7-oxo-7h-pyrido(1,2,3-de)(1,4)benzoxadine-6-caroxylic acid and its ester

PURPOSE: To obtain the subject new compounds useful in treating infectious diseases caused by hepatitis virus, cytomegarovirus, HIV virus or the like. CONSTITUTION: A compound shown by formula I. e.g. ethyl 9,10-difluoro-2-(2- methoxy-phenyl)-7-oxo-7H-pyrido(1,2,3-de) (1,4)benzoxadine-6-carboxylate, is obtained by reacting a compound of formula III (T is a halogen) with a compound denoted by the formula R 1 -H in an inert solvent in the presence of a base such as triethylamine or the like. In formula I, R 1 is a halogen, 1- piperidinyl, formula II (A is O, CH 2 or the like; R 5 , R 6 are each H, cyclohexyl, phenyl, a 1-4C alkyl or the like) or the like; R 2 is H, a 1-4C perfluoroalkyl, a (substituted) 1-6C alkyl or the like; R 3 is H, phenyl, trifluoromethyl or the like; R 4 is H, a 1-4C alkyl. COPYRIGHT: (C)1994,JPO