Yield:115661-89-7 73%

Reaction Conditions:

with boron trichloride in 1,2-dichloro-ethane;

Steps:

88 EXAMPLE 88

EXAMPLE 88 To 5 ml of a solution of 2.02M of boron trichloride in 1,2-dichloroethane was added 1.35 g of 3,4-dihydro-2H-1,4-benzoxazine in 10 ml of 1,2-dichloroethane under ice-cooling, and further a solution of 0.82 ml of methyl thiocyanate and 2.9 ml of n-tributylamine in 10 ml of 1,2-dichloroethane was added dropwise to the mixture within 6 min. After stirring at room temperature for 5 hr., the mixture was poured into 60 ml of saturated aqueous sodium hydrogencarbonate and stirred at 110° C. on an oil bath. After evaporating 1,2-dichloroethane, the mixture was stirred for 1 hr. at the same temperature. After cooling, the reaction mixture was extracted with toluene, washed with dilute HCl and water and dried over anhydrous magnesium sulfate. Under reduced pressure toluene was evaporated. The residue was chromatographed on a column of silica gel and the elude with methylene chloride was evaporated and recrystallized from ether--petroleum ether to give 1.17 g of 8-cyano-3,4-dihydro-2H-1,4-benzoxazine as white crystals melting at 79°-80° C. Yield: 73% Anal Calcd (%) for C₉ H₈ N₂ O: C, 67.48; H, 5.03; N, 17.49; Found (%): C, 67.72; H, 5.16; N, 17.58. IR (CHCl₃): 3430, 2214 cm^-1.

References:

US4774331,1988,A