Abstract
The bromination reaction of 2‐ethoxycarbonyl‐4‐methyl‐4‐substituted butanolides has been studied, and it has been established that bromination with equimolar quantity of bromine in dry carbon tetrachloride was obtained in good yields of 2‐ethoxycarbonyl‐2‐bromo‐4‐methyl‐4‐substituted butanolides. The interaction of the latter with thiourea and substituted thioureas has been investigated. It has been shown that under conditions of Hunch's reaction, as a result of heterocyclization were obtained spiroheteryl‐joint lactones of a new generation—2‐aza‐3‐amino or substituted amino‐4‐thia‐7‐oxa‐8‐methyl‐8‐substituted spiro[4,4]‐2‐, nonene‐1,6‐diones.