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supporting information; experimental part
p. 4228 - 4230
(2009/03/12)
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- Radical fixation of functionalized carbon resources: α-sp 3C - H carbamoylation of tertiary amines with aryl isocyanates
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A new carbamoylation of tertiary amines is reported. This rare C - H transformation features the direct generation of α-aminoalkyl radicals from tertiary amines, followed by the addition of the resultant nucleophilic radicals to isocyanates, enabling unique access to N,N-dialkylated amino acid derivatives. The authors put forward a mechanistic proposal that is based on the isolation of borinamides produced by capturing nitrogen radical intermediates with Et3B. The present transformation provides a novel one-step process for producing mepivacaine, a clinically important local anesthetic, from readily available materials.
- Yoshimitsu, Takehiko,Matsuda, Kenichi,Nagaoka, Hiroto,Tsukamoto, Koji,Tanaka, Tetsuaki
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p. 5115 - 5118
(2008/03/28)
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- Potential of gas chromatography-orthogonal acceleration time-of-flight mass spectrometry (GC-oaTOFMS) in flavor research
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Gas chromatography-orthogonal acceleration time-of-flight mass spectrometry (GC-oaTOFMS) is an emerging technique offering a straightforward access to a resolving power up to 7000. This paper deals with the use of GC-oaTOFMS to identify the flavor components of a complex seafood flavor extract and to quantify furanones formed in model Maillard reactions. A seafood extract was selected as a representative example for complex food flavors and was previously analyzed using GC-quadrupole MS, leaving several molecules unidentified. GC-oaTOFMS analysis was focused on these unknowns to evaluate its potential in flavor research, particularly for determining exact masses, N-Methyldithiodimethylamine, 6-methyl-5-hepten-2-one, and tetrahydro-2,4-dimethyl-4H-pyrrolo- [2,1-d]-1,3,5-dithiazine were successfully identified on the basis of the precise mass determination of their molecular ions and their major fragments. A second set of experiments was performed to test the capabilities of the GC-oaTOFMS for quantification. Calibration curves were found to be linear over a dynamic range of 103 for the quantification of furanones. The quantitative data obtained using GC-oaTOFMS confirmed earlier results that the formation of 4-hydroxy-2,5-dimethyl-3(2H)-furanone was favored in the xylose/glycine model reaction and 2(or 5) -ethyl-4-hydroxy-5(or2)-methyl-3(2H)-furanone in the xylose/alanine model reaction. It was concluded that GC-oaTOFMS may become a powerful analytical tool for the flavor chemist for both identification and quantification purposes, the latter in particular when combined with stable isotope dilution assay.
- Fay, Laurent B.,Newton, Anthony,Simian, Herve,Robert, Fabien,Douce, David,Hancock, Peter,Green, Martin,Blank, Imre
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p. 2708 - 2713
(2007/10/03)
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- Carbonylation of doubly lithiated N′-aryl-N,N-dimethylureas: A novel approach to isatins via intramolecular trapping of acyllithiums
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Lithiation of N′-(2-bromoaryl)-N,N-dimethylureas with methyllithium and tert-butyllithium under nitrogen in anhydrous THF at 0°C gave doubly lithiated arylurea derivatives, which react with carbon monoxide at 0°C to give isatins in good yields. The scope of the reaction has been demonstrated by application to the synthesis of isatin itself and four substituted isatins beating alkyl, chloro or fluoro groups.
- Smith, Keith,El-Hiti, Gamal A.,Hawes, Anthony C.
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p. 2047 - 2052
(2007/10/03)
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- Phenylureas. Part 1. Mechanism of the basic hydrolysis of phenylureas
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The mechanism of the hydrolytic decomposition of phenylureas in basic media in the pH range 12 to 14 is investigated. In this pH range a levelling of the rate-pH curve is observed as well as a change of the substituent influence on the hydrolysis rate. These experimental findings suggest the formation of an unreactive side product of the phenylurea in a parasitic side equilibrium at sufficiently high pH. The urea dissociates at the aryl-NH group to give its conjugate base. For the hydrolytic decomposition of phenylureas an addition-elimination mechanism is proposed as has been established for the alkaline hydrolysis of carboxylic acid esters and amides.
- Laudien,Mitzner
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p. 2226 - 2229
(2007/10/03)
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- Synthesis of aromatic urea herbicides by the selenium-assisted carbonylation using carbon monoxide with sulfur
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Commercially useful aromatic urea herbicides were synthesized in good yields from lithium amides of aromatic amines with thiocarbamates, which were prepared by the selenium-assisted carbonylation of secondary amines with carbon monoxide and sulfur under mild conditions.
- Mizuno, Takumi,Kino, Takanobu,Takatoshi, Ito,Miyata, Toshiyuki
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p. 1675 - 1688
(2007/10/03)
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- Halopyridyl triazolinone herbicides and herbicidal use thereof
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Disclosed are herbicidal halopyridyl triazolinones, herbicidal compositions comprising the halopyridyl triazolinones, and herbicidal use of the compounds and compositions. Such compounds and compositions are useful as both preemergence and postemergence herbicides in a variety of crops.
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- Herbicidal composition for upland farming and weeding method
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A herbicidal composition for upland farming which can control weeds that have been difficult to control, for example, cleavers, chickweed, birdseye speedwell and violet, said composition containing as active ingredients a 3-substituted phenylpyrazole derivative represented by the general formula (I): STR1 (wherein R is a hydrogen atom, a C1-6 alkyl group, a C3-6 cycloalkyl group, a C1-6 haloalkyl group, a C2-6 alkenyl group or a C2-6 alkynyl group, R1 is a C1-6 alkyl group, X1 and X2, which may be the same or different, are halogen atoms, and Y is an oxygen atom or a sulfur atom) and at least one compound selected from the group consisting of sulfonylurea derivatives, phenylurea derivatives and phenoxy fatty acid derivatives; and a weeding method using said composition.
