- Preparation method of paraxanthine
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The invention discloses a preparation method of paraxanthine, which comprises the following steps: carrying out N methylation on 7-site and 1-site of guanine nucleoside (V), hydrolyzing glycosyl to obtain a compound (II), reacting the compound (II) with a diazotization reagent, and hydrolyzing to obtain the paraxanthine (I). The raw materials and the auxiliary materials are cheap and easy to obtain, and the industrial price of the main raw material guanosine is only 90 yuan/KG; the steps are short, and the total yield is not less than 70%; the reaction conditions are mild, and the method is safe and reliable; and the method is simple to operate, stable in process and suitable for industrialization.
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- Preparation method of 1,7-dimethylxanthine
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The invention provides a preparation method of 1,7-dimethylxanthine. The method specifically includes firstly, a compound (III) reacts with a methylation reagent in a certain solvent in the presence or absence of alkali to obtain a compound (II); secondly
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Paragraph 0045; 0048; 0049; 0052; 0061; 0064; 0065; 0068
(2019/06/27)
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- Preparation methods of 1, 7-dimethylxanthine and intermediate thereof, and intermediate
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The invention provides two preparation methods of 1, 7-dimethylxanthine, an intermediate thereof and a preparation method of the intermediate. The two preparation methods of 1, 7-dimethylxanthine, provided by the invention, have advantages of convenient o
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- MLKL INHIBITORS
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Purine derivatives that inhibit cellular necroptosis and/or human MLKL, pharmaceutical compositions thereof, and methods of treating an MLKL-mediated disorder with an effective amount of the compound or composition. Said MLKL-mediated disorder is pathology associated necroptosis, including ischemia-reperfusion damage, neurodegeneration, and inflammatory diseases such as acute pancreatitis, multiple sclerosis, inflammatory bowel disease, and allergic colitis.
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Paragraph 0613-0614; 0725-0726
(2018/09/26)
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- Discovery of a new class of highly potent necroptosis inhibitors targeting the mixed lineage kinase domain-like protein
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We report the development of novel Mixed Lineage Kinase Domain-Like protein (MLKL) inhibitors with single nanomolar potency (compound 15 is also named as TC13172). Using the converting biochemistry to chemistry activity-based protein profiling (BTC-ABPP) method, we were able to determine that the inhibitors covalently bind to Cysteine86 (Cys-86) of MLKL. This is the first example of the use of LC-MS/MS to identify the binding site of an MLKL inhibitor. The novel MLKL inhibitors provide powerful tools to study the biological function of MLKL and demonstrate that MLKL should be viewed as a druggable target.
- Yan, Bo,Liu, Lei,Huang, Shaoqiang,Ren, Yan,Wang, Huayi,Yao, Zhenglin,Li, Lin,Chen, She,Wang, Xiaodong,Zhang, Zhiyuan
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supporting information
p. 3637 - 3640
(2017/04/03)
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- Inhibition of radical-induced DNA strand breaks by water-soluble constituents of coffee: Phenolics and caffeine metabolites
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Epidemiological studies have associated coffee consumption with an inverse risk of developing Parkinson's disease, hepatocellular carcinoma and cirrhosis. The molecular mechanisms by which low concentrations of the constituents of coffee measured in human plasma can reduce the incidence of such diseases are not clear. Using an in vitro plasmid DNA system and radiolytically generated reactive oxygen species under constant radical scavenging conditions, we have shown that coffee chlorogenic acid, its derivatives and certain metabolites of caffeine reduce some of the free radical damage sustained to the DNA. A reduction in the amount of prompt DNA single-strand breaks (SSBs) was observed for all compounds whose radical one-electron reduction potential is a limited antioxidant role for such compounds in their interaction with DNA radicals.
- Rathod,Patel,Das,Tipparaju,Shinde,Anderson, Robert F.
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p. 480 - 487
(2013/07/19)
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- Relative contribution of rat cytochrome P450 isoforms to the metabolism of caffeine: The pathway and concentration dependence
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The aim of the present study was to estimate the relative contribution of rat P450 isoforms to the metabolism of caffeine and to assess the usefulness of caffeine as a marker substance for estimating the activity of P450 in rat liver and its potential for
- Kot, Marta,Daniel, Wladyslawa A.
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p. 1538 - 1549
(2008/09/16)
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- The relative contribution of human cytochrome P450 isoforms to the four caffeine oxidation pathways: An in vitro comparative study with cDNA-expressed P450s including CYP2C isoforms
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The aim of the present study was to estimate the relative contribution of cytochrome P450 isoforms (P450s), including P450s of the CYP2C subfamily, to the metabolism of caffeine in human liver. The experiments were carried out in vitro using cDNA-expresse
- Kot, Marta,Daniel, Wladyslawa A.
