Vobasinyl moiety

Tabemaemontana corymbosa also provided several new bisindole alkaloids, conodiparines A-D (362-365) which are constituted from union of iboga and vobasinyl moieties [237]. The spectral data indicated that in conodiparines A (362) and C (364), the dimers are branched from C(3) of the vobasinyl unit to C(IO ) of the iboga unit whereas in conodiparines B (363) and D (365), the connection is from C(3) to C(12 ). The configuration of C( 19 ) in conodiparines A (362) and B (363) was determined to be 5 from examination of the carbon shifts of C(15 ) and C(2r) which corresponds to those of the iboga alkaloid heyneanine (345), exemplifying the 19(5) series in iboga alkaloids with a hydroxylethyl side chain [238]. 

Kam T, Sim K (2003) Conodirinines A and B, novel vobasine-/f>oga bisindoles incorporating an additional tetrahydro-1, 3-oxazine nnit on the vobasinyl moiety. Helv Chim Acta 86 122-126... 

The Malaysian T. corymbosa provided, in addition to vobasonidine (313), vobatricine (398) 210), conodurine, conoduramine, ervahanine 293), and tabemamine derivatives 300), a series of new vobasinyl-iboga alkaloids, 497-506, characterized by the presence of hydroxymethyl group at C(16) of the vobasinyl moiety 211,305). 

Ceridimine (303), from Pagiantha cerifera was the first example of a qua-sidimeric-type alkaloid in which the additional tryptamine unit has a free side chain and is linked by its aromatic moiety to the monoterpenoid indole unit 203). The primary amine function was readily acetylated and methylated, and its partial synthesis via coupling of vobasinol with tryptamine confirmed the structure assignment. Demethylceridimine (304) was later obtained from P. buchtieni T. buchtieni), which also provided another quasidimer, buchtienine (254) vide supra) 153). The third member of this group, hunteriatryptamine (305), was obtained from Hunteria zeylanica from Thailand. It differs from the previous two alkaloids by the presence of a hydroxymethyl function on the vobasinyl C(16) in place of H 204). 

In contrast to the many Aspidosperma-Aspidosperma type bisindoles found in the leaf extract of the Malaysian T. divaricata vide infra), the stem extract provided only one bisindole, conodusarine (509), which was of the iboga-vobasine type 309). The spectral data indicated that conodusarine (509) is constituted from the union of 3-vobasinyl and 3-oxovoacangine moieties via a 3-11 bond. The presence of the latter alkaloid in the same plant provided additional support for the assignment. 

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