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The stereoselective total synthesis of cytotoxic marine macrolide callyspongiolide has been reported. The 14-membered macrolactone ring along with Z -olefin in the molecule was constructed via an intramolecular Horner–Wadsworth–Emmons olefination in a Z -selective fashion. The other E -olefinic moiety as well as the C9 stereocenter was introduced via stereoselective addition of the methyl group in an S N 2′ fashion. The C5 stereocenter was installed via Sakurai allylation, whereas the C7 center was fixed by Jacobsen hydrolytic kinetic resolution. The C12 methyl and C13 hydroxy centers were fixed via Macmillan coupling reaction. The macrolactone core with a vinyl iodide side chain was coupled with the known alkyne fragment to complete the synthesis.

A concise synthetic strategy has been developed for the synthesis of the macrolactone core 2 of a unique polyketide callyspongiolide 1. The key features of the strategy included an Evan's asymmetric alkylation, diastereoselective Michael type alkylation, Brown's asymmetric allylation reaction, an allylic alkylation of an activated Z-allylic alcohol and an intramolecular Z-selective intramolecular H-W-E olefination.

SummaryA practical, mild and efficient protocol for the Pictet–Spengler reaction catalyzed by cyanuric chloride (trichloro-1,3,5-triazine, TCT) is described. The 6-endo cyclization of tryptophan/tryptamine and modified Pictet–Spengler substrates with both electron-withdrawing and electron-donating aldehydes was carried out by using a catalytic amount of TCT (10 mol %) in DMSO under a nitrogen atmosphere. TCT catalyzed the Pictet–Spengler reaction involving electron-donating aldehydes in excellent yield. Thus, it has a distinct advantage over the existing methodologies where electron-donating aldehydes failed to undergo 6-endo cyclization. Our methodology provided broad substrate scope and diversity. This is indeed the first report of the use of TCT as a catalyst for the Pictet–Spengler reaction.

A wide range of substituted pyridine derivatives were synthesized in moderate to good yields from N‐propargylic α‐enamino esters. The synthetic strategy involved regioselective addition of a propargylamine to the α‐carbon atom of an alkynyl ester to produce the N‐propargylic α‐enamino ester, which acted as the key intermediate in the synthesis.

The present anticancer research demands more potent anticancer agents with fewer side effects than the existing ones. A series of novel substituted thiazole and benzothiazole containing nitrogen mustards (5-8; 15-17; 22-23) were synthesized and the structures of the compounds were analyzed by IR, NMR and mass spectras. Their in-vitro cytotoxicity against human lung carcinoma (A549) was investigated by MTT Assay. The compounds 16, 8 showed promising activity against A549 human lung carcinoma cell lines with % CPI 52 (More than Cisplatin) and 45.9 respectively. The DNA binding properties of the compounds were also evaluated based on their affinity or intercalation with CT-DNA measured with absorption titration. The compounds 22 and 5 showed the highest binding affinity with binding constant (Ki) 48.34 and 41.8 respectively.

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The design, synthesis, X-ray structural, and biological evaluation of a series of highly potent HIV-1 protease inhibitors are reported herein. These inhibitors incorporate novel cyclohexane-fused tricyclic bis-tetrahydrofuran as P2 ligands in combination with a variety of P1 and P2' ligands. The inhibitor with a difluoromethylphenyl P1 ligand and a cyclopropylaminobenzothiazole P2' ligand exhibited the most potent antiviral activity. Also, it maintained potent antiviral activity against a panel of highly multidrug-resistant HIV-1 variants. The corresponding inhibitor with an enantiomeric ligand was significantly less potent in these antiviral assays. The new P2 ligands were synthesized in optically active form using enzymatic desymmetrization of meso-diols as the key step. To obtain molecular insight, two high-resolution X-ray structures of inhibitor-bound HIV-1 protease were determined and structural analyses have been highlighted.