FIG 6.

Identification of the purified product. (A) HPLC chromatogram of the purified product. Shown are the authentic standard of riboflavin (upper), authentic standard of lumichrome (middle), and purified product (lower). (B) ¹H NMR spectrum of the purified product. Shown are the authentic standard of lumichrome (upper) and the reaction product (lower). ¹H NMR (400 MHz, pyridine-d₅) δ 2.26 and 2.33 (each 3H, s), 7.89 and 8.06 (1H, s), 13.86 (2H, br). (C) ¹³C NMR spectrum of the purified product. Shown are the authentic standard of lumichrome (upper) and the reaction product (lower). ¹³C NMR (100 MHz, pyridine-d₅) δ 20.20, 20.77, 127.53, 130.07, 131.39, 139.46, 140.19, 143.40, 145.18, 148.06, 152.16, 162.41.