cas 1202-25-1, METHYL 4-DIMETHYLAMINOBENZOATE

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The development of coumarin Schiff base system applied as highly selective fluorescent/colorimetric probes for Cu2+ and tumor biomarker glutathione detection
Overexpression of tumor biomarker glutathione (GSH) has been documented in numerous types of cancers, therefor GSH-activated light-up chemosensors for tumor identification require great attention. A new colorimetric/fluorescent probe (7-(diethylamino)-2-oxo-2H-chromen-3-yl)methylene)-4-(dimethylamino) benzohydrazide (HL) was prepared, which could be applied in discriminating Cu2+ and further recognizing GSH based on its Cu complex. Firstly, the probe HL toward Cu2+ exhibited selective fluorescence quenching and obvious color change from yellow to orange-red under visible light. Further, when GSH was introduced to the Cu2+-2HL system, the fluorescence recovered rapidly due to the high affinity of GSH to Cu2+, meanwhile the color reverted back to former yellow. Based on fluorescence titration, the detection limits were calculated as 2.40 × 10?8 M and 1.29 × 10?7 M for Cu2+ and GSH, respectively. The combination mode of HL with Cu2+ was investigated in detail by Job plots, ESI-MS, FT-IR, and DFT studies. Probes HL and Cu2+-2HL showed relatively less toxicity and were employed for biological imaging in cells and zebrafish. Remarkably, the detection for endogenous GSH by this developed sensor platform implied great potential application prospect in cancer diagnosis.
Wang, Zhi-Gang,Ding, Xiao-Jing,Huang, Yu-Ying,Yan, Xiao-Jing,Ding, Bin,Li, Qing-Zhong,Xie, Cheng-Zhi,Xu, Jing-Yuan
(2020)
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Simple, efficient protocols for the Pd-catalyzed cross-coupling reaction of aryl chlorides and dimethylamine
Simple and efficient procedures for the Pd-catalyzed cross-coupling reaction of aryl chlorides and dimethylamine are described. At room temperature with a strong base, t-BuXPhos is employed as the supporting ligand; at 110 °C with a weak base, XPhos is employed as the supporting ligand. In each of these cases, commercially available solutions constitute the source of the dimethylamine, and recently disclosed precatalysts constitute the source of the ligand and Pd. This work further expands the utility of these precatalysts in reactions that benefit from an easily activated source of L1Pd(0).
Lee, Brian K.,Biscoe, Mark R.,Buchwald, Stephen L.
p. 3672 - 3674
(2009)
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A chromone hydrazide Schiff base fluorescence probe with high selectivity and sensitivity for the detection and discrimination of human serum albumin (HSA) and bovine serum albumin (BSA)
The discrimination and identification of human serum albumin (HSA) and bovine serum albumin (BSA) is very important, which is due to the vital roles of two SAs in biological and pharmaceutical research. Based on structural screening and docking calculation from a series of homologues, a coumarin Schiff base fluorescent probe 3-hydroxy-N′-((4-oxo-4H-chromen-3-yl)methylene)-2-naphthohydrazide (HCNH) has been designed and synthesized, which could effectively discriminate HSA and BSA. The probe HCNH exhibited superior sensitivity toward HSA and BSA with the detection limits of 10.62 nM and 16.03 nM in PBS solution, respectively. The binding mechanism of HCNH with SAs was studied by Job's plot analysis, SA destruction and displacement assay. Molecular docking and DFT methods were utilized to provide deep insight into the spatial conformation change of HCNH and binding sites in HSA/BSA. The conformation of HCNH was significantly influenced by the microenvironment provided by HSA and BSA, therefore its fluorescence emission was affected correspondingly. Non-toxic probe HCNH could be successfully used for fluorescence bio-imaging of HSA in cancer cells, which is significantly different from normal cells and favors the application in medical diagnosis.
Fan, Jing,Li, Qing-Zhong,Li, Zhe,Liu, Hai-Bo,Wang, Zhi-Gang,Xie, Cheng-Zhi,Xu, Jing-Yuan,Yan, Xiao-Jing
(2021/10/12)

Aminomethylation of Aryl Bromides by Nickel-Catalyzed Electrochemical Redox Neutral Cross Coupling
We develop an electrochemical nickel-catalyzed aminomethylation of aryl bromides under mild conditions. The convergent paired electrolysis makes full use of anode and cathode processes, free of a terminal oxidant, a sacrificial anode, a metal reductant, and a prefunctionalized radical precursor. In addition, this method exhibits wide functional group tolerance (63 examples), including some sensitive substituents and aromatic heterocycles. This redox neutral cross coupling provides a more environmentally friendly and synthetic practical protocol for forging C(sp2)–C(sp3) bonds.
Ma, Yueyue,Hong, Jufei,Yao, Xiantong,Liu, Chengyu,Zhang, Ling,Fu, Youtian,Sun, Maolin,Cheng, Ruihua,Li, Zhong,Ye, Jinxing
supporting information
p. 9387 - 9392
(2021/12/17)

CO2-tuned highly selective reduction of formamides to the corresponding methylamines
We herein describe an efficient, CO2-tuned and highly selective C-O bond cleavage of N-methylated formanilides. With easy-to-handle and commercially available NaBH4 as the reductant, a variety of formanilides could be turned into the desired tertiary amines in moderate to excellent yields. The role of CO2 has been investigated in detail, and the mechanism is proposed on the basis of experiments.
Chao, Jianbin,Guo, Zhiqiang,Pang, Tengfei,Wei, Xuehong,Xi, Chanjuan,Yan, Leilei
supporting information
p. 7534 - 7538
(2021/10/12)

Utilization of renewable formic acid from lignocellulosic biomass for the selective hydrogenation and/or N-methylation
Lignocellulosic biomass is one of the most abundant renewable sources in nature. Herein, we have developed the utilization of renewable formic acid from lignocellulosic biomass as a hydrogen source and a carbon source for the selective hydrogenation and further N-methylation of various quinolines and the derivatives, various indoles under mild conditions in high efficiencies. N-methylation of various anilines is also developed. Mechanistic studies indicate that the hydrogenation occurs via a transfer hydrogenation pathway.
Zhou, Chao-Zheng,Zhao, Yu-Rou,Tan, Fang-Fang,Guo, Yan-Jun,Li, Yang
p. 4724 - 4728
(2021/09/06)

