Privileged substructures are of potentially great importance in medicinal chemistry. These scaffolds are characterized by their ability to promiscuously bind to a multitude of receptors through a variety of favorable characteristics. This may include presentation of their substituents in a spatially defined manner and perhaps also the ability to directly bind to the receptor itself, as well as exhibiting promising characteristics to aid bioavailability of the overall molecule. It is believed that some privileged substructures achieve this through the mimicry of common protein surface elements that are responsible for binding, such as β- and gamma;-turns. As a result, these structures represent a promising means by which new lead compounds may be identified.

The combinatorial synthesis of bicyclic privileged structures or privileged substructures

The biochemistry and medical significance of the flavonoids.

Recent Developments in Ring Opening Polymerization of Lactones for Biomedical Applications

Polycaprolactone (PCL) is an important polymer due to its mechanical properties, miscibility with a large range of other polymers and biodegradability. Two main pathways to produce polycaprolactone have been described in the literature: the polycondensation of a hydroxycarboxylic acid: 6-hydroxyhexanoic acid, and the ring-opening polymerisation (ROP) of a lactone: e-caprolactone (e-CL). This critical review summarises the different conditions which have been described to synthesise PCL, and gives a broad overview of the different catalytic systems that were used (enzymatic, organic and metal catalyst systems). A surprising variety of catalytic systems have been studied, touching on virtually every section of the periodic table. A detailed list of reaction conditions and catalysts/initiators is given and reaction mechanisms are presented where known. Emphasis is put on the ROP pathway due to its prevalence in the literature and the superior polymer that is obtained. In addition, ineffective systems that have been tried to catalyse the production of PCL are included in the electronic supplementary information for completeness (141 references).

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Synthesis of polycaprolactone: a review

Biodegradable synthetic polymers: Preparation, functionalization and biomedical application

Several compounds from Piper species bearing methylenedioxyphenyl moieties are reported for the first time to effectively inhibit the rat liver microsome-mediated aflatoxin B1-DNA binding in vitro. From the preliminary results obtained, a structure-activity relationship is proposed.

Methylenedioxyphenyl Substituted Compounds from Piper Species as Inhibitors of Liver Microsome-Mediated Aflatoxin B1-DNA Binding in vitro.

Enantioselection effected by commercially available hydrolytic enzymes reported in recent years from our own laboratory and those published by other groups is described. The discussion is confined to enantioselection in symmetric diols, amino acids and benzopyran derivatives only. The paper describes a variety of substrates accepted by these hydrolytic enzymes to produce compounds in high enantiomeric excess which can be used as chiral building blocks for the synthesis of compounds of pharmaceutical and synthetic interest.

Chiral Discrimination by Hydrolytic Enzymes in the Synthesis of Optically Pure Materials

[reaction: see text] Using a chemoenzymatic synthetic strategy, (S)-imperanene and its (R)-enantiomer has been synthesized from vanillin in nine steps. The key step in the synthesis involves the use of Pseudomonas cepacia lipase (PS-30) to induce asymmetrization of the intermediary prochiral 1,3-diol in >97% ee.

Enantioselective Synthesis of Imperanene via Enzymatic Asymmetrization of an Intermediary 1,3‐Diol.

Disclosed is a method of synthesizing new optically pure heterocyclic compounds using Pd(0) catalyzed intramolecular cyclizations. Analogs of cyclopentanes, like isoxazoline-2-oxide and furan, with similar framework to the cyclopentanes act as anti-HIV and anticancer agents which opens a whole new field for application of these compounds. Starting from a meso-diol, optically pure compounds were prepared without utilizing chiral ligands at any stage of the synthesis. The stereochemical outcome of the product (>99% ee) was influenced by desymmetrization catalyzed by Pseudomonas cepacia lipase and the stereoselective nature of the palladium catalyzed transformations.

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Kirpal S. Bisht

Papers

Methylenedioxyphenyl Substituted Compounds from Piper Species as Inhibitors of Liver Microsome-Mediated Aflatoxin B1-DNA Binding in vitro.

Chiral Discrimination by Hydrolytic Enzymes in the Synthesis of Optically Pure Materials

Enantioselective Synthesis of Imperanene via Enzymatic Asymmetrization of an Intermediary 1,3‐Diol.

Formation of cyclopentene nitro-ester and derivatives

Unusual Regioselectivity in Pd(0)-Catalyzed Coupling of Allylic Monoacetates and Nitroalkenes: One-Pot Isomerization—Alkylation.