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p. 543 - 551
(2008/12/20)
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- Determination of P4501A2 activity in human liver microsomes using [3-14C-methyl]caffeine
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Caffeine N3-demethylation, the major pathway of caffeine metabolism in man, is mediated by P4501A2. The carbon of the methyl group lost during N3-demethylation is eliminated as carbon dioxide in vivo, or as formaldehyde and formic acid in vitro. A simple
- Bloomer,Clarke,Chenery
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p. 917 - 927
(2007/10/03)
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- Purines. XIV [1]. Synthesis and properties of 8-nitroxanthine and its N- methyl derivatives
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Xanthine (1) and its N-methyl derivatives 2-16 have been nitrated to the corresponding 8-nitro derivatives 17-32 under different reaction conditions. Nitration in glacial acetic acid with nitric acid works well with the N-7 unsubstituted and some of the 9-methylxanthines, respectively, whereas the 7- methylxanthine derivatives react best with nitronium tetrafluoroborate in sulfolane or glacial acetic acid. The 8-nitro group can be displaced nucleophilically to form 8-chloro-, 33, 34, 8-ethoxy-, 35, 36, and uric acid derivatives 37-40, respectively. The newly synthesized 8-nitroxanthines have been characterized by elemental analyses, pK-determinations and uv and 1H- nmr spectra.
- Mosselhi,Pfleiderer
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p. 1221 - 1228
(2007/10/02)
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- Purines. XLIX. Synthesis and proton nuclear magnetic resonance study of 3,7-dialkylxanthines and 1,3,7-trialkylxanthines
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A general synthetic route to 3,7-dialkylxanthines (type 9) from 3,7-dialkyladenines (6) [hence from 3- or 7-alkyladenines (11 or 10)] has been established. The route started with ethoxycarbonylation of 1-alkyl-4-(alkylamino)1H-imidazole-5-carboxamides (7), readily obtainable from 6 by alkaline hydrolysis, and proceeded through cyclization of the resulting carbamates (8) under alkaline conditions. Alkylation of 9 with alkyl halide in N,N-dimethylformamide in the presence of anhydrous K2CO3 extended the above synthetic route to the 1,3,7-trialkylxanthine level (type 14). Hydrogenolytic deb nzylation of 3-benzyl-1,7-dimethylxanthine (16), prepared by following this general synthetic route, furnished paraxanthine (26) in fair yield. Conversion of 26 into 3-(4-hydroxy-3-nitrobenzyl)-1,7-dimethylxanthine (24), isomeric with the bryozoan purine phidolopin (2), was effected through aralkylation with 4-(methoxymethoxy)-3-nitrobenzyl bromide (28) followed by O-deprotection. On the basis of proton nuclear magnetic resonance data for the 3,7-dialkylxanthines (3 and 9b-i) and 1,3,7-trialkylxanthines (5 and 14-22) thus prepared, reliable criteria for distinguishing signals of N-alkyl substituents at various positions are put forward.
- Fujii,Saito,Tamura
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p. 2855 - 2862
(2007/10/02)
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- PURINES, PYRIMIDINES, AND CONDENSED SYSTEMS BASED ON THEM VII. A NEW METHOD FOR THE SYNTHESIS OF 1,7-DIALKYLXANTHINES
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1-Methyl-3-aminoxanthine (yield 55percent) and 1-methyl-3,7-diaminoxanthine (10percent) were obtained by the amination of 1-methylxanthine by hydroxylamine-O-sulfonic acid in an aqueous alkaline medium.Alkylation of the 1-methyl-3-aminoxanthine potassium
- Gulevskaya, A. V.,Kuz'menko, V. V.,Pozharskii, A. F.,Kuz'menko, T. I.
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p. 1142 - 1145
(2007/10/02)
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- 2,6-Dialkoxy-7-methylpurines
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The preparation of unsymmetrical 2,6-dialkoxy-7-methylpurines (2), and 2-alkoxy-1,7-dialkyl-6-oxo-1,6-dihydropurines (5) is described.In contrast to 1 and 2, a facile thermal lactim-lactam rearrangement from hypoxanthines 5 and 7 into xanthines 6 was observed. - Keywords: Nucleophilic heteroaromatic substitution; thermal lactim-lactam rearrangement; Sigmatropic shifts; Dialkoxy-7H-purines; Dialkyl-1H(or 3H),7H-hypoxanthines; Trialkyl-7H-xanthines
- Kowalska, Alicja,Maslankiewicz, Andrzej,Syrek, Barbara,Cieplinski, Piotr
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p. 341 - 352
(2007/10/02)
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