1,6-Naphthyridine derivatives, and antidinic and cerebral circulation
申请人:Nippon Kayaku Kabushiki Kaisha
公开号:US04308273A1
公开(公告)日:1981-12-29
This invention relates to the novel 1,6-naphthyridine derivatives useful as antidinic and/or cerebral circulation improver, such novel derivatives being represented by the following general formula: ##STR1## (wherein R is a C.sub.2-10 alkyl which may have hydroxyl, lower alkylcarbonyl, lower alkyloxycarbonyl or phenoxy as a substituent; a C.sub.2-10 unsaturated aliphatic hydrocarbon group having unsaturated double bond(s); a phenyl-lower alkyl which may have halogen, lower alkyl, lower alkoxy or lower alkylthio as substituent(s) attached to the phenyl ring; a cinnamyl which may have halogen, nitro, lower alkyl or lower alkoxy as substituent(s) attached to the phenyl ring; propargyl; 1-naphthylmethyl; 2-thenyl; cyclohexenyl; a cycloalkyl-lower alkyl with a 3- to 6-membered ring; 1/2(C.sub.2-4 alkylene); 1/2(butenylene), or diphenylmethyl, and in case two alkoxyl groups are present attached to the phenyl ring, they may be bonded to form a ring) and salt thereof.
A number of 6-substituted 5, 6, 7, 8-tetrahydro-1, 6-naphthyridines designed as cyclic homologues of betahistine, 2-(2-methylaminoethyl) pyridine, were synthesized by the reduction of the corresponding 1, 6-naphthyridinium salts. The antivertigo activity of these derivatives was evaluated in terms of their ability to inhibit spontaneous nystagmus in cats. The relationships between the molecular structures of the test compounds and their antivertigo activities were investigated by a regression analysis based on the lipophilicity (π) of the substituents at the 6-position and by a conformational analysis of the compounds of interest using the modified neglect of diatomic overlap molecular orbital method. Among these compounds, the 6-allyl-and 6-cyclopropylmethyl derivatives exhibited extremely potent activity with greatly reduced hypotensive action.