2-Methyl-4-(1-piperaziny1)-10H-thieno(2,3-b][1,51benzodi-azepine (N-demethylolanzapine) was alkylated witch Mel in presence of K2CO3, Bu4NBr and DMF at room temp. in microvawe field to olanzapine and its derivatives. The addn. of DMF resulted in increasing the product yield. The maximum product yield 64% and purity (after 15 s) were reached at egui-mol. N-demetylolanzapine/Mel ratio.