ethyl-9',10'-difluoro-7'-oxospiro[cyclopentane-1,3'(2'H)-[7H]pyrido[1,2,3-de][1,4]benzoxazine]-6'-carboxylate → 9',10'-Difluoro-7'-oxo-2'H,7'H-spiro[cyclopentane-1,3'-[1,4]oxazino[2,3,4-IJ]quinoline]-6'-carboxylic acid

Participants

Reaction Steps

A solution of ethyl-9′,10′-difluoro-7′-oxospiro[cyclopentane-1,3′(2′H)-[7H]pyrido[1,2,3-de][1,4]benzoxazine]-6′-carboxylate (13.2 g, 38 mmol) in a mixture of acetic acid/water/H2SO4 (8:6:1 v/v, 75 mL) was heated under reflux for 2 h. The reaction mixture was poured into ice water. A precipitate formed and was collected by filtration, washed with water and then dried to give the title compound (10.5 g, 32.7 mmol, 86%) as a light yellow solid.

Provenance & Evidence