A Novel (3 + 2) Annulation: Synthesis and X-Ray Crystallographic Structure of a Novel Tetrahydropyrazolo(1,5-a)quinoline, an Intermediate Towards New Tricyclic Quinolone Antibacterials.

The synthesis and X-ray crystallographic structure of tetrahydropyrazolo[1,5-a]quinoline 10, an intermediate for novel DNA gyrase inhibitors, via a tandem 1,4-conjugate addition-Michael ring closure protocol are described.