Preparation of some light-sensitive 2-nitrophenyl-2,3-dihydro-1H-benzodiazepines

Lewis Acid‐Mediated Ring Contraction of 2,4‐Diaryl‐2,3‐dihydro‐1H‐1,5‐benzodiazepines: Access to 2‐Aryl‐1‐styrylbenzimidazoles

“…The results supported our identification on the structure of the major product 1m , because the electron‐rich 4,5‐dimethylbenzene‐1,2‐diamine favorably underwent the Michael addition and subsequent imine formation. Although it was reported that the reaction of 4‐methylbenzene‐1,2‐diamine and chalcone produced 8‐methyl‐2,4‐diphenyl‐2,3‐dihydro‐1 H‐ 1,5‐benzodiazepine ( 1m′ ) only in a previous paper, [22] on the basis of our results, the reaction does generate two regioisomeric products 1m and 1m′ . Moreover, the substrates 1n and 1o generated the corresponding products 2n and 2o in 66 % and 50 % yields, respectively, under the standard reaction conditions.…”

“…However, the two regioisomers 1m and 1m′ cannot be separated on common silica gel column and were subjected to the standard reaction conditions, resulting in formation of mixed products 2m and 2m′ in a total yield of 69 %. 7,8‐Dimethyl‐ and 7,8‐dichloro‐2,4‐diphenyl‐2,3‐dihydro‐1 H‐ 1,5‐benzodiazepines ( 1n and 1o ) were prepared in 57 % and 18 % yields from 4,5‐dimethyl and 4,5‐dichlorobenzene‐1,2‐diamines with chalcone [22,23] . The electron‐rich 4,5‐dimethylbenzene‐1,2‐diamine showed better reactivity than the electron‐deficient 4,5‐dichlorobenzene‐1,2‐diamine in the formation of substrates 1n and 1o .…”

“…Subsequently, to further examine the influence of the substituent on the benzo ring, the substrates 1m-1o with different substituents on the benzo ring were prepared. [10,22,23] A mixture of regioisomeric 7-and 8methyl-2,4-diphenyl-2,3-dihydro-1H-1,5-benzodiazepines (1m and 1m') was obtained in 35 % yield in a ratio of 3 : 2 from 4-methylbenzene-1,2-diamine and chalcone. The structure of major product 1m was identified on the basis of the formation mechanism of 2,3-dihydro-1H-1,5-benzodiazepines.…”

Chalcone‐inspired rA1/A2A adenosine receptor ligands: Ring closure as an alternative to a reactive substructure

“…For the same reasons, compound 3c was prepared at a low temperature and in the absence of light and oxygen, otherwise following the methods described by El Shehry et al ( 2010) and Moustafa (2003). A previously reported synthetic route also guided the preparation of the benzodiazepines (3b and 4b; Rodriguez et al, 2004). As o-PDA is moisture-and light-sensitive, as well as incompatible with strong oxidising agents (Sigma-Aldrich, 2020c), reactions were performed in the absence of light (as previously reported) and oxygen.…”

Wells-Dawson Type Catalyst: An Efficient, Recoverable and Reusable Solid Acid Catalyst for the Solvent-Free Synthesis of Benzodiazepines

“…Among the group of heterocyclic heptagonal molecules are benzodiazepines, bicyclic compounds which possess a benzene ring attached to a heptagonal heterocyclic ring with two nitrogen atoms in their structure. These compounds have been previously tested for their medical use as anxiolytic, anti-inflammatory, sedative, antidepressant [1], antifungal, and antibacterial agents [2]; benzodiazepines are also used as insecticides and herbicides [3][4][5], and as light-sensitive fibers in photography [6].…”