Current Organic Chemistry - Volume 13, Issue 4, 2009

This review summarizes the synthesis of pheromones published in the triennium 2002-2004. The syntheses of a total of 66 pheromone compounds (65 from insects, 1 from a crustacean species), belonging to 9 different structural categories, are presented in schemes. New methodologies, but also well-known reactions have been employed to achieve the (in many cases stereoselective) synthesis of the compounds.

In the paper rotaxanes containing an electron accepting ring are described, they are followed by those having electron donating ring. Syntheses, properties and possible applications of considered species are presented.

The protoberberines are a widespread, important group of isoquinoline alkaloids. Due to the potent pharmacological and other bioactive properties they have achieved an increasing attention in medicinal chemistry and drug research. This article will give a brief structural classification of the protoberberines and related compounds, the biosynthesis, a compilation of new alkaloids isolated during the last decade including source, structure and analytical/spectral data. The main part of the present review is focused on recent synthesis pathways to the title compounds.

We review recent progress in the discovery and development of small molecule inhibitors against chronic hepatitis B and C infections by listing of the current therapeutic agents and in-depth discussing chemical synthesis and biological results of the recent inhibitor candidates. At present six antiviral drugs have been formally licensed for treatment of chronic HBV infection namely interferon alfa, pegylated interferon alfa-2a and antiviral agents; lamivudine, entecavir, telbivudine and adefovir. Unfortunately, treatment is associated with several side effects and the response rate has been unsatisfactory. β-LPA was recently discovered as a new drug candidate that inhibits viral replication and still in phases II of clinical development. There is an urgent need for the development of novel classes of anti-HBV agents with new molecular structures and optimal pharmacological profiles for the chemotherapy of HBV infection. Although HCV infection can be cured in up to 40% of patients, current treatment is not ideal and is associated with a wide spectrum of side effects and complications. Treatment for HCV has gone through several milestones with the introduction of interferon (IFN) in the early 1990s, the addition of ribavirin in the late 1990s, the pegylation of IFN, and now to the new oral therapies such as BILN 2061, VX-950, JTK-109 and many peptides inhibitors that inhibit viral replication or the translation of viral RNA are in various phases of clinical development. In general, the development of drug-like inhibitors has proven to be a challenging task.

This work aimed at selective synthesis of analogues of cephalostatin 1, a highly anti-cancer marine natural product according to NCI measurements. We summarized here the work done in our laboratories of five years studying the selectivity of certain reactions of cephalostatin-like bis-steroidal pyrazines and hence, the biological activity variation. This study includes chemo-, regio- and stereoselective reactions of analogues starting from the symmetrical bis-steroidal diketone (3), which can be synthesized in a gram scale from the commercially available hecogenine acetate (1a). The following routes have been tested: the regioselective hydroboration of the exocyclic double bond at C-12, the regioselective F-ring opening of the spiroketals moieties, the chemo- and regioselective hydroboration of Δ14,15 double bond and finally, the chemo- and regioselective reduction of the carbonyl group at C-12.