Crystal Structure of 2,4-Dimethyl-1,5-BenzodiazepiniumHydrogensulfate

摘要

2,4-Dimethyl-1,5-benzodiazepine (1) can be easily synthesized by reacting1,2-phenylenediamine and acetylacetone without solvent using H2SO4.SiO2 as a catalyst.1The benzodiazepine skeleton is known as a considerable bio-active heterocycle and istherefore an important molecular structure in biology and pharmacy.2,4-Dimethyl-1,5-benzodiazepinium cation (1H~+) having quasi-aromaticity can be easily obtained byprotonation of 1.2 Quasi-aromaticity was described in 1971 by Lloyd and Marshall as theproperty of the diazepinium cation.Several crystal structures of 2,4-dimethyl-1,5-benzodiazepinium salts (1H~+·X~-[X~-= PF_6~(-3),Cl~(-4),ZnI_4~(2-5)]) have been reported so far.Molecular structures of their cation are almost planer because of electronic delocalization inthe N-C-C-C-N moiety of seven-membered ring.We herein report that the crystal structureof 2,4-dimethyl-1,5-benzodiazepinium hydrogensulfate (1H~+·HSO_4~-).