FK-037 can be obtained by related ways: 1) The formylation of 5-amino-1-(2-hydroxyethyl)pyrazole (I) with formic acid - acetic anhydride gives 5-formamido-1-(2-hydroxyethyl)pyrazole (II), which is condensed with 7beta-(tert-butoxycarbonylamino)-3-(chloromethyl)-3-cephem-4-carboxylic acid diphenylmethyl ester (III) by means of NaI in DMF, yielding 7beta-(tert-butoxycarbonylamino)-3-[3-formamido-2-(2-formyloxyethyl)-1-pyrazoliomethyl]-3-cephem-4-carboxylic acid diphenylmethyl ester iodide (IV). The treatment of (IV), first with trifluoroacetic acid and anisole and then with HCl, affords 7beta-amino-3-[3-amino-2-(2-hydroxyethyl)-1-pyrazoliomethyl]-3-cephem-4-carboxylic acid chloride (V). The condensation of (V) with 2-(2-formamidothiazol-4-yl)-2(Z)-(methoxyimino)acetic acid (VI) by means of POCl3 in ethyl acetate gives 3-[3-amino-2-(2-hydroxyethyl)-1-pyrazoliomethyl]-7beta-[2-(2-formamido-thiazol-4-yl)-2(Z)-(methoxyimino)acetamido]-3-cephem-4-carboxylate (VII), which is deformylated with HCl affording 3-[3-amino-2-(2-hydroxyethyl)-1-pyrazoliomethyl]-7beta-[2-(2-aminothiazol-4-yl)-2(Z)-(methoxyimino)acetamido]-3-cephem-4-carboxylate (VIII). Finally, this compound is treated with H2SO4 to give FK-037. 2) Compound (VIII) can also be obtained by condensation of (V) with 1-[2-(2-aminothiazol-4-yl)-2(Z)-(methoxyimino)acetyl]benzo- triazole-3-oxide (IX) in THF.
3) The condensation of 4-chloro-2(Z)-(methoxyimino)-3-oxobutyric acid (IX) with 7beta-amino-3-[3-amino-2-(2-hydroxyethyl)-1-pyrazoliomethyl]-3-cephem-4-carboxylate (X) by means of POCl3 in DMF gives the corresponding acetamide (XI), which is then cyclized with thiourea by means of sodium acetate in water to obtain compound (VII). Finally, this compound is treated with H2SO4 to give FK-037.