881847-12-7Relevant articles and documents
AN IMPROVED PROCESS FOR THE PRODUCTION OF DERIVATIVES OF THIOZOLIDINEDIONES AND THEIR PRECURSORS
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Page/Page column 23; 24, (2010/10/20)
The invention provides a process for preparing derivatives of thiozolidinediones and their precursors comprising, (a) reacting a compound of general formula I wherein R1, R2 and R3 may be same or different and represent H, alkyl or alkoxy with C varying from 1 to 6, halogens, mono or di-substituted alkyl and aryl amines, and M represents hydrogen (H) or alkali metal selected from Na, K or Li with a compound of formula II, wherein R4 has the same meaning as R1 or R2 or R3 and X is halogen in presence or absence of solvent(s) under effective conditions to produce nitro ethers of general formula III, where in R1 to R4 has the same meaning as given above, provided when M is H and not its alkali metal salt, an alkali metal salt such as hydroxide or carbonate is required to be added while conducting the said reaction, (b) subjecting the said nitro ethers, with or without isolation, to Raney nickel-catalyzed reduction under conditions effective to produce corresponding nitro aniline ethers (c) coupling the said aniline ether with acrylates under Meerwein arylation conditions in presence of hydrobromic acid to produce α bromo substituted carboxylic acid derivatives followed by subjecting to solvent extractive purification (d) cyclising the purified derivative of α bromo substituted carboxylic acid as obtained in step (c) with thiourea to yield 2-imino -4-thiazolidinones then (e) hydrolyzing the said 2-imino-4-thiazolidinones to produce 2, 4-thiazolidinones and converting the same to its hydrochloride salts as white crystalline solids known to exhibit antidiabetic activity, by conventional methods.
