Volume 20, Issue 2

The genus Neolitsea (Lauraceae) contains over 85 species distributed around the world. These plants have been found to be rich in sesquiterpenes, triterpenes, steroids, and alkaloids. This review summarizes the phytochemical progress and list of all the constituents isolated from the genus Neolitsea over the past few decades. Some biological activities of compounds isolated from this genus are also included.

2,5-Dihydro-2-oxofuran-3-carboxamides were synthesized by a one-pot two-step reaction catalyzed by sodium methoxide. Readily available tertiary α-hydroxyketones were condensed with substituted cyanoacetamides to give 2-imino-2,5-dihydrofuran-3-carboxamides that, without isolation, were hydrolized to the title products.

A new series of 3-aryl-2-hydroxyquinoline-4-carboxylic acids 17a,b , 2-aryl-3-hydroxyquinoline-4-carboxylic acids 12a–d and their derivatives 13–16 and 18–21 were designed, synthesized and evaluated for their antioxidant activity using the ABTS assay method. Compounds 14 and 21a,b showed good antioxidant activity, whereas the remaining compounds displayed mild to moderate activity. All compounds were characterized by physical and spectral data.

Alkanoic acid derivatives bearing a nitroxyl moiety 3a – e were synthesized from 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl ( 1 ) and the corresponding 2-bromoalkane carboxylic acids 2a – e . The herbicidal and antifungal activity of 3a – e was tested. No herbicidal activity of the tested compounds was found. The 2-[(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)oxy]butanoic acid 3c revealed a strong antifungal activity against the pathogenic fungus Phytophthora cactorum .

2-Amino-3-cyanopyridine is a simple precursor for the synthesis of analogues of Egyptian natural products visnagin and khellin. Fused pyrido[2,3- d ]pyrimidines were prepared under mild reaction conditions. The detailed syntheses and spectroscopic data of the synthesised compounds are reported. Some isolated compounds show antibacterial and antifungal activity.

Indole and carbazole derivatives were designed as non-competitive antagonists of the GluK2 receptor. The synthesized compounds were found to interact with the transduction domain of the receptor. The binding pocket is situated within one receptor subunit.

Twenty new N -pyrrolylcarboxylic acids were designed to assume the architecture of contemporary selective COX-2 inhibitors as potential anti-inflammatory agents. The targeted products were synthesized in 70–82% yields by Paal-Knorr cyclization of a set of eight amino acids, acting as primary amines, and four 1,4-dicarbonyl compounds. The latter substrates were prepared by C -alkylation of three commercially available β -dicarbonyl compounds with two ω-bromoacetophenones and used in situ . These compounds inhibit carrageenin-induced rat paw edema and show analgesic activity.

Structural modifications were performed on isoalantolactone in an effort to find compounds with potential anticancer activity. Seven previously unknown adducts of active methylene compounds with isoalantolactone were synthesized by the Michael reaction. Moreover, four derivatives of aryl-substituted isoalantolactone were prepared by the Heck reaction. All synthetic products were evaluated for toxic activities against three different hepatoma cell lines, Bel-7402, SMMC-7721, and Hep G2. Products prepared through the Heck reaction and 3a,b show potential antiproliferative activity against the Hep G2 cell.

Catalytic quantities (2 mol%) of a complex of cobalt containing guanidine and 2,6-pyridinedicarboxylic acid ligands (PDAG-Co) were used for the efficient three-component Mannich reactions of tetrahydro-4-pyranone ( 1 ) with different aromatic aldehydes and aniline derivatives in a one-pot process. Reactions rapidly gave high yields of the corresponding three-substituted tetrahydro-4-pyranones at room temperature. Spectroscopic and X-ray analyses support the formation of anti diastereomers as the major or sole products of the reactions.

A series of new 7-heteroaryl and arylchromones 6a–l were synthesized in moderate to good yields by the Suzuki reaction of the triflate (pseudo halide) 5 and a variety of heteroaryl and aryl boronic acids. The resulting products may be used as precursors for synthesis of potentially relevant compounds. The structures of all synthesized compounds were established based on IR, 1 H NMR, 13 C NMR, and DIPMS.