Synthesis of 1,5‐Benzodiazepine Derivatives Catalyzed by Zinc Chloride.

Abstract

Multi-membered N-heterocycles R 0690 Synthesis of 1,5-Benzodiazepine Derivatives Catalyzed by Zinc Chloride. -Zinc chloride is a useful catalyst for the cyclocondensation of ketones with o-phenylenediamine. -(PASHA*, M. A.; JAYASHANKARA, V. P.; Heterocycles 68 (2006) 5, 1017-1023; Dep. Stud. Chem., Cent. Coll., Bangalore Univ., Bangalore 560 001, India; Eng.) -Mais 40-176

SiO2-NaHSO4 as an Efficient Reusable Heterogeneous Catalyst for the One-Pot Three-Component Synthesis of Octahydro-quinazolin-2,5-diones in Water

“…Furthermore, SiO 2 -NaHSO 4 has been used in the protection of aldehydes with 2-mercaptoethanol [18]. In a continuation of our work into the synthesis of biologically active heterocyclic compounds using readily available, inexpensive, and environment friendly catalysts [21][22][23][24][25][26], herein we are report the synthesis of octahydro-quinazolin-2,5-diones by the one-pot multi-component reaction of aromatic aldehydes, dimedone, and urea using SiO 2 -NaHSO 4 as an efficient catalyst in water. We have found that SiO 2 -NaHSO 4 catalyzes the reaction between aromatic aldehydes, dimedone, and urea in an aqueous medium efficiently to afford the desired products in excellent yield within 1-2 h. The catalyst can be easily prepared [18] and safely handled, making the method more advantageous over other conventional methods and catalysts.…”

A Novel Method for Synthesis of Bis(indolyl)methanes Using 1,3-Dibromo-5,5-dimethylhydantoin as a Highly Efficient Catalyst Under Solvent-free Conditions

“…of indole with the carbonyl groups. Various Brönsted acids, [6][7][8] Lewis acids, 9-11 heterogeneous acidic catalyst,…”

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.…”