摘要:
Herein is disclosed a novel and industrially advantageous process for synthesizing acyclic nucleosides such as acyclovir and ganciclovir from ribonucleosides, which process comprises adding an acid catalyst and an acid anhydride to a solution of a ribonucleoside such as guanosine and an ester derivative of an acyclic sugar, and heating the mixture, whereby a transglycosilation reaction takes place between the ribose moiety of the ribonucleoside and the ester derivative of the acyclic sugar. Herein is also disclosed an industrially favorable method for the separation of 9-substituted purine nucleosides which are important intermediates for the synthesis of acyclic nucleosides such as acyclovir, ganciclovir, and the like from ribonucleosides, which method comprises crystallizing only the 9-isomer from a solution or suspension containing both a 9-substituted purine nucleoside and a 7-substituted purine nucleoside by cooling the solution or/and by adding a crystallizing solvent thereto.
摘要:
Herein is disclosed a novel and industrially advantageous process for synthesizing acyclic nucleosides such as acyclovir and ganciclovir from ribonucleosides, which process comprises adding an acid catalyst and an acid anhydride to a solution of a ribonucleoside such as guanosine and an ester derivative of an acyclic sugar, and heating the mixture, whereby a transglycosilation reaction takes place between the ribose moiety of the ribonucleoside and the ester derivative of the acyclic sugar.
摘要:
Herein is disclosed a novel and industrially advantageous process for synthesizing acyclic nucleosides such as acyclovir and ganciclovir from ribonucleosides, which process comprises adding an acid catalyst and an acid anhydride to a solution of a ribonucleoside such as guanosine and an ester derivative of an acyclic sugar, and heating the mixture, whereby a transglycosilation reaction takes place between the ribose moiety of the ribonucleoside and the ester derivative of the acyclic sugar. Herein is also disclosed an industrially favorable method for the separation of 9-substituted purine nucleosides which are important intermediates for the synthesis of acyclic nucleosides such as acyclovir, ganciclovir, and the like from ribonucleosides, which method comprises crystallizing only the 9-isomer from a solution or suspension containing both a 9-substituted purine nucleoside and a 7-substituted purine nucleoside by cooling the solution or/and by adding a crystallizing solvent thereto.
摘要:
Purine derivatives in which a desired substituent is introduced into the 9-position only are synthesized by first introducing an easily-removable substituent in the 7-position of a purine base of natural purine nucleosides obtained through fermentation or derivatives thereof, then hydrolyzing the ribose moiety to form purine derivatives having the substituent in the 7-position, subsequently introducing the desired substituent in the 9-position, and then removing the substituent in the 7-position.
摘要:
Nucleoside derivatives such as 2'-deoxy-2'-bromo-5'-O-acetyl-5-methyluridine, etc., are important intermediates which can be converted into nucleoside derivatives, such as 3'-azido-3'-deoxythymidine, etc., which are useful as medicines.
摘要:
A process for preparing 7-benzylpurine derivatives is provided. An acetylpurine nucleoside is reacted with a benzyl halide to benzylate the 7-position of the purine base, and an acid is then added to the reaction mixture to hydrolyze the glycoside bond. The 7-benzylpurines may be used to prepare 9-substituted purine derivatives.
摘要:
A process for preparing a 2', 3'-dideoxy-2',3'-didehydropyrimidine nucleoside comprising reacting the pyrimidine ribofuranoside with a trialkyl orthoester to yield the 2',3'-O-alkoxyethylidene derivative; which is reacted with hydrogen bromide in acetic acid or acetyl bromide to yield the 2-deoxy-2'-bromo-3'-acetyl-pyrimidine nucleoside; which is then reduced with zinc to yield the 2',3'-olefin of the pyrimidine nucleoside.
摘要:
A crude 2',3'-dideoxynucleoside compound is purified by extracting with an organic solvent, or crystallizing, the 2',3'-dideoxynucleoside compound from a basic aqueous solution having a pH of not less than 12 containing the same. In another embodiment of purification a basic aqueous solution having a pH of not less than 11 of a crude 2',3'-dideoxynucleoside derivative is brought into contact with a nonpolar porous resin, whereby the derivative is adsorbed on the resin, and then the thus adsorbed derivative is desorbed with an aqueous alcoholic solution.2',3'-Dideoxynucleoside compounds which have utility as anti-AIDS drugs or anti-virus drugs can be isolated and purified in high purity and in high yield from their crude products containing impurities.
摘要:
A process for preparing 7-benzylpurine derivatives is provided. An acetylpurine nucleoside is reacted with a benzyl halide to benzylate the 7-position of the purine base, and an acid is then added to the reaction mixture to hydrolyze the glycoside bond. The 7-benzylpurines may be used to prepare 9-substituted purine derivatives. Specifically, a process for producing a 7-benzylpurine compound of Formula (5):