An nBu4NI-catalyzed oxidative cross-dehydrogenative-coupling of β-dicarbonyl compounds with acetone undermild reaction conditions is described. This methodology provides a straightforward pathway to synthesize 2-carbonyl-1,4-diketones and features a simple system, low reaction temperature, and environmental friendliness.
Pyrrole compounds that are potent and selective inhibitors of PDE4, as well as methods of making the same, are disclosed. Use of the compounds in the treatment of inflammatory diseases and other diseases involving elevated levels of cytokines, as well as central nervous system (CNS) disorders, also is disclosed.
The synthesis and chemistry of azolenines. Part 18. Preparation of 3-ethoxycarbonyl-3-pyrroles the paal-knorr reaction, and sigmatropic rearrangements involving competitive ester migrations to c-2, c-4 and n.
作者:Chiu Pak-Kan、Sannes Michael P.
DOI:10.1016/s0040-4020(01)81514-3
日期:1990.1
N-esters (13) of 1H-pyrroles via competitive [1,5]sigmatropic rearrangements. Isolable intermediate 2H-pyrrole-2-carboxylic esters (l2) are converted similarly into the same products, under the same conditions. Detection of 3H-pyrroles (4) as intermediates in the latter reaction demonstrates for the first time the reversibility of the thermal 2H-pyrrole to 3H-pyrrole interconversion.
The acid catalysed reaction of 1,4-diketones with hydrogen sulphide
作者:F. Duus
DOI:10.1016/0040-4020(76)80129-9
日期:1976.1
with H2S in acidic ethanol to give 2,5- or higher substituted thiophens as resulting from a spontaneous ring-closure reaction of initially formed sulphur analogues of the starting diketones. In some the corresponding 2-mercapto-2,3-dihydrothiophens and/or 2,5-dimercaptotetrahydrothiophens were formed as by-products. 1,4-Diphenyl-1,4-diketones behaved exceptionally under similar reaction conditions yielding