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Pyrrole derivativesPyrrole derivatives R 0120New Ring Expansion of Cyclobutanones: Synthesis of Pyrrolinones, Pyrrolidines and Pyrroles. -Ring opening of 2,2-dichlorocyclobutanones such as (I) with primary amines gives the ω,ω-dichlorobutanamides (III). They can be sequentially converted to the pharmacologically interesting pyrrole dyes in a convenient manner. -(VERNIEST, G.; BOTERBERG, S.; BOMBEKE, F.; STEVENS, C. V.; DE KIMPE*,

2,2-Dichlorocyclobutanones reacted with various amines to give ring opening leading to 4,4-dichlorobutanamides. These compounds proved to be suitable substrates for the synthesis of 3-pyrrolin-2-ones, 2-pyrrolidinones, pyrrolidines and pyrroles.

The recently reported cyclopropane derivatives (I) are used for the preparation of the title compounds. The latter are useful synthons for pyrroles with pharmacologically interesting substitution patterns. -(VERNIEST, G.; CLAESSENS, S.; BOMBEKE, F.; VAN THIENEN, T.; DE KIMPE*, N.; Tetrahedron 61 (2005) 11, 2879-2887; Dep. Org. Chem., Fac. Biosci. Eng., Univ. Gent, B-9000 Gent, Belg.; Eng.) -Nuesgen 30-095