Patent ID: 7115736

Claim:
A process for preparing an imidazopyran derivative of the following formula (9), wherein R 1 is halogen atom, hydrogen atom, C 1 –C 3 alkyl group, aryl group, or C 1 –C 3 alkyl group substituted by aryl group, which comprises reacting dinitroimidazole of the following formula (1), wherein R 1 is the same as defined above, with 2,3-epoxy-1-propanol of the following formula (2), in the presence of a fluoride salt to prepare a diol compound of the following formula (3), wherein R 1 is the same as defined above, reacting this compound (3) with a silyl halide of the following formula (4), R 2 R 3 R 4 SiX (4) wherein R 2 , R 3 and R 4 are independently C 1 –C 6 alkyl group, aryl group or C 1 –C 3 alkyl group substituted by aryl group, and X is halogen atom in the presence of a base to prepare a compound of the following formula (5), wherein R 1 , R 2 , R 3 and R 4 are the same as defined above, reacting this compound (5) with a compound of the following formula (6), R 5 COY (6) wherein R 5 is aryl group or C 2 –C 4 alkenyl group substituted by aryl group, and Y is hydroxy group, halogen atom or alkoxy group, to prepare a compound of the following formula (7), wherein R 1 , R 2 , R 3 , R 4 and R 5 are defined above, desilylating and cyclizing this compound (7) to prepare a compound of the following formula (8), wherein R 1 and R 5 are the same as defined above, and then deprotecting this compound (8) in the presence of metallic catalyst to prepare above imidazopyran derivative (9).