Spirocyclopropane compounds. I. Synthesis and reactivity of spiro(cyclopropane-1,2'-(2H)indol)-3'(1'H)-ones.

Abstract

A spirocompound, 1'-acetylspiro [cyclopropane-1, 2'-[2H] indol]-3'(1'H)-one (III-1), was synthesized from anthranilic acid in three steps, which involve the condensation of anthranilic acid with α-bromo-γ-butyrolactone, followed by spiroannelation with acetic anhydride and triethylamine, and subsequent decarboxylation in the presence of sodium chloride to afford III-1 in good yield. Various derivatives (III-2-III-9) were similarly prepared. Some compounds of this series showed an intense fluorescence in solution. The reactivities of III-1 to electrophiles and nucleophiles, as well as its reaction with reducing agents, were investigated.