Stereochemistry of N_5-acyltetrahydro-1,5-benzodiazepines-NMR spectra and semiempirical MO calculations

摘要

The conformational preferences of N_5-acyltetrahydro-1,5-benzodiazepines 3-5 have been studied using NMR spectral techniques and semiempirical MO calculations(AMI and PM3 methods).The N_5-formyl-,N_5-acetyl-and N_5-benzoyl-tetrahydro-2-methyl-2,4-diphenyl-1H-1,5 benzodiazepines 3-5 prefer boat conformations BE with exo orientation of the acyl groups at N_5.The X-ray crystal structure of N_5-acetyl derivative 4 also shows a boat conformation BE with exo orientation of acetyl group at N_5.The results obtained from semiempirical MO calculations(AMI and PM3)are in excellent agreement with the results obtained from solution and solid states.