A convenient procedure for the synthesis of ceramides

A procedure for the preparation of ceramides by direct coupling of long-chain bases and fatty acids in the presence of a mixed carbodiimide is described. This method has been used to prepare ceramides containing sphing-4-enine or sphinganine and various saturated and unsaturated fatty acids as well as saturated 2-hydroxy acids. Ceramides containing 4-hydroxy sphinganine and saturated nonhydroxy acids have also been prepared. The yields were 60-75%. The characterization of these compounds by gas-liquid chromatography-mass spectrometry as trimethylsilyl derivatives has been previously reported. Some of the ceramides are further characterized in this report by infrared spectroscopy and one compound, in addition, by elementary analysis. Use of racemic constituents for 2-hydroxy acid ceramide syntheses leads to the formation of diastereoisomers which separate by thin-layer chromatography. These were characterized by gas-liquid chromatography-mass spectrometry as the trimethylsilyl derivatives and by infrared spectroscopy. Their configurations were established by syntheses with optically active constituents.     

A convenient procedure for the synthesis of nonsymmetrical bivalent selective serotonin reuptake inhibitors using polymer-supported reagents

A convenient synthesis of nonsymmetrical bivalent inhibitors of the serotonin transporter is described. The synthesis utilizes polymer-supported reagents that allow for rapid access to novel bivalent ligands without the need for isolation or purification of synthetic intermediates.     

A convenient microtitre tray procedure for yeast identification

Media for yeast identification tests were incorporated into the wells of a microtitre tray. The tests included fermentation and assimilation of carbohydrates, assimilation of nitrogen compounds, growth in vitamin-free medium, resistance to cycloheximide, and observations for cell morphology and sporulation. Results of tests conducted in the trays showed very good agreement with those obtained by conventional methods. Eighteen reference yeasts were correctly identified from tests conducted in the trays. The trays of media could be stored, and provided a convenient system for yeast identification.     

A convenient microtitre tray procedure for yeast identification

Media for yeast identification tests were incorporated into the wells of a microtitre tray. The tests included fermentation and assimilation of carbohydrates, assimilation of nitrogen compounds, growth in vitamin-free medium, resistance to cycloheximide, and observations for cell morphology and sporulation. Results of tests conducted in the trays showed very good agreement with those obtained by conventional methods. Eighteen reference yeasts were correctly identified from tests conducted in the trays. The trays of media could be stored, and provided a convenient system for yeast identification.     

A convenient method for the synthesis of oligonucleotide-cationic peptide conjugates

A method was developed for the synthesis of oligonucleotide-cationic peptide conjugates in solution phase by disulfide bond formation. Precipitation was avoided by the easily removable triethylammonium trifluoroacetate (TEATFAc) salt which served at the same time as a buffer of the reaction mixture. The fast and high yielding disulfide bond formation was due to the Npys thio protecting and activating group of Cys. A solution of the free 5-thiol modified oligonucleotide obtained from Poly-Pak purification was used for conjugation.     

An efficient and convenient procedure for the synthesis of nα-Fmoc-O-monobenzyl phosphonotyrosine

An efficient procedure is described for the synthesis of N^α-Fmoc-O-monobenzyl phosphonotyrosine from the corresponding dibenzyl derivative by monodebenzylation in the presence of sodium iodide. A simple work up procedure removes the by-products and the monobenzylated phosphono product is obtained in high yield. © 1998 European Peptide Society and John Wiley & Sons, Ltd.     

A test for choosing the most convenient procedure for chloropigment analysis by RP-HPLC

A test to choose the most appropriate procedure for the analysisof chloropigments in natural marine samples is described. Thistest allows the selection of the most convenient RP-HPLC method:a rapid one or a gradient method with which both polar and non-polarchloropigments can be analysed.     

A convenient method of isoflavonone synthesis

Reaction of 2-hydroxydeoxybenzoins with bis(dimethylamino)methane in ethanol results in isoflavonones.     

A convenient synthesis of glucose monomycolate

An efficient synthesis of glucose monomycolate, an important lipidic antigen from Mycobacterium tuberculosis is described.     

A convenient synthesis of GDP D-glycero-alpha-D-manno-heptopyranose

GDP D-glycero-alpha-D-manno-Heptopyranose has been prepared in good overall yield from 2,3,4,6,7-penta-O-acetyl-D-glycero-D-manno-heptopyranose by a short-step synthesis. Phosphitylation using the phosphoramidite procedure afforded the alpha-anomer in high selectivity. Subsequent oxidation and partial deprotection gave the acetylated phosphate derivative, which was subjected to the coupling reaction with GMP-morpholidate to furnish the acetylated heptose nucleoside diphosphate in good yield. De-O-acetylation and final purification afforded the target GDP D-glycero-alpha-D-manno-heptopyranose, which serves as the substrate of the heptosyl transferase in Aneurinibacillus thermoaerophilus DSM 10155 and occurs as an intermediate in the biosynthesis of GDP 6-deoxy-heptose in Yersinia pseudotuberculosis.     

A convenient procedure for rapid release of protoplasts from Ustilago maydis

Filtrates from cultures of Trichoderma harzianum, grown on a liquid mineral salts medium containing vitamin and trace element supplements, 0.5 g/l glucose and 2 g/l of dried residue of ethanol-extracted commercial mushrooms (Agaricus brunnescens), are a good source of enzymes for the release of protoplasts from the sporidia of Ustilago maydis. When concentrated 50-fold by (NH4)2SO4 precipitation, the enzymes liberated 95% of the protoplasts from the sporidia within 40 min.     

A convenient method of isoflavonone synthesis

Reaction of 2-hydroxydeoxybenzoins with bis(dimethylamino)methane in ethanol results in isoflavonones.