Natural Abundance 13C‐NMR. of Reduced Isoalloxazine

Abstract
When an isoalloxazine derivative (1) was reduced (2) its 13C‐NMR. resonances were all shifted upfield and the largest shifts were observed for C (4a), C(6) and C(8) but downfield shifts for C(2), C(4) and C(10a). The results and their biochemical implications are shortly discussed.