A method is provided to conveniently separate racemic (3R,4S)-3-acetamido-4-allyl-N-(tert-butyl)pyrrolidine-3-carboxamide and (3S,4R)-3-acetamido-4-allyl-N-(tert-butyl)pyrrolidine-3-carboxamide using selective crystallization with chiral carboxylic acids.

A method for preparing an intermediate for avibactam, and specifically relates to a method for preparing ({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulfonyl)tetrabutylammonium salt (II). With 5R-[(benzyloxy) amino] piperidine-2S-carboxylate oxalate (III) as the raw material is reacted with the amide of Formula IV via amidation to prepare the compound of Formula V; the resulting compound of Formula V is reacted with the carbonylation reagent via urea cyclization to obtain the compound of Formula VI; the benzyl or the substituted benzyl in the compound of Formula VI is removed by catalytic hydrogeneration, then the resulting compound is sulfatated by sulfur trioxide complex and is salinized into tetrabutylammonium to obtain the final product (II).

A method for preparing an intermediate for avibactam, and specifically relates to a method for preparing ({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulfonyl)tetrabutylammonium salt (II). With 5R-[(benzyloxy) amino] piperidine-2S-carboxylate oxalate (III) as the raw material is reacted with the amide of Formula IV via amidation to prepare the compound of Formula V; the resulting compound of Formula V is reacted with the carbonylation reagent via urea cyclization to obtain the compound of Formula VI; the benzyl or the substituted benzyl in the compound of Formula VI is removed by catalytic hydrogeneration, then the resulting compound is sulfatated by sulfur trioxide complex and is salinized into tetrabutylammonium to obtain the final product (II).

A compound of Formula III as the raw material is hydrolyzed in an alkaline condition, then acidized to prepare a compound of Formula IV, and the resulting compound of formula IV and a solid phosgene or diphosgene are concurrently subjected to the urea cyclization and the chloroformylation reaction in the presence of an organic base and a catalyst to obtain a compound of formula V, and then the compound of formula V is amidated to obtain the final product (II). In the present invention, a one-pot method is adopted for urea cyclization, chloroformylation, and amidation reaction, and the intermediate products do not need post-treatments such as separation and purification.

A compound of Formula III as the raw material is hydrolyzed in an alkaline condition, then acidized to prepare a compound of Formula IV, and the resulting compound of formula IV and a solid phosgene or diphosgene are concurrently subjected to the urea cyclization and the chloroformylation reaction in the presence of an organic base and a catalyst to obtain a compound of formula V, and then the compound of formula V is amidated to obtain the final product (II). In the present invention, a one-pot method is adopted for urea cyclization, chloroformylation, and amidation reaction, and the intermediate products do not need post-treatments such as separation and purification.

The present invention relates to stereochemically defined polypropionates and methods for preparing and using the same. The stereochemically defined polypropionates may be useful in the synthesis of natural products and/or natural product-like libraries.

The present invention relates to stereochemically defined polypropionates and methods for preparing and using the same. The stereochemically defined polypropionates may be useful in the synthesis of natural products and/or natural product-like libraries.

The present invention relates to a novel polyfluorene appended with protected glutamic acid of Formula (I) for heterogeneous enantioselective separation and sensing of amino acids, amino alcohol, hydroxyl acid, sugar, aromatic drug and ascorbic acid from racemic mixture in water and process for preparation thereof. The present invention further provides a process for separation of enantiomers and diastereomers into their individual isomers using a polyfluorene compounds of Formula (I). ##STR00001##

The present invention relates to a novel polyfluorene appended with protected glutamic acid of Formula (I) for heterogeneous enantioselective separation and sensing of amino acids, amino alcohol, hydroxyl acid, sugar, aromatic drug and ascorbic acid from racemic mixture in water and process for preparation thereof. The present invention further provides a process for separation of enantiomers and diastereomers into their individual isomers using a polyfluorene compounds of Formula (I). ##STR00001##

Provided herein are cinchonium betaine catalysts and methods of promoting asymmetric butenolide isomerization reactions using the same.