- REACTION OF BENZOTHIOPHENE-5- AND 6-METHANOLS WITH n-BUTYLLITHIUM. DIRECTED LITHIATION IN THE BENZENE RING
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The preparation of 3-methylbenzothiophene-6-methanol (3) is described.Treatment of 3 with n-butyllithium followed by CO2 gave, in addition to the expected 2-carboxylic acid 2, a substantial quantity of the lactone 11 formed via lithiation at the 7-position.It was concluded that lithiation at 7-position is favoured by a co-operative effect of the anion of the alcohol and the ring sulphur atom, as well as the 3-methyl group which reduces the rate of lithiation at the 2-position.In the case of compounds in which the alcohol group is at the 5-position or which lack the 3-methyl group, lithiation in the benzene ring was much less favoured .
- Cross, Peter E.,Dickinson, Roger P.
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p. 2391 - 2400
(2007/10/02)
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- Heterocyclic thromboxane synthetase inhibitors and pharmaceutical compositions containing them
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Heterocyclic thromboxane synthetase inhibitors of the formula STR1 wherein R1, which is attached to the 2-, 3- or 4-position, is hydrogen, halogen, C1 -C4 alkyl, hydroxy or C1 -C4 alkoxy; Y, which is attached to the 2- or 3-position, is --COOH, --COO(C1 -C4 alkyl) or --CONH2 ; X is O, S, NH, N(C1 -C4 alkyl) or N(benzyl); and R, which is attached to the 5-, 6- or 7-position, is a group of the formula STR2 or (3- or 4-pyridyl)-Z2 - wherein Z1 is --CH2 --, --CH2 CH2 -- or --CH2 CH2 O-- and Z2 is --CH2 --, --CH2 CH2 --, --CH=CH--, --CH2 O-- or --OCH2 --; and their pharmaceutically acceptable salts; processes for their preparation, and pharmaceutical compositions containing them.
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