Pluracidomycin A2, a new carbapenem bearing a sulfinic acid, and other minor pluracidomycins.

(FERM BP-174) was found to produce additional 13-lactam components besides the previously reported pluracidomycins (PLM) A, B and C1'. In particular, fermentation at 38`C resulted in an increase of the minor components with a decrease of PLM C, while the yields of PLM A and PLM B remained almost unchanged. Reported here are the isolation and structure elucidation of these minor pluracidomycins. The pluracidomycins were isolated from the fermentation filtrate as previously reported using phase-transfer extraction, ion-exchange chromatography on QAE-Sephadex and gel filtration of the respective fractions to obtain fractions A, B, C and D (in the order of decreasing acidity). Fraction A containing the main component PLM A, (formerly PLM A), a new minor component PLM A,, and a considerable amount of PLM B, was separated by column chromatography on MCI GEL CHP20P (Mitsubishi Chem. Ind.) using 15°°,' NaCI solution. Fraction B contained a small amount of PLM A., and the second major component PLM B and was separated with a CHP20P column, as was fraction A. The PLM A., portions were combined, desalted by gel filtration on Biogel P-2 and freeze-dried. Fraction C was further fractionated on active principles of fractions C, and C, were assumed to be new compounds according to HPLC data but those of fraction C, were identified as MM 4550 and MM 17880''. Fraction C, was rechromatographed on CHP20P using 5'1,, NaC1, desalted and freeze-dried. When the minor component was purified by HPLC on Nucleosil C, (Macherey-Nagel) with 0.1 M phosphate buffer (pH 7.0), desalted and freeze-dried, a new component PLM C, was obtained in extremely poor yield. Further purification of fraction C, on CHP20P column using 3 NaCI solution, desalting and freeze-drying gave a new component PLM C3. Fraction D had three active components, MM 4550, MM 17880 and a new substance according to the HPLC data. In chromatography with a CHP20P column, the new substance, PLM D, was eluted by 10% NaCI solution, while the two known antibiotics were eluted by water. The PLM D fractions were combined, desalted and freeze-dried. The yields of the new components, isolated from about 500 liters of filtrate as respective sodium salts, were approximately 40 mg of PLNI A.,, 3 mg of PLM C,, 15 mg of PLM C, and 100 mg of PLM D. The 1H NMR spectra in D._,O of these pluracidomycins are shown in Fig. 1, and the relative mobilities on paper electro-phoresis …