Hydrochloric Acid → 2-chloro-11-fluoro-6H-pyrido[2',3':5,6][1,3]oxazino[3,4-a]indole-6-carboxylic acid

Temperature

80 °C

A mixture of ethyl 2-chloro-11-fluoro-6H-pyrido[2′,3′:5,6][1,3]oxazino[3,4-a]indole-6-carboxylate (606 mg, 1.75 mmol) and LiOH (168 mg, 7.00 mmol) in dioxane/H2O (6 mL/5 mL) was stirred at 80° C. for 2 hours. The reaction was monitored using TLC. When the reaction was completed, the mixture was adjusted to pH 4-5 with 1 N HCl aqueous. The mixture was extracted with EtOAc (10 mL*3). The combined organic layer was washed with brine (30 mL), dried over Na2SO4 and concentrated under reduce pressure, afforded the desired product of 2-chloro-11-fluoro-6H-pyrido[2′,3′:5,6][1,3]oxazino[3,4-a]indole-6-carboxylic acid (crude: 590 mg, yield: 99%). 1H-NMR (400 MHz, DMSO-d6) δ 7.74 (d, J=8.6 Hz, 1H), 7.56˜7.43 (m, 2H), 7.37 (s, 1H), 7.34˜7.25 (m, 1H), 7.15 (s, 1H), 7.02˜6.92 (m, 1H). MS (M+H)+: 319.

1. extractionThe mixture was extracted with EtOAc (10 mL*3)
2. washThe combined organic layer was washed with brine (30 mL)
3. dry with materialdried over Na2SO4
4. concentrationconcentrated

ORD record

ord-b2147a6486bd404786b154e17e813c1f

Source dataset

uspto-grants-2016_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09265773B2