Heterocyclic compounds. X. A new synthesis of thiadiazasteroids

The reaction of ν‐ketoacids or ν‐aldehydo acids with o‐amino amides results in the formation of 4‐quinazolones. Using this reaction a number of polyheterosteroid analogs were synthesized. Thus, when 2‐amino‐3‐carboxamido‐4,5,6,7‐tetrahydrobenzothiophene (9) was refluxed with levulinic acid (10) in a high boiling solvent, thiadiazasteroid analog (11) was obtained in 78% yield. It was found that this facile one‐step reaction could be used to synthesize a variety of tetra and pentacyclic compounds. Nmr spectroscopy was used to assign stereochemistry to the 17‐methyl “steroids” (31) and (32).