Abstract: The present disclosure relates to a method for preparing caronic anhydride. The method comprises cyclizing caronic acid to obtain crude caronic anhydride; and using isopropyl ether to recrystallize the crude caronic anhydride to obtain caronic anhydride.

Abstract: Provided is a preparation method for 1-substituted-1H-1, 2, 3-triazole-4-carboxylic acid. 1-Substituted-4, 5-dibromo-1H-1,2,3-triazole is added to an isopropylmagnesium chloride to obtain 1-substituted-4-bromo-1H-1,2,3-triazole by a reaction; then an isopropylmagnesium chloride-lithium chloride composite is added directly to obtain a mixture of 1-substituted-1H-1,2,3-triazole-4-carboxylic acid and 1-substituted-4-bromo-1H-1,2,3-triazole-5-carboxylic acid; secondly, to the mixture, a base and iodomethane are added to obtain 1-substituted-4-bromo-1H-1,2,3-triazole-5-carboxylic acid methyl ester by a reaction; the aqueous layer is adjusted with hydrochloric acid to pH=1-5, extracted with an organic solvent and dried; then 1-substituted-1H-1,2,3-triazole-4-carboxylic acid is obtained by concentration and crystallization. The method is suitable for industrialized production and has a greater application value.

Abstract: Provided is a preparation method for 1-substituted-1H-1, 2, 3-triazole-4-carboxylic acid. 1-Substituted-4, 5-dibromo-1H-1,2,3-triazole is added to an isopropylmagnesium chloride to obtain 1-substituted-4-bromo-1H-1,2,3-triazole by a reaction; then an isopropylmagnesium chloride-lithium chloride composite is added directly to obtain a mixture of 1-substituted-1H-1,2,3-triazole-4-carboxylic acid and 1-substituted-4-bromo-1H-1,2,3-triazole-5-carboxylic acid; secondly, to the mixture, a base and iodomethane are added to obtain 1-substituted-4-bromo-1H-1,2,3-triazole-5-carboxylic acid methyl ester by a reaction; the aqueous layer is adjusted with hydrochloric acid to pH=1-5, extracted with an organic solvent and dried; then 1-substituted-1H-1,2,3-triazole-4-carboxylic acid is obtained by concentration and crystallization. The method is suitable for industrialized production and has a greater application value.

Abstract: Disclosed is a 2-substituted-2H-1,2,3-triazole derivative, a compound as represented by formula I or II. Also disclosed is a preparation method of the compound as represented by formula I or II, in particular to a preparation method of 2-substituted-4-bromo-5-chloro-1H-1,2,3-triazole, 2-substituted-4-bromo-5-iodo-1H-1,2,3-triazole, and 2-substituted-5-chloro-1H-1,2,3-triazole-4-carboxylic acid. The preparation methods of the present invention are simple and feasible, and has high yield of the obtained compounds.

Abstract: Disclosed is a 2-substituted-2H-1,2,3-triazole derivative, a compound as represented by formula I or II. Also disclosed is a preparation method of the compound as represented by formula I or II, in particular to a preparation method of 2-substituted-4-bromo-5-chloro-1H-1,2,3-triazole, 2-substituted-4-bromo-5-iodo-1H-1,2,3-triazole, and 2-substituted-5-chloro-1H-1,2,3-triazole-4-carboxylic acid. The preparation methods of the present invention are simple and feasible, and has high yield of the obtained compounds.

Abstract: A method for preparing 2-(N-substituted)-amino-benzimidazole derivatives is provided, which comprises the following steps: (1) reacting a compound of 2-(N-protecting group)-O-aryl diamine with a compound of N-phenoxycarbonyl monosubstituted amine to obtain a compound of 2-(N-protecting group)-amino aryl urea; (2) in a suitable organic solvent, performing dehydrating cyclization reaction of the compound of 2-(N-protecting group)-amino aryl urea in the presence of an organic base and dichloro triphenylphosphine prepared by triphenylphosphine oxide with oxalyl chloride or diphosgene or triphosgene, or dibromo triphenylphosphine prepared by triphenylphosphine oxide with bromine, to produce a compound of 1-protecting group-2-(N-substituted)-amino-benzimidazole; (3) deprotecting the resulting compound of 1-protecting group-2-(N-substituted)-amino-benzimidazole to obtain the compound 2-(N-substituted)-amino-benzimidazole.

Abstract: Disclosed is a preparation method of high-optical purity N2-[1-(S)-ethoxycarbonyl-3-phenylpropyl]-N6-trifluoroacetyl-L-lysine. The method includes: adding crude N2-[1-(S)-ethoxycarbonyl-3-phenylpropyl]-N6-trifluoroacetyl-L-lysine to one or more organic solvents, and then reacting with an organic acid to form a salt, which is precipitated, thereby achieving the purpose of separation and purification; next, adding the obtained solid or mother concentrate into deionized water, and then adding an inorganic base or an organic base for basification, so as to adjust the pH value, removing the organic acid, filtering, washing and drying, to obtain the high-optical purity N2-[1-(S)-ethoxycarbonyl-3-phenylpropyl]-N6-trifluoroacetyl-L-lysine, where the molar ratio of 1S-isomer to 1R-isomer is equal to or greater than 99:1.

Abstract: A method for preparing 2-(N-substituted)-amino-benzimidazole derivatives is provided, which comprises the following steps: (1) reacting a compound of 2-(N-protecting group)-O-aryl diamine with a compound of N-phenoxycarbonyl monosubstituted amine to obtain a compound of 2-(N-protecting group)-amino aryl urea; (2) in a suitable organic solvent, performing dehydrating cyclization reaction of the compound of 2-(N-protecting group)-amino aryl urea in the presence of an organic base and dichloro triphenylphosphine prepared by triphenylphosphine oxide with oxalyl chloride or diphosgene or triphosgene, or dibromo triphenylphosphine prepared by triphenylphosphine oxide with bromine, to produce a compound of 1-protecting group-2-(N-substituted)-amino-benzimidazole; (3) deprotecting the resulting compound of 1-protecting group-2-(N-substituted)-amino-benzimidazole to obtain the compound 2-(N-substituted)-amino-benzimidazole.

Abstract: Disclosed is a preparation method of high-optical purity N2-[1-(S)-ethoxycarbonyl-3-phenylpropyl]-N6-trifluoroacetyl-L-lysine. The method includes: adding crude N2-[1-(S)-ethoxycarbonyl-3-phenylpropyl]-N6-trifluoroacetyl-L-lysine to one or more organic solvents, and then reacting with an organic acid to form a salt, which is precipitated, thereby achieving the purpose of separation and purification; next, adding the obtained solid or mother concentrate into deionized water, and then adding an inorganic base or an organic base for basification, so as to adjust the pH value, removing the organic acid, filtering, washing and drying, to obtain the high-optical purity N2-[1-(S)-ethoxycarbonyl-3-phenylpropyl]-N6-trifluoroacetyl-L-lysine, where the molar ratio of 1S-isomer to 1R-isomer is equal to or greater than 99:1.