Über Pterinchemie. 65 Mitteilung [1]. Herstellung von (6 R , S )‐5,6,7,8‐Tetrahydro‐ L ‐biopterin, 7,8‐Dihydro‐ L ‐biopterin, L ‐Sepiapterin, Deoxysepiapterin, (6 R , S )‐5,6‐Dihydrodeoxysepiapterin und 2′‐Deoxybiopterin

Preparation of (6 R , S )‐5,6,7,8‐tetrahydro‐ L ‐biopterine, 7,8‐dihydro‐ L ‐biopterine, L ‐sepiapterine, deoxysepiapterine, (6 R , S )‐5,6‐dihydrodeoxysepiapterine and 2′‐deoxybiopterine We describe the preparation of (6 R , S )‐5,6,7,8‐tetrahydro‐ L ‐biopterine (II) by catalytic‐ (reported in our short communication [2]) and natriumdithionite reduction of L ‐biopterine (I) and a preparation of 7,8‐dihydro‐ L ‐biopterine (IV) by treatment of L ‐biopterine (I) with natriumdithionite. Whereas oxidation of tetrahydrobiopterine II in the presence of oxygen leads to L ‐sepiapterine (III), dihydrobiopterine IV in acetic acid without oxygen gives deoxysepiapterine (VII), 5,6‐dihydro‐deoxysepiapterine (VI) and 2′‐deoxybiopterine (V) by a disproportionation reaction.