Showing papers on "Diazomethane published in 1977"
TL;DR: In this paper, the synthesis of the methyl esters of N -methoxycarbonyl- and N -benzyloxy carbonylaziridine-2-carboxylic acid by reacting methyl 2-chloro- N -carbalkoxyglycinate 1 with diazomethane is described.
66 citations
31 citations
TL;DR: In this article, the 13C and 15N n.m.r. results for a series of diazo compounds are reported and it is found that the diazomethane carbon is shielded by an extraordinary amount compared with normal sp2 hybridized carbons.
Abstract: The 13C and 15N n.m.r. results for a series of diazo compounds are reported. It is found that the diazo carbon is shielded by an extraordinary amount compared with normal sp2 hybridized carbons. The 15N chemical shifts reveal that the terminal nitrogen is deshielded relative to the central one. This is contrary to that expected from charge effects but support is found for this phenomenon in other systems. One-bond 13C14N coupling in diazomethane is also reported for the first time. INDO MO calculations of the charges and finite perturbation calculations of 13C14N and CH couplings are compared with the experimental results.
31 citations
TL;DR: 2,4,5-trichlorophenol is a urinary metabolite of hexachlorobenzene (HCB) and was identified by the R f value, uv absorbance, mp, mixed mp, ir-, nmr-, and mass spectroscopy and synthetized by the reaction of TCP with diazomethane.
25 citations
TL;DR: Experiments with 5-O-desmethyl-indomethacin have demonstrated that using the described diazomethane methylation conditions no alkylation of the phenolic group occurs, allowing quantitative assay of the drug at the submicrogram level.
24 citations
TL;DR: In this article, the protected guanosine derivative (5a) with diazomethane and then removing the protecting groups (5b) was prepared from (4a) in good yield.
Abstract: N 2
-Methylguanosine (1c) may be prepared in satisfactory yield by treating the protected guanosine derivative (5a) with diazomethane and then removing the protecting groups; (5a), which readily reacts with dimethylamine to give (5c), may be prepared from (4a) in good yield.
20 citations
TL;DR: The products from the periodate oxidation of 1,2-O-isopropylidene-alpha-D-glucofuranose were converted by ethynylmagnesium bromide into a separable, 14:11 mixture of 6,7-dideoxy-1,2
19 citations
TL;DR: NMR data showed that the loss of biologic activity upon 2'(3')-O-methylation was not due to a change of conformation of the nucleoside sugar moiety, and found both derivatives to be inactive, relative to the parent compound, against several virus types in cell culture.
Abstract: Diazomethane treatment of ribavirin (1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide) in the presence of SnCl2 as catalyst led to quantitative formation of the 2'-O-methyl and 3'-O-methyl derivatives of the parent compound. The products were successfully fractionated on a basic ion-exchange column and isolated in crystalline form. Indentification was based on the elution sequence from the column and on 1H NMR spectroscopy. Both derivatives were found to be inactive, relative to the parent compound, against several virus types in cell culture. Unlike ribavirin itself, the 2'(3')-O-methyl derivatives did not suppress cellular DNA synthesis. NMR data showed that the loss of biologic activity upon 2'(3')-O-methylation was not due to a change of conformation of the nucleoside sugar moiety.
16 citations
14 citations
TL;DR: A number of the products of dipolar addition have been converted into new D-ribofuranosyl-pyrazoles and -triazoles by hydrogenolysis.
14 citations
TL;DR: In this paper, the reactons of polyfluoroazaolefins with diazomethane are described, and the results are shown that 5-H-decafluoro-2-azahex-hex-2-(Z)-ene yields 1-trifluoromethyl-methyl 2-fluoro 2-(1,1,2,3,3-3-hexafluoropropyl)-aziridine as the sole isolable product.
TL;DR: In this paper, N,N-Dimethyl-l,3-propanediamine reacted with I to give XI directly and gave N-substituted maleimides at 170-180°C.
Abstract: N-Carbethoxymaleimide (I), a convenient intermediate to maleoylamino acids in aqueous solution, also undergoes facile reaction with amines in ether. Thermolyses of the resulting imide-amides at 170-180°C gave N-substituted maleimides. N,N-Dimethyl-l,3-propanediamine reacted with I to give XI directly. Copolymers prepared and studied were those of divinyl ether with N-carbethoxymaleimide, maleoylglycine, maleoyl-DL-alanine, maleoyl-DL-phenylalanine, maleoyl-L-phenylalanine, maleoyl-DL-methionine and maleoyl-DL-leucine. These copolymers were characterized by elemental analyses to establish the comonomer ratios, by viscosity measurements, and in certain instances by determination of molecular weight by membrane osmometry after esterifica-tion with diazomethane.
TL;DR: Methylation of ( R,S )-DOPA with diazomethane gave the trimethyl derivative in which the phenolic hydroxy groups and the carboxy group were methylated, and N -Methylated side products were formed.
TL;DR: Phenyl(trimethylsilyl)ketene was prepared by zinc dehalogenation of phenyl bromoacetyl chloride (PBP) as mentioned in this paper.
TL;DR: In this paper, the Loroglossine is shown to be bis[4-(β-D-glucopyranosyloxy)-benzyl]-(2R, 3S)-2-isobutyl-tartrate (1).
