Showing papers on "Diazomethane published in 1967"
66 citations
TL;DR: In this paper, the same type of disproportionation reaction was applied to N-styrylindolin, which was converted to N-(β-phenylethyl) indole, and a separate proof for the vinylene group connecting the two heterocycles was available through its reduction in a Pd catalyzed reaction at the expense of a dehydrogenation of the dihydroindole system.
34 citations
31 citations
TL;DR: Diazomethylation esterified all tested acidic indoles without appreciable loss and led to the selection of Versamid 900, HI-EFF 8 BP, and SE-30 as permitting complete separation of all indole esters, while SE-52 was unsatisfactory.
24 citations
TL;DR: In this paper, an improved synthesis and physicochemical evidences for the stereochemical assignments of (+/-)-11-deoxyprostaglandin F1beta were reported.
22 citations
19 citations
Journal Article•
TL;DR: In this article, an improved synthesis and physicochemical evidences for the stereochemical assignments of (+/-)-11-deoxyprostaglandin F1beta were reported.
19 citations
18 citations
TL;DR: The Hofmann degradation of 3-phenylisoxazole-4,5-dicarboxamide gave 3.5-pyrimidin-5,7(4H, 6H)-dione as mentioned in this paper.
18 citations
17 citations
TL;DR: If the isolated complex is stabilized with diazomethane and then digested with trypsin, the peptides formed can be isolated by ion exchange chromatography, which suggests that the 14CO2 is bound to a specific site in the enzyme.
Abstract: THE mechanism of action of Carboxydismutase—the enzyme which catalyses the fixing of carbon dioxide in plants—has been the subject of numerous investigations. The enzyme requires two substrates, ribulose-1,5-diphosphate (RuDP) and bicarbonate, and is found to form a 14CO2–carboxydismutase complex1. If the isolated complex is stabilized with diazomethane and then digested with trypsin, the peptides formed can be isolated by ion exchange chromatography. It is found that only one of these peptides is highly radioactive, which suggests that the 14CO2 is bound to a specific site in the enzyme2.
TL;DR: In this paper, trifluoroacetylation of indoles accompanied by gas chromatography and electron capture analysis of the derivatives offers a more sensitive method of detecting these compounds compared with flame ionization detection.
TL;DR: In this paper, the 2′-OH group adjacent to the internucleotide linkage is responsible for this hydrolysis caused by diazomethane, and a larger excess of DMD leads to a higher degree of fission.
TL;DR: In this paper, the reaction of thioxanthylium perchlorate with diazomethane was investigated and seven compounds (II, III, V, VI, VIII, IX, and X) were formed which were identified on the basis of spectral data (mainly mass spectra) and chemical reactions.
TL;DR: The NMR spectrum of 1-pyrindine (3) indicates the presence of the 5H and 7H tautomers in solution as discussed by the authors, and the properties and possible structures of the intermediate methiodide and methochloride compounds formed from 3 are discussed.
TL;DR: In this article, the ultraviolet and NMR spectra of these compounds are discussed and the results of the reaction are compared with the results obtained for the synthesis of uridylyl-(3′-5′)-inosine with dimethylsulfate.
TL;DR: A procedure for the separation and estimation of mixtures of the four lower normal alkyl p-hydroxybenzoates as derivatives is described, and Diazomethane did not alkylate quantitatively when catalyzed in the same manner as Diazoethane.
TL;DR: Phenolic oxidative coupling of N-methylcoclaurine with potassium ferricyanide afforded (±)-glaziovine (III), whose methylation with diazomethane gave (±)pronuciferine (VI) as discussed by the authors.
Abstract: Phenolic oxidative coupling of (±)-N-methylcoclaurine with potassium ferricyanide afforded (±)-glaziovine (III), whose methylation with diazomethane gave (±)-pronuciferine (VI). A very interesting dimeric compound (VIII) was also obtained.
TL;DR: Heptafluoroquinoline with aqueous sodium hydroxide or with potassium hyroxide in t-butyl alcohol gives a mixture of 2- and 4-hydroxyhexafluoroisoquinolines; heptafloquinoline reacts to give the 1-hydrox-derivative 2-hydrohexafloorquinoline and 1-hexafloorois-oquinoline as tautomers and react with diazomethane giving a mixture O- and N-methyl derivatives as discussed by the authors.
Abstract: Heptafluoroquinoline with aqueous sodium hydroxide or with potassium hydroxide in t-butyl alcohol gives a mixture of 2- and 4-hydroxyhexafluoroquinolines; heptafluoroisoquinoline reacts to give the 1-hydroxy-derivative 2-Hydroxyhexafluoroquinoline and 1-hydroxyhexafluoroisoquinoline exist as tautomers and react with diazomethane giving a mixture of O- and N-methyl derivatives whereas 4-hydroxyhexafluoroquinoline gives only an O-methyl derivative The factors affecting tautomerism in these systems are outlined
TL;DR: In this article, the authors investigated the grafting mechanisms in aqueous lithium bromide-potassium persulfate redox system and potassium persulfates system and showed that the graft copolymerization is initiated within the fibers by the free radicals which are formed by the action of the sulfate ion or hydroxyl radicals on thiol groups but not on tyrosine residues.
Abstract: In order to clarify the grafting mechanisms in aqueous lithium bromide-potassium persulfate redox system and potassium persulfate system. Methyl-methacrylate (MMA) grafting was performed onto modified wool and silk fibroin fibers at 30°C and 40°C. In the LiBr-K2S2O8 system, MMA grafton for wool is diminished by pre-treatment with aqueous bromine, peracetic acid, acetic anhydride, diazomethane, 2:4-dinitrofluorobenzene and nitric acid. On the other hand, in the K2S2O8 system, the graft-on is diminished by acetic anhydride, 2:4-dinitrofluorobenzene and nitric acid, but not changed by diazomethane. In the LiBr-K2S2O8 system, MMA graft-on for silk is diminished by the treatment with aqueous bromine, diazomethane, acetic anhydride and nitric acid. In the K2S2O8 system, however, the graft-on is not changed by all the treatments except nitric acid leading to decrease. The grafting onto the wool fibers treated with absolute alcohol solution of bromine is not changed in both grafting system, until almost all the tyrosine is brominated to 3:5-dibromotyrosine. The graft-on, however, is sharply decreased when the oxidation of thiol groups must have occurred. The graft-on is not changed for silk fibers treated with absolute alcohol solution of bromine.Acetylated wool has less graft-on because it has a lower concentration of persulfate inside the fibers compared with unmodified wool. Sharp decrease of graft-on for nitrated wool or silk seems to be due to the “retarder” effect of aromatic nitro compounds. By the treatment with diazomethane on wool fibers, the absorption of potassium persulfate is increased remarkably, but the graft-on does not change in the K2S2O8 system. From these results, it is suggested that graft copolymerization is initiated within the fibers by the free radicals which are formed by the action of the sulfate ion or hydroxyl radicals on thiol groups but not on tyrosine residues. Thus, the thiol groups in wool fibers have an essential role on the grafting and even though a large amount of persulfate is absorbed the grafting is limited by the content of thiol groups. These results lead to the same conclusion as that of the treatment with thioglycollic acid, alkyl halide after reduction, and potassium cyanide in our previous report. Inhibition of homopolymerization in the LiBr-K2S2O8 system is due to the bromination of monomers by liberated bromine. The liberated bromine will act to react with the easily oxidized component of wool or silk fibers. This consumption of bromine will contribute to proceed the graft copolymerization without homopolymerization regulating the bromination of monomers.
TL;DR: In this article, the steric effects in a manner very similar to that found by Huisgen for corresponding reactions of diphenyldiazomethane have been investigated, and it was shown that the relative rate coefficients for reaction with tetrahydrofuran fall in the sequence 100 : 6·1 : 0·8, respectively.
Abstract: The kinetics of reactions between diazomethane and several conjugated unsaturated esters have been investigated. Reaction rates are governed by steric effects in a manner very similar to that found by Huisgen for corresponding reactions of diphenyldiazomethane. For the series of esters CH2:CH·CO·OEt, CH2:C(CH3)·CO·OEt, CH3·CH:CH·CO2Et, the relative rate coefficients for reaction with diazomethane in tetrahydrofuran fall in the sequence 100 : 6·1 : 0·8, respectively. These observations strongly support a concerted cycloaddition process for the reaction mechanism.
TL;DR: In this paper, it was shown that 3,5-Dimethoxyphenylacetyl chloride has been converted into 1-(3, 5-dimethyoxymethoxymethyl)heptan-2-one, and then demethylated into 3, 5 -dimethyoxide-dimethyl-dihydroxymynyl (DDEH) heptan 2-one by demethylation.
Abstract: 3,5-Dimethoxyphenylacetyl chloride has been converted into 1-(3,5-dimethyoxyphenyl)heptan-2-one, and thence by demethylation into 1-(3,5-dihydroxyphenyl)heptan-2-one. Reduction of the latter with sodium borohydride, followed by carboxylation, gave (±)-1-(4-carboxy-3,5-dihydroxyphenyl)-heptan-2-ol. This reacted readily with ethyl orthoformate to give (±)-pulvilloric acid. Carboxylation of the (+)-heptan-2-ol followed by esterification with diazomethane and treatment with dimethoxymethane gave a very low yield of (±)-methyl dihydropulvillorate.Several other compounds are described which were obtained during a study of alternative routes to the above heptan-2-one and heptan-2-ol.
TL;DR: The order of reactivity of ribonucleosides toward diazomethane, a reagent that attacks at the site of the most acidic hydrogen, has been found to be guanosine and uridine, cytidine, and adenosine, the latter two being much less susceptible to methylation than the others.
Abstract: Publisher Summary This chapter focuses on the general techniques and materials for chemical methylation of nucleic acid and its components such as nucleoside phosphates, nucleoside 5'-pyrophosphates, and homo-polyribonucleotides. For chemical methylation studies, two general types of reagents are used—firstly, methyl esters of strong acids, such as dimethyl sulfate, methyl methanesulfonate, or methyl p-toluenesulfonate, and secondly, diazomethane. Investigations involving the methylation of simple nucleosides, at or around physiological pH and in aqueous media, reveal different bases, which are attacked by these reagents, and the positions of the reactive sites. The order of reactivity of the principal ribonucleosides toward electrophilic reagents such as the methyl esters of strong acids has been shown to be guanosine, adenosine, and cytidine, with uridine virtually inert. The order of reactivity of ribonucleosides toward diazomethane, a reagent that attacks at the site of the most acidic hydrogen, has been found to be guanosine and uridine, cytidine, and adenosine, the latter two being much less susceptible to methylation than the others. The principal position of base attack by diazomethane is N (7) in guanine, N (3) in uracil (or thymine), N (3) in cytosine, and N (1) in adenine.
TL;DR: Phenolic oxidative coupling of 1-(3,4-dihydroxybenzyl)-1,2,3, 4-tetrahydro-7-hydroxy-6-methoxy-2,2-dimethyl-isoquinolinium iodide gave 2.3,5-trihexyltrihydroxymethylpolymorphine methopicrate as discussed by the authors.
Abstract: Phenolic oxidative coupling of 1-(3,4-dihydroxybenzyl)-1,2,3,4-tetrahydro-7-hydroxy-6-methoxy-2,2-dimethyl-isoquinolinium iodide gave 2,3,5-trihydroxy-6-methoxyaporphine methopicrate, which was methylated with diazomethane to give glaucine methopicrate, identical with an authentic sample obtained by an alternative synthetic method.
TL;DR: A procedure for the analysis of 4,6-dinitro-o-set-butylphenol (DNOSBP) in fruits and almonds by electron-capture gas chromatography is described in this paper.
Abstract: SUMMARY— A procedure for the analysis of 4,6-dinitro-o-set-butylphenol (DNOSBP) in fruits and almonds by electron-capture gas chromatography is described. The alkanolamine salts of DNOSBP are converted to DNOSBP with acid prior to extraction with benzene. The extracted DNOSBP is then cleaned-up by column chromatography, methylated with diazomethane, and analyzed as the methyl ether. The overall average recovery of DNOSBP residues on almonds, cherries, peaches, and apricots (fortified with 0.01–0.5 ppm DNOSBP) was 90%.