نتایج جستجو برای: amino alcohols
تعداد نتایج: 217020 فیلتر نتایج به سال:
Primary alcohols can be coupled with secondary benzylic alcohols by an air-stable catalytic system involving terpyridine ruthenium or iridium complexes.
Broadband dielectric spectra of supercooled 1,2,6-hexanetriol are presented in order to reveal physical picture behind a glass transition of polyhydric alcohols. It has been reported so far that temperature dependences of alpha relaxation time for sugar alcohols exhibit systematic trend against number of carbon atoms or OH groups per molecule. However, because each molecule is composed of equal...
ALIPHATIC ALCOHOLS METHANOL, ETHANOL, 1-BUTANOL Eva Mračková Abstract: It is introduced the explosion Chamber VK 100 in the paper, in which we determined the lower explosive limits (LEL) of selected aliphatic alcohols as flammable liquids methanol, ethanol, 1-butanol. First, the calculations of the volume of flammable liquid necessary for setting of LEL were carried out. Next, it was carried ou...
The anionic peroxidase associated with the suberization response in potato (Solanum tuberosum L.) tubers during wound healing has been purified and partially characterized at the biochemical level. It is a 45-kD, class III (plant secretory) peroxidase that is localized to suberizing tissues and shows a preference for feruloyl (o-methoxyphenol)-substituted substrates (order of substrate preferen...
A switchable site-selective catalytic carboxylation of allylic alcohols has been developed in which CO2 is used with dual roles, both facilitating C-OH cleavage and as a C1 source. This protocol is characterized by its mild reaction conditions, absence of stoichiometric amounts of organometallic reagents, broad scope, and exquisite regiodivergency which can be modulated by the type of ligand em...
We have developed a novel and simple protocol for the direct incorporation of a difluoromethyl (CF2 H) group into alkenes by visible-light-driven photoredox catalysis. The use of fac-[Ir(ppy)3] (ppy=2-pyridylphenyl) photocatalyst and shelf-stable Hu's reagent, N-tosyl-S-difluoromethyl-S-phenylsulfoximine, as a CF2 H source is the key to success. The well-designed photoredox system achieves synt...
The enantioselective addition of phenylethynylzinc to aldehydes catalyzed by a series of cyclopropane-based amino alcohol ligands 7 was investigated. The reactions afforded chiral propargylic alcohols in high yields (up to 96%) and with excellent enantioselectivities (up to 98% ee) under mild conditions. Furthermore, studies on the structural relationship show that the matching of the chiral ce...
The γ-amino alcohol structural motif is often encountered in drugs and natural products. We developed two complementary catalytic diastereoselective methods for the synthesis of N-PMP-protected γ-amino alcohols from the corresponding ketones. The anti-products were obtained through Ir-catalyzed asymmetric transfer hydrogenation, the syn-products via Rh-catalyzed asymmetric hydrogenation.
The syntheses of the perfluorinated alcohols (F(5)C(6))(F(3)C)(2)COH (1) and (F(5)C(6))(C(5)F(10))COH (2) are described. Both compounds were prepared in reasonable yields (1: 65%, 2: 85%) by reacting the corresponding ketone with C(6)F(5)MgBr, followed by acidic work-up. The alcohols were characterized by NMR, vibrational spectroscopy, single-crystal X-ray diffraction, acidity measurements and ...
A oxidação de álcoois homoalílicos terciários com trinitrato de tálio (TTN) foi investigada. Os álcoois que possuem uma metila na posição alílica perdem uma molécula de acetona via uma reação de fragmentação, levando a uma mistura de álcoois alílicos isoméricos como principais produtos, juntamente com os correspondentes derivados acetilados. Por outro lado, o tratamento com TTN de álcoois terci...
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