Additive-freeN-methylation of amines with methanol over supported iridium catalyst
An efficient and versatile zinc oxide-supported iridium (Ir/ZnO) catalyst was developed to catalyze the additive-freeN-methylation of amines with methanol. Mechanistic studies suggested that the high catalytic reactivity is rooted in the small sizes (1.4 nm) of Ir nanoparticles and the high ratio (93%) of oxidized iridium species (IrOx, Ir3+and Ir4+) on the catalyst. Moreover, the delicate cooperation between the IrOxand ZnO support also promoted its high reactivity. The selectivity of this catalyticN-methylation was controllable between dimethylation and monomethylation by carefully tuning the catalyst loading and reaction solvent. Specifically, neat methanol with high catalyst loading (2 mol% Ir) favored the formation ofN,N-dimethylated amine, while the mesitylene/methanol mixture with low catalyst loading (0.5 mol% Ir) was prone to producing mono-N-methylated amines. An environmentally benign continuous flow system with a recycled mode was also developed for the efficient production ofN-methylated amines. With optimal flow rates and amine concentrations, a variety ofN-methylamines were produced with good to excellent yields in this Ir/ZnO-based flow system, providing a starting point for the clean and efficient production ofN-methylamines with this cost-effective chemical process.
Liu, Xiang,Loh, Teck-Peng,Qiang, Wenwen,Wang, Jing,Ye, Sen,Zhu, Longfei
p. 3364 - 3375
(2021/06/06)

Preparation method of N-alkylated derivative of primary amine compound
The invention relates to a preparation method of an N-alkylated derivative of a primary amine compound. The method comprises the following steps: uniformly mixing a primary amine compound, an alcohol compound and a catalyst in a reactor, and heating to react for a period of time to generate an N-alkylated substituted tertiary amine compound; wherein the catalyst is a copper-cobalt bimetallic catalyst, and the carrier of the catalyst is Al2O3. According to the method, alcohol is adopted as an alkylating reagent and is low in price and easy to obtain, a byproduct is water, no pollution is caused to the environment, and the overall reaction atom economy is high; the catalyst is simple in preparation method, low in cost, high in reaction activity and good in structural stability; meanwhile, by using the copper-cobalt bimetallic catalyst, the use of strong base additives can be avoided, and the requirement on reaction equipment is low; and the reaction post-treatment is convenient, and the catalyst can be recycled and is environment-friendly.
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(2021/07/09)

Palladium-Catalyzed Chlorocarbonylation of Aryl (Pseudo)Halides Through In Situ Generation of Carbon Monoxide
An efficient palladium-catalyzed chlorocarbonylation of aryl (pseudo)halides that gives access to a wide range of carboxylic acid derivatives has been developed. The use of butyryl chloride as a combined CO and Cl source eludes the need for toxic, gaseous carbon monoxide, thus facilitating the synthesis of high-value products from readily available aryl (pseudo)halides. The combination of palladium(0), Xantphos, and an amine base is essential to promote this broadly applicable catalytic reaction. Overall, this reaction provides access to a great variety of carbonyl-containing products through in situ transformation of the generated aroyl chloride. Combined experimental and computational studies support a reaction mechanism involving in situ generation of CO.
Bismuto, Alessandro,Boehm, Philip,Morandi, Bill,Roediger, Sven
supporting information
p. 17887 - 17896
(2020/08/19)

Imidazotetrazines as Weighable Diazomethane Surrogates for Esterifications and Cyclopropanations
Diazomethane is one of the most versatile reagents in organic synthesis, but its utility is limited by its hazardous nature. Although alternative methods exist to perform the unique chemistry of diazomethane, these suffer from diminished reactivity and/or correspondingly harsher conditions. Herein, we describe the repurposing of imidazotetrazines (such as temozolomide, TMZ, the standard of care for glioblastoma) for use as synthetic precursors of alkyl diazonium reagents. TMZ was employed to conduct esterifications and metal-catalyzed cyclopropanations, and results show that methyl ester formation from a wide variety of substrates is especially efficient and operationally simple. TMZ is a commercially available solid that is non-explosive and non-toxic, and should find broad utility as a replacement for diazomethane.
Svec, Riley L.,Hergenrother, Paul J.
supporting information
p. 1857 - 1862
(2019/12/27)

Dehydrogenative Coupling of Aldehydes with Alcohols Catalyzed by a Nickel Hydride Complex
A nickel hydride complex, {2,6-(iPr2PO)2C6H3}NiH, has been shown to catalyze the coupling of RCHO and R′OH to yield RCO2R′ and RCH2OH, where the aldehyde also acts as a hydrogen acceptor and the alcohol also serves as the solvent. Functional groups tolerated by this catalytic system include CF3, NO2, Cl, Br, NHCOMe, and NMe2, whereas phenol-containing compounds are not viable substrates or solvents. The dehydrogenative coupling reaction can alternatively be catalyzed by an air-stable nickel chloride complex, {2,6-(iPr2PO)2C6H3}NiCl, in conjunction with NaOMe. Acids in unpurified aldehydes react with the hydride to form nickel carboxylate complexes, which are catalytically inactive. Water, if present in a significant quantity, decreases the catalytic efficiency by forming {2,6-(iPr2PO)2C6H3}NiOH, which causes catalyst degradation. On the other hand, in the presence of a drying agent, {2,6-(iPr2PO)2C6H3}NiOH generated in situ from {2,6-(iPr2PO)2C6H3}NiCl and NaOH can be converted to an alkoxide species, becoming catalytically competent. The proposed catalytic mechanism features aldehyde insertion into the nickel hydride as well as into a nickel alkoxide intermediate, both of which have been experimentally observed. Several mechanistically relevant nickel species including {2,6-(iPr2PO)2C6H3}NiOC(O)Ph, {2,6-(iPr2PO)2C6H3}NiOPh, and {2,6-(iPr2PO)2C6H3}NiOPh·HOPh have been independently synthesized, crystallographically characterized, and tested for the catalytic reaction. While phenol-containing molecules cannot be used as substrates or solvents, both {2,6-(iPr2PO)2C6H3}NiOPh and {2,6-(iPr2PO)2C6H3}NiOPh·HOPh are efficient in catalyzing the dehydrogenative coupling of PhCHO with EtOH.
Eberhardt, Nathan A.,Wellala, Nadeesha P. N.,Li, Yingze,Krause, Jeanette A.,Guan, Hairong
p. 1468 - 1478
(2019/04/17)

