4-Methylmorpholine → Methyl 4-[6-(cyclopentyloxycarbonyl) amino-2,3-dihydrobenz-1,4-oxazin-4-ylmethyl]-3-methoxybenzoate

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Reaction Steps

Cyclopentyl chloroformate (0.5 g.) was added in a single portion to a stirred solution of methyl 4-(6-amino-2,3-dihydrobenz-1,4-oxazin-4-ylmethyl)-3-methoxybenzoate (L) (1.0 g.) and N-methylmorpholine (0.314 g.) in dichloromethane (30 ml.), under an atmosphere of nitrogen. After one hour, the mixture was diluted with dichloromethane and washed successively with 1M hydrochloric acid, 5% w/v sodium bicarbonate solution, and saturated brine, then dried (MgSO4) and evaporated. The residue was purified by flash chromatography on silica gel (4 cm. diameter column), eluting with dichloromethane to give the title compound (0.7 g, 52%) as an oil; NMR (80 MHz, CDCl3): 1.69[m,8H, (CH2)4 ], 3.39(t,2H, OCH2CH2N), 3.90(s,3H, OCH3), 3.91 (s,3H, OCH3), 4.23(t,2H, OCH2CH2H), 4.45(s,2H, CH2.AR), 5.10(m,1H, --CHO--), 6.2(br s,1H, NHCO), 6.59-7.62(m,6H).

Provenance & Evidence