Biomedical subjects
Publications and source records attributed to M Calmes.
The preparation of a new optically active alcohol with a carboxylic function that allowed its attachment to an amine-functionalized insoluble polymer is described. Its first use as a polymer supported chiral auxiliary is demonstrated by asymmetric transformation of two racemic aryl propionic acids via ketene formation (95-96% ee).
Various methodologies published in the literature dealing with alpha-amino carboxylic acid asymmetric synthesis are presented in a digest form. In each case, only some recent or most typical works are mentioned.
Some of the chemistry of amino acids going on in our laboratory (Laboratoire des Amino acides Peptides et Protéines) is described as well as some mass spectrometry methodology for their characterization particularly on solid supports. Several aspects are presented including: (i) the stereoselective synthesis of natural and unnatural amino acids using 2-hydroxypinan-3-one as chiral auxiliary; (ii) the stereoselective synthesis of natural and unnatural amino acids by deracemization of alpha-amino acids via their ketene derivatives; (iii) the synthesis of alpha-aryl-alpha-amino acids via reaction of organometallics with a glycine cation; (iv) the diastereoselective synthesis of glycosyl-alpha-amino acids; (v) the synthesis of beta-amino acids using alpha-aminopyrrolidinopiperazinediones as chiral templates; (vi) the reactivity of urethane-N-protected N-carboxyanhydrides. To characterize natural and non natural amino acids through their immonium ions by mass spectrometry, some methodology is also described.
A new handle usable for solid-phase peptide amide synthesis was designed. New releasing conditions of the peptide using sonication allowed much shorter reaction times at lower TFA concentrations.
A general strategy for the synthesis of destruxin analogues is described and applied to a particular example, D-Lac-6 destruxin E. The tetrapeptide Boc-Ile-N-MeVal-N-MeAla-beta-Ala-OMe (2) was chosen as the basic starting compound, and its preparation was optimized. This fragment was then coupled with the compound (D)Lac-Pro, and the resulting peptide was cyclized by the DEPC or DPPA/HOBt/DMAP methods at 21 and 30% yield, respectively. The biological activity of the analogue obtained was established by injection to an insect host.
In a study of the occurrence of detectable antibodies to SS-A and SS-B in 300 randomly selected mother-infant pairs, three (1%) mother-infant pairs were positive for precipitating antibodies to SS-A. No matched pairs were positive for SS-B. Review of the clinical history of the mother-infant pairs with SS-A antibodies failed to reveal evidence of connective tissue disease or the neonatal lupus syndrome. Follow up of two of the three SS-A positive mother-infant pairs two months after delivery also showed no evidence of disease. While the SS-A antibody may be closely associated with the development of the neonatal lupus syndrome, our study does not support the proposed aetiological nature of the antibody. Random maternal screening for possible SS-A antibody positivity and potential neonatal lupus syndrome does not appear to be warranted.