Identification d'un nouveau alcaloïde de canneberges

Abstract

The structure of a new cranberry alkaloid, 12-methyl-1,2,3,4,6,7,12,12b-octahydroindolo[2,3-a]quinolizine was established using mass spectroscopy and by synthesis.

Oxidation of indolic bases by cytochrome P450 and ferrous picolinate

“…The mass chromatograms were run using M+2 ion intensity for the reduction products, M+14 ion for the keto/epoxy, M+16 ion for the hydroxy and M+32 ion for the diol. The findings were confirmed by the comparison with available standards [13,18,19]. The origin of M+2 ion for the compounds 2-4 can be explained by the sequence of demethylation of OCH 3 or NCH 3 groups, followed by monohydroxylation.…”

“…The carboline 1 and its deuterated carbolines were synthesized by ourselves [18,19] according to the modified Gribble procedure [20,21]. The bases 2-4 were obtained from Aldrich Chemical Co.…”

“…For compound 1, the mono-hydroxycarboline, a major hydroxylation product, observed from the profile of m/z 242 ion, was identified as 6-hydroxycarboline. For the carboline (1), the same position was activated by all Gif catalysts previously studied by our group [19].…”

Reactions of carboline

“…The addition of a CH 3 O-ion to the imine N 5 -C 12a intermediate was not observed. The results obtained from deuteration experiments on both intermediates (5 and 6) enabled to better characterise the enamine N 5 -C 4 =C 3 , azadiene and imine N 5 -C 12a systems present in the C/D rings junction proximity of this tetracyclic alkaloid according to the intermediates discussed by Barton [7,17] and postulated by Gribble [18][19][20]. It is finally interesting to notice that both rearranged carboline derivatives, both bearing the spiro C ring,were not detected in various biomimetic (e.g., Gif IV, Gif-Orsay, Fenton, picolinate FeII) as well as in the cytochrome P450 and the radiolytic oxidations of 1a reported in this paper [5,6].…”

“…The rearrengement of 3a under acidic conditions led to obtaining two products, one being deprotected, beta hydroxy carboline 3b, the second one underwent the rearrangement to the oxindole displaying the lactam bond (m/z 241 M-H, 149, 97, etc.). When the crude mixture of the lead tetraacetate oxidation of 1a is treated with NaBD 4 according to the Gribble procedure [18][19][20] the intriguing isomeric compound is obtained. This compound is displaying characteristic M-D + ion at m/z 225 (100%).…”