The plant Pluchea indica is known for its anti-inflammatory, anti-ulcer, anti-pyretic, hypoglycemic, diuretic and anti-microbial activities besides many other pharmacological activities. We have isolated and purified seven compounds from the methanolic root extract of this plant by column chromatography. The compounds were identified by spectroscopic analyses. The anti-amoebic activities of the pure compound R/J/3 was investigated against the HM1 strain of Entamoeba histolytica. The compound, R/J/3 showed the most pronounced anti-proliferative activity at a dose of 50 μg/ml. It also showed a marked activity on cell lysis of trophozoites, 4 h after administration. The cell lytic activity was compared with metronidazole (5 μg/ml) as positive control.

A general and convergent route for the synthesis of the 4a-methylhydrofluorene diterpenoids has been established through a common hexahydrofluorenone intermediate (10) obtained via Pd(0)-catalyzed reductive cyclization of a substituted 2-(2-bromobenzyl) methylene cyclohexane (13). The strategy has been successfully utilized for the synthesis of (+/-)-taiwaniaquinones D (3) and H (5), (+/-)-taiwaniaquinol B (1), (+/-)-dichroanal B (7), and (+/-)-dichroanone (8).

Using Vorbrüggen's protocol, reaction of persilylated uracil with xylofuranose derivatives having 3beta-oxy-3alpha-alkyl substitution produced both alpha- and beta-nucleosides. Only the beta-nucleosides were formed from substrates having the reverse stereochemistry at C-3 or lacking the 3-alkyl substituent. Participation of the 3beta-oxy substituent in stabilizing the incipient C-1 carbonium ion (or oxonium ion) intermediate has been suggested from analysis of energy-minimized conformations.

Insertion of an amino functionality at C-5 Of D-glucose with inversion of configuration, followed by imine formation with the latent aldehyde at C-1 and concomitant reduction furnished the 1-deoxynojirimycin skeleton.

4a-substituted 1,1-dimethyl or 1-carboniethoxy-1-methyl hydrofluorenes carrying various substituents in the aromatic ring could be conveniently synthesized by Pd(0)-catalyzed Heck reaction. The required bromobenzyl-substituted ethylidene cyclohexane substrates were derived from Hagemann's ester (methyl analogue) via condensation with appropriate benzyl bromide, hydrolytic decarboxylation of the ester, 1,4-addition of methyl or cyano group followed by necessary functional group Manipulation, and Wittig olefination. Simple organic transformations converted the vinyl group to carboxy, formyl or hydroxymethyl. The ring juncture stereochemistry of the products Could be ascertained by correlation approach.

A convenient and general method for the synthesis of isoindoline fused with triazoles from ortho-iodobenzyl azide and acetylenes through palladium-copper catalysis is described. (c) 2005 Elsevier Ltd. All rights reserved.

Seven hopane-type saponins were isolated from the methanol extract of Glinus lotoides. Six of them were identified as novel compounds and designated as lotoideside A [3-O-beta-D-xylopyranosyl (1-->2)-alpha-L-rhamnopyranosyl-6 alpha-O-beta-D-xylopyranosyl-22-beta-O-beta-D-glucopyranosyl-16 beta-hydroxy hopane (1)], lotoideside B [3-O-beta-D-xylopyranosyl (1-->2)-alpha-L-rhamnopyranosyl-22-beta-O-beta-D-glucopyranosyl-6 alpha,16 beta-dihydroxyhopane (2)], lotoideside C [3-OD-xylopyranosyl-6 alpha-O-beta-D-xylopyranosyl-16 beta-O-beta-D-xylopyranosyl-22 beta-hydroxyhopane (3)], lotoideside D [3-O-beta-D-xylopyranosyl-16 beta-O-alpha-L-arabinopyranosyl-6 alpha,22-beta-dihydroxyhopane (4)], lotoideside E [3-O-beta-D-xylopyranosyl-6 alpha-O-beta-D-xylopyranosyl-16 beta,22-beta-dihydroxyhopane (5)], and lotoideside F [3-O-beta-D-xylopyranosyl-22-beta-O-beta-D-glucopyranosyl-16 beta-hydroxyhopan-6-one (6)]. The known compound succulentoside B (7) was also encountered. Their structures were elucidated on the basis of one-and two-dimensional NMR spectroscopic techniques, ESIMS and chemical evidences.

From the rhizomes of Curculigo orchioides two phenolic glucosides named orchiosides A and B were isolated besides four known compounds and their structures were elucidated by the combination of 2D-NMR analysis, mass spectrometry and chemical evidences.

Intramolecular [3+2] nitrilimine cycloaddition reactions on carbohydrate-derived substrates proceed in a regioselective fashion, affording structurally novel chiral glycopyrazoles (4–6 and 10a–c) in good yields. The products can be subsequently transformed to bicyclic pyrazoles (viz. 11 from 4) or nucleoside analogues (viz. 12 from 4).

