Prodrug design, synthesis and pharmacokinetic evaluation of (3' R, 4' R)-3-hydroxymethyl-4-methyl-3',4'-di-O-(S)-camphanoyl-(+)-cis-khellactone.

3-Hydroxymethyl-4-methyl-DCK (3, HMDCK) was discovered previously as a potent HIV non-nucleoside reverse transcriptase inhibitor (NNRTIs) (EC50: 0.004 µM, TI: 6225) with a novel mechanism of action. It exerts anti-HIV activity by inhibiting the production of HIV-1 double-stranded viral DNA from a single-stranded DNA intermediate, rather than blocking the generation of single-stranded DNA from a RNA template, which is the mechanism of action of current HIV-1 RT inhibitors. However, the insufficient metabolic stability of 3 limits its further clinical development. In the current study, a series of ester prodrugs of 3 was designed and synthesized to explore the new drug candidates as NNRTIs. The l-alanine ester prodrug 10 exhibited desirable pharmacokinetic properties in vitro and in vivo and showed improved oral bioavailability of 26% in rat, and would be a potential clinical candidate as a new anti-AIDS drug.

[Synthesis and antinociceptive activity of seselin derivatives].

Natural product seselin and related derivatives with an angular pyranocoumarin skeleton were synthesized from 8-acetyl-7-hydroxycoumarins by condensation with acetone, reduction, and dehydration successively under mild conditions with total yield of > 50%. Twelve seselin derivatives were tested by the writhing response assay induced by acetic acid at a dose of 40 mg x kg(-1). Seselin (4a) and 4,8,8-trimethyl-9,9-dihydro-pyran[2,3-f] chromene-2,10-dione (2b) showed obviously antinociceptive activity with inhibitory effect of 85% and 50%, respectively, more or quite potent than aspirin in the same assay, suggesting that seselin derivatives could be a novel kind of potential antinociceptive agents.

Development and preclinical studies of broad-spectrum anti-HIV agent (3'R,4'R)-3-cyanomethyl-4-methyl-3',4'-di-O-(S)-camphanoyl-(+)-cis-khellactone (3-cyanomethyl-4-methyl-DCK).

In prior investigation, we discovered that (3'R,4'R)-3-cyanomethyl-4-methyl-3',4'-di-O-(S)-camphanoyl-(+)-cis-khellactone (4, 3-cyanomethyl-4-methyl-DCK) showed promising anti-HIV activity. In these current studies, we developed and optimized successfully a practical 10-step synthesis for scale-up preparation to increase the overall yield of 4 from 7.8% to 32%. Furthermore, compound 4 exhibited broad-spectrum anti-HIV activity against wild-type and drug-resistant viral infection of CD4+ T cell lines as well as peripheral blood mononuclear cells by both laboratory-adapted and primary HIV-1 isolates with distinct subtypes and tropisms. Compound 4 was further subjected to in vitro and in vivo pharmacokinetic studies. These studies indicated that 4 has moderate cell permeability, moderate oral bioavailability, and low systemic clearance. These results suggest that 4 should be developed as a promising anti-HIV agent for development as a clinical trial candidate.

Synthesis of unsymmetrical biphenyls as potent cytotoxic agents.

Twenty-six unsymmetrical biphenyls were synthesized and evaluated for cytotoxic activity against DU145, A549, KB and KB-Vin tumor cell lines. Three compounds 27, 35 and 40 showed very potent activity against the HTCL panel with an IC(50) value range of 0.04-3.23 microM. In addition, fourteen active compounds were all more potent against the drug-resistant KB-Vin cell line than the parental KB cell line. Preliminary SAR analysis indicated that two bulky substituents on the 2,2'-positions of unsymmetrical biphenyl skeleton are necessary and crucial for in vitro anticancer activity, thus providing a good starting point to develop unsymmetrical biphenyls as novel anticancer agents.

[Progress in the new nonnucleoside anti-HIV reverse transcriptase inhibitor-DCK].

3',4'-Di-O-(S)-comphanoyl-(+)-cis-khellactone (DCK) is a synthetic khellactone ester that exhibits potent anti-HIV activity with a mechanism distinct from clinically used anti-HIV agents. Several series of DCK analoges have been synthesized and evaluated for inhibitory effects against HIV. This review article describes recent progress in the discovery, structural modification, and structure-activity relationship studies of potent anti-HIV DCK derivatives.