ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The reduction products voacanginol (3) and conopharynginol (4), obtained from the indole alkaloids voacangine (1) and conopharyngine (2) respectively, gave, by the treatment of their tosylates 5 und 6 with triethylamine, two fragmentation products, voaenamine (7) (70-80%) and conoenamine (8) (25-45%) respectively (Scheme 1). The structures of 7 and 8 were derived from spectroscopic evidence and some chemical transformations.Conopharynginol tosylate (6) gave with tertiary base, besides 8, the quaternary aziridinium salt 12 (58%) (Scheme 3). This salt could undergo nucleophilic attack, giving compounds of the A-series with a C-homo-conopharyngine skeleton (due to attack at C(18)) and compounds of the B-series with a spiro-centre (due to attack at carbon(5)) (Scheme 3). The structures of these compounds were elucidated using D-incorporation experiments, 1H- and 13C-NMR. and mass spectra. On heating to 230°, acetylated spiroalcohol 22 was converted, probably via the ion pair 23, into the base 16, which on catalytic reduction gave 13, a member of the A-series.The reactions mentioned above constitute interesting skeletal isomerisations of the conopharyngine skeleton.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19750580130
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