Intramolecular 1,3-dipolar cycloaddition as a route to triazolobenzodiazepines and pyrrolobenzodiazepines

摘要

Intramolecular 1,3-dipolar cycloaddition between an alkyne and an azide leads to a series of 1,2,3-triazolo-fused 1,4-benzodiazepines, 1,2,5-benzothiadiazepines, pyrrolobenzodiazepines and pyrrolobenzothiadiaze-pines (eight examples). The products are privileged structures in medicinal chemistry. The precursor azido alkynes are obtained, usually as transient intermediates, by treatment of the corresponding aldehydes (derived from α-amino acids) with the Bestmann-Ohira reagent.