ABSTRACT
A facile strategy for the preparation of A-ring fused pyridosteroids has been accomplished in high yields by the reaction of Vilsmeier reagent (chloromethyleneiminium salt) with steroidal A-ring enamides (2- and 3-ene) under thermal conditions. The structure of 6'-chloro-5alpha-cholest [3,2-b]pyridine was determined by X-ray analysis.
Subject(s)
Chemistry, Organic/methods , Pyridines/chemistry , Pyridines/chemical synthesis , Steroids/chemistry , Steroids/chemical synthesis , Anaerobiosis , Crystallography, X-Ray , Hot Temperature , Molecular ConformationABSTRACT
The preparation of 3-oxo-4-azasteroid from A-nor-3,5-secosteroid-3-oic acid is described in a solventless condition catalysed by Lewis acid under microwave irradiation. We utilized urea as an environmentally benign source for the generation of ammonia for the aza cyclization reaction.
Subject(s)
Acids/chemistry , Azasteroids/chemical synthesis , Microwaves , Solvents/chemistry , Azasteroids/chemistry , Catalysis , Spectroscopy, Fourier Transform InfraredABSTRACT
The preparation of ring-A fused steroidal dehydropiperazine at the 3,4-position is herein described. The novel steroidal dehydropiperazines were prepared from the annulation reaction of ethylenediamine with 3-keto-4-en steroids in a one-pot reaction under microwave irradiation. The key step involves base catalysed aerial oxidation of the C-6 methylene group followed by cyclocondensation of ethylenediamine via Michael addition reaction.
