- Practical acetalization and transacetalization of carbonyl compounds catalyzed by recyclable PVP-I
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A novel PVP-I catalyzed acetalizations/transacetalizations of carbonyl compounds has been developed processing with a mild and easy handling fashion. Different types of Acyclic and cyclic acetals were prepared from carbonyl compounds or their acetals successfully. Further applications of newly developed catalytic combination were testified. This protocol featured with simplicity of operation, mild reaction condition, short reaction time, recyclable of catalyst and broad substrates scope with excellent yields.
- Cao, Fu-Rong,Lu, Guangying,Ren, Jiangmeng,Wang, Di,Zeng, Bu-Bing
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- Synthesis of thienoimidazo[4,5-b]pyridines and thenylidenoimidazolinones
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The two isomers 2-amino-1-methylimidazo[4,5-b]thieno[3,2-e]pyridine (3) and 2-amino-1-methylimidazo[4,5-b]thieno[2,3-e]pyridine (4) were synthesized by the Friedlaender reaction starting from creatinine and the appropriate aminothiophenecarbaldehydes (11 and 13). Creatinine was also condensed with 2-nitro-3-thiophenecarbaldehyde (10) in ethylene glycol to yield the 2-amino-1-methyl-5-[2-(2-nitro-3-thenylidene)]-2-imidazolin-4-one (7a), with 3-amino-2-thiophenecarbaldehyde (13) under Perkin conditions to yield 2-acetamido-5-[2-(3-acetamido-2-thenylidene)]-1-methyl-2-imidazolin-4-on e (8), and with 4-azido-3-thiophenecarbaldehyde (17) in acetic acid to yield 2-amino-5-[2-(4-azido-3-thenylidene)]-1-methyl-2-imidazolin-4-one (9). The thenylidenoimidazolinone (8) was converted into compound (4).{A figure is presented}.
- Bjoerk, Malin,Grivas, Spiros
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p. 2369 - 2380
(2007/10/03)
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