نتایج جستجو برای: conjugated diene value
تعداد نتایج: 762715 فیلتر نتایج به سال:
Abstract 1,2,4‐Trisubstituted 1,3‐butadienes were prepared in a stereocontrolled manner by carbenoid eliminative cross‐coupling between stereodefined lithiated secondary allylic carbamates and α‐carbamoyloxyalkyl boronates. All four geometric isomers of 4,7‐dimethyl‐1‐phenylocta‐3,5‐diene stereospecifically generated [yields 44–73 %, dr (Δ 3,4 )=84 : 16 to 97 3] appropriate combinations (S,E)‐ ...
Frying oils showed an increase in Peroxide Value (PV) at the initial stages of the frying process followed by a decrease, and there was no correlation between PV and Total Polar Compounds (TPC) in the same set of frying oils. All the frying oils had PVs lower than 4.42 meq O2 kg -1 oil during the frying process and, consequently, none of them was above the limit of 10 meq O2 kg -1 oil for edibl...
The hetero-Diels-Alder reaction between a nitroso dienophile and a conjugated diene to give the 3,6-dihydro-2H-1,2-oxazine scaffold is useful for the synthesis of many biologically interesting molecules due to the diverse opportunities created by subsequent transformations of the resulting 1,2-oxazine ring. This review discusses the rationale for the observed regio- and stereoselectivity and th...
the present study was carried out to investigate the effect of various refining processes’ conditions on conjugated dienes in soybean oil. conjugated dienes contents of soybean oil were found to undergo reduction in neutralization and bleaching steps while being increased in deodorization. it was observed that alkali refining (neutralization) through 12 and 14 °bé, bleaching with either acid ac...
Versipelostatin (VST) is an unusual 17-membered macrocyclic polyketide product that contains a spirotetronate skeleton. In this study, the entire VST biosynthetic gene cluster (vst) spanning 108 kb from Streptomyces versipellis 4083-SVS6 was identified by heterologous expression using a bacterial artificial chromosome vector. Here, we demonstrate that an enzyme, VstJ, catalyzes the stereoselect...
* corresponding author. e-mail: [email protected] Butyl-substituted 1-amino-3-oxocyclohexane-1-carboxylic acid derivatives have been prepared from 5,5-tethered dienes of (2R)-2,5-dihydro-2-isopropyl-3,6-dimethoxypyrazine in stereoselective synthesis. RCM reactions of the diene afforded a heterospirenone which was the substrate for the conjugated addition reaction with lithium dibutylcuprate. Hydrol...
New antibiotics phoslactomycins A, B, C, D, E and F, which contain alpha, beta-unsaturated delta-lactone, phosphate ester, conjugated diene and cyclohexane ring moieties, were isolated from the culture broth of a soil isolate actinomycete. Morphological, cultural and physiological studies revealed that the isolate is a strain of Streptomyces nigrescens. Phoslactomycins were obtained by butanol ...
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