N–Alkylation of Amines Catalyzed by a Ruthenium–Pincer Complex in the Presence of in situ Generated Sodium Alkoxide
We report the use of ruthenium–NNN-pincer complexes of the type (R2NNN)RuCl2(PPh3) (R = tBu, iPr, Cy and Ph) for the catalytic N-alkylation of primary amines under solvent-free conditions. For the first time, the base that is required to promote these reactions is generated in situ from the alcohol by the use of sodium. The resulting sodium alkoxide regenerates the alcohol substrate while acting as the water scavenger thus mitigating the need of an additional base. Among the catalysts screened, (tBu2NNN)RuCl2(PPh3) (0.02 mol-%) gives very high turnovers and good yields at 140 °C. The (tBu2NNN)RuCl2(PPh3) catalyzed N-alkylation tolerates a variety of amine and alcohol substrates. While excellent turnover (29000) was obtained for the (tBu2NNN)RuCl2(PPh3) (0.002 mol-%) catalyzed alkylation of aniline with cyclohexyl methanol, the turnovers obtained in the corresponding catalytic methylation of p-anisidine was also very high (12000). The (tBu2NNN)RuCl2(PPh3) catalyzed reactions have also been accomplished under open-vessel conditions resulting in a net dehydrogenative coupling reaction. This protocol has been used to transform benzene-1,2-diamines to benzimidazoles with high productivity (12000 turnovers). DFT studies indicate that while β-hydride elimination is rate-determining (RDTS: 24.31 kcal/mol) for the alcohol dehydrogenation segment which is endothermic, insertion of the imine is rate-determining (RDTS: 11.26 kcal/mol) for its hydrogenation that is exothermic.
Das, Kanu,Nandi, Pran Gobinda,Islam, Khadimul,Srivastava, Hemant Kumar,Kumar, Akshai
p. 6855 - 6866
(2019/11/03)

Iron-Catalyzed Selective N-Methylation and N-Formylation of Amines with CO2
We herein describe an efficient iron-catalyzed selective N-methylation and N-formylation of amines with CO2 and silane using mono-phosphine as ligand. With commercially available [CpFe(CO)2]2 as catalyst, Fe-catalyzed methylation of amines was achieved with triphenylphosphine as a ligand. Using tributylphosphine as a ligand, Fe-catalyzed formylation of amines was realized at a lower temperature. The method was successfully applied in the late-stage methylation and formylation of drug molecules containing amine moiety. (Figure presented.).
Li, Wen-Duo,Zhu, Dao-Yong,Li, Gang,Chen, Jie,Xia, Ji-Bao
supporting information
p. 5098 - 5104
(2019/11/03)

UiO-type metal-organic frameworks with NHC or metal-NHC functionalities for: N-methylation using CO2 as the carbon source
We demonstrate the first metal-organic framework (MOF) that catalyzes N-methylation of amines using 1 atm CO2 and phenylsilane under ambient conditions. Compared with its homogeneous analog, the incorporation of N-heterocyclic carbene (NHC) into the MOF provides more efficient catalysis with improved reaction kinetics, turnover numbers and recyclability. Moreover, the metalated NHC functionalized MOF achieves direct N-methylation of amines bearing carboxylate moieties, which are common building blocks in pharmaceutical chemistry.
Zhang, Xu,Jiang, Yilin,Fei, Honghan
supporting information
p. 11928 - 11931
(2019/10/11)

Synergistic catalysis of Cu+/Cu0 for efficient and selective N-methylation of nitroarenes with para-formaldehyde
In this paper, an inexpensive heterogeneous copper nanoparticles catalyst derived from CuAl-layered double hydroxide via an in situ topotactic transformation process was developed. Cu nanoparticles with uniform size were homogeneously dispersed on amorphous Al2O3 with strong metal-support interaction. Characterization results reveals that the Cu0 and Cu+ were simultaneously formed with Cu+ species as the dominant sites on the surface during the reduction process. The resultant catalyst Cu/Al2O3 demonstrates high catalytic activity, selectivity and durability for the reductive N-methylation of easily available nitroarenes in a cost-efficient, environmentally friendly and cascade manner. A broad spectrum of nitroarenes could be efficiently N-methylated to their corresponding N,N-dimethyl amines with good compatibility of various functional groups. The protocol is also applicable for the late-stage functionalization of biologically and pharmaceutically active nitro molecules. A structure-function relationship discloses that Cu0 and Cu+ sites on the surface pronouncedly boosts the reaction efficiency in a synergistic manner, in which Cu0 could facilitate H2 production and N-methylation of anilines, while Cu+ is considerably more active and participates in the overall process of the selective N-methylation of nitroarenes. Moreover, the catalyst also showed a strong stability and could be easily separated for successive reuses without an appreciable loss in activity and selectivity.
Dong, Xiaosu,Wang, Zhaozhan,Yuan, Youzhu,Yang, Yong
p. 304 - 313
(2019/07/02)

Transformation of N, N-Dimethylaniline N-Oxides into Diverse Tetrahydroquinoline Scaffolds via Formal Povarov Reactions
A one-pot protocol for the assembly of diversely functionalized tetrahydro-, hexahydrofuro-, hexahydropyrano-, and tetrahydrobenzofuroquinolines from N,N-dimethylaniline N-oxides and various electron-rich olefins in a tandem Polonovski-Povarov sequence is reported. Following activation of the N-O bond with Boc2O, an exocyclic iminium ion is unveiled upon exposure to tin(IV) chloride. A formal inverse-electron-demand aza-Diels-Alder cyclization generates the tetrahydroquinoline core of 29 examples in up to 92% yield.
Bush, Timothy S.,Yap, Glenn P. A.,Chain, William J.
supporting information
p. 5406 - 5409
(2018/09/13)

