نتایج جستجو برای: fluoro β diketones

تعداد نتایج: 185255  

The reaction of P-diketones 1 with phenyl hydrazine afforded 5-aryl-3-(1- methyl-5-nitro-2-imidazoly1)-1-phenylpyrazole (2) and 3-aryl-5-(1-methyl-5- nitro-2-imidazoly1) -1-phenylpyrazole (3). The reaction of diketones (1) with urea in the presence of p-toluenesulfonic acid gave 4-(or 6-)aryl-6-(or 4-)(1-methyl- 5-nitro-2-imidazolyl)-1-(lH)pyrimidones (4). The structures of all compounds w...

Journal: :Acta Chemica Scandinavica 1989

2016
James K Howard Marion Müller Alan Berry Adam Nelson

The trans-o-hydroxybenzylidene pyruvate aldolase-catalysed reactions between fluoropyruvate and many (hetero)aromatic aldehydes yield aldol adducts without subsequent dehydration. Treatment of the reaction products with hydrogen peroxide yields the corresponding syn-configured α-fluoro β-hydroxy carboxylic acids which have >98 % ee. The overall chemoenzymatic approach, in which fluoropyruvate s...

Journal: :Chemical communications 2009
Haijun Li Wenjuan Li Zhiping Li

Iron-catalyzed cross-aldol reactions of ortho-diketones and methyl ketones were developed and the thus formed aldol products were efficiently transformed into cyclohepta-2,4,6-trienone derivatives (tropones) under thermal conditions via ring-expansion.

Journal: :Chemical science 2015
Alan R Burns Amaël G E Madec Darryl W Low Iain D Roy Hon Wai Lam

2,2-Disubstituted cyclic 1,3-diketones containing a tethered electron-deficient alkene undergo chiral phosphoric acid-catalyzed desymmetrizing Michael cyclizations to give bridged bicyclic products in high enantioselectivities. Both bicyclo[3.2.1]octanes and bicyclo[3.3.1]nonanes are accessible using this methodology.

Journal: :Microchemical Journal 2021

A green chiral lab-on-a-chip cyclodextrin-based microchip electrophoretic method was developed for enantioseparation of baclofen (BCN) and phenylalanine (Phe) enantiomers the first time. All BCN Phe were offline labeled with 4-fluoro-7-nitrobenzofurazan (NBD-F) or fluorescein-5-isothiocyanate (FITC) fluorogenic reagents prior to microfluidic injection in a dynamically coated polymethylmethacryl...

2013
Lin Yan Zhiqiang Han Bo Zhu Caiyun Yang Choon-Hong Tan Zhiyong Jiang

In the presence of a commercially available Cinchona alkaloid as catalyst, the asymmetric allylic alkylation of Morita-Baylis-Hillman carbonates, with α-fluoro-β-keto esters as nucleophiles, have been successfully developed. A series of important fluorinated adducts, with chiral quaternary carbon centres containing a fluorine atom, was achieved in good yields (up to 93%), with good to excellent...

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