Upgrading Sustainable Polyurethane Foam Based on Greener Polyols: Succinic-Based Polyol and Mannich-Based Polyol.

It is well known that the traditional synthetic polymers, such as Polyurethane foams, require raw materials that are not fully sustainable and are based on oil-feedstocks. For this reason, renewable resources such as biomass, polysaccharides and proteins are still recognized as one of the most promising approaches for substituting oil-based raw materials (mainly polyols). However, polyurethanes from renewable sources exhibit poor physical and functional performances.

Greener Nanocomposite Polyurethane Foam Based on Sustainable Polyol and Natural Fillers: Investigation of Chemico-Physical and Mechanical Properties.

Nowadays, the chemical industry is looking for sustainable chemicals to synthesize nanocomposite bio-based polyurethane foams, PUs, with the aim to replace the conventional petrochemical precursors. Some possibilities to increase the environmental sustainability in the synthesis of nanocomposite PUs include the use of chemicals and additives derived from renewable sources (such as vegetable oils or biomass wastes), which comprise increasingly wider base raw materials. Generally, sustainable PUs exhibit chemico-physical, mechanical and functional properties, which are not comparable with those of PUs produced from petrochemical precursors.

Impact of Stereochemistry on Ligand Binding: X-ray Crystallographic Analysis of an Epoxide-Based HIV Protease Inhibitor.

A new pseudopeptide epoxide inhibitor, designed for irreversible binding to HIV protease (HIV-PR), has been synthesized and characterized in solution and in the solid state. However, the crystal structure of the complex obtained by inhibitor-enzyme cocrystallization revealed that a minor isomer, with inverted configuration of the epoxide carbons, has been selected by HIV-PR during crystallization. The structural characterization of the well-ordered pseudopeptide, inserted in the catalytic channel with its epoxide group intact, provides deeper insights into inhibitor binding and HIV-PR stereoselectivity, which aids development of future epoxide-based HIV inhibitors.

Synthesis and biological activity of potent HIV-1 protease inhibitors based on Phe-Pro dihydroxyethylene isosteres.

Peptidomimetic inhibitors of HIV-1 PR are still a key resource in the fight against AIDS. Here we describe the synthesis and biological activity of HIV-1 PR inhibitors based on four novel dihydroxyethylene isosteres of the Phe-Pro and Pro-Pro dipeptides. The isosteres, containing four stereogenic centers, were synthesized in high yield and excellent stereoselectivity via the cyclization of epoxy amines derived from α-amino acids.

Synthesis and characterization of novel cardanol based benzoxazines.

Benzoxazines are a class of phenolic compounds extensively studied in polymer science because of their properties as fiber reinforcements, fire-retardants and curing agents. In this article is described a solvent-less process, based on a Mannich reaction involving a primary amine and an aldehyde, for the preparation of new benzoxazines deriving from cardanol (a well known phenol obtained as a renewable organic resource and harmful by-product of the cashew industry). Particular attention is given to the synthesis and chemical characterization (both by 1H NMR spectroscopy and HPLC), while the thermal polymerization process has been monitored by differential scanning calorimetry.

Stereocontrolled synthesis and biological activity of two diastereoisomers of the potent HIV-1 protease inhibitor saquinavir.

A general enantioselective synthesis of new syn-hydroxyethylamine isosteres has been developed. The approach, based on the controlled opening of functionalized optically active 2,3-epoxy amines, can be conveniently used for the preparation of new peptidomimetics with various residues. Finally the total synthesis of two diastereoisomer analogues of HIV-Protease inhibitor Saquinavir has been achieved and their biological activity evaluated.

Development and evaluation of an immunoassay for the monitoring of the anti-HIV drug amprenavir.

An assay for routine therapeutic drug monitoring of anti-HIV HAART drugs in clinical use is highly desirable, in order to rapidly measure the pharmacokinetic parameters on single patients. We have started a project to develop a panel of enzyme-linked immunosorbent assays (ELISA) for the whole set of HAART drugs, and the development, performance and evaluation of the assay for amprenavir is described here. A diazo conjugate of amprenavir has been used in order to raise polyclonal anti-amprenavir antibodies in rabbits.

Synthesis of amino acid derived seven-membered lactams by RCM and their evaluation against HIV protease.

A versatile synthesis of hydroxylated and epoxy 1-azepin 2-ones substituted at N1, C-3 and C-4 or C-7 has been developed. The sequence involves ring-closing metathesis of an amino acid derived diene amide, followed by either epoxidation or dihydroxylation, of the resulting alkene. Assay of the product epoxides (10, 18, 25) and diols (9a, 17, 24) against HIV protease reveals micromolar inhibition.

Stereoselective hydroazidation of amino enones: synthesis of the ritonavir/lopinavir core.

[reaction: see text] The base-catalyzed hydroazidation of alpha'-amino alpha,beta-unsaturated ketones with in situ generated hydrazoic acid was found to proceed with high stereoselectivity in favor of the syn product. The stereoselectivity is controlled by the configuration of the enone and syn/anti ratios up to 7:1 were obtained with secondary and tertiary amines at low temperature. By this route the diamino alcohol core of HIV-PR inhibitors ritonavir and lopinavir was synthesized in 37% yield from phenylalanine.

Synthesis of oligonucleotide-peptide PEG-conjugated: the EGG (oligonucleotide)-chicken (peptide) dilemma?

The synthesis of a peptide-PEG-oligonucleotide chimera is compared when starting from the peptide or from the oligonucleotide sequence.