Synthesis of Halogenated Anilines by Treatment of N, N-Dialkylaniline N-Oxides with Thionyl Halides
The special reactivity of N,N-dialkylaniline N-oxides allows practical and convenient access to electron-rich aryl halides. A complementary pair of reaction protocols allow for the selective para-bromination or ortho-chlorination of N,N-dialkylanilines in up to 69% isolated yield. The generation of a diverse array of halogenated anilines is made possible by a temporary oxidation level increase of N,N-dialkylanilines to the corresponding N,N-dialkylaniline N-oxides and the excision of the resultant weak N-O bond via treatment with thionyl bromide or thionyl chloride at low temperature.
Reed, Hayley,Paul, Tyler R.,Chain, William J.
p. 11359 - 11368
(2018/08/06)

Structural design, synthesis and substituent effect of hydrazone-N-acylhydrazones reveal potent immunomodulatory agents
4-(Nitrophenyl)hydrazone derivatives of N-acylhydrazone were synthesized and screened for suppress lymphocyte proliferation and nitrite inhibition in macrophages. Compared to an unsubstituted N-acylhydrazone, active compounds were identified within initial series when hydroxyl, chloride and nitro substituents were employed. Structure-activity relationship was further developed by varying the position of these substituents as well as attaching structurally-related substituents. Changing substituent position revealed a more promising compound series of anti-inflammatory agents. In contrast, an N-methyl group appended to the 4-(nitrophenyl)hydrazone moiety reduced activity. Anti-inflammatory activity of compounds is achieved by modulating IL-1β secretion and prostaglandin E2 synthesis in macrophages and by inhibiting calcineurin phosphatase activity in lymphocytes. Compound SintMed65 was advanced into an acute model of peritonitis in mice, where it inhibited the neutrophil infiltration after being orally administered. In summary, we demonstrated in great details the structural requirements and the underlying mechanism for anti-inflammatory activity of a new family of hydrazone-N-acylhydrazone, which may represent a valuable medicinal chemistry direction for the anti-inflammatory drug development in general.
Meira, Cássio S.,dos Santos Filho, José Maurício,Sousa, Caroline C.,Anjos, Pamela S.,Cerqueira, Jéssica V.,Dias Neto, Humberto A.,da Silveira, Rafael G.,Russo, Helena M.,Wolfender, Jean-Luc,Queiroz, Emerson F.,Moreira, Diogo R.M.,Soares, Milena B.P.
p. 1971 - 1985
(2018/03/12)

Silver-catalyzed intermolecular amination of fluoroarenes
A novel highly selective Ag-catalyzed intermolecular amination of fluoroarenes has been developed. This transformation starts from readily available 4-carbonyl fluorobenzene and NaN3 or other nitrogen-source, via amination followed by C-F bond cleavage, thus affording the desired 4-carbonyl arylamine products under mild conditions. The reaction is accelerated using a small amount of water. This pathway is distinct from a previously reported radical amination reaction.
Wang, Yu,Wei, Chenlong,Tang, Ruyun,Zhan, Haosheng,Lin, Jing,Liu, Zhenhua,Tao, Weihua,Fang, Zhongxue
supporting information
p. 6191 - 6194
(2018/09/10)

1,4-Dioxane-Tuned Catalyst-Free Methylation of Amines by CO2 and NaBH4
A catalyst-free reductive functionalization of CO2 with amines and NaBH4 was developed. The N-methylation of amines was carried out with CO2 as a C1 building block and 1,4-dioxane as the solvent. Notably, the six-electron reduction of CO2 to form the methyl group occurred simultaneously with formation of the C?N bond to give the N-methylated amine.
Guo, Zhiqiang,Zhang, Bo,Wei, Xuehong,Xi, Chanjuan
p. 2296 - 2299
(2018/07/31)

DBU-Catalyzed Selective N-Methylation and N-Formylation of Amines with CO2 and Polymethylhydrosiloxane
We describe herein an efficient organocatalytic system for the selective N-methylation and N-formylation of amines with carbon dioxide (CO2) as a sustainable C1 feedstock and polymethylhydrosiloxane (PMHS) as a cost-effectvie reducing reagent. High-yielding N-methylation products are obtained with low catalyst loading (1%) of DBU. Selective N-formylation of amines is achieved using the same catalytic system at a lower reaction temperature. (Figure presented.).
Li, Gang,Chen, Jie,Zhu, Dao-Yong,Chen, Ye,Xia, Ji-Bao
supporting information
p. 2364 - 2369
(2018/05/07)

Expedient Synthesis of N-Methyl- and N-Alkylamines by Reductive Amination using Reusable Cobalt Oxide Nanoparticles
N-Methyl- and N-alkylamines represent important fine and bulk chemicals that are extensively used in both academic research and industrial production. Notably, these structural motifs are found in a large number of life-science molecules and play vital roles in regulating their activities. Therefore, the development of convenient and cost-effective methods for the synthesis and functionalization of amines by using earth-abundant metal-based catalysts is of scientific interest. In this regard, herein we report an expedient reductive amination process for the selective synthesis of N-methylated and N-alkylated amines by using nitrogen-doped, graphene-activated nanoscale Co3O4-based catalysts. Starting from inexpensive and easily accessible nitroarenes or amines and aqueous formaldehyde or aldehydes in the presence of formic acid, this cost-efficient reductive amination protocol allows the synthesis of various N-methyl- and N-alkylamines, amino acid derivatives, and existing drug molecules.
Senthamarai, Thirusangumurugan,Murugesan, Kathiravan,Natte, Kishore,Kalevaru, Narayana V.,Neumann, Helfried,Kamer, Paul C. J.,Jagadeesh, Rajenahally V.
p. 1235 - 1240
(2018/02/09)

Convenient Synthesis of p-Aminobenzoic Acids and their Methyl Esters
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Pietrzak, Marek,J?drzejewska, Beata,M?drzejewska, Dorota,Bajorek, Agnieszka
p. 45 - 52
(2017/01/22)

