p-nitrobenzoic acid promoted synthesis of 1,5-benzodiazepine derivatives

Abstract

Entre vários ácidos carboxílicos testados, o ácido p-nitrobenzóico mostrou ser o mais versátil para a preparação de derivados de 1,5-benzodiazepinas a partir de uma série de ofenilenodiaminas substituídas e cetonas. Os produtos foram obtidos em bons rendimentos (62-92%) sob condições brandas, usando acetonitrila como solvente, a temperatura ambiente. Adicionalmente, o reagente pode ser facilmente recuperado e re-utilizado. p-Nitrobenzoic acid was found to be the versatile Bronsted organic acid promoter among the carboxylic acids tested for the preparation of 1,5-benzodiazepine derivatives from a wide range of substituted o-phenylenediamines and ketones. The corresponding products were obtained in good isolated yields (62-92%) under mild conditions using acetonitrile as solvent at ambient temperature. Further, the reagent could be easily recovered and reused.

Investigation of Various Organocatalysts for Improved and Efficient One Pot Synthesis of 2,3-Dihydro-1H-1,5-benzodiazepines Under Solvent-Free Condition

“…In particular, 1,5-benzodiazepines are useful precursors for the synthesis of fused ring benzodiazepine derivatives such as triazolo, oxadiazolo, oxazino, furano benzodiazepines 2 . More recently their use has been extended to various diseases such as cancer, viral infections (non-nucleoside inhibitors of HIV-1 reverse transcriptase) and cardiovascular diseases 3 .…”

Rapid and Efficient Synthesis of 2,3-Dihydro-1H-1,5-Benzodiazepines Catalyzed by Chloroacetic Acid Screened among Various Aliphatic Acids

“…The wide range of applications of benzodiazepines has attracted many researchers and various methods are known for their synthesis using different catalysts under different conditions. These methods include condensation of o-phenylenediamine and ketones in the presence of a variety of catalysts like p-toluenesulfonic acid 8 , silica sulfuric acid 9 , p-nitro benzoic acid 10 , sodium tetrachloroaurate(III) dehydrate 11 , AlCl 3 12 , polyethylene glycol 13 . But these methods involve many limitations like tedious work up procedure, producing undesired washes, applications of expensive catalyst and reagents, long reaction times, unsatisfactory yield; require separation of the catalyst from the product and formation of side products.…”

SiO2/H2SO4: An Efficient Catalytic System for Solvent-free 1, 5-benzodiazepines Synthesis

“…A variety of reagents, such as BF 3 -etherate, NaBH 4 , polyphosphoric acid, MgO/POCl 3 , Yb(OTf) 3 , Sc(OTf) 3 , Al 2 O 3 /P 2 O 5 , or AcOH are utilized for this condensation reaction (9). Most recently, this condensation reaction has also been reported to proceed in the presence of CAN, (bromodimethyl) sulfonium bromide, AgNO 3 , NBS, organic acids such as p-nitrobenzoic acid, montmorillonite K10, PPA, 2,4,6-trichloro-1,3,5-triazine (TCT), sulfanilic acid, ZrOCl 2 , MgBr 2 and Ga(OTf) 3 (10-13). …”