Chemical manipulation studies were conducted on betulinic acid (1), twenty-one new rationally designed analogues of 1 with modifications at C-28 were synthesized for their evaluation of inhibitory effects on α-glucosidase and LPS-stimulated nitric oxide production in mouse macrophage RAW 264.7 cells. Compound 2 (IC = 5.4 μM) exhibited an almost 1.4-fold increase in α-glucosidase inhibitory activity on yeast α-glucosidase while analogues 5 (IC 16.4 μM) and 11 (IC 16.6 μM) exhibited a 2-fold enhanced inhibitory activity on NO-production than betulinic acid.

The first total synthesis of 16-Methyleicos-(4E)-en-1-yn-3-ol, a bioactive component of the marine sponge Cribrochalina vasculum was achieved by Evans auxiliary methylation followed by resolution of the corresponding racemates using lipase formulation Novozyme 435 and Mosher's ester method. We report the asymmetric syntheses of four diastereomers (1 a-d) of the natural compound 1 and established the absolute configuration of chiral centers, leading to the revision of the natural product configuration from 3 S to 3 R.

Cu 2+ -doped zeolitic imidazolate framework-8 (ZIF-8)-catalyzed one-pot procedure to synthesize β-keto and vinyl sulfones by the direct oxysulfonylation and hydrosulfonylation of alkynes via radical reaction under mild conditions has been described. The advantages of this protocol included broad substrate scope and excellent β-keto and E-stereoselectivity. The Cu/ZIF-8 catalyst not only exhibited excellent performance but also had a great stability in the reaction, successfully allowing its reuse up to five cycles. This efficient Cu/ZIF-8 heterogeneous catalyst is explored for the first time to generate β-keto and vinyl sulfones.

An efficient bioinspired stereoselective first total synthesis of spinosulfate B has been accomplished following Jacobsen's hydrolytic kinetic resolution, Stille coupling, olefin-cross metathesis (OCM), Horner Wadsworth Emmons olefination, and De Brabander's esterification as key steps. 2 3 4 5 6 7 8

The total syntheses of four polyketides, surinone B (1), alatanones A-B (2-3), and trineurone A (4) were accomplished through an efficient and unified strategy via one-pot C-acylation reaction coupling 1,3-cyclohexadiones with EDC-activated acids under mild conditions. Alatanone A (2) was found to be a potent anti-microbial agent against Gram-positive and Gram-negative bacteria with MIC 31.25 μg/ml while alatanone B (3) was found to be a potent anti-fungal agent against Cladosporium cladosporioides with MIC 62.5 μg/ml compared to cycloheximide MIC 125 μg/ml. Our methodology allows performing kilogram scale of these scarce polyketides for the development of new antimicrobials.