Rh(I)-Catalyzed 1,4-Conjugate Addition of Alkenylboronic Acids to a Cyclopentenone Useful for the Synthesis of Prostaglandins.

An efficient and trans-diastereoselective Rh(I)-catalyzed 1,4-conjugate addition reaction of alkenylboronic acids and a homochiral (R)-4-silyloxycyclopentenone useful for the synthesis of derivatives of prostaglandins E and F is described for the first time. The reaction functions under mild conditions and is particularly rapid (≤6 h) under low power (50 W) microwave irradiation at 30 °C in MeOH in the presence of a catalytic amount of KOH. Under these conditions, 3 mol % of [RhCl(COD)]2 is typically required to produce high yields. The method also functions without microwave irradiation at 3 °C in the presence of a stoichiometric amount of KOH. Under these conditions, only 1.5 mol % of [RhCl(COD)]2 is needed, but the reaction is considerably slower. The method accepts a range of aryl- and alkyl-substituted alkenylboronic acids, and its utility has been demonstrated by the synthesis of PGF2α (dinoprost) and tafluprost.

Enhanced anti-influenza agents conjugated with anti-inflammatory activity.

Influenza therapy with a single targeted compound is often limited in efficacy due to the rapidly developed drug resistance. Moreover, the uncontrolled virus-induced cytokines could cause the high mortality of human infected by H5N1 avian influenza virus. In this study, we explored the novel dual-targeted bifunctional anti-influenza drugs formed by conjugation with anti-inflammatory agents. In particular, the caffeic acid (CA)-bearing zanamivir (ZA) conjugates ZA-7-CA (1) and ZA-7-CA-amide (7) showed simultaneous inhibition of influenza virus neuraminidase and suppression of pro-inflammatory cytokines. These ZA conjugates provided remarkable protection of cells and mice against influenza infections. Intranasal administration of low dosage (<1.2 µmol/kg/day) of ZA conjugates exhibited much greater effect than the combination therapy with ZA and the anti-inflammatory agents in protection of the lethally infected mice by H1N1 or H5N1 influenza viruses.

Intramolecular ion-pair prodrugs of zanamivir and guanidino-oseltamivir.

Zanamivir (ZA) is a potent anti-influenza drug, but it cannot be administrated orally because of the hydrophilic carboxylate and guanidinium groups. Guanidino-oseltamivir (GO) is another effective neuraminidase inhibitor with polar guanidinium group under physiological conditions. The ester prodrugs ZA-HNAP (5) and GO-HNAP (6) were prepared to incorporate a 1-hydroxy-2-naphthoic (HNAP) moiety to attain good lipophilicity in the intramolecular ion-pairing forms. ZA-HNAP resumed high anti-influenza activity (EC(50)=48 nM), in cell-based anti-influenza assays, by releasing zanamivir along with nontoxic HNAP. Under similar conditions, the hydrolysis of the GO-HNAP ester was too sluggish to show the desired anti-influenza activity.

Overcoming the drug resistance in breast cancer cells by rational design of efficient glutathione S-transferase inhibitors.

A new type of competitive human GST inhibitors has been developed via the bioisostere and structure activity profile strategies; we report their discovery, preparation, inhibitory activity, and synergetic effect in combination with chemotherapy drugs against breast cancer cells.