The first synthesis of N-acetylneuraminic acid 1,7-lactone

N-Acetylneuraminic acid is transformed into its until now unavailable and rather unwieldy 1,7-lactone, via the manageable 2-benzyloxycarbonyl N-acetylneuraminic acid 1,7-lactone which generates the free lactone in quantitative yield by hydrogenolysis.     

Acylation of N-acetylneuraminic acid

Summary The direct acylation of N-acetylneuraminic acid takes place ambiguously and leads to two reaction products: the acylated -lactone and the acylated derivative of the pyranose form of the acid.Khimiya Prirodnykh Soedinenii, Vol. 3, No. 2, pp. 191–197, 1967     

Glycosidation of N-acetylneuraminic acid

Conclusions The synthesis of the methyl esters of 9-O-(-D-glucopyranosyl)- and 9-O-(-D-galaetopyranosyl)-N-acetylneuraminic acid is described.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 215–217, January, 1968.     

A new synthesis of lysergic acid

[reaction: see text] (+/-)-Lysergic acid has been synthesized via an economical 8-step route from 4-bromoindole and isocinchomeronic acid without the need to protect the indole during the synthesis. Initial efforts to form the simpler 3-acylindole derivatives first and then cyclize these were unsuccessful in the cyclization step.     

The benzhydryl ester of N-acetylneuraminic acid

Conclusions Benzhydryl protection of the carboxy group of N-acetylneuraminic acid has been described for the first time.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1261–1262, July, 1966.     

A new method for the synthesis of levulinic acid

A two- step method is described for the synthesis of levulinic acid from ethyl acetoacetate and ethyl chloroacetate in 70% yield.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 474–475, February, 1990.     

A new facile synthesis of 5-arninopyridazine-4-carboxylic acid

Hofmann rearrangement of 5-carbamylpyridazine-4-carboxylic acid ( 6 ), obtained from pyrida-zine-4,5-dicarboxylic acid ( 3 ) through the corresponding anhydride ( 5 ), afforded 5-aminopyrida-zine-4-carboxylic acid ( 1 ) in good yield. Compound 1 cyclised with benzoyl chloride in pyridine to give 2-phenylpyridazino[ 4 ,5-d]-1,3-oxazin-4-one ( 7 ), a new heterocyclic ring system. J. Heterocyclic Chem., 14, 1099 (1977)     

A new total synthesis of (±)-clavulanic acid

Regioselective reactions at the terminal double bond of the racemic azetidinone dienylether (4), provides a source of clavulanic acid and several analogues.     

A new process for acrylic acid synthesis by fermentative process

With the synthesis of chemical products through biotechnological processes, it is possible to discover and to explore innumerable routes that can be used to obtain products of high added value. Each route may have particular advantages in obtaining a desired product, compared with others, especially in terms of yield, productivity, easiness to separate the product, economy, and environmental impact. The purpose of this work is the development of a deterministic model for the biochemical synthesis of acrylic acid in order to explore an alternative process. The model is built-up with the tubular reactor equations together with the kinetic representation based on the structured model. The proposed process makes possible to obtain acrylic acid continuously from the sugar cane fermentation.     

Phase managed organic synthesis 2. A new polymer assisted synthesis of acid anhydrides.

A solid-phase copolymer of 4-vinylpyridine is shown to be a highly effective reagent/ catalyst for the synthesis of acid anhydrides from mixtures containing equimolar quantities of carboxylic acids and acid chlorides. The process may be carried out in batch or column mode.     

A capillary zone electrophoresis method for determining N-acetylneuraminic acid in glycoproteins and blood sera

A simple capillary zone electrophoresis (CZE) method for the determination of the content of the major sialic acid form N-acetylneuraminic acid (Neu5Ac) in glycoproteins was established. The present method utilizes a simplified hydrolysis-purification procedure consisting of mild acid hydrolysis (25 mM trifluoroacetic acid for 2h at 80 degrees C) to release Neu5Ac and ultrafiltration on Centricon-3 membrane to remove the obtained asialoglycoproteins and other macromolecules present in biologic samples. Derivatization with benzoic anhydride at 80 degrees C for 20 min resulted in complete conversion of Neu5Ac to per-O-benzoylated Neu5Ac. CZE analysis was performed using the operating buffer 25mM phosphate, pH 3.5, containing 50% (v/v) acetonitrile as organic modifier at 30 kV, and detection of the per-O-benzoylated Neu5Ac at 231 nm. The method showed excellent repeatability (RDS<1.98%) and a linearity range from 5 microg/mL to 5mg/mL with a detection limit of 2 microM. Application of the method to microanalysis of human alpha(1)-acid glycoprotein and blood serum samples showed excellent agreement with previously published values, suggesting a high precision for the developed CZE method.     

A new one-pot synthesis of all E-retinoic acid via a new enaminodiester synthon

A ‘one-pot’ synthesis of allE-retinoic acid from a new enaminodiester was described. The enaminodiester was easily produced from methyl isopropylidenemalonate and DMF-DMA.     

A new one-pot synthesis of difluoro(organylsulfinyl)acetic acid esters

A novel single-step method for the synthesis of esters of difluoro(organylsulfinyl)acetic acids, by reacting aromatic compounds with isopropyl chlorosulfinyldifluoroacetate, was developed. The feasibility of transforming the sulfoxide intermediates into corresponding sulfides and sulfones was demonstrated.     

A new three-step procedure for the synthesis of cyanuric acid from urea

A new procedure for preparing high-purity cyanuric acid from urea was suggested and experimentally checked. The procedure is based on urea silylation, followed by pyrolysis of the silyl derivative and fractional distillation of the trimethylsilyl isocyanate formed, for which the temperature limits of mild hydrolysis were determined.