Intramolecular cyclization of 2-pyridyl radicals derived from 2-bromopyridin-3-yl Substituted methylenecycloalkanes 1922, vinylcycloalkanols 23 and 24, allylcycloalkanols 26-28, and butenylcycloalkanols 32-34 proceed via 6-, 7-, 8-, and 9-endo-trig pathways, giving six-, seven-. eight-, and nine-membered ring annulated pyridines respectively. However, the vinyl cyclopentanol 25 produced only the 6-exo-cyclized product 46, while the substituted allylcyclohexanol 29 and the butenylcyclohexanol 31 failed to cyclize, producing only the double bond isomerized debrominated olefins. Thus the method provides a Useful entry to diverse classes of fused pyridines, with the ring size of the cycloalkane and the presence of additional substituents in the ring playing an important role in determining the outcome of the reactions.

[reaction: see text] An efficient, flexible, and stereoselective convergent route for constructing the trans-10-hydroxy-1,1-dimethyloctahydrodibenzo[a,d]cyclohepten-7-ones (5a-c) was achieved via intramolecular Heck reaction. This strategy has been successfully implemented for the syntheses of (+/-)-komaroviquinone (3) through (+/-)-coulterone dimethyl ether (5c) and (+/-)-faveline methyl ether (1a).

The origin and growth of the chemistry of 1,4-benzodioxins. 1,4-benzoxazines and their 2.3-dihydro derivatives are briefly described. This class of compounds has attracted special attention due to their natural occurrence and important biological activities. The structural scaffolds of these heterocycles serve as building blocks in various useful syntheses. The introduction of palladium-catalyzed reactions has added a new dimension to this field by making the synthesis more convenient and general. The purpose of this account is to facilitate and revitalize interest in this field within the synthetic community.

[reaction: see text] A simple synthesis of the 4a-methyltetrahydrofluorene diterpenoids (+/-)-dichroanal B and (+/-)-dichroanone has been achieved through a common hexahydrofluorenone intermediate obtained via Pd(0)-catalyzed reductive cyclization of a substituted 2-(2-bromobenzyl) methylene cyclohexane.

Synthesis of enantiomerically pure carbocyclic nucleoside analogues 10-16 with five-, six-and seven-membered rings has been achieved starting from D-glucose derived tetracyclic isoxazolidinocarbocycle precursors 1-3.Cyclization of 6-chloro pyrimidine derivatives 7-9 to purine derivatives was found to be accomplished by nucleophilic displacement of 6-chloro substituent (by dimethylamino and/or methoxy groups).Apparently, hydrogen bonding between N-3 of the purine ring and a hydoxy substituent at C-2 / plays a crucial role in this transformation.

Functionalized furanose-fused piperidines 4-6 and oxazepines 15-17, useful precursors for structurally unique bioactive nucleosides as well as for potential glycosidase inhibitors, have been synthesized by the application of 1,3-dipolar azide cycloaddition (DAC) reaction on d-glucose based substrates. The strategy works well even with the nucleoside analogue 8, affording the bicyclic nucleoside analogues 11 and 12.

A simple synthesis of chiral spironucleosides and spirobisnucleosides is described. Intramolecular 1,3-dipolar nitrone cycloaddition reaction of d-glucose-derived precursors having olefin at C-3 and nitrone at C-5, C-1, or C-2 (in nor-series) furnished bisisoxazolidinospirocycles 4-7, 11, and 12 in good yields. Reductive ring opening of the isoxazolidine moieties in 4-6 followed by construction of a nucleoside base upon the generated amino groups smoothly yielded spirobisnucleosides 17 and 18 and spironucleosides 20 and 21.

The [3+2] intramolecular nitrone cycloaddition (INC) reaction on appropriately designed olefinic nitrones derived from D-glucose, having the nitrone at C-1 and alpha, beta-unsaturated ester functionalities at C-5 of the sugar backbone, afforded the isoxazolidine fused carbocycles 11-13, which were subsequently transformed into the chiral, tetrahydroxylated cis-azabicyclo[3.3.0]octanones 14-18 in good yields. (C) 2004 Elsevier Ltd. All rights reserved.

An inseparable mixture of nitrogenous glycerolipids was isolated from the Dragendorff positive fraction of the methanol extract of the marine green alga Ulva fasciata, collected from Okha (22°28' N, 69°05' E) at Gujarat (India) coast. Monoacylglyceryl-N,N,N-trimethylhomoserine having 16 : 0 and 18 : 2 fatty acid residues were found to he the predominant components of this fraction. This is the first report of their occurrence in this source.