- An improved new path to synthesize gemfibrozil
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A new route has been developed for synthesis of gemfibrozil in good yield with high purity. The obtained gemfibrozil was characterized by using IR, 1H NMR, 13C NMR and mass spectral studies. According to Biopharmaceutical Classification System, gemfibrozil is classified under class-II drugs (low solubility-high permeability) and an antihyperlipidimic. So it's admirable to synthesize the intention molecule in easy and economical way.
- Nunna, Rambabu,Jayanna,Ramachandran
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- Intramolecular functionalisation by a methylene radical of a 1,2-diol and a vicinal amino alcohol: Models for coenzyme B12-dependent diol dehydratase and ethanolamine ammonia lyase
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Coenzyme B12-dependent diol dehydratase converts 1,2-diols (e.g. propane-1,2-diol) into the corresponding aldehyde and water. The similar enzyme ethanolamine ammonia lyase transforms vicinal aminoalcohols (e.g. 2-aminoethanol) into the corresponding aldehyde and ammonia. Model systems have been developed that replicate key features of the putative enzymatic mechanism, i.e. removal of a hydrogen atom from the CH2OH group of a 1,2-diol or vicinal aminoalcohol by a methylene radical derived from an alkylcobalt compound, and conversion of a 1,2-diol or vicinal aminoalcohol into a carbonyl compound and water or ammonia triggered by such a methylene radical. The models are based on alkyl(pyridine)bis(dimethylglyoximato)cobalt complexes [alkyl(pyridine)cobaloximes, Cbx], which were synthesised from appropriate organic precursors using standard methodology. The complexes contain a 1,2-diol [as in 4,5-dihydroxy-2,2-dimethylpentyl(pyridine)cobaloxime] or vicinal aminoalcohol [as in 6-amino-5-hydroxy-2,2-dimethylhexyl(pyridine)cobaloxime] tethered to the cobalt by a carbon chain. Photolysis or thermolysis of 4,5-dihydroxy-2,2-dimethylpentyl(pyridine)cobaloxime at pH 3 or 9 gave 4,4-dimethylpentanal. It is proposed that homolysis of the Co-C bond of 4,5-dihydroxy-2,2-dimethylpentyl(pyridine)cobaloxime induced by photolysis or thermolysis affords the 1,2-dihydroxy-4,4-dimethyl-l-pentyl radical via a 1,5-H shift, which is converted into the 4,4-dimethyl-1-oxo-2-pentyl radical, and hence 4,4-dimethylpentanal. The pathway for formation of the aldehyde was diagnosed using the specifically deuteriated analogue [5,5-2H 2]-4,5-dihydroxy-2,2-dimethylpentyl(pyridine)-cobaloxime, which gave [1,5-2H2]-4,4-dimethylpentanal accompanied by 3,3-dimethylbutanal on thermolysis or photolysis at pH 3. The protected model compound 2a was hydrolysed to 6-amino-5-hydroxy-2,2-dimethylhexyl(pyridine)cobaloxime, which was heated at pH 3 or 9 to give 5,5-dimethylhexan-2-one and ammonia. The Royal Society of Chemistry 2000.
- Andersen, Rosaleen J.,Ashwell, Susan,Garnett, Ian,Golding, Bernard T.
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p. 4488 - 4498
(2007/10/03)
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- Competitive reactivity as a probe for reaction coordinates in gas-phase ion-molecule chemistry
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Using the method of competitive reactivity of two functional groups in the same molecule, anionic elimination reactions show considerable kinetic selectivity for small differences in leaving group thermochemistry, in structures of the general type YCH2CH2CH2Z, where Y and Z are good anionic leaving groups.
- Holman, Robert W.,Sumpter, Terry L.,Farrar, John,Weigel, Kurt,Bartmess, John E.
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p. 585 - 589
(2007/10/03)
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- Method for producing α,α-dimethyl-Δ-valerolactone
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A method for producing α,α-dimethyl-δ-valerolactone which comprises carrying out the addition reaction of hydrogen bromide and 2,2-dimethyl-4-pentenoic acid in the presence or absence of a catalyst to synthesize 2,2-dimethyl-5-bromovaleric acid which is then subjected to ring-closure reaction by alkali treatment.
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