Anopteryl alcohol

Oxidation of anopteryl alcohol with alkaline potassium ferricyanide yielded the carbinolamine ether (56 or 57) as a minor product (8%) and compound 58 as the major product. The structure of 58 was elucidated by an X-ray crystal analysis. Compound 58 was isolated from the oxidation reaction mixture only after acetylating the mixture, from which the carbinolamine ether was first removed, and then hydrolyzing the acetylated product. Acetylation of compound 58 gave triacetyl derivative 59, in which the epoxide ring was opened. 

Treatment of anopteryl alcohol with acetic anhydride and pyridine at 100° for 4 hr or longer gave tetraacetylanopteryl alcohol (54) in high yield. Less drastic acetylation conditions gave a mixture of compound 54, triacetyl derivatives 60 and 61, and diacetylanopteryl alcohol 62. The structures of these acetylated derivatives were based on -NMR data. 

The structures of anopterine (73) and its hydrolysis product, anopteryl alcohol (74), had previously been assigned on the basis of an X-ray crystallographic study of the azomethine iodide (75) formed on treatment of tetra-acetylanopteryl alcohol (76) with methyl iodide. The structure of the original alkaloid was derived from this azomethine by an n.m.r. study43 (c/. Vol. 4, p. 325). 

Oxidation of anopteryl alcohol (74) with potassium ferricyanide gave an 8% yield of a compound with either structure (78) or (79). The major product of this reaction (following purification by acetylation and then alkaline hydrolysis of the acetylated product) was determined to be (80) by an X-ray crystallographic analysis. Acetylation of (80) gave (81). 

Acetylation of anopteryl alcohol with acetic anhydride-pyridine at 100 °C for four hours gave (76). Less drastic conditions produced a mixture of products, including (76), (82), (83), and (84). These assignments were based on n.m.r. data. 

Oxidation of anopterine with chromic acid-pyridine followed by hydrolysis afforded (85). Oxidation of anopterine with Jones reagent, followed by hydrolysis, was shown to yield a monoketone, which was assigned probable structure (86). Reduction of (86) with sodium borohydride gave a 4 1 mixture, with anopteryl alcohol as the major product. Jones oxidation of anopteryl alcohol gave a mixture of (87) and (88). On oxidation of (85) (from anopterine) with Jones reagent, the tetraketone (89) was obtained. 

These studies were supported by detailed H and 13C n.m.r. data, 13C n.m.r. shielding data for anopterine, anopteryl alcohol, (76), (83), (80), and (81) being presented in tabular form. 

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