HIMBACINE ANALOGUE HAVING ALIPHATIC HETEROGENEOUS RING

PROBLEM TO BE SOLVED: To provide a new hydronaphtho[2,3-c]furan derivative exhibiting a strong and selective antagonistic activity against muscarine M2receptors and a physiologically acceptable acid adduct salts thereof, to provide a method for producing the same, and to provide an Alzheimer's disease medicine containing the same as an active ingredient. SOLUTION: This hydronaphtho [2,3-c]furan derivative having aliphatic heterogeneous ring represented by the general formula (1) (R1and R2are each identically or differently H or a lower alkyl; R3is H, a lower alkyl or a substituted or unsubstituted aralkyl; A is combined with R4to form a group represented by the general formula (2); R4is a 5 to 14-membered heteroaliphatic ring which may have one or more substituents and may contain one or more heterogeneous atoms such as O, N, and S; R5and R6together express an oxygen atom or the like, and an acid adduct salt thereof. COPYRIGHT: (C)2003,JPO