Lipase‐Catalyzed Acetylation of 3‐Substituted 2,3‐Dihydro‐1H‐1,4‐benzodiazepin‐2‐ones: Effect of temperature and conformation on enantioselectivity and configuration

Abstract

Enantioselectivity of acetylation by vinyl acetate/AcOEt catalyzed by immobilized Cundidu untarctica lipase (Noi~o:~.m 435) is studied for ruc-3-(hydroxymethyl)-I .4-benzodiazepin-2-ones 7, 9, 14 ( n = 1 ; number of CH, groups i n the chain at C(3)), 20 ( n = 2), and for prochiral 3,3-bis(hydroxymethyI) derivative 16. Enantiomeric

How the mode of Candida antarctica lipase B immobilization affects the continuous-flow kinetic resolution of racemic amines at various temperatures

“…Occasionally, temperature had no effect on enantioselectivity [28], whereas in other cases a maximum of enantioselectivity at a certain temperature was found [29]. Effect of the temperature on selectivity in CaLB-catalyzed hydrolysis [30][31][32][33], ammonolysis [34], direct esterification [35,36], enantioselective acylation of prochiral diols [37] and kinetic resolution of alcohols [29,38,39] has already been reported. In most of the quoted examples the enzyme-catalyzed reactions were performed in batch mode (in stirred or shaken flasks).…”

Experimental and Computational Studies of Ring Inversion of 1,4-Benzodiazepin-2-ones: Implications for Memory of Chirality Transformations

“…Structurally related enantiopure 3,3-disubstituted "quaternary" benzodiaz- epines have rarely been explored, [15][16][17][18] despite their potential usefulness, due to the fact that the corresponding quaternary amino acids 19 are generally not commercially available. 20,21 To enable the enantioselective syntheses of "quaternary" benzodiazepines, we have recently reported an enantioselective R-alkylation route 22 that relies upon a "memory of chirality" mechanism. [23][24][25][26][27][28][29] Our approach is shown in Scheme 1: the parent 1,4benzodiazepin-2-one (henceforth BZD) 2 is synthesized from the corresponding proteinogenic amino acid 1 using a modification of Shea's protocol.…”

Synthesis of Substituted 3‐Anilino‐5‐phenyl‐1,3‐dihydro‐ 2H‐1,4‐benzodiazepine‐2‐ones and their Evaluation as Cholecystokinin‐Ligands

“…Various approaches towards oxazepam were available, such as the oxidation of the 3-position of diazepam [27]. Oxazepam was claimed to be synthesized via the known Polonowski rearrangement of the N-oxide on an industrial scale [28].…”