Diplorrhyncus mossambicensis

Among the seven alkaloids that were isolated from Diplorrhyncus mossambicensis was a base C19H20N2O with unusually high rotation (— 1230° in chloroform). Its carbonyl activity and UV-spectrum (A, 242, 299, 360 mp) were reminiscent of fluorocurarine (Chapter 15, Refs. 133-137) and comparison of the methochloride of the new base with fluorocurarine demonstrated complete identity. The alkaloid is therefore norfluorocurarine (CCXL, 116, 132). 

Notmacusine-B was first obtained by the thermal decomposition of its quaternary methochloride, macusine-B, which was isolated from Strychnos toxifera It was found to be identical with 10-deoxysarpagine (CCCXX) and its IVa-methyldihydro derivative was identical with deoxyisoajmalol-B (CCCXXIII) (172, 173), thus establishing its structure and absolute stereochemistry (177, see Chapter 22). Subsequently, normacusine-B has been found in Diplorrhyncus mossambicensis (named tombozine, 116, 121, 122) and in Aspidosperma polyneuron (165). 

Stemmadenine (CCXIII) was first isolated from Stemmadenia donnell-smithii (8), where it occurs with (+ )-quebrachamine (I) and some iboga-type bases. Subsequently, it has also been found in Diplorrhyncus condylocarpon ssp. mossambicensis, where it occurs together with condylocarpine (CCXV), normacusine-B (Section VIII, B), two yohimbines, norfluorocurarine, and mossambine (Section VI, B and C, Ref. 116). 

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