Fluorocarbon derivatives of nitrogen. Part 17. Oxidation of unsymmetrical polyfluorinated diareno-1,2-diazepines. X-Ray molecular structures of 1,3,4-trifluoro-7,9-dimethyl-11H-pyrido[4,3-c][1,2]benzodiazepine 5-oxide and 5,6-dioxide

Abstract

1,3,4-Trifluoro-7,9-dimethyl-11H-pyrido[4,3-c][1,2]benzodiazepine 5- and 6-oxide (7) and (6) and 5,6-dioxide (8) have been synthesized via oxidation of the parent diazepine (1) with 30% H₂O₂–AcOH and/or 85% H₂O₂–(CF₃CO)₂O–CH₂Cl₂. Use of chromic anhydride as the oxidant in boiling glacial acetic acid gave 1,3,4-trifluoro-7,9-dimethylpyrido[4,3-c][1,2]benzodiazepin-11-one, 1,3,4-trifluoro-7-methyl-11H-pyrido[4,3-c][1,2] benzodiazepine-9-carboxylic acid, and 1,3,4-trifluoro-7-methyl-11-oxopyrido[4,3-c][1,2]benzodiazepine-9-carboxylic acid. 1,3,4-Trifluoro-7,9-dimethyl-2-trifluoromethyl-11H-dibenzo[c,f][1,2]diazepine 5- and 6-oxide, 5,6-dioxide, and 1,3,4-trifluoro-7,9-dimethyl-2-(trifluoromethyl)dibenzo[c,f][1,2]diazepin-11-one plus 1,3,4-trifluoro-7-methyl-2-trifluoromethyl-11H-dibenzo[c,f][1,2]diazepine-9-carboxylic acid have been prepared similarly starting from 1,3,4-trifluoro-7,9-dimethyl-2-trifluoromethyl-11H-dibenzo[c,f][1,2]diazepine (2). Oxidation (30% H₂O₂–AcOH) of trans-tetrafluoro-4-(2,4,6-trimethylphenylazo)pyridine gave trans-2,3,5,6-tetrafluoro-4-(2,4,6-trimethylphenyl-ONN-azoxy)pyridine almost quantitatively. X-Ray crystallographic data for 1,3,4-trifluoro-7,9-dimethyl-11H-pyrido[4,3-c][1,2]benzodiazepine 5-oxide (7) and the corresponding 5,6-dioxide (8) are presented, as are details of n.m.r. analyses (¹³C, ¹H, ¹⁹F, and ¹⁵N) carried out on the parent diazepines (1) and (2) and their various oxidation products.