Aspidosperma excelsum

New normal yohimbine-type alkaloids, isolated or characterized, together with their primary sources, are listed in Table I. Note that aspexcine, isolated from Aspidosperma excelsum Benth., has earlier been characterized as a 10-methoxyisositsirikine. This alkaloid, however, proved to be identical with excel-sinine (81) (53) (see Section II.B. 14.). 

Yohimbine-Corynantheine (and Related Oxindoles) Group, a-Yohimbine (9a) has been isolated18 from Aspidosperma excelsum. The alcohol (9b) can be produced19 from apoyohimbine (9c) by sequential catalytic reduction, epimerization at C(16), and lithium aluminium hydride reduction, or more easily by the lithium aluminium hydride treatment of /7-yohimbine 17-O-tosylate (9d). 

Full papers dealing with the chemistry of gambirtannine, oxy-gambirtannine, dihydrogambirtannine 56), deserpidine, and raujemi-dine (57) have appeared. A new base, excelsinine (10-methoxycorynan-thine, C26H26N2O4, mp 201°) has been isolated from Aspidosperma excelsum (58). A new synthesis of ( )-yohimbane has been published (59), and 7-benzyl-7i/-yohimbanes have been prepared and their ORD curves examined (60). 

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