Abstract: The Constitution of Loroglossine
Loroglossine, a characteristic constituent of orchids, is shown to be bis[4-(β-D-glucopyranosyloxy)-benzyl]-(2R, 3S)-2-isobutyl-tartrate (1). Base catalysed hydrolysis and esterification with diazomethane gave 1 mol-equiv. of dimethyl (+)-2-isobutyl-erythro-tartrate ((+)-3) and 2 mol-equiv. of a glucoside which after acetylation formed 4 identical with a synthetic sample. The structure of (+)-3 follows from the synthesis of (±)-3 by osmium tetroxide oxidation of isobutyl-maleic acid anhydride and subsequent esterification. The absolute configuration of (+)-3 was based on Horeau experiments and NMR. data of the diastereomeric mixture of its esters 15 and 16 and pure 15 with (S)-(+)- and (R)-(−)-α-phenyl-butyric acid, respectively.
TL;DR: The palladium catalyzed hydrogenation of 7,14-cyclodihydrocodeinone (1) leads to 14-methyl-C-nor-dihydroid codeinone, a starting material for the synthesis of hitherto unknown morphine and codeine derivatives as mentioned in this paper.
Abstract: The palladium catalyzed hydrogenation of 7,14-cyclodihydrocodeinone (1) leads to 14-methyl-C-nor-dihydrocodeinone (2 a), a starting material for the synthesis of hitherto unknown morphine and codeine derivatives Ring expansion with diazomethane yields 14-methyl-dihydrocodeinone besides the spiro-oxiranes8 and10
TL;DR: In this article, (−)-t-ButylNEophylphenyltin hydride reacts with diazomethane to give (−)- t-butylmethylneophyl phenyltins, while (−)- or (+)-methyl NEophylPNyltIN hydrides add to the double bond of bifluorenylidene to give
Journal Article•
TL;DR: Diazomethane treatment of formycin A in the presence or absence of SnCl2 as catalyst, was used for the preparation of the two possible dimethylated derivatives, 2'(3")-O,N1(N2)-dimethylformycins, and the four possible dim methylated derivatives were obtained by controlled treatment offormycin with diazometrichane, and subsequent column chromatography for product isolation.
Abstract: 1. Diazomethane treatment of formycin A in the presence or absence of SnCl2 as catalyst, was used for the preparation of the 2'-O-methyl, 3'-O-methyl, N1-methyl and N2-methyl derivatives. The four possible dimethylated derivatives, 2'(3")-O,N1(N2)-dimethylformycins, were obtained by controlled treatment of formycin with diazomethane in the presence of SnCl2, and subsequent column chromatography for product isolation. 2. All the foregoing products were characterized and identified by chromatography, ultraviolet absorption spectra, and proton magnetic resonance spectroscopy. Extensive u.v. spectral data, and spectrally determined pK values, for the various derivatives are presented. 3. N2-Methylformycin B was also prepared by enzymatic deamination of the parent N2-methylformycin A. 4. The sequence of elution of N1-methylformycin and N2-methylformycin on a strongly basic ion exchange column suggested that the latter is in the syn conformation. The susceptibility of N2-methylformycin to adenosine deaminase shows that this analogue may adopt the anti conformation on reaction with the enzyme. 5. The active species in the SnCl2-catalysed monomethylation of the 2'(3') cishydroxyls of ribonucleosides by diazomethane was shown to be an organo-tin product of the reaction of SnC2 with diazomethane. This product, not identified, contained no nitrogen or chlorine. 6. A simple column chromatographic procedure is described for the desalting of heterocyclic bases and their nucleosides with pK values for ring protonation down to about 0.
TL;DR: In this article, a large excess of paraformaldehyde and potassium hydroxide in ethanol gave 3-(2,3,5-tri-O-benzyl-β-D-ribofuranosyl)prop-2-yn-1-ol (5) in 70% yield.
Abstract: Treatment of 2,3,5-ri-O-benzyl-β-D-ribofuranosylethyne (2) with a large excess of paraformaldehyde and potassium hydroxide in ethanol gave 3-(2,3,5-tri-O-benzyl-β-D-ribofuranosyl)prop-2-yn-1-ol (5) in 70% yield. Oxidation of (5) with chromic oxide (Jones reagent) afforded the carboxylic acid (4)(75%), esterification of which with diazomethane gave the known ester (7). Similar reactions and correlations have been carried out in the α-series.Reaction of the Grignard reagent (14) of 3-(tetrahydropyran-2-yloxy)propyne with 2,3,5-tri-O-benzyl-D-ribofuranose (19) followed by ring closure and removal of the tetrahydropyranyl ether group gave the alcohol (5) in 52% overall yield.Careful oxidation of (5) gave the corresponding aldehyde (3) which yielded the known pyrazole (1)(72%) on treatment with hydrazine. When 1,2-dideoxy-4,5:7,8-di-O-isopropylidene-D-manno-oct-1-yn-3-ulofuranose (22) was treated with hydrazine, 3(5)-(1,2:4,5-di-O-isopropylidene-D-manno-pentahydroxypentyl)pyrazole (23) was isolated in 93% yield.
TL;DR: In this paper, the synthesis of cinnamylidene malonic or cyanacetic esters bearