Showing papers on "Alkylation published in 1976"
195 citations
Journal Article•
TL;DR: Deuterated analogs of the two metabolites have been synthesized and used to determine that alkylation proceeds directly via an aziridinium intermediate rather than a direct SN2 displacement of the chlorine atom.
Abstract: Summary The relative alkylating activities of two of the cytotoxic metabolites of cyclophosphamide, phosphoramide mustard and nornitrogen mustard, have been studied at pH 46 and 74 The products formed on alkylation of ethanethiol by these metabolites have been identified, confirming that phosphoramide mustard undergoes alkylation reactions as an intact molecule Deuterated analogs of the two metabolites have been synthesized, namely N,N-bis(2,2-dideutero-2-chloroethyl)-phosphorodiamidic acid and N,N-bis(2,2-dideutero-2-chloroethyl)amine, and used to determine that alkylation proceeds directly via an aziridinium intermediate rather than a direct SN2 displacement of the chlorine atom
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Patent•
11 Jun 1976TL;DR: In this paper, a two-step method was proposed to obtain substituted carboxylic acids of the type prepared by the alkylation of maleic anhydride with an olefin polymer (e.g., polybutene).
Abstract: Substituted carboxylic acids of the type prepared by the alkylation of maleic anhydride with an olefin polymer (e.g., polybutene) are prepared by a two-step method which is more economical and efficient than previously known methods. In the first step, the alkylating hydrocarbon is reacted with an unsaturated dicarboxylic acid or derivative thereof in an amount of the latter equal to about 30-90% by weight of the amount required to afford the desired product, optionally in the presence of a small amount of chlorine. In the second step, additional acid or derivative thereof is added and the reaction is continued in the presence of added chlorine.
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TL;DR: In this paper, a photolysis of these compounds in the presence of molecular oxygen yield new complexes for which structure ROOCoTPP (II) is assumed, and Electrochemical studies of complexes I and II are reported.
TL;DR: In this article, the rearrangement of trifluoromethanesulfinates (triflones) was developed as a synthetic method for obtaining these compounds and their utility as reagents for the construction of carbon skeletons was explored with regard to reactions such as alkylation, conjugation addition, and cycloaddition.
Patent•
24 May 1976TL;DR: A cleaning formulation for stubborn stains comprises an aqueous solution of (a) an alkali metal alkyl sulfate wherein the alkyls is a straight chain of from about 6 to 20 carbon atoms, such as sodium dodecyl diphenyl oxide disulfonate, (b) a branched chain alky l aryl sulfonate or (c) mixtures thereof as a detergent with less than one weight percent of sodium hypochlorite and with an amount of an alkaline builder to maintain the pH above about 11.
Abstract: A cleaning formulation for cleaning stubborn stains comprises an aqueous solution of (a) an alkali metal alkyl sulfate wherein the alkyl is a straight chain of from about 6 to 20 carbon atoms, (b) an alkylated diphenyl oxide sulfonic acid alkali metal salt, such as sodium dodecyl diphenyl oxide disulfonate, (c) a branched chain alkyl aryl sulfonate wherein the alkyl group contains from 8 to 18 carbon atoms or (d) mixtures thereof as a detergent with less than one weight percent of sodium hypochlorite and with an amount of an alkaline builder to maintain the pH above about 11.0.
Patent•
04 Mar 1976TL;DR: In this paper, a process and a catalyst for the conversion of hydrocarbons is described, supported by a solid perfluorinated polymer containing pendent sulfonic acid groups.
Abstract: A process and catalyst for the conversion of hydrocarbons is disclosed. The catalyst is supported solid perfluorinated polymer containing pendent sulfonic acid groups. The processes include alkylation of isoparaffins, isomerization of normal alkanes, disproportionation of toluene, and the alkylation of benzene.
TL;DR: All O2 and O4 alkyl 1-substituted 2,4-dioxopyrimidines are dealkylated in weak acid but the O2Alkyl group is the more stable.
Abstract: In non-aqueous solution, diazomethane and diazoethane react with the O2, O4 and N-3 sites of uridine, thymidine, 1-methyluracil and 1-methylthymine. Diazoethane has a higher affinity for alkylating oxygens than does diazomethane. The relative ratio of O2:O4:N-3 methyl products is 1:2:16 and of ethyl products the ratio is 1:1:2. When the diazoethane reaction is performed in neutral buffered solution, the same proportion of O2:O4:N-3 ethyl products is found, but the extent of reaction is very low. O2-alkylation greatly labilizes the glycosidic bond of thymidine and uridine toward acid hydrolysis. All O2 and O4 alkyl 1-substituted 2,4-dioxopyrimidines are dealkylated in weak acid but the O2 alkyl group is the more stable.
