- Regiospecific S-aminoalkylation of 5-substituted 6-hydroxy-2-thiouracil derivatives in the synthesis of structural analogs of isothiobarbamine
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Regiospecific S-monoaminoalkylation of 5-substituted derivatives of 6-hydroxy-2-thiouracil with free N,N-dialkyl-N-(2-chloroethyl)amines in anhydrous PriOH was described for the first time. In compliance with the rules and regulations of green chemistry, this approach was used to synthesize a number of structural analogs of isothiobarbamine in high yield and purity, which are potential synthetic actoprotectors of immediate action.
- Brunilina, L. L.,Chapurkin, V. V.,Deshevov, P. P.,Kirillov, I. A.,Korenkov, B. D.,Nawrozkij, M. B.,Novakov, I. A.,Sheikin, D. S.,Vostrikova, O. V.
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Read Online
- Dehydroxymethylation of alcohols enabled by cerium photocatalysis
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Dehydroxymethylation, the direct conversion of alcohol feedstocks as alkyl synthons containing one less carbon atom, is an unconventional and underexplored strategy to exploit the ubiquity and robustness of alcohol materials. Under mild and redox-neutral reaction conditions, utilizing inexpensive cerium catalyst, the photocatalytic dehydroxymethylation platform has been furnished. Enabled by ligand-to-metal charge transfer catalysis, an alcohol functionality has been reliably transferred into nucleophilic radicals with the loss of one molecule of formaldehyde. Intriguingly, we found that the dehydroxymethylation process can be significantly promoted by the cerium catalyst, and the stabilization effect of the fragmented radicals also plays a significant role. This operationally simple protocol has enabled the direct utilization of primary alcohols as unconventional alkyl nucleophiles for radical-mediated 1,4-conjugate additions with Michael acceptors. A broad range of alcohols, from simple ethanol to complex nucleosides and steroids, have been successfully applied to this fragment coupling transformation. Furthermore, the modularity of this catalytic system has been demonstrated in diversified radical-mediated transformations including hydrogenation, amination, alkenylation, and oxidation.
- Zhang, Kaining,Chang, Liang,An, Qing,Wang, Xin,Zuo, Zhiwei
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supporting information
p. 10556 - 10564
(2019/08/20)
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- Dehydroxymethylation of Alcohols Enabled by Cerium Photocatalysis
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Dehydroxymethylation, the direct conversion of alcohol feedstocks as alkyl synthons containing one less carbon atom, is an unconventional and underexplored strategy to exploit the ubiquity and robustness of alcohol materials. Under mild and redox-neutral reaction conditions, utilizing inexpensive cerium catalyst, the photocatalytic dehydroxymethylation platform has been furnished. Enabled by ligand-to-metal charge transfer catalysis, an alcohol functionality has been reliably transferred into nucleophilic radicals with the loss of one molecule of formaldehyde. Intriguingly, we found that the dehydroxymethylation process can be significantly promoted by the cerium catalyst, and the stabilization effect of the fragmented radicals also plays a significant role. This operationally simple protocol has enabled the direct utilization of primary alcohols as unconventional alkyl nucleophiles for radical-mediated 1,4-conjugate additions with Michael acceptors. A broad range of alcohols, from simple ethanol to complex nucleosides and steroids, have been successfully applied to this fragment coupling transformation. Furthermore, the modularity of this catalytic system has been demonstrated in diversified radical-mediated transformations including hydrogenation, amination, alkenylation, and oxidation.
- Zhang, Kaining,Chang, Liang,An, Qing,Wang, Xin,Zuo, Zhiwei
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supporting information
p. 10556 - 10564
(2019/08/28)
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- Secobarbital artificial antigen and preparation method thereof
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The objective of the invention is to provide a secobarbital artificial antigen and a preparation method thereof. According to the invention, malonate and urea are used as main raw materials for synthesis of the secobarbital antigen. The method comprises the following steps: reacting halogenated pentane with malonate to prepare 2-(1-methylbutyl)malonate; subjecting a malonate derivative and urea toa cyclization reaction to prepare barbitone derivative; reacting long-chain halogenated olefine acid with the barbitone derivative to prepare a hapten; and reacting the hapten reacts with N-hydroxysuccinimide and N,N-cyclohexylcarbodiimide under nitrogen protection to obtain active ester, subjecting the active ester and a protein to a coupling reaction, and simultaneously removing a trifluoroacetyl protecting group so as to obtain the secobarbital artificial antigen. The preparation method provided by the invention is simple in process, low in production cost, and not limited in raw materialsources. The prepared artificial antigen can be used for animal immunization to obtain corresponding antibodies, is used for the research of various barbitone immunoassays and the production of rapiddetection kits, and has a wide application scope.
