نتایج جستجو برای: strecker
تعداد نتایج: 288 فیلتر نتایج به سال:
El tema de conservación y administración sitios arqueológicos y, en particular, del arte rupestre ha sido tratado Latinoamérica desde los años 1990 (ver Strecker Taboada, 1995); sin embargo, es un desafío permanente que requiere esfuerzos considerables la coordinación a nivel regional con principales actores responsables. A pesar cantidad aportes publicaciones existentes numerosos países, inter...
Bismuth metal–organic frameworks (MOFs) as heterogeneous catalysts are scarce, and there is little knowledge on the influence of MOF features their resulting activity behavior. Here, we present synthesis, characterization, catalytic in one-pot multicomponent Strecker reaction with ketones three new MOFs prepared combination indium or bismuth 4,4′,4′′,4′′′-methanetetrayltetrabenzoic acid. One th...
The asymmetric catalytic Strecker reaction of achiral N-phosphonyl imines with Et(2)AlCN has been established. Both free amino alcohols and BINOLs have been proven to be effective catalysts to afford excellent enantioselectivities and yields. The N-phosphonyl group can be readily cleaved under mild conditions and enable purification of crude products by simple washing with hexane. The cleaved N...
Herein, we report a short, three-step synthesis of d-[1-(14) C]-serine (4) in high enantiomeric purity. Starting from [(14) C]-KCN and 2-(benzyloxy)acetaldehyde, Strecker reaction using (R)-1-phenylethylamine as the chiral auxiliary gave two diastereomeric aminonitriles 1 and 2 in the ratio of 4:3, which were conveniently separated and purified chromatographically. Following hydrolysis and subs...
Choline [(CH3)3N+CH2CH2OH], also known as trimethyl ethanolamine, is an essential component of mammalian diets as it is required for normal function of cells. It was discovered by Andreas Strecker in 1862, but it remained unrecognized as an essential nutrient for humans until 1998, when dietary reference intakes were established. Choline was initially determined to be essential in the preventio...
A camphor-derived sulfonimine with a conjugated carbonyl group, oxoimine 1 (O2SNC10H13O), reacts with amino acids (glycine, L-alanine, L-phenylalanine, L-leucine) to form a compound O2SNC10H13NC10H14NSO2 (2) which was characterized by spectroscopic means (MS and NMR) and supported by DFT calculations. The product, a single diastereoisomer, contains two oxoimine units connected by a -N= bridge, ...
Philip R. Dormitzer,* Pirada Suphaphiphat, Daniel G. Gibson, David E. Wentworth, Timothy B. Stockwell, Mikkel A. Algire, Nina Alperovich, Mario Barro, David M. Brown, Stewart Craig, Brian M. Dattilo, Evgeniya A. Denisova, Ivna De Souza, Markus Eickmann, Vivien G. Dugan, Annette Ferrari, Raul C. Gomila, Liqun Han, Casey Judge, Sarthak Mane, Mikhail Matrosovich, Chuck Merryman, Giuseppe Palladino...
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