From the trunk bark of Strychnos brasiliensis (Spreng.) Mart., spermostrychnine (I) and six new indoline alkaloids have been isolated and their structures and configurations determined. They were named: 12-hydroxy-11-methoxyspermostrychnine (II), strychnobrasiline (III), 12-hydroxy-11-methoxystrychnobrasiline (IV), 10,11-dimethoxystrychnobrasiline (V), strychnosilidine (VI), and strychnosiline (VII)
An unexpected molecular rearrangement in lithium aluminium hydride reduction of the indole alkaloid strychnobrasiline was observed. The resulting derivatives obtained were evaluated as modulators of chloroquine resistance in Plasmodium falciparum. (C) 1999 Elsevier Science Ltd. All rights reserved.
Synthesis and chloroquine-enhancing activity of Na-deacetyl-ferrocenoyl-strychnobrasiline
Several strychnobrasiline derivatives have been synthesized to overcome the lack of in vivo reversal activity of the parent compound. In the present study, N-a-deacetyl-ferrocenoyl-strychnobrasiline was synthesized by condensing N-a-deacetyl-strychnobrasiline with ferrocenic acid previously treated with oxalyl chloride. While the in vitro antiplasmodial activity of the test compound (IC50 = 4.83 mug/mL) was increased 15-fold compared to that of strychnobrasiline, and the in vitro enhancing activity was found to be similar to that of the parent compound, the compound was devoid of any in vivo potentiating effect, and an antagonistic effect was even observed at higher doses. Based on the overall results on the hemisynthesis of strychnobrasiline derivatives for better reversal activity, this strategy has appeared to be of little value for useful drugs. (C) 2004 Elsevier Ltd. All rights reserved.
Oxidation of indolines to nitrones and new rearrangement in seco-curane type indoline alkaloids
作者:François Trigalo、Marie-Thérèse Martin、Benoı̂t Rasolondratovo、Alain Blond、Jean Jacques Youte、Philippe Rasoanaivo、François Frappier
DOI:10.1016/s0040-4020(02)00407-6
日期:2002.5
At room temperature 3-chloroperoxybenzoic acid oxidizes the deacetylated strychnobrasiline to the corresponding nitrone. Two unexpected rearrangements are observed when the reaction is performed at 40°C.