反应详情

(E)-3-[4-(tert-Butoxycarbonyl)-3,4-dihydro-2H-pyrido[3,2-b]-1,4-oxazin-7-yl]acrylic acid (1.17 g, 2.95 mmole) was dissolved in 4 N HCl in dioxane (15 mL). After 72 hr the mixture was concentrated. The residue was taken up in 1:1 MeOH/H2O (20 mL). 1.0 N LiOH (15 mL, 15 mmole) was added and the mixture was heated to reflux. After 18 hr the mixture was cooled to RT and concentrated to approximately ⅓ volume. The mixture was adjusted to pH 6 using 10% HCl. The solid was collected by filtration, washed with H2O and dried in vacuo to give the title compound (315 mg, 52% over 2 steps): MS (ES) m/e 207 (M+H)+.

1. concentrationAfter 72 hr the mixture was concentrated
2. temperaturethe mixture was heated to reflux
3. concentrationconcentrated to approximately ⅓ volume
4. filtrationThe solid was collected by filtration
5. washwashed with H2O
6. customdried in vacuo