Rachida Benhaddou

Acidic activation of cellulose and its esterification by long‐chain fatty acid

Cellulose-enriched residues from wheat bran can be transformed in bioplastics after esterification of the cellulose by lauroyl chloride. Before the esterification reaction, an activation step with a swelling of the sample in dilute acid and subsequent drying was required. This activation had a marked influence on the amount of esterified product and its degree of substitution. Using pure cellulose as well as cellulose-enriched agricultural residues, we have shown that the cellulose was totally recovered after this pretreatment and that partial hydrolysis of cellulose chains occurred during the drying step, which probably improved the accessibility to chemical reagents. The possible role of sulfuric acid as catalyst for the esterification reaction of the cellulose by lauroyl chloride was discussed.

Valorization of maize bran to obtain biodegradable plastic films

Cellulose-enriched residues from maize bran can be transformed into plastic films after esterification of the cellulose by various fatty acid chlorides. Alkali pretreatment and acidic activation of the sample are necessary before the esterification reaction in order to form esters. The degradation by microorganisms of the plastic film was also studied. We showed that the isolated strain (chromobacterium violaceum) can hydrolyze modified cellulose plastic films.

Synthesis and Antiviral Evaluation of Pyrazinones Substituted with Acyclic Chains.

The synthesis of a series of pyrazine analogues of the anti-herpes compound, acyclovir is described. These syntheses were accomplished by various methods: in the presence of a Lewis acid or NaH for hydroxyethoxymethyl and hydroxybutyl groups or by sequential oxidation/reduction of 1-(beta-D-ribofuranosyl)-2-pyrazinones for 2,3-acyclonucleosides. Antiviral (HSV-1, CMV, Cox B4, HIV-1) properties of these compounds were determined.

Preparation of biodegradable plastic in microwave oven and solvent-free conditions

Abstract With the aim of the obtention of biodegradable material, we describe a new method for the esterification of microcrystalline cellulose. This methodology uses microwave irradiation under solvent-free conditions in the presence of basic catalysts.

Synthesis and antiretroviral evaluation of 3-alkyl 2-piperazinone nucleoside analogs

Abstract Glycosylation of 3-alkyl N 4 -(3-hydroxypropyl) 2-piperazinones by protected 1- O -acetyl ribofuranoses produces nucleoside analogs in which the base is separated from the sugar by a hydrocarbon spacer arm. The preliminary in vitro test results against retroviruses seem promising for compounds bearing a long alkyl chain.

Synthesis and biological evaluation of thioglycosylated meso-arylporphyrins

A new class of porphyrins bearing thioglycosyl groups is presented in order to improve targeting of malignant cells and resistance to glycosidases. These compounds were synthesized in four steps. They produced 1O2 and their photocytotoxicity against the yeast Saccharomyces cerevisiae was compared with the effect of haematoporphyrin.

An Unexpected Result in the Alkylation of Thymine

Abstract A moderate yield (55%) preparation of N-1 substituted thymine has been achieved by reacting an excess of 4-bromobutylacetate at 100 °C for 48 hrs. N-1, N-3 bisalkylated and O-alkylated compounds were also obtained as by-products.

Potential Antiviral Agents. Part II. Synthesis and Antiviral Evaluation of Pyrazinones Substituted With Acyclic Chains

The synthesis of a series of 4-substituted hydroxybutyl pyrazine analogues of the anti-herpes compound, acyclovir, is described. The compounds were characterized with 1H and 13C nmr, mass and IR spectroscopy. Antiviral (HSV-1, CMV, Cox B4, HIV-1) properties of these compounds were examined. None of these compounds were active against these viruses.

A novel route to β-thymidine

Abstract A stereoselective synthesis of β-thymidine using 2-deoxy- D -erythro-pentofuranosyl-trichloroacetimidate as the activating group is reported. This five-step route includes only one chromatographic purification with an overall yield of 30% in β-thymidine and stereoselectivity of approximately 80%.