Synthesis of 4''-(3''',4'''-Diaza-2'''-imino-1'''-thia-1''',4'''-butylene)-4''- deoxyavermectin B1a Derivatives

Ten new 4''-(3''',4'''-diaza-2'''-imino-1'''-thia-1''',4'''-butylene)-4''-deoxyavermectin B1a derivatives 7a~7j were synthesized from avermectin B1a by the selective protection of C-5-hydroxy group and oxidation of C-5''-hydroxy group followed by condensation with N-substituted thiosemicarbazides, oxidative cyclization by treatment with manganese dioxide and deprotection. The structures of the target compounds were con- firmed by 1 H NMR, 13 C NMR and MS techniques.