Two New N ‐( O ‐Carbamoylglucopyranosyl)‐ N ‐dimethylansamitocins from Actinosynnema pretiosum

Two new and a known N ‐( O ‐carbamoylglucopyranosyl)ansamitocins were isolated from Actinosynnema pretiosum ssp. auranticum ATCC 31565. The known N ‐(4‐ O‐ carbamoyl‐ β ‐ D ‐glucopyranosyl)‐ N ‐demethylansamitocin P 2 (=ACGP‐2; 1 ) was assigned according to 1D‐ and 2D‐NMR data, and the two new compounds were identified as N ‐(6‐ O‐ carbamoyl‐ β ‐ D ‐glucopyranosyl)‐ N ‐demethylansamitocin P 2 (=ACGP‐2′; 2 ) and N ‐(4‐ O‐ carbamoyl‐ β ‐ D ‐glucopyranosyl)‐ N ‐demethylansamitocin P 1 (=ACGP‐1; 3 ) on the basis of spectroscopic data interpretation including 2D‐NMR and tandem MS analysis.