Preparation of 1,4-disubstituted piperazine

PURPOSE: To obtain a 1,4-disubstituted piperazine useful as a chemotherapeutic agent readily in high yield, by reacting a pyridopyrimidine derivative with an alkylating agent. CONSTITUTION: A pyridopyrimidine derivative shown by the formula I (R 1 is lower alkyl or lower alkenyl; R 2 is H or lower alkyl) is reacted with an alkylating agent, e.g., methyl iodide, benzyl chloride, propargyl bromide, etc. directly or in a proper solvent, e.g., water, ethanol, dioxane, etc. at from room temperature to 160°C, to give the desired compound shown by the formula II (R 3 is lower alkyl, or lower alkynyl). The amount of the alkylating agent used is preferably an equimolar amout with the raw material compound shown by the formula I or a little excess. COPYRIGHT: (C)1981,JPO&Japio