Efficient and Selective N-Methylation of Nitroarenes under Mild Reaction Conditions
Herein, we report a straightforward protocol for the preparation of N,N-dimethylated amines from readily available nitro starting materials using formic acid as a renewable C1 source and silanes as reducing agents. This tandem process is efficiently accomplished in the presence of a cubane-type Mo3PtS4 catalyst. For the preparation of the novel [Mo3Pt(PPh3)S4Cl3(dmen)3]+ (3+) (dmen: N,N′-dimethylethylenediamine) compound we have followed a [3+1] building block strategy starting from the trinuclear [Mo3S4Cl3(dmen)3]+ (1+) and Pt(PPh3)4 (2) complexes. The heterobimetallic 3+ cation preserves the main structural features of its 1+ cluster precursor. Interestingly, this catalytic protocol operates at room temperature with high chemoselectivity when the 3+ catalyst co-exists with its trinuclear 1+ precursor. N-heterocyclic arenes, double bonds, ketones, cyanides and ester functional groups are well retained after N-methylation of the corresponding functionalized nitroarenes. In addition, benzylic-type as well as aliphatic nitro compounds can also be methylated following this protocol.
Pedrajas, Elena,Sorribes, Iván,Guillamón, Eva,Junge, Kathrin,Beller, Matthias,Llusar, Rosa
p. 13205 - 13212
(2017/09/12)

Chemoselective dehydrogenative esterification of aldehydes and alcohols with a dimeric rhodium(II) catalyst
Dehydrogenative cross-coupling of aldehydes with alcohols as well as dehydrogentive cross-coupling of primary alcohols to produce esters have been developed using a Rh-terpyridine catalyst. The catalyst demonstrates broad substrate scope and good functional group tolerance, affording esters highly selectively. The high chemoselectivity of the catalyst stems from its preference for dehydrogenation of benzylic alcohols over aliphatic ones. Preliminary mechanistic studies suggest that the active catalyst is a dimeric Rh(ii) species, operating via a mechanism involving metal-base-metal cooperativity.
Cheng, Junjie,Zhu, Meijuan,Wang, Chao,Li, Junjun,Jiang, Xue,Wei, Yawen,Tang, Weijun,Xue, Dong,Xiao, Jianliang
p. 4428 - 4434
(2016/07/07)

Design, Synthesis, and Pharmacological Evaluation of Novel N-Acylhydrazone Derivatives as Potent Histone Deacetylase 6/8 Dual Inhibitors
This manuscript describes a novel class of N-acylhydrazone (NAH) derivatives that act as histone deacetylase (HDAC) 6/8 dual inhibitors and were designed from the structure of trichostatin A (1). Para-substituted phenyl-hydroxamic acids presented a more potent inhibition of HDAC6/8 than their meta analogs. In addition, the effect of compounds (E)-4-((2-(4-(dimethylamino)benzoyl)hydrazono)methyl)-N-hydroxybenzamide (3c) and (E)-4-((2-(4-(dimethylamino)benzoyl)-2-methylhydrazono)methyl)-N-hydroxybenzamide (3f) on the acetylation of α-tubulin revealed an increased level of acetylation. These two compounds also affected cell migration, indicating their inhibition of HDAC6. An analysis of the antiproliferative activity of these compounds, which presented the most potent activity, showed that compound 3c induced cell cycle arrest and 3g induced apoptosis through caspase 3/7 activation. These results suggest HDAC6/8 as a potential target of future molecular therapies for cancer.
Rodrigues, Daniel A.,Ferreira-Silva, Guilherme à.,Ferreira, Ana C. S.,Fernandes, Renan A.,Kwee, Jolie K.,SantAnna, Carlos M. R.,Ionta, Marisa,Fraga, Carlos A. M.
p. 655 - 670
(2016/02/05)

Rhodium-Catalyzed Double Alkyl-Oxygen Bond Cleavage: An Alkyl Transfer Reaction from Bis/Tris(o-alkyloxyphenyl)phosphine to Aryl Acids
An unprecedented rhodium-catalyzed selective cleavage of double alkyl-oxygen bonds of bis/tris(o-alkyloxyphenyl)phosphine has been realized, in which P atom functions as a directing group and simple aryl acids are the methyl group acceptor to provide methyl esters and a quaternary phosphonium salt. The preliminary mechanism was investigated via an 18O labeling experiment and stoichiometric reaction between a Rh-A crystal and an aromatic acid.
Zhou, Hui,Zhang, Jinlong,Yang, Huameng,Xia, Chungu,Jiang, Gaoxi
supporting information
p. 3406 - 3412
(2016/10/21)

Preparation method of N,N-dimethyl benzoate composite
The invention relates to a preparation method of an N,N-dimethyl benzoate composite, in particular to a preparation method for preparing N,N-dimethyl benzoate by using N,N-dimethylaniline, bi(trichloromethyl)carbonic ester and alcohol as raw materials. The raw materials are cheap and easy to obtain, the yield is high, a midbody does not need to be purified, a continuous reaction can be performed without replacing solvents, the preparation method is cheap, environmentally friendly, easy to implement and suitable for industrialization, and the method can be used for preparing the important chemical and medical midbody through N,N-dimethyl benzoyl chloride.
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(2016/10/09)

General catalytic methylation of amines with formic acid under mild reaction conditions
A general catalytic protocol for the methylation of amines has been developed applying, for the first time, formic acid as the C1 building block and silanes as reducing agents. A broad range of aromatic and aliphatic, both primary and secondary, amines has been converted to the corresponding tertiary amines including [N-13C]-labelled drugs in good to excellent yields under mild conditions. Methylation made easy: A general catalytic protocol for the methylation of amines has been developed applying, for the first time, formic acid as the C1 building block and silanes as reducing agents. A broad range of aromatic and aliphatic, both primary and secondary, amines has been converted to the corresponding tertiary amines, including [N-13C]-labelled drugs, in good to excellent yields at mild conditions (see scheme; dppp=(1,3-bis(diphenylphosphino)propane)).
Sorribes, Ivan,Junge, Kathrin,Beller, Matthias
supporting information
p. 7879 - 7883
(2014/07/07)

