- Method for preparing telmisartan and intermediates thereof
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Disclosed is a telmisartan preparation method, characterized in that: 2-n-propyl-4-methyl-6-(1-methyl benzimidazole-2-yl) benzimidazole (compound I) and 4'-halomethyl diphenyl-2-substituted compound (compound II) conduct a nucleophilic substitution reaction to obtain a compound III; when R is COOH, the compound III is telmisartan; and when R is COOR' or CN, the compound III can be hydrolyzed to obtain telmisartan.
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Paragraph 0112-0113; 0115
(2017/08/31)
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- Process for brominating the side chain of 4-methylbiphenyl derivatives substituted in the 2' position
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A process for preparing 4-bromomethylbiphenyl derivatives substituted in the 2′ position of general formula (I) 1by brominating 4-methylbiphenyl derivatives substituted in the 2′ position of general formula (II) 2wherein: R is CN, COOR1, CONR1R2, or C(OR3)=NR4, or 5-tetrazolyl optionally substituted by benzyl, methyloxycarbonyl, ethyloxycarbonyl, 9-fluorenylmethyloxycarbonyl, 2,2,2-trichloroethyloxycarbonyl, benzyloxycarbonyl, tert-butyloxycarbonyl, allyloxycarbonyl, trichloroacetyl, trifluoroacetyl, or trityl; R1 and R2 which are identical or different are hydrogen or C1-C6-alkyl; R3 and R4 together are a C2-C3-alkylene bridge optionally mono-, di-, tri-, or tetra- substituted by one or more of the groups methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, phenyl, or naphthyl, wherein the brominating is carried out by means of an N-bromoimide or N-bromoamide in a solvent of organic carboxylic acid esters.
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- Method for preparing bromomenthyl-biphenyl derivatives
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The present invention relates to a process for the preparation of 4′-bromomethyl-biphenyl derivatives of the formula: by reacting a 4′-methyl-biphenyl derivative of the formula: with a brominating agent a in a hydrobromic acid/alkali metal bromate system in a two-phase medium, and under photo-iradiation, where R is as defined in the specification.
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- Synthesis of 2-substituted-1-benzimidazoles
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A four step synthetic sequence leading to the title compounds through the formation of 4'-methylbiphenyl-2-carboxylic acid via catalysed "Gomberg reaction" is described.
- Bedi, Preet Mohinder Singh,Verma, Raman K.,Singh, Manjeet
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p. 801 - 803
(2007/10/03)
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- Process for producing 4-bromomethylbiphenyl compounds
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A process for the production of a compound of general formula STR1 wherein R represents cyano, carboxy which may be esterified or amidated or tetrazolyl which may be substituted, comprising brominating the corresponding methyl compound with a brominating agent such as N -bromoacetamide, N-bromophtalimide, N-bromosuccinimide and so on in a halogenated hydrocarbon solvent in the presence of an azobis compound.
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