MeCO-CH,*CH,SmR. Me*COCH,-CH,*CH*CO*Me I (1) C H ,-S*R (11) [R = -C H,.C H (NH ,)*CO,H] two singlets at 'C 7.78 and 7.73 (two different C-Me groups), a doublet centred at T 7.18 (-COCH,-), a multiplet at T 7.06 (-SCH,-) and a triplet at T 5.57 ()CH-NH,) . Although cyclisation and dehydration of (I) to a 1,4-thiazepine is possible, no such compound was isolated. However, the equimolar reaction between methyl vinyl ketone and 2-mercapoethylamine ...