BENZYLISOQUINOLINE DERIVATIVE

NEW MATERIAL:A compound shown by formula I (R is H or CH3; R1 and R2 are H or benzyloxy; R2 is OCH3 or benzyloxy; Bz is benzyl; with the proviso that a case where R and R1 are H, R2 is OCH3 and R3 is benzyloxy is omitted). EXAMPLE:5-Benzyloxy-6-methoxy-1,2,3,4-tetrahydro-1-(4-benzyloxybenzyl) -isoqui noline. USE:A drug. An inhibitor of blood platelet aggregation having excellent inhibitory action on blood platelet aggregation. PREPARATION:A compound shown by formula II is reacted with a compound shown by formula III (X is halogen or OH) to give a compound shown by formula IV, which is reacted with POCl3 in a solvent such as benzene, etc., at 80-130 deg.C and catalytically reduced with a reducing agent such as sodium boron cyanohydride, etc., to give a compound shown by formula I when R is H. This compound is reacted with formaldehyde in a solvent such as methanol, etc., at room temperature and catalytically reduced in the same way as the above- mentioned reaction to give a compound shown by the formula I when R is CH3.