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Paragraph 0029; 0058-0062
(2018/09/28)
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- Barbiturate assay, tracers, immunogens and antibodies
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The present invention is directed to a fluorescence polarization immunoassay for barbiturates, to the various components needed for preparing and carrying out such an assay, and to methods of making these components. Specifically, tracers, immunogens and antibodies are disclosed, as well as methods for preparing them. The tracers and the immunogens are made from substituted barbiturate compounds. A fluorescein moiety is included in the tracer, while a poly(amino acid) forms a part of the immunogen. The assay is conducted by measuring the degree of polarization retention of plane-polarized light that has been passed through a sample containing antiserum and tracer.
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- Barbiturate assay, tracers, immunogens, antibodies and kit
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The present invention is directed to a fluorescence polarization immunoassay for barbiturates, to the various components needed for preparing and carrying out such an assay, and to methods of making these components. Specifically, tracers, immunogens and antibodies are disclosed, as well as methods for preparing them and a reagent kit containing them. The tracers and the immunogens are made from substituted barbiturate compounds. A fluorescein moiety is included in the tracer, while a poly(amino acid) forms a part of the immunogen. The assay is conducted by measuring the degree of polarization retention of plane-polarized light that has been passed through a sample containing antiserum and tracer.
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- Mechanism of the Grignard Adddition Reaction. XVI. Homolytic and Concerted Mechanisms in the Reaction of α,β-Unsatureted Carbonyl Compounds with Grignard Reagents
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Kinetic measurements have shown that the addition of Grignard reagents to α,β-unsaturated carbonyl compounds takes place either by a concerted mechanism or by a homolytic mechanism.Phenylmagnesium bromide, which is incapable of homolysis, reacts rapidly in a 1,4-fashion if an s-cis conformation exists between the C=C and the C=O bonds, but only 1,2-addition takes place if the conformation is s-trans.tert-Butylmagnesium bromide is unsuited to the concerted reaction, but 1,4-addition takes place via homolysis.Primary and secondary Grignard reagents, like phenyl, react rapidly in a concerted manner with s-cis substrates, but unlike phenyl, these Grignard reagents may, with s-trans substrates, produce some 1,4-adduct via the homolytic mechanism.
- Holm, Torkil
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p. 925 - 929
(2007/10/02)
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- ALKYLATION OF MALONIC ESTER AND MONOALKYLMALONIC ESTERS UNDER THE CONDITIONS OF PHASE-TRANSFER CATALYSIS
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Simple procedures were developed for the monoalkylation of malonic ester in the potassium hydroxide-DMFA (DMFA-acetone)-triethylbenzylammonium chloride system and the alkylation of alkylmalonic esters to dialkylmalonic esters in the calcium oxide-DMFA system.
- Sukhanov, N. N.,Trappel', L. N.,Chetverikov, V. P.,Yanovskaya, L. A.
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p. 2288 - 2290
(2007/10/02)
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- The Reactivity of Carbenes from Photolysis of Diazo-Compounds towards Carbon-Hydrogen Bonds. Effects of Structure, Temperature, and Matrix on the Insertion Selectivity
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Direct and/or sensitized photolyses of diazo-acetate (1a) and -malonate (1b) in hydrocarbons and ether were investigated at various temperatures in order to learn more about the nature of the C-H insertion process and the structural factors governing positional selectivity within the matrix.Photolysis of the diazo-compounds in a rigid matrix resulted in a marked decrease in the insertion selectivity, which may be interpreted as indicating that the matrix imposes severe steric demand especially on the direct C-H insertion process of the singlet carbene.The addition of a sensitizer in matrix photolysis causes a marked increase in the selectivity in the case of (1a), as is observed in the comparable liquid-phase experiment, but it causes a decrease in the case of (1b).This is interpreted as suggesting that the excited triplet (1b) itself is involved in C-H insertion under these conditions.More extensive temperature studies show that, as the temperature decreases, the C-H insertion selectivity of :CHCO2R decreases regularly regardless of the reaction phase, whereas that of :C(CO2R)2 increases in the liquid phase but decreases in the solid phase.This difference in the temperature dependence is explained by assuming that the singlet carbene is responsible for the C-H insertion of :CHCO2R throughout the temperature range studied, while both singlet and triplet are involved in the insertion of :C(CO2R)2.
- Tomioka, Hideo,Itoh, Masami,Yamakawa, Shyoji,Izawa, Yasuji
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p. 603 - 609
(2007/10/02)
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