Palladium on carbon-bromobenzene mediated esterification and transesterification
A series of carboxylic acids were converted into their corresponding esters using the Pd/C catalyzed hydrogenation conditions in the presence of catalytic bromobenzene in alcohols and the method could also be applicable for the transesterification of esters. Good to excellent yields were obtained for different aliphatic or aromatic starting materials. The success of this esterification relies on the in situ generation of hydrobromic acid (HBr) from bromobenzene which provides a mild and acidic reaction environment. The palladium catalyst exhibits a remarkable activity and is reusable for up-to three consecutive cycles.
Aavula, Sanjeev Kumar,Chikkulapalli, Anil,Hanumanthappa,Jyothi, Indira,Vinod Kumar,Manjunatha, Sulur G.
p. 5690 - 5694
(2013/09/24)

Selective methylation of amines with carbon dioxide and H2
Put a label on it: Carbon dioxide with H2 is shown to be an efficient and selective methylation reagent for aromatic and aliphatic amines (see scheme; acac=acetylacetonate, triphos = 1,1,1- tris(diphenylphosphanylmethyl)ethane). A variety of functionalized amines including 13C-labelled drugs were obtained with good yields and functional-group tolerance. Copyright
Li, Yuehui,Sorribes, Ivan,Yan, Tao,Junge, Kathrin,Beller, Matthias
supporting information
p. 12156 - 12160
(2013/12/04)

A simple approach to aggregation-induced emission in difluoroboron dibenzoylmethane derivatives
The first example of an AIE active BF2dbm derivative with a single dimethylamino group connecting to the phenyl ring was revealed. It also showed capability of sensing HCl gas both in solution and in the solid state.
Hu, Junyi,He, Zhen,Wang, Zhi,Li, Xiaoyu,You, Jingsong,Gao, Ge
supporting information
p. 4167 - 4170
(2013/07/26)

Synthesis, biological evaluation and molecular docking studies of novel 2-(1,3,4-oxadiazol-2-ylthio)-1-phenylethanone derivatives
In present study, a series of new 2-(1,3,4-oxadiazol-2-ylthio)-1- phenylethanone derivatives (6a-6x) as potential focal adhesion kinase (FAK) inhibitors were synthesized. The bioassay assays demonstrated that compound 6i showed the most potent activity, which inhibited the growth of MCF-7 and A431 cell lines with IC50 values of 140 ± 10 nM and 10 ± 1 nM, respectively. Compound 6i also exhibited significant FAK inhibitory activity (IC50 = 20 ± 1 nM). Docking simulation was performed to position compound 6i into the active site of FAK to determine the probable binding model.
Zhang, Li-Rong,Liu, Zhi-Jun,Zhang, Hui,Sun, Jian,Luo, Yin,Zhao, Ting-Ting,Gong, Hai-Bin,Zhu, Hai-Liang
scheme or table
p. 3615 - 3621
(2012/07/27)

Preparation and spectral characterization of fluorescence probes based on 4-N,N-dimethylamino benzoic acid and sterically hindered amines
The adducts of simple chromophore 4-N,N-dimethylamino benzoic acid with 2,2,6,6-tetrametyl-4-hydroxyor 4-amino-piperidine were examined as fluorescence probes (spin double sensors) to monitor radical processes. The links in the adducts were either an ester or amide group, and the sterically hindered amines were in the form of -NH, -NO? and -NOR. The spectral properties of the three related derivatives (esters or amides) were quite similar. The maxima of the absorption spectra were in the range of 295-315 nm, and the maximum of fluorescence was located in the range of 330-360 nm, depending on the polarity of the solvent. In polar solvents, a red-shifted fluorescence band at 460-475 nm was observed. The fluorescence of these derivatives was rather weak as compared to anthracene under the same conditions. The Stokes shift was large, as high as 6,000 cm-1, indicating the formation of a twisted intramolecular charge transfer (TICT) state. No large differences in Stokes shifts were observed in polymer matrices of poly (methyl methacrylate), polystyrene and poly(vinyl chloride). The extent of intramolecular quenching was expressed as φNX/φNO (X=H, NOR) and was in the range of 1-3 in solution and as high as 8 in polymer matrices. The low efficiency of intramolecular quenching limits the application of these new adducts as fluorescence probes for the monitoring of radical processes in solution but favors their application in polymer matrices. Springer Science+Business Media, LLC 2012.
Kósa, Csaba,Danko, Martin,Hrdlovi?, Pavol
p. 1371 - 1381
(2013/01/15)

The first general and selective palladium(II)-catalyzed alkoxycarbonylation of arylboronates: Interplay among benzoquinone-ligated palladium(0) complex, organoboron, and alcohol solvent
Methoxycarbonylation of aryl- and alken-ylboron compounds was performed using the palladium (II) acetate/triphenylphosphine [PdACHTUNGTRENNUNG(OAc) 2/PPh3] catalyst with p-benzoquinone as a stoichiometric oxidant in methanol at ambient temperature to obtain the corresponding methyl esters in good yields. A wide variety of functional groups including various carbonyl functionalities, nitrile, nitro, sulfone, and unprotected pyrrole rings were tolerated in the methoxycarbonlation, while the use of higher alcohols except for tert-butanol afforded various pchlorobenzoates in moderate to high yields. The catalytic alkoxycarbonylation proceeded without any acid or base additive, and an oxidative transmetalation step is proposed to explain the exceptional efficacy of this protocol. DFT and MP2 calculations support the proposed mechanism.
Yamamoto, Yoshihiko
supporting information; experimental part
p. 478 - 492
(2010/07/03)

