Scopolamine configuration

Proton61 and carbon-1362 n.m.r. spectroscopy have recently been used extensively for the analysis of tropane alkaloids. The non-equivalence of H-6 and H-7 on the one hand and of H-2 and H-4 on the other in atropine and scopolamine is due to the non-symmetrical shielding by the tropic acid moiety. The configuration of A-substituents, e.g. N-oxides, has been determined by studying the deshielding of the 6- and 7/3-hydrogens. All of these results should be useful for the identification of new tropane alkaloids and other related systems in the future. 

Tropane Alkaloids.—It is known that tropine (26) is a precursor for meteloidine (27),42 and its close relative hyoscyamine (29) is a precursor for scopolamine (28).43 Experiments with samples of (26) labelled with /3-tritium at C-6 and C-7 show that entry of the two /S-hydroxy-groups in (27) must occur with normal retention of configuration since almost complete loss of tritium occurred.44 Tritium was again lost almost completely on formation of scopolamine (28). On the assumption that early conclusions45 on the sequential intermediacy of (30) and (31) in the biosynthesis of (28) are correct, formation of (30) involves normal retention of configuration (loss of half the tritium) and cis-dehydration then occurs to give (31) (loss of remaining tritium). [In these experiments the hyoscyamine (29) isolated showed appropriately no loss of tritium.]44... 

The exact correlation of the configuration of the C3-OH group in valeroidine and in scopolamine with that of tropine could be realized by converting scopolamine and valeroidine into tropine (65). Dehydration of ( ) 3a,6j8-dihydroxytropane (XLII) led to ( ) tropene oxide, ... 

D.innoxia scopolamine proved much more stable than atropine. Isolation of 6j8-hydroxyhyoscyamine (9) and apohyoscine from Physochlaina alaica has been described. The relative configurations of four new Knightia deplanchei Vieill. ex Brongn. et Gris, alkaloids (10)—(12) have now been established by n.m.r. A... 

Troplc acid is found in nature as the acid moiety of the anticholinergic ester alkaloids hyoscyamine (Scheme 57.4) and scopolamine. These tropane alkaloids can be extracted from plants of the Solanaceae family. Once proven that racemic tropic acid ethyl ester rac-8, which bears a primary hydroxyl group, is enantioselectively acylated with vinyl acetate in the presence of Celite-supported PS lipase and that the product thus formed has the required S configuration, Hossain and Atuu attempted the enzymatic acylation... 

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