نتایج جستجو برای: β acetamido ester
تعداد نتایج: 214161 فیلتر نتایج به سال:
Nonviral gene therapy holds great promise but has not delivered treatments for clinical application to date. Lack of safe and efficient gene delivery vectors is the major hurdle. Among nonviral gene delivery vectors, poly(β-amino ester)s are one of the most versatile candidates because of their wide monomer availability, high polymer flexibility, and superior gene transfection performance both ...
An efficient catalytic synthesis of α-amino-β-keto esters has been newly developed. Cross-coupling of various aldehydes with α-imino ester, catalyzed by N-heterocyclic carbene, leads chemoselectively to α-amino-β-keto esters in moderate to good yields with high atom efficiency. The reaction mechanism is discussed, and it is proposed that the α-amino-β-keto esters are formed under thermodynamic ...
Synthesis of poly(vinyl chloride-g-β-butyrolactone) [poly(VC-g-BL)] graft copolymer was carried out by means “click” chemistry terminally propargyl polyβ-butyrolactone ester (PBL-propargyl) and polyvinyl chloride with pendant azido group (PVC-N3). PVC-N3 synthesized reaction purified PVC sodium azide. PBL-propargyl obtained the β-butyrolactone alcohol ring-opening polymerization. By using PBL-p...
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.
Two glycosides were isolated from the n-Butanol soluble portion of the ethanolic portion of the stem and leaves part of stachytarpheta angustifolia. Their structures were elucidated as Iridoid glycoside (1) and a caffeic glycoside ester named as –β(3 1 , 4 1 dihydroxyphenyl)–ethyl-O-α-L-rhamnopyranosyl-(1-3)-β-D-(4-O-Caffeoyl) glucopyranoside (2) by spectroscopic Method.
Highly enantioselective NHC-organocatalyzed synthesis of functionalized cyclopentenes proceeding via α,β-unsaturated acyl azolium intermediates is reported. The organocascade reaction of modified enals with malonic ester derivatives having a γ-benzoyl group involves the Michael-intramolecular aldol-β-lactonization-decarboxylation sequence to deliver cyclopentenes in good yields and excellent ee...
Sequential Wolff rearrangement of α-diazo-β-ketoesters followed by trapping of the ketene intermediates with enol ethers generated a variety of γ,δ-unsaturated β-ketoesters. This method involves a novel thermal cascade reaction and allows the synthesis of γ,δ-unsaturated β-ketoesters with trans-stereochemistry under catalyst-free conditions. The synthesized compounds were further transformed in...
A study exploring the chemical behavior of some dihydroxylated β-amino ester stereo- and regioisomers, derived from unsaturated cyclic β-amino acids is described. The nucleophilic fluorinations involving hydroxy-fluorine exchange of some highly functionalized alicyclic diol derivatives have been carried out in view of selective fluorination, investigating substrate dependence, neighboring group...
Abstract. The Ti(OiPr)4/tartaric acid diethyl ester/t-BuOOH complex (Sharpless catalyst) was successfully used for the direct asymmetric oxidation of ketones resulting in lactones from cyclobutanones; α,β-dihydroxy ketones from β-hydroxy ketones; alkyl lactone carboxylic acids from 3-alkylcyclopentane-1,2-diones; and spiro-γ-dilactone from 3-(2-hydroxyethyl)cyclopentane1,2-dione in high enantio...
A simple and efficient synthetic route to substituted N-sulfinyl and N-sulfonyl azetidines is described involving imino-aldol reaction of ester enolates with racemic and non-racemic aldimines for obtaining β-amino esters as a key step. These β-amino esters on subsequent reduction followed by TsCl/KOH mediated cyclization produced the corresponding racemic and non-racemic azetidines with high yi...
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