摘要:
The present invention relates to a process for the preparation of 5-amino-3H-thiazolo[4,5-d]pyrimidin-2-one which is a useful intermediate in the preparation of certain thiazolo[4,5-d]pyrimidine nucleosides. The process comprises halogenating 2,4-diaminopyrimidine to form 2,4-diamino-5-halo-pyrimidine and then cyclocondensing the 2,4-diamino-5-halo-pyrimidine to form 5-amino-3H-thiazolo[4,5-d]pyrimidin-2-thione. The 5-amino-3H-thiazolo[4,5-d]pyrimidin-2-thione is then oxidized to afford the 5-amino-3H-thiazolo[4,5-d]pyrimidin-2-one.
摘要:
Chiral hydroxyethylamine, hydroxyethylurea or hydroxyethylsulfonamide isostere containing retroviral protease and renin inhibitors can be prepared by multi-step syntheses that utilize key chiral amine intermediates. This invention is a cost effective method of obtaining such key chiral amine intermediates enantiomerically, diastereomerically and chemically pure. The method is suitable for large scale (multikilogram) productions. This invention also encompasses organic acid and inorganic acid salts of the amine intermediates.
摘要:
Multiple novel reaction schemes, novel process steps and novel intermediates are provided for the synthesis of epoxymexrenone and other compounds of Formula I wherein: -A-A- represents the group —CHR4—CHR5— or CR4═CR5— R3, R4 and R5 are independently selected from the group consisting of hydrogen, halo, hydroxy, lower alkyl, lower alkoxy, hydroxyalkyl, alkoxyalkyl, hydroxycarbonyl, cyano, aryloxy, R1 represents an alpha-oriented lower alkoxycarbonyl or hydroxyalkyl radical, -B-B- represents the group —CHR6—CHR7— or an alpha- or beta-oriented group: where R6 and R7 are independently selected from the group consisting of hydrogen, halo, lower alkoxy, acyl, hydroxyalkyl, alkoxyalkyl, hydroxycarbonyl, alkyl, alkoxycarbonyl, acyloxyalkyl, cyano, aryloxy, and R8 and R9 are independently selected from the group consisting of hydrogen, halo, lower alkoxy, acyl, hydroxyalkyl, alkoxyalkyl, hydroxycarbonyl, alkyl, alkoxycarbonyl, acyloxyalkyl, cyano, aryloxy, or R8 and R9 together comprise a carbocyclic or heterocyclic ring structure, or R8 or R9 together with R6 or R7 comprise a carbocyclic or heterocyclic ring structure fused to the pentacyclic D ring.
摘要:
Multiple novel reaction schemes, novel process steps and novel intermediates are provided for the synthesis of epoxymexrenone and other compounds of Formula I wherein: —A—A—, —B—B—, R1, R3, R8 and R9 are as defined in the specification.
摘要:
Chiral hydroxyethylamine, hydroxyethylurea or hydroxyethylsulfonamide isostere containing retroviral protease and renin inhibitors can be prepared by multi-step syntheses that utilize key chiral amine intermediates. This invention is a cost effective method of obtaining such key chiral amine intermediates enantiomerically, diastereomerically and chemically pure. The method is suitable for large scale (multikilogram) productions. This invention also encompasses organic acid and inorganic acid salts of the amine intermediates.
摘要:
A method of separating enantiomeric lactam esters. The lactam esters are contacted with a biocatalyst, such as an enzyme or a microorganism, in a solution wherein only one enantiomer is selectively hydrolyzed to give the optically active isomer of the corresponding acid. The hydrolysis product is then separated from the unreacted lactam esters. The enzyme is then recycled for reuse in the next enzymatic resolution. The undesired isomer is also racemized and reused in the next enzymatic resolution.
摘要:
A method for preparing a chiral beta amino acid or its corresponding esters which comprises contacting a racemic beta amino acid, an acyl donor and Penicillin G acylase enzyme under conditions appropriate to stereoselectively acylate one enantiomer of the racemic beta amino acid to its corresponding N-acylated derivative whereby the opposite enantiomer of the beta amino acid is retained in enantiomerically enriched form.
摘要:
A synthesis is described for intermediates which are readily amenable to the large scale preparation of hydroxyethylurea-based chiral HIV protease inhibitors. The method includes forming a diastereoselective epoxide or cyanohydrin from a chiral alpha amino aldehyde.
摘要:
A process for preparing higher order cuprate complexes by reacting an alkyne with zirconocene chloride hydride to produce a zirconium intermediate which is reacted with an alkyllithium and a first copper reagent selected from R.sup.2 Cu(CN)Li or the mixture CuCN and R.sup.2 Li to produce a higher order cuprate complex.
摘要:
This invention encompasses a process for preparing higher order cuprate complexes which contain a carbanion for the formation of carbon to carbon bonds in reactions such as epoxide addition. The complex is formed by reacting a first cuprate complex with a stannane such that the carbanion to be used to form carbon to carbon bonds is transferred from the stannane to the first cuprate complex to form a different higher order cuprate complex. This process permits the in situ preparation of a higher order cuprate complex having the carbanion desired to be used in a synthetic reaction. Higher order cuprate complexes derived from the reaction of a cuprate complex with 1,2-bis-tri-n-butylstannyl ethylene are particularly useful for the addition to epoxides to form vinyl tin intermediates useful for preparing omega side chains of prostaglandins.