4-Methylmorpholine → 3-Methoxy-2-cephem-4alpha-carboxylic acid diphenylmethyl ester

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Reaction Conditions

Reaction Steps

If, in the above process, 0.09 g of D-α-tert.-butoxycarbonylamino-α-(1,4-cyclohexadienyl)-acetic acid, 0.038 ml of N-methyl-morpholine and 0.052 ml of chloroformic acid isobutyl ester are used and the mixture is stirred for 30 minutes at -15° C under a nitrogen atmosphere, then treated with 0.125 g of 7β-amino-3-methoxy-3-cephem-4-carboxylic acid diphenylmethyl ester and 0.035 ml of N-methyl-morpholine, stirred for 30 minutes at -10° C and for 30 minutes at 0° C and worked up as described above, a crude product is obtained, which is purified by means of preparative layer chromatography (silica gel; system: diethyl ether; identification with ultraviolet light, λ = 254 μ). At Rf~0.51, 7β- D-α-tert.-butoxycarbonylamino-(1,4-cyclohexadienyl)-acetylamino!-3-methoxy-2-cephem-4α-carboxylic acid diphenylmethyl ester is thus obtained, melting point = 153°-154° C after crystallisation from a mixture of methylene chloride and pentane; thin layer chromatogram (silica gel; identification with iodine): Rf~0.51 (system: diethyl ether); α!D20 = +176° ± 1° (c = 0.541 in chloroform); ultraviolet absorption spectrum (in 95% strength aqueous ethanol): λmax = 257 mμ (ε = 3,600); and infrared absorption spectrum (in methylene chloride): characteristic bands at 2.96 μ, 5.64 μ, 5.76 μ, 5.92 μ, 6.18 μ and 6.75 μ; whilst at Rf~0.39 7β- D-α-tert.-butoxycarbonyl-amino-α-(1,4-cyclohexadienyl)-acetylamino!-3-methoxy-3-cephem-4-carboxylic acid diphenylmethyl ester is obtained, which is identical with the product obtainable according to the process described above.

Provenance & Evidence