40 results about "N acylation" patented technology

Provided herein are processes for the preparation of N-acylated amines. In particular, the processes comprise contacting an amine with an acid comprising a carboxylic acid group to form the N-acylated amine.

The present invention provides, as for a method for analyzing the C-terminal amino acid sequence of a peptide by using a reaction for successively releasing the C-terminal amino acids of the peptide, which method can suppress, when successively releasing the C-terminal amino acids of a peptide of long amino acid length, such a undesirable side reaction as cleavage of peptide bond in the intermediate position of the peptide and can carry out the chemical treatment thereof under widely applicable conditions, a following method wherein a dry sample of a peptide with long amino acid length is beforehand subjected to an N-acylation treatment; by using a reaction reagent where an alkanoic acid anhydride is combined with a small amount of a perfluoroalkanoic acid, successive release of C-terminal amino acids is conducted under mild conditions; a hydrolysis treatment is applied; then, selective fragmentization at site of arginine residue is performed by digestion by trypsin; thereafter, decreases in molecular weight are measured for the C-terminal side fragments derived from a series of reaction products by analysis in negative mode of a MALDI-TOF-MS apparatus; thereby, the C-terminal amino acid sequence of the peptide sample is identified.

The present invention provides a method for analyzing the C-terminal amino acid sequence of a peptide by using a reaction for successively releasing the C-terminal amino acids of the peptide, which method can suppress, when successively releasing the C-terminal amino acids of a peptide of long amino acid length, such a undesirable side reaction as cleavage of peptide bond in the intermediate position of the peptide and can carry out the chemical treatment thereof under widely applicable conditions; In the method, a dry sample of a peptide with long amino acid length is beforehand subjected to an N-acylation treatment; by using a reaction reagent where an alkanoic acid anhydride is combined with a small amount of a perfluoroalkanoic acid, successive release of C-terminal amino acids is conducted under mild conditions; a hydrolysis treatment is applied; then, selective fragmentization at site of arginine residue is performed by digestion by trypsin; thereafter, decreases in molecular weight are measured for the C-terminal side fragments derived from a series of reaction products with use of a MALDI-TOF-MS apparatus; thereby, the C-terminal amino acid sequence of the peptide sample is identified.

The invention belongs to the technical field of antibiotic drug synthesis, and particularly relates to a preparation method of cefotiam hydrochloride. The preparation method comprises the following steps of: adding formamido thiazole acetic acid to an organic solvent, adding base and dithio-bisbenzothiazole, stirring, then adding a catalyst, and carrying out condensation reaction, thus obtaining an active ester A, wherein the catalyst is triethyl phosphate; dissolving 7-ACMT in an alkali liquor of the organic solvent, adding the active ester A for carrying out N acylation reaction, adding a water solution after reaction is ended, getting a water layer, adding hydrochloric acid for hydrolysis, and dropwise adding a hydrophilic solvent to separate out the cefotiam hydrochloride. The preparation method has the advantages that reaction conditions are mild, strict anhydrous and anaerobic conditions are not needed, the cost is low, the synthesis process is simple, and the purity and the yield are high.

Provided is a method for producing an optically active ceramide by an N-acylation (amidation) reaction of an optically active aminodiol, wherein a crude ceramide produced therein is purified by an industrially advantageous process. Namely, provided is a method for producing a high-purity ceramide that has high diastereo purity with high yield. A high-purity ceramide is produced by: a step wherein a ceramide represented by general formula (1) is produced by reacting an aminodiol with an alkyl ester having 1-5 carbon atoms of an aliphatic carboxylic acid having 12-24 carbon atoms, said aliphatic carboxylic acid optionally having a hydroxyl group, in a hydrocarbon solvent having 5-10 carbon atoms; and a step wherein an alcohol having 1-3 carbon atoms is added into the reaction mixture obtained in the preceding step, thereby causing crystals to precipitate.(In the formula, R1 represents an alkyl group which has 13-17 carbon atoms and optionally has a carbon-carbon unsaturated bond; R2 represents an alkyl group which has 11-23 carbon atoms and optionally has a hydroxyl group; and * represents an optically active state.).

The present disclosure is related to an improved and efficient process for preparation of (3R,4R)-(1-benzyl-4-methylpiperidin-3-yl)-methylamine which comprises:(a) N-acylation of 3-Amino-4-methyl pyridine; (b) Quarternization of 3-Acetylamino-4-methyl pyridine using benzyl halide; (c) Partial reduction of quarternized 3-Acetylamino-4-methyl pyridine by Sodium borohydride in Methanol or water; (d) Hydrolysis of partially reduced product to 1-Benzyl-4-methylpiperidin-3-one in presence of acid; (e) Reductive amination of 1-Benzyl-4-methylpiperidin-3-one using Methanolic methylamine in presence of Titanium(IV) isopropoxide in Methanol; (f) Resolution of 1-Benzyl-4-methylpiperidin-3-yl)-methylamine using Ditoluoyl (L) tartaric acid to get (3R,4R)-(1-benzyl-4-methylpiperidin-3-yl)-methylamine. The disclosure is also related to novel intermediates:wherein R, R′ and X are as described in the specification.

The beta-amino acid resolving process includes the first N acylation of amino acid; hydrolyzing the acyl radical of the N acylated beta-amino acid in some one configuration in high selectivity with properly selected enzyme while not affecting its antimer and extracting according to the difference of different matters in water solubility and fat solubility to obtain one kind of corresponding optically pure beta-amino acid; and hydrolyzing the acyl radical of the N acylated beta-amino acid in one other configuration with one other kind of selected enzyme to obtain one other kind of optically pure beta-amino acid similarly. The said process is stable, environment friendly, safe, low in cost and with mild production conditions, and the product reach optical purity of 99.9 wt%. The present invention provides one new way for producing optically pure beta-amino acid.