TL;DR: In this article, an efficient asymmetric synthesis of D-α-amino-acid derivatives was achieved by alkylation of a Schiff base prepared from glycine t-butyl ester and (1S,2S,5S)-2-hydroxypinan-3-one.
Abstract: An efficient asymmetric synthesis of D-α-amino-acid derivatives has been achieved by alkylation of a Schiff base prepared from glycine t-butyl ester and (1S,2S,5S)-2-hydroxypinan-3-one.
TL;DR: A laser Raman study of the alkylation of calf thymus DNA has been made using two water soluble alkylating agents: an antitumor drug, the difunctional methyl nitrogen mustard, which froms interstrand cross-links, and the dimethyl nitrogen half mustard.
Abstract: A laser Raman study of the alkylation of calf thymus DNA, poly(dG)-poly(dC) and poly(dA)-(dT) has been made using two water soluble alkylating agents: an antitumor drug, the difunctional methyl nitrogen mustard (HN2), which froms interstrand cross-links, and the dimethyl nitrogen half mustard (HN1). When an excess of the alkylating agent was used, the observed Raman frequencies due to the guanine ring modes in DNA and poly(dG)-poly(dC) changed virtually quantitatively to those of 7-methylguanosine (7-Me-Guo) showing that essentially all of the guanine bases were alkylated in the N-7 position. Furthermore, this alkylated DNA formed a stable double helical complex at neutral pH in which the alkylated guanine residues are in the keto form. No changes in the Raman bands of any of the other bases were observed in alkylated DNA. The DNA double helix, completely alkylated in at the N-7 position of guanine, melts about 35 degrees C below that of the native DNA. Upon melting, the alkylated guanine changes from the keto to the zwitterionic form.
TL;DR: The verification of a number of assumptions made about cycloamylose structure, substrate binding and catalysis is dependent on the ability to 3-O -alkylate selectively these oligosaccharides as discussed by the authors.
TL;DR: A versatile method for the determination of the ionization of guanosine is described, ideally suited for application to micro samples since any quantitative method can be used to determine the partition coefficient.
TL;DR: In this paper, Tetrangulol and its 3,8-dihydroxy-1-methyl isomer were obtained from 5-acetoxy-3-[β-(3-acetoxyphenyl)ethyl]-2-chloro-4-naphthoquinone.
Abstract: Hydroxybenz[a]anthracene-7,12-quinones can be prepared from 2-chloro-1,4-naphthoquinones by decarboxylative alkylation at C-3 with β-(3-acetoxyphenyl)propionic acids followed by treatment with sodium carbonate, which results in hydrolysis, cyclisation, and dehydrogenation. In this way tetrangulol and its 3,8-dihydroxy-1-methyl isomer were obtained from 5-acetoxy-3-[β-(3-acetoxy-5-methylphenyl)ethyl]-2-chloro-4-naphthoquinone.
TL;DR: A kinetic analysis of the inactivation of alkylating reagent in the presence of succinate or malonate suggests that N-ethylmaleimide acts as a site-directed inhibitor, and the mechanism of the first step of succinated oxidation, including a nucleophilic attack of substrate by the active-site sulfhydryl group, is discussed.
Abstract: Soluble succinate dehydrogenase prepared by butanol extraction reacts with N-ethylmaleimide according to first-order kinetics with respect to both remaining active enzyme and the inhibitor concentration. Binding of the sulfhydryl groups of the enzyme prevents its alkylation by N-ethylmaleimide and inhibition by oxaloacetate. A kinetic analysis of the inactivation by alkylating reagent in the presence of succinate or malonate suggests that N-ethylmaleimide acts as a sitedirected inhibitor. The apparent first-order rate constant of alkylation increases between pH 5.8 and 7.8 indicating a pKa value for the enzyme sulfhydryl group equal to 7.0 at 22 °C in 50 mM Tris sulfate buffer. Certain anions (phosphate, citrate, maleate and acetate) decrease the reactivity of the enzyme towards the alkylating reagent. Succinate/phenazine methosulfate reductase activity measured in the presence of a saturating concentration of succinate shows the same pH-dependence as the alkylation rate by N-ethylmaleimide. The mechanism of the first step of succinate oxidation, including a nucleophilic attack of substrate by the active-site sulfhydryl group, is discussed.
TL;DR: In the presence of [Ni(dppp)Cl2] as a catalyst, vic-bromotrimethylsiloxyalkenes (1)couple with Grignard reagents to produce alkylated and arylated silyl enol ethers, or, after acid hydrolysis, the corresponding α-alkylated and α-arylated carbonyl compounds.
Abstract: In the presence of [Ni(dppp)Cl2] as a catalyst, vic-bromotrimethylsiloxyalkenes (1)couple with Grignard reagents to produce alkylated and arylated silyl enol ethers, or, after acid hydrolysis, the corresponding α-alkylated and α-arylated carbonyl compounds. In these reactions, 1 can be regarded as an enolonium equivalent.