نتایج جستجو برای: β keto ester
تعداد نتایج: 218663 فیلتر نتایج به سال:
FeCl3.6H2O was used as an efficient catalyst for the synthesis of highly functionalized piperidines via a one-pot five-component reaction of aromatic amines, aromatic aldehydes and β-keto esters in EtOH at room temperature. The remarkable advantages offered by this method are good yields, simple procedure, short reaction times, no need to column chromatography and easy work-up. The structures o...
Isothiourea HBTM-2.1 catalyzes the asymmetric Michael addition/lactonization of aryl- and alkenylacetic acids using α-keto-β,γ-unsaturated phosphonates as α,β-unsaturated ester surrogates, giving access to a diverse range of stereodefined lactones or enantioenriched functionalized diesters upon ring-opening.
Rhodium-, copper- and iridium-catalyzed reactions of the (13)C-labelled diazo carbonyl substrates 18* and 19* were performed. Results obtained from copper- and iridium-catalyzed reactions of the (13)C-labelled α-diazo β-keto ester 19* indicate that either or both of these reactions do not proceed via a free oxonium ylide but instead follow a competing non-ylide route that delivers apparent [2,3...
FeCl3.6H2O was used as an efficient catalyst for the synthesis of highly functionalized piperidines via a one-pot five-component reaction of aromatic amines, aromatic aldehydes and β-keto esters in EtOH at room temperature. The remarkable advantages offered by this method are good yields, simple procedure, short reaction times, no need to column chromatography and easy work-up. The structures o...
This study was designed to determine whether whole cells or crude enzyme extracts are more effective for preparative-scale ketone reductions by dehydrogenases as well as learning which cofactor regeneration scheme is most effective. Based on results from three representative ketone substrates (an α-fluoro-β-keto ester, a bis-trifluoromethylated acetophenone, and a symmetrical β-diketone), our r...
Straightforward conversion of (+)-6,8-dimethoxy-3,4-dihydro-3- undecylisocoumarin (3) to the title isocoumarin was carried out. Hydrolytic ring opening of (3) afforded the hydroxy acid (4) which was immediately oxidized to keto acid (5) using chromic acid, Cyclodehydration of (5) afforded the 6,8- dimethoxy-3-undecylisocoumarin (6) which on selective demethylation of 8- methoxy group furni...
For the total synthesis of novel cyclodepsipeptide homophymine A, (2R,3R,4R)-2-amino-3-hydroxy-4,5-dimethylhexanoic acid was successfully synthesized by Evans' asymmetric alkylation and the anti-selective asymmetric hydrogenation of a chiral α-amino-β-keto ester as the key steps.
straightforward conversion of (+)-6,8-dimethoxy-3,4-dihydro-3- undecylisocoumarin (3) to the title isocoumarin was carried out. hydrolytic ring opening of (3) afforded the hydroxy acid (4) which was immediately oxidized to keto acid (5) using chromic acid, cyclodehydration of (5) afforded the 6,8- dimethoxy-3-undecylisocoumarin (6) which on selective demethylation of 8- methoxy group furnished ...
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