4H-[1,2,5]Oxadiazolo[3,4-d]pyrimidine-5,7-dione 1-oxides (2) are conveniently prepared in high yields by the oxidative intramolecular cyclization of 6-amino-5-nitro-1H-pyrimidine-2,4-diones (1) employing iodosylbenzene diacetate as an oxidant in the presence of lithium hydride. The generation of nitric oxide (NO) and NO-related species from 2 occurs in the presence of thiols such as N-acetylcysteamine
Process for preparing the antiviral agent [1S-(1alpha,3 alpha,4beta)]-2-amino-1,9-dihydro-9-[4-hydroxy-3-(hydroxymethyl)-2-methylenecyclopentyl]-6H-purin-6-one
申请人:——
公开号:US20040192912A1
公开(公告)日:2004-09-30
Processes are disclosed for preparing the antiviral agent entecavir. A resin adsorption process for the isolation and purification of entecavir is also disclosed. Various intermediates useful in the preparation of entecavir are also disclosed.
Process for preparing the antiviral agent [1S-(1alpha,3 alpha,4beta )]-2-amino-1,9-dihydro-9-[4-hydroxy-3-(hydroxymethyl)-2-methylenecyclopentyl]-6H-purin-6-one
申请人:Bristol-Myers Squibb Company
公开号:US07034152B2
公开(公告)日:2006-04-25
Processes are disclosed for preparing the antiviral agent entecavir. A resin adsorption process for the isolation and purification of entecavir is also disclosed. Various intermediates useful in the preparation of entecavir are also disclosed.
Inhibition of Human <i>O</i><sup>6</sup>-Alkylguanine-DNA Alkyltransferase and Potentiation of the Cytotoxicity of Chloroethylnitrosourea by 4(6)-(Benzyloxy)-2,6(4)-diamino-5-(nitro or nitroso)pyrimidine Derivatives and Analogues
作者:Isamu Terashima、Kohfuku Kohda
DOI:10.1021/jm970363i
日期:1998.2.1
A series of 4(6)-(benzyloxy)-2,6(4)-diamino-5-(nitro or nitroso)pyrimidine derivatives and analogues of which 4(6)-benzyloxy groups were replaced with a (2-, 3-, or 4-fluorobenzyl)oxy or (2-, 3-, or 4-pyridylmethyl)oxy group, was synthesized. The abilities of these compounds to inhibit human O-6-alkylguanine DNA alkyltransferase (AGAT) in vitro and to potentiate the cytotoxicity of 1-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-3-(2-chloroethyl)-3-nitrosourea (ACNU) toward HeLa S3 cells were evaluated. 2,4-Diamino-6-[(2-fluorobenzyl)oxy]-5-nitropyrimidine (3) and 2,4-diamino-5-nitro-6-(2-pyridylmethoxy) (6), whose ortho positions of the 6-substituent are modified, were much weaker in terms of these abilities than the corresponding meta-or para-modified compounds. These results are consistent with those,of our previous study using a series of O-6-benzylguanine derivatives. All 5-nitrosopyrimidine derivatives examined exerted both stronger AGAT-inhibition and ACNU-enhancement abilities than the corresponding 5-nitro derivatives. Among a variety of compounds that we have examined to date, 2,4-diamino-6-[(4-fluorobenzyl)oxy]-5-nitrbsopyrimidine (10) exhibited the strongest ability to inhibit AGAT, and its magnitude was 2.5 and 50 times those of 4-(benzyloxy)-2,6-diamino-5-nitrosopyrimidine (9) and O-6-benzylguanine (1), respectively. A strong positive correlation was observed between the ability to inhibit AGAT and to potentiate the cytotoxicity of ACNU. This strongly indicates that 4(6)-(benzyloxy)pyrimidine derivatives and their analogues potentiate ACNU cytotoxicity by inhibiting AGAT activity. To characterize the reactivity of test compounds, alkyl-transfer reactions were also carried out using the biomimetic alkyl-transfer system.