Pyridine → HCID 13816784, compound

Participants

Reaction Conditions

Reaction Steps

One gram of (±)-9,10-difluoro-3-hydroxymethyl-7-oxo-2,3-dihydro-7H-pyrido[1,2,3-de][1,4]benzoxazine-6-carboxylic acid ethyl ester (I) and 500 mg of pyridine were suspended in 100 ml of anhydrous tetrahydrofuran (THF), and 1.6 g of 3,5-dinitrobenzoyl chloride was added thereto, followed by refluxing at 90° C. The suspension was once dissolved, and a colorless precipitate was then formed. The reaction was continued for 1.5 hours. After cooling, the precipitate was collected by filtration, washed with methanol and diethyl ether and dried to obtain 1.2 g of (±)-9,10-difluoro-3-(3,5-dinitrobenzoyloxy)methyl-7-oxo-2,3-dihydro-7H-pyrido[1,2,3-de][1,4]benzoxazine-6-carboxylic acid ethyl ester (II) as a colorless powder having a melting point of 240°-242° C. NMR (CDCl3 /5% DMSO-d6) δ(ppm); 1,30 (3H, t, J=7.0 Hz, --CH2CH3), 4.26 (2H, q, J=7.0 Hz, --CH2CH3), 4.4-4.5 (5H, m), 7.76 (1H, dd, J=11.0 Hz, 7.0 Hz, C8 -H), 8.8 (1H, s, C5 -H), 9.0 (2H, d, J=3.0 Hz, aromatic ring proton) and 9.2 (1H, t, J=3.0 Hz, aromatic ring proton).

Provenance & Evidence