- Synthesis and characterization of potential impurities of Vigabatrin-An anti epileptic drug
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The present work describes the synthesis and characterization of four potential impurities of Vigabatrin (1) namely 2-(2-aminobut-3-enyl)malonic acid (2) (Vigabatrin USP impurity-E), 2-(2-oxo-5-vinylpyrrolidin-1-yl)acetic acid (3) (USP Tablets impurity), 4-aminohexanoic acid (4) and 2,2′-oxo-5,5′-bispyrrolidinyl ether (5). Compound 4 is a possible process related impurity of 1 where as compound 5 is a process related impurity of 5-ethoxy-2-pyrrolinone (16). All these impurities have a significant impact on the quality of the drug product. This work is extremely useful for generic pharmaceutical industry.
- Karumanchi, Kishore,Natarajan, Senthil Kumar,Gadde, Sunil,Chavakula, Ramadas,Korupolu, Raghu Babu,Bonige, Kishore Babu
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- Substitution reactions of 2-phenylsulphonyl-piperidines and -pyrrolidines with carbon nucleophiles: Synthesis of the pyrrolidine alkaloids norruspoline and ruspolinone
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Several 2-phenylsulphonyl-piperidines and -pyrrolidines were prepared from the corresponding N-acyl aminals by treatment with benzenesulphinic acid. On reaction with various carbon nucleophiles these sulphones gave good yields of substitution products. Typical nucleophiles used in these studies were organometallic reagents derived from Grignard reagents and zinc halide together with silyl enol ethers, silyl ketene acetals, allylsilanes and trimethylsilyl cyanide in the presence of a Lewis acid. These methods were employed in the synthesis of two natural product alkaloids; Norruspoline (38) and Ruspolinone (40).
- Brown, Dearg S.,Charreau, Philippe,Hansson, Thomas,Ley, Steven V.
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p. 1311 - 1328
(2007/10/02)
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- REACTION OF OXIRANES WITH DIANIONS OF SECONDARY AMINES. NEW ENTRY TO 5-ALKYLSUBSTITUTED γ-LACTAMS
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The oxirane ring cleavage with dilithiated secondary amides was accelerated by the addition of boron trifluoride-etherate to afford γ-hydroxyamides, which were transformed into 5-alkylsubstituted γ-lactams via an intramolecular N-alkylation reaction.
- Takahata, Hiroki,Wang, Eng-Chi,Yamazaki, Takao
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p. 1159 - 1166
(2007/10/02)
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- APPLICATIONS OF THE THERMAL ENE REACTION OF ALDEHYDE t-BUTYL- AND PHENYL- HYDRAZONES
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The Thermal Ene reaction of aldehyde t-butyl- and phenyl- hydrazones with enophiles gave C-trapped azo-adducts which can be diverted into synthetically useful γ-keto-esters, γ-keto-nitriles, γ-alkyl-2-pyrrolidones, and γ-amino-esters.
- Baldwin, Jack E.,Adlington, Robert M.,Jain, Ashok U.,Kolhe, Jayant N.,Perry, Matthew W. D.
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p. 4247 - 4252
(2007/10/02)
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- Michael Additions of Hydrazones for Carbon-Carbon Bond Formation
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The lithium salts of t-butyl- and trityl-hydrazones react with methyl crotonate to form C-trapped azo-esters and similar products were observed from a thermal ene-reaction of aldehyde t-butylhydrazones with methyl acrylate or acrylonitrile, and aldehyde phenylhydrazones with methyl acrylate; these products can be diverted into synthetically useful γ-keto-esters, γ-keto-nitriles, saturated esters, γ-alkyl-2-pyrrrolidones, and γ-amino-esters.
- Baldwin, Jack E.,Adlington, Robert M.,Bottaro, Jeffrey C.,Jain, Ashok U.,Kolhe, Jayant N.,et al.
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p. 1095 - 1096
(2007/10/02)
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