New chromene derivatives useful as phosphodiesterase IV inhibitors

摘要

Chromene compounds of formula (I), their salts and pyridyl N-oxides are new: R1 = 1-4C alkoxy (optionally partially or fully fluorinated); R2, R3 = H, 1-7C alkyl, 3-7C cycloalkyl or 3-7C cycloalkylmethyl; or CR2R3 = 3-7C cycloalkyl; R3a, R3b = H; or R3a+R3b = a C-C bond; R4 = H or OH; R5 = H; or R4+R5 = a C-C bond; R6 = H or CN; and R7 = pyridyl.