This compound can be obtained by two related ways: 1) The reaction of vinblastine (I) with anhydrous hydrazine in hot ethanol gives 4-deacetylvinblastine-23-acid hydrazide (II), which by reaction with HCl and NaNO2 in cool methanol - water is converted into the corresponding azide (III). Finally, this compound is condensed with L-tryptophan ethyl ester (IV) in dichloromethane. 2) The hydrolysis of vinblastine (I) with NaOH in refluxing ethanol gives 4-deacetylvinblastoic acid (V), which is condensed with L-tryptophan ethyl ester (IV) by means of isobutyl chloroformate (VI) and N-ethylmorpholine in DMF to afford the 4-O-(isobutoxycarbonyl) derivative (VII). Finally, this compound is partially hydrolyzed with KOH in ethanol.
The condensation of 2-[2-(benzoyloxycarbonylamino)thiazol-4-yl]-4-(benzyloxycarbonyl)-2-butenoic acid (I) with 7beta-amino-3-cephem-4-carboxylic acid diphenylmethyl ester (II) by means of mesyl chloride, phosphorus oxychloride or thionyl chloride in basic medium and dichloromethane as solvent gives the protected derivative of the desired product (III), which is then treated with AlCl3 and anisole and acidified with diluted HCl.
The Wittig condensation of diphenylmethyl 2-[2-(benzyloxycarbonylamino)thiazol-4 yl-2-formyl acetate with benzyloxycarbonylmethylene triphenylphosphorane (II) in toluene or dioxane gives 2-[2-(benzyloxycarbonylamino)thiazol-4-yl]-4 (benzyloxycarbonyl)-2-butenoic acid diphenylmethyl ester (III), which is hydrolyzed partiaily wth trifluoroacetic acid and anisole to the 2-butenoic acid (IV). The condensation of (IV) with 7-beta-amino-3-cephem-4-carboxylic acid benzyl ester (V) by means of dicyclohexylcarbodiimide (DCC) in dichloromethane affords the protected final product (VI), which is finally debenzylated by means of AlCl3 and anisole in methylene chloride.