Jp. Michael et al., Reformatsky reactions with N-arylpyrrolidine-2-thiones: synthesis of tricyclic analogues of quinolone antibacterial agents, TETRAHEDRON, 57(47), 2001, pp. 9635-9648
A convenient synthesis of 5-oxo-1,2,3,5-tetrahydropyrrolo[1,2-a]quinoline-4
-carboxylic acids, tricyclic analogues of the quinolone antibiotics, is des
cribed. Key steps in the route are a novel zinc-mediated Reformatsky reacti
on between diethyl bromomalonate and N-arylpyrrolidine-2-thiones 18, and cy
clisation of the resulting diethyl pyrrolidinylidenemalonate intermediates
19 in polyphosphoric acid. The products proved to be devoid of biological a
ctivity. (C) 2001 Elsevier Science Ltd. All rights reserved.