Design, synthesis, antimicrobial activity and molecular modeling studies of novel benzofuroxan derivatives against Staphylococcus aureus
Molecular modification is a quite promising strategy in the design and development of drug analogs with better bioavailability, higher intrinsic activity and less toxicity. In the search of new leads with potential antimicrobial activity, a new series of 14 4-substituted [N′-(benzofuroxan-5-yl)methylene]benzohydrazides, nifuroxazide derivatives, were synthesized and tested against standard and multidrug-resistant Staphylococcus aureus strains. The selection of the substituent groups was based on physicochemical properties, such as hydrophobicity and electronic effect. These properties were also evaluated through the lipophilic and electrostatic potential maps, respectively, considering the compounds with better biological profile. Twelve compounds exhibited similar bacteriostatic activity against standard and multidrug-resistant strains. The most active compound was the 4-CF3 substituted derivative, which presented a minimum inhibitory concentration (MIC) value of 14.6-13.1 μg/mL, and a Clog P value of 1.87. The results highlight the benzofuroxan derivatives as potential leads for designing new future antimicrobial drug candidates.
Jorge, Salomao Doria,Masunari, Andrea,Rangel-Yagui, Carlota Oliveira,Pasqualoto, Kerly Fernanda Mesquita,Tavares, Leoberto Costa
experimental part
p. 3028 - 3036
(2009/09/08)

Antileishmanial activity screening of 5-nitro-2-heterocyclic benzylidene hydrazides
A series of 53 nitro derivatives rationally designed were obtained by parallel synthesis and screened against Leishmania donovani. Six compounds exhibited IC50 values lower than standard drugs. Brief SAR analysis revealed that substitution is important to the activity. Nitrothiophene analogues were more potent than the nitrofuran ones. This was attributed to the ability of sulfur atoms in accommodating electrons from nitro group, which facilitate its reduction and therefore the formation of free radicals lethal to parasites.
Rando, Daniela G.,Avery, Mitchell A.,Tekwani, Babu L.,Khan, Shabana I.,Ferreira, Elizabeth I.
p. 6724 - 6731
(2008/12/22)

Carboxylation of organoboronic esters catalyzed by N-heterocyclic carbene copper(I) complexes
Copper complexes with a CO2 fixation: Copper(I) complexes serve as excellent catalysts for the carboxylation of aryl- and alkenylboronic esters with CO2, affording a variety of functionalized carboxylic acid derivatives (see scheme). Important active intermediates such as the copper(I) aryl and carboxylate complexes, [(IPr)CuR] and [(IPr)CuOCOR] (R = 4-MeOC 6H4, IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2- ylidene), are isolated and structurally characterized. (Chemical Equation Presented).
Ohishi, Takeshi,Nishiura, Masayoshi,Hou, Zhaomin
supporting information; experimental part
p. 5792 - 5795
(2009/03/11)

Competitive demethylation and substitution in N,N,N-trimethylanilinium fluorides
Fluorination of aromatic compounds by nucleophilic displacement of trimethylanilinium salts by fluoride is a commonly used reaction for radiotracer synthesis. Though the liberated trimethylamine is thought to be an excellent leaving group for this type of SNAr reaction, scattered reports show that amine demethylation (reverse Menschutkin reaction) sometimes dominates over substitution, particularly when relatively electron rich fluoroarenes are the desired targets. Here we provide systematic experimental and theoretical studies of trimethylanilinium demethylation and substitution. Results from these studies highlight the limits of this leaving group in fluoroarene synthesis and have important ramifications for the design of nucleophilic fluorinating agents featuring ammonium cations.
Sun, Haoran,DiMagno, Stephen G.
p. 806 - 812
(2008/03/14)

Selective N,N-dimethylation of primary aromatic amines with methyl alkyl carbonates in the presence of phosphonium salts
In the presence of onium salts, at 140-170 °C. methyl alkyl carbonates [1a-c, ROCO2Me, R = MeO(CH2)2[O(CH 2)2]n; n = 2-0, respectively] react with primary aromatic amines (XC6H4NH2, X = p-OMe, p-Me, H, p-Cl, p-CO2Me, o-Et, and 2,3-Me2C 6H3NH2) to yield the corresponding N,N-dimethyl derivatives (ArNMe2) with high selectivity (up to 96%) and good isolated yields (78-95%). Phosphonium salts (e.g., Ph3PEtI and n-Bu4PBr) are particularly efficient catalysts. Overall, a solvent-free reaction is coupled with safe methylating agents (1a-c) made from nontoxic dimethyl carbonate.
Selva, Maurizio,Perosa, Alvise,Tundo, Pietro,Brunelli, Davide
p. 5770 - 5773
(2007/10/03)

N,N′-Diiodo-N,N′-1,2-ethanediylbis(p-toluenesulfonamide) as a reagent for conversion of aldehydes to methyl esters
N,N′-Diiodo-N,N′-1,2-ethanediylbis(p-toluenesulfonamide) (NIBTS) can be used for the oxidation of aldehydes to the corresponding methyl esters with high efficiency in a single step.
Ghorbani-Vaghei, Ramin,Shahbazee, Elham,Veisi, Hojat
p. 207 - 208
(2007/10/03)

Mono-N-methylation of functionalized anilines with alkyl methyl carbonates over NaY faujasites. 4. Kinetics and selectivity
(Chemical Equation Presented) In the presence of NaY faujasite as the catalyst, the reaction of bifunctional anilines (1-4: XC6H 4-NH2; X = OH, CO2H, CH2OH, and CONH2) with methyl alkyl carbonates [MeOCO2R′: R′ = Me or MeO(CH2)2O(CH2)2] proceeds with a very high mono-N-methyl selectivity (XC6H 4NHMe up to 99%), and chemoselectivity as well, with other nucleophilic functions (OH, CO2H, CH2OH, CONH2) fully preserved from alkylation and/or transesterification reactions. Aromatic substituents, however, modify the relative reactivity of amines 1-4: good evidence suggests that, not only steric and electronic effects, but, importantly, direct acid-base interactions between substituents and the catalyst are involved. Weakly acidic groups (OH, CH2OH, CONH2, pKa ≥ 10) may help the reaction, while aminobenzoic acids (pK a of 4-5) are the least reactive substrates. The solvent polarity also affects the reaction, which is faster in xylene than in the more polar diglyme. The mono-N-methyl selectivity is explained by the adsorption pattern of reagents within the zeolite pores: a BAl2 displacement of the amine on methyl alkyl carbonate should occur aided by the geometric features of the NaY supercavities. Different factors account for the reaction chemoselectivity. Evidence proves that the polarizability of the two nucleophilic terms (NH 2 and X groups) of anilines is relevant, although adsorption and confinement phenomena of reagents promoted by the zeolite should also be considered.
Selva, Maurizio,Tundo, Pietro,Foccardi, Tommaso
p. 2476 - 2485
(2007/10/03)

