Simplest derivatives of the cotarnine alkaloid, like cotarnone and 1,2-dihydrocotarnine, undergo electrophilic Einhorn acylamidomethylation (with 60–95% yield) and sulfochlorination with chlorosulfonic acid at position 5. At the same time cotarnone and its derivatives undergo additional O-protodemethylation. Using these and some other reactions, we synthesized a number of previously unknown derivatives of two substrates with 5-chloroacetamidomethyl, 5-arylaminomethyl, 5-aminomethyl and 5-sulfamide groups.