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- α-Haloalkyl Haloformates and Related Compounds 3.1 A Facile Synthesis of Symmetrical and Unsymmetrical Ureas via Chloromethyl Carbamates
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Chloromethyl carbamates were prepared by the reaction of chloromethyl chloroformates with amines and found to produce mono-, symmetrically or unsymmetrically di- and trisubstituted ureas including their N-hydroxy and N-alkoxy derivatives in moderate to good yield.
- Patonay, Tamas,Patonay-Peli, Erzsebet,Zolnai, Laszlo,Mogyorodi, Ferenc
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p. 4253 - 4265
(2007/10/03)
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- REACTION OF AMINES WITH N-ARYLUREAS, ALKYL N-ARYLCARBAMATES, AND SALTS OF THIOCARBAMIC ACIDS
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The reaction of amines with N-arylureas, alkyl N-arylcarbamates, and salts of thiocarbamic acids is studied. The regularities found are explained by the characteristic features of hydrogen bond formation.
- Manov-Yuvenskii, V. I.,Kuznetsov, S. L.
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p. 1063 - 1069
(2007/10/02)
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- Biocide composition and use
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A stable liquid dispersion in an non-polar organic solvent containing an alkylsulphonylhalopyridine and a dispersing agent which is the reaction product of a hydroxyalkylcarboxylic acid and an amine or salt thereof. The alkylsulphonylhalopyridine may be 2,3,5,6-tetrachloro-4-(methylsulphenyl)pyridine and the hydroxycarboxylic acid may be poly(12-hydroxystearic acid) and the amine may be either dimethylamino propylamine or polyethyleneimine. The solvent may be white spirit or an ester or vegetable oil which is a plasticiser for PVC.
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- Process for the preparation of pure, unsymmetrically disubstituted ureas
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Process for the preparation of pure, unsymmetrically disubstituted ureas of the general formula STR1 in which R denotes a phenyl radical which is unsubstituted, or monosubstituted or polysubstituted by halogen atoms or alkyl, alkoxy, aryloxy or trifluoromethyl groups, an oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, benzoxazolyl or benzothiazolyl radical which is unsubstituted, or monosubstituted or polysubstituted by halogen atoms or alkyl, alkoxy or trifluoromethyl groups and R1 and R2 independently of one another denote a hydrogen atom or an alkyl group, where R1 and R2 are not simultaneously hydrogen or R1 and R2 together denote a butylene or pentylene group, by reaction of an N-alkyl- or N,N-dialkylurea with an unsubstituted or substituted arylamine or a heterocyclic amine in the presence of that amine which is already present in the starting material, the respective N-alkyl- or N,N-dialkylurea.
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- Process of improving activity of herbicides and fertilizers using N-(2-hydroxyethyl)-acetamide or -propanamide
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The invention is related to the use of certain water-soluble compounds known as such and having the Formula for the modulation of membrane dependent metabolism processes within living cells, in particular with relation to transport phenomena and cell procedures which are induced or influenced by active agents supplied from outside the cell, products containing these substances for the above described uses and processes using these products.
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- Aromatic tertiary amines, enamines, deoxybenzoins and benzils
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A novel synthesis of aromatic tertiary amines involves reacting an aromatic anil and an aromatic ether in a molar ratio of 1:1; adjusting the ratio to 2:1 produces novel enamines and by employing a two step process for enamine production, various unsymmetrically substituted enamines can be obtained which are readily hydrolyzed to corresponding deoxybenzoins which in turn are readily oxidized to benzils, the aromatic tertiary amines may be used to produce charge transport layers in xerography, while the benzils may be used to produce a variety of desired polymers.
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- NEW ACYCLIC AND FUSED TRICYCLIC PHOSPHORUS COMPOUNDS AFFORDED BY NOVEL CONDENSATION
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The condensation of 1-(2-benzothiazolyl)-4-phenylsemicarbazide with (R2N)2PX (X = R2N, RO, Ph) proceeds with cleavage of the N-C(O) bond and formation of the title compounds which were also synthesized via similar treatment of 2-hydrazinobenzothiazole in good yields.Reactivities of (R2N)2PX, spectroscopic properties of the products and preliminary mechanism of these reactions were discussed.
- Zhang, Jing-Lin,Ma, Xiao-Bo
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p. 291 - 298
(2007/10/02)
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- NEW DERIVATIVES OF 4,5-BENZO-1,3,2-OXAZA (OR DIAZA)-PHOSPHOLANE FROM CONVENIENT CONDENSATION OF SUBSTITUTED UREA WITH TRIS(DIALKYLAMINO)PHOSPHINE
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The condensation of N-phenyl-N'-(2-hydroxylphenyl)urea or N-phenyl-N'-(2-aminophenyl)urea with tris(dialkylamino)phosphine afforded derivatives of 4,5-benzo-1,3,2-oxaza (or diaza)-phospholane which formed intramolecular hydrogen bond.The cleavage of the amide bond to give N,N-dialkyl-N'-phenylurea together with polymers of 1,3,2-benzodiazaphosphole was observed in the latter reaction.
- Ma, Xiao-bo,Zhang, Jing-lin
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p. 227 - 231
(2007/10/02)
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