Intramolecular charge transfer dual fluorescence of p- dimethylaminobenzoates
A series of ester, p-N,N-dimethylaminobenzoates ((CH3) 2NC6H4COOR, R=n-CnH2n+1, n=1,2,...,8), were synthesized and their fluorescence spectra were recorded. Intramolecular charge transfer (CT) dual fluorescence was found in common organic solvent or in water with cetyltrimethylammonium bromide (CTAB) micelle. The fluorescence intensity ratio of CT band to normal band (I CT/ILE) was decreased dramatically with the increasing of carbon number of R group when the carbon number of R group were 1-3, but the dependence was not obvious when the carbon number of R group were 4-8. Oppositely, the ICT/ILE was increased with increasing of carbon number of R group in water with CTAB micelle.
Zhang, Cai-Hong,Chen, Zhao-Bin,Jiang, Yun-Bao
p. 2729 - 2732
(2007/10/03)

Characterization of 2-aryl-1,3,4-oxadiazoles by 15N and 13C NMR spectroscopy
15N NMR chemical shifts of 2-aryl-1,3,4-oxadiazoles were assigned on the basis of the 1H-15N HMBC experiment. Chemical shifts of the nitrogen and carbon atoms in the oxadiazole ring correlate with the Hammett σ-constants of substituents in the aryl ring (r2 ≥ 0.966 for N atoms). 15N NMR data are a suitable and sensitive means for characterizing long-range electronic substituent effects. Additionally, 13C NMR data for these compounds are presented. Copyright
Nowak-Wydra, Barbara,Gierczyk, Blazej,Schroeder, Grzegorz
p. 689 - 692
(2007/10/03)

A simple method removing 2-oxazolidinone and 2-hydroxyethylamine auxiliaries in methoxide-carbonate systems for synthesis of planar-chiral nicotinate
A facile and practical removal of 2-oxazolidinone and 2-hydroxyethylamine auxiliaries was accomplished by treating the corresponding N-acyl-2-oxazolidinone and N-(2-hydroxyethyl)amide derivatives in simple methoxide-carbonate systems. The presence of excess DMC (dimethyl carbonate) accelerates the N-acyl bond cleavage for those substrates under mild reaction conditions, and the present method was found to be useful especially for the synthesis of planar-chiral nicotinate.
Kanomata, Nobuhiro,Maruyama, Satoshi,Tomono, Katsuhito,Anada, Shinnosuke
p. 3599 - 3603
(2007/10/03)

Potential tuberculostatic agents. Topliss application on benzoic acid [(5-nitro-thiophen-2-yl)-methylene]-hydrazide series.
Nitroaromatic compounds such as nifuroxazide are used in many human enteropathogenic bacteria infections without causing an increase in the plasmidial antibiotic resistance of the aerobic Gram-negative intestinal Enterobacteriaceae. For these reasons, these compounds have been synthesized using the rational approach of Topliss' decision tree. Generally, this approach allows us to obtain the most active derivative from the series in a few steps. These compounds were tested against Mycobacterium tuberculosis in vitro and the most active of the series identified. A new lead for potential tuberculostatic activity has been predicted and will be used in further QSAR studies.
Rando, Daniela G,Sato, Dayse N,Siqueira, Leonardo,Malvezzi, Alberto,Leite, Clarice Q F,do Amaral, Antonia T,Ferreira, Elizabeth I,Tavares, Leoberto C
p. 557 - 560
(2007/10/03)

Reductive methylation using decaborane in methanol
Amines (primary and secondary) were methylated to the corresponding tertiary amine using 37% formaldehyde and decaborane in methanol at room temperature under nitrogen in high yields.
Yeon Joo Jung,Jong Woo Bae,Choon-Ock Maing Yoon,Byung Woo Yoo,Cheol Min Yoon
p. 3417 - 3421
(2007/10/03)

Synthesis and biological activity of nifuroxazide and analogs
Nifuroxazide and thirteen analogs were synthesized from substituted benzoic acids and minimal inhibitory concentrations were determined using the serial dilution tests, in three sequential steps. Nifuroxazide and chloramphenicol were used as reference standards. The tests were performed in TSB against the standard bacterial strain of Staphylococcus aureus ATCC 25923.
Tavares,Penna,Amaral
p. 244 - 249
(2007/10/03)

Selective deoxygenation of amine N-oxides using borohydride exchange resin-copper sulfate in methanol
Borohydride exchange resin-copper sulfate in methanol readily deoxygenates quantitatively both tertiary amine N-oxides and heteroaromatic N-oxides at room temperature or under reflux. It tolerates many functional groups such as carbon-carbon double bond, chloride, epoxide, ester, amide, nitrile, sulfoxide, sulfone, and aliphatic disulfide moieties.
Sim, Tae Bo,Ahn, Jin Hee,Yoon, Nung Min
p. 324 - 326
(2007/10/03)

Correlation of Carbon-13 Substituent-Induced Chemical Shifts: meta- and para-Substituted Methyl Benzoates
Carbon-13 NMR spectra are reported for 69 substituted methyl benzoates in deuteriochloroform or in its mixture with dimethyl sulphoxide-d6.The substituent-induced chemical shifts (SCS) of the CO carbon correlate poorly with dual substituent parameters (DSP) in all possible modifications, and for meta derivatives in particular this correlation is both overparameterized and imprecise.A much better correlation was obtained with parameters (designated Bm, Bp and Cp) derived previously by principal component analysis (PCA) from a larger set.The SCS of the CH3 carbon correlate very well with the original simple Hammett equation, and no DSP treatment is needed.The clustering of substituents is not consequential in such a large set.KEY WORDS Methyl benzoates 13C NMR Substituent effects
Budesinsky, Milos,Exner, Otto
p. 585 - 591
(2007/10/02)