- Continuous flow multipoint dosing approach for selectivity engineering in sulfoxidation
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A continuous synthesis approach with multipoint dosing of one of the reagents is demonstrated for the synthesis of sulfoxide compounds such as proton pump inhibitors. Use of multipoint dosing of the oxidizing agent helped to minimize the possibility of over-oxidation leading to sulfone. Different oxidizing agents were used, and the effect of various parameters (viz. mole ratio of sulfide to oxidizing agent, temperature, residence time, concentration of oxidizing agent, etc.) on the yield of the desired sulfoxide compound was studied. Single-point and multipoint dosing approaches of the oxidizing agent were used for the most promising set of parameters. The performance was compared in terms of conversion of sulfide and the selectivity of the desired sulfoxide. Numbering up approach was used to produce the sulfoxide in a relatively large quantity at laboratory scale with complete conversion and over 99% selectivity for the sulfoxide.
- Kulkarni,Nivangune,Joshi,Joshi
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- Synthesis and characterization of metabolites and potential impurities of the antiulcerative drug tenatoprazole
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Tenatoprazole (Ulsacare) is a recently developed antiulcerative drug used for the treatment of both erosive and nonerosive gastroesophageal reflux disease. During the bulk synthesis of tenatoprazole, we have observed four impurities (tenatoprazole N-oxide, tenatoprazole sulfone N-oxide, N-methyl tenatoprazole, and desmethoxy tenatoprazole) and two metabolites (tenatoprazole sulfide and tenatoprazole sulfone). The present work describes the synthesis and characterization of these impurities. Copyright Taylor & Francis Group, LLC.
- Reddy, Ganta Madhusudhan,Prasada Raju,Babu, J. Moses,Praveen,Khunt, Mayur,Mukkanti,Pratap Reddy, Padi
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- Improved synthetic approach to tenatoprazole
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An improved synthetic approach to tenatoprazole 1 is described. It started from 2,3,5-trimethyl-4-nitropyridine-N-oxide 2 with acetic anhydride via rearrangement and hydrolysis to give 3, Chlorination with SOCl2 yielded 2-chloromethyl-3,5-dimethyl-4-nitropyridine hydrochloride 4, then 4 condensed with 2-mercapto-5-methoxy imidazole [4,5-b]pyridine 5 to give 5-methoxy-2-[(4-nitro-3,5-dimethyl-2-pyridinyl)methylthio]imidazole[4,5-b] pyridine 6. At last the title compound 1 was produced by two methods: 6 was oxidized with MCPBA and then methoxylated with CH3ONa to give 1 and 6 was first methoxylated with CH3ONa and then oxidized with MCPBA to give 1. The overall yield is around 26% for both five-step syntheses. Copyright Taylor & Francis Group, LLC.
- Dai, Liyan,Fan, Dongbo,Wang, Xiaozhong,Chen, Yingqi
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- An improved synthesis of antiulcerative drug: Tenatoprazole
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An efficient, cost-effective and multikilogram-scale process for the synthesis of tenatoprazole 1, an antiulcerative drug, is described. The key steps in this synthesis involve the coupling of 2-mercapto-5-methoxyimidazo[4,5- b]pyridine 2 with 2-chloromethyl-4-methoxy-3,5-dimethyl pyridine hydrochloride 3 to yield 4 and its subsequent oxidation with m-CPBA to produce sulfoxide 1. The process has been scaled up for the multikilogram-scale of compound 1 with an overall yield of 72%. The new process requires no purification process and affords the target compound 1 with 99.8% purity by HPLC.
- Sripathi, Somaiah,Bojja, Ramachandra Reddy,Karnati, Venugopal Reddy,Prasada Raju,Khunt, Mayur D.
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- CONTINUOUS FLOW PROCESS FOR THE PREPARATION OF SULPHOXIDE COMPOUNDS
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A continuous micromixer based process for the synthesis of sulphoxide compounds with a reaction time of less than or equal one minute is disclosed. The process shows selectivity of > 95% towards the sulphoxide compounds.
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(2012/02/01)
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- Continuous Flow Process For The Preparation Of Sulphoxide Compounds
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A continuous micromixer based process for the synthesis of sulphoxide compounds with a reaction time of less than or equal one minute is disclosed. The process shows selectivity of >95% towards the sulphoxide compounds.
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Page/Page column 4
(2012/08/27)
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