The condensation of 4-amino-2(Z)-buten-1-ol (I) with 2-bromo-4-(piperidinomethyl)pyridine (II) by means of NaH in refluxing THF gives 4-[4-(piperidinomethyl)pyridin-2-yloxy]-2(Z)-butenylamine (III), which is allowed to react with 3,4,-dimethoxy-3-cyclobutene-1,2-dione (IV) in methanol to afford 3-methoxy-4-[4-[4-(piperidinomethyl)pyridin-2-yloxy]-2(Z)-butenylamino]-3-cyclobutene-1,2-dione (V). Finally, this compound is treated with dry ammonia in methanol.