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Über Pterinchemie. 77. Mitteilung)Das (6R,S)-5-Formyl-6-methyl-5,6,7,8-tetrahydropterin: Synthese, chemische und physikalisch-chemische Eigenschaften

✍ Scribed by Abhoy N. Ganguly; Jost H. Bieri; M. Viscontini

Publisher
John Wiley and Sons
Year
1981
Tongue
German
Weight
233 KB
Volume
64
Category
Article
ISSN
0018-019X

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✦ Synopsis

(6__R,S__)‐5‐Formyl‐6‐methyl‐5,6,7,8‐tetrahydropterine: Synthesis, Chemical and Physico‐chemical Properties

(6__R, S__)‐5‐Formyl‐6‐methyl‐5,6,7,8‐tetrahydropterine (III), a model substance for the biologically important 6‐substituted 5‐formyl‐5,6,7,8‐tetrahydropterines, was obtained for the first time by formylation of the corresponding tetrahydropterine with formic acid. Compound III, analogously to the other known 5‐acyltetrahydropterines, exists in solution (except in DMSO) as a mixture of two rotamers IIIa and IIIb. The two H‐C(7) in III have the same chemical shift and the same coupling constant to H‐C(6), giving rise to a A,A',X,C‐system. Conformational analysis of III, based on its ^1^H‐NMR,‐spectrum, shows that the methyl group is pseudo‐axial and the formyl group pseudo‐equatorial. Moreover, the H(X)‐C(6) bond lies nearly in the plane bisecting the C(6)‐C(7)‐H(A), C(6)‐C(7)‐H(A') dihedral angle; the C(6) and C(7) lie outside the N(5)‐C(4a)‐C(8a) plane and the tetrahydropyrazine cycle must be extremely strained, according to Dreiding models.

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