0000000000465951
AUTHOR
Angel Serrano
Novel isoquinoline derivatives as antimicrobial agents.
The wide variety of potent biological activities of natural and synthetic isoquinoline alkaloids encouraged us to develop novel antimicrobial isoquinoline compounds. We synthesized a variety of differently functionalized 1-pentyl-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolines (THIQs), including dihydroisoquinolinium salts (2 and 5), methyl pentanoate-THIQ (6), 1-pentanol-THIQ (7), ester derivatives (8-15) and carbamate derivatives (16-23). We employed classic intramolecular Bischler-Napieralski cyclodehydration to generate the isoquinoline core. All the structures were characterized by nuclear magnetic resonance and mass spectrometry. The bactericide and fungicide activities were evaluated f…
ChemInform Abstract: Enantioselective Syntheses of Dopaminergic (R)- and (S)-Benzyltetrahydroisoquinolines.
Optically pure (1S,R)- and (1R,S)-benzyltetrahydroisoquinolines (BTHIQs), 12a,b as the major diastereomers, were prepared by stereoselective reduction of the isoquinolinium salt possessing (R)- and (S)-phenylglycinol as the chiral auxiliary, respectively. The absolute configurations of (1S,R)-13a hydrochloride (O-debenzoylated derivative from 12a) and (1R,S)-12b diastereomers were unambiguously determined by single-crystal X-ray analysis. Reductive removal of the chiral auxiliary group, subsequent N-propylation, and cleavage of the methylenedioxy group furnished the optically active catecholamines (1S)-16a and (1R)-16b in good overall yield. We have separately prepared for the first time pa…
ChemInform Abstract: Synthesis of (+)-Isoalantolactone and (+)-Isoalloalantolactone from (-) -Santonin.
Abstract This paper reports on the chemical conversion of (−)-santonin into (+)-isoalantolactone and (+)-isoalloalantolactone involving functionality transfer from C 6 to C 8 , refunctionalization of the ring A and the formation of the α-methylene-8 β,12-olide moiety.
Structure-activity relationship of dopaminergic halogenated 1-benzyl-tetrahydroisoquinoline derivatives
Two series of halogenated 1-benzyl-7-chloro-6-hydroxy-tetrahydroisoquinolines were prepared to explore the influence of each series on the affinity for dopamine receptors. All the compounds displayed a high affinity for D(1)-like and/or D(2)-like dopamine receptors in striatal membranes, although they were unable to inhibit [(3)H]-dopamine uptake in striatal synaptosomes. The halogen placed on the benzylic ring in 1-benzyl-THIQs, compounds of the series 1, 2'-bromobenzyl derivatives with K(i) values into the nanomolar range, and the series 2, 2',4'-dichlorobenzyl-THIQ homologues, proves to be an important factor to modulate affinity at dopamine receptor. (C) 2009 Elsevier Masson SAS. All ri…
Epoxy-Acetogenins and other Polyketide Epoxy Derivatives as Inhibitors of the Mitochondrial Respiratory Chain Complex I
Annonaceous acetogenins (ACG), an extensive group of cytotoxic natural products, are antitumor agents whose main mode of action is inhibition of the mammalian mitochondrial complex I. Herein we describe the importance of the different chemical groups along the alkyl chain for optimal inhibitory potency, discussing the structurally relevant factors present in these compounds. For this purpose, a series of epoxide derivatives from alpha-linolenic acid were prepared and their activity compared with that of epoxy-acetogenins and tetrahydrofuranic (THF) acetogenins isolated from Rollinia membranacea.
Preparation of 7-Alkoxylated Furanopyrones: Semisynthesis of (−)-Etharvensin, a New Styryl-Lactone from Goniothalamus arvensis
A new furanopyrone derivative, (−)-etharvensin (1), was isolated from the stem bark of Goniothalamus arvensis. Semisynthesis of the 7-ethoxyfuranopyrone 1 was achieved by addition of EtOH in concentrated acid medium to the unsaturated α-pyrone (+)-altholactone (2). This protocol constitutes a novel, direct (single-step), and efficient method to prepare this class of bioactive compounds.
Xanthones from Hypericum reflexum
Abstract The aerial parts of Hypericum reflexum contain six xanthones, two pyranoxanthones, two xanthonolignoids and a biphenyl. Six of these compounds are described for the first time.
A chemotaxonomic survey of Sonchus subgenus Sonchus
Abstract Five species of Sonchus subgenus Sonchus were surveyed for their phenolic constituents. Seven flavonoids were identified: luteolin, luteolin-7-glucoside, apigenin, apigenin-3-glucoside, quercetin, quercetin-3-glucoside and quercetin-3-galactoside; three were phenolic acids; caffeic, chlorogenic and isochlorogenic; and two were coumarins: aesculetin and cichoriin. Their systematic significance for this genus is discussed.
Synthesis of (+)-Isoalantolactone and (+)-Isoalloalantolactone from (−)-Santonin
Abstract This paper reports on the chemical conversion of (−)-santonin into (+)-isoalantolactone and (+)-isoalloalantolactone involving functionality transfer from C 6 to C 8 , refunctionalization of the ring A and the formation of the α-methylene-8 β,12-olide moiety.
Enantioselective syntheses of dopaminergic (R)- and (S)-benzyltetrahydroisoquinolines.
Optically pure (1S,R)- and (1R,S)-benzyltetrahydroisoquinolines (BTHIQs), 12a,b as the major diastereomers, were prepared by stereoselective reduction of the isoquinolinium salt possessing (R)- and (S)-phenylglycinol as the chiral auxiliary, respectively. The absolute configurations of (1S,R)-13a hydrochloride (O-debenzoylated derivative from 12a) and (1R,S)-12b diastereomers were unambiguously determined by single-crystal X-ray analysis. Reductive removal of the chiral auxiliary group, subsequent N-propylation, and cleavage of the methylenedioxy group furnished the optically active catecholamines (1S)-16a and (1R)-16b in good overall yield. We have separately prepared for the first time pa…
Spiroterpenoids from Hypericum reflexum
Abstract Two new spiroterpenoids, hyperireflexolide A and B, were isolated from Hypericum reflexum . Their structures and stereochemistry were established by spectroscopic methods, including 13 C NMR, DEPT and HMQC, and X-ray data.
Different mechanism of relaxation induced by aporphine alkaloids in rat uterus.
Abstract We have examined the uterine relaxant action of three aporphine molecules (S-glaucine, S-boldine and R-apomorphine) in two experimental conditions, with and without calcium in the bathing solution, and compared these effects with those obtained with the calcium antagonists verapamil and diltiazem. The present study shows that the alkaloids relax the uterine muscle but with different mechanisms of action. In Ca2+-containing solution all three alkaloids relaxed the uterus previously contracted by KCl or acetylcholine, but in Ca2+-free medium only R-apomorphine was able to relax oxytocin-induced contraction. The calcium antagonists, verapamil and diltiazem, relaxed KCl- or acetylcholi…