18257-46-0Relevant articles and documents
Method for preparing Fimasartan
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Paragraph 0037; 0038, (2019/01/16)
The invention discloses a method for preparing Fimasartan. The method comprises the steps that valeronitrile is used as a raw material to prepare pentanimidamide hydrochloride, then pentanimidamide hydrochloride and acetylsuccinic acid diethyl ester conduct a cyclization reaction and an amidation reaction to prepare 2-(2-normal-butyl-4-hydroxyl-6-methylpyrimidine-5-radical)-N,N-dimethylacetamide (intermediate II), the intermediate II is subjected to sulfo-carbonylation through a Lawesson's reagent to obtain 2-(2-normal-butyl-4-hydroxyl-6-methylpyrimidine-5-radical)-N,N-dimethylacetamide (intermediate III), the intermediate III is subjected to an N-alkylation reaction, radicals are protected through detritylation, and Fimasartan is prepared. The preparation method has the advantages of highreaction selectivity, high synthesis yield, high reaction efficiency and the like.
'Green' synthesis of 2-substituted 6-hydroxy-[3H]-pyrimidin-4-ones and 4,6-dichloropyrimidines: Improved strategies and mechanistic study
Opitz, Andreas,Sulger, Werner,Daltrozzo, Ewald,Koch, Rainer
, p. 814 - 824 (2015/05/20)
An improved route to 2-substituted 6-hydroxy-[3H]-pyrimidin-4-ones 4 and to 2-substituted 4,6-dichloropyrimidines 5 is reported. Without using highly toxic reactants, compounds 4 can be prepared conveniently in a one pot synthesis on a one mol scale with average yields up to 80%. 4,6-Dichloropyrimidines 5, which are usually prepared in small quantities, are synthesized with average yields of 80%, using up to 80g of starting material. The mechanism of the chlorination of 4 is investigated computationally for the first time. The results suggest that the chlorination with phosphoryl chloride occurs in an alternating phosphorylation-chlorination manner (pathway 1) which is preferred over a sequence which starts with two phosphorylations. The investigated 4,6-dichloropyrimidines described herein form strong complexes with dichlorophosphoric acid but weak complexes with hydrochloric acid (generated during workup). These latter complexes explain the necessity of using aqueous sodium carbonate during the working up. In order to prevent possible formation of pyrimidinium salts between intermediates or the final dichloropyrimidines and unreacted hydroxypyrimidone, the latter could be deactivated with a strong acid such as dichlorophosphoric acid, thus allowing chlorination but prohibiting salt formation. Because of its general applicability to all nitrogen heterocycle chlorinations with phosphoryl chloride, the proposed route to dichloropyrimidines without solvent or side products, using less toxic reactants, is of general synthetic interest.
Dihydropyrimidine derivatives
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, (2008/06/13)
Novel A-II receptor antagonists have the formula STR1 and its isomer STR2 wherein R 1, R 2, R 3, R 4, R 5, R 6, R 7 and R 8 are as defined herein.