Photochemical reactivity of α,β‐unsaturated δ‐lactams: Synthesis of seco‐steroids. Photochemical reactions. XIII [1]

Abstract

SummaryThe UV. irradiation of 17P-hydroxy-2-aza-4-androsten-3-one (l), N-methyl-17~-hydroxy-2-aza-4-androsten-3-one (3), 17~-hydroxy-4-aza-5~-androst-l -en-3-one (2) and N-methyl-17~-hydroxy-4-aza-5P-androst-l -en-3-one (4), gives rise to 1,lO-seco (from 1 and 3 ) and 5,lO-seco (from 2 and 4) steroids.Introduction. -Although in photochemical studies, lactams have received less attention than lactones and ketones, several examples can be found. Monocyclic [2] and bicyclic [3] compounds yield mainly fragmentation and sometimes [2b] dimerization products and the di-n-methane rearrangement of a lactam has been observed [4]. In the steroid field, several unsaturated lactams have been investigated. Enamidic lactams undergo photooxidation [5 J or photoisomerization [6], and A-homolactams yield mainly dimers [7]. Owing to the little work done on n,a-unsaturated 8-lactams, we decided to investigate the photolytic behaviour of lactams 1 , 2 , 3 and 4 (Scheme I).