A Novel Route to the 5,6‐Dihydro‐4H‐thieno[3,2‐b]pyrrol‐5‐one Ring System Involving an Intermediate Substituted‐Thiophene Synthesis.

Abstract

Pyrrole derivatives R 0120A Novel Route to the 5,6-Dihydro-4H-thieno[3,2-b]pyrrol-5-one Ring System Involving an Intermediate Substituted-Thiophene Synthesis. -The concise, three-step route to thienopyrrolones and related ring-fused derivatives employs readily available substituted acrylonitriles like (I) or suitably derivatized heterocycles in a condensation reaction with ethyl mercaptopyruvate (II). The final heterocycles, e.g. (V), are generated via a subsequent reduction and lactamization process. The generality of this protocol is established by investigating the reactivity of (II) with a range of α-or β-halo-substituted acrylonitriles, e.g. (VI) and (VIII), because this step is anticipated to be the key determinant of the overall efficiency. -(HU*, S.; HUANG, Y.; POSS, M. A.; GENTLES, R. G.; J. Heterocycl. Chem. 42 (2005) 4, 661-667; Discovery Chem., Bristol-Myers Squibb Pharm. Res. Inst., Wallingford, CT 06492, USA; Eng.) -H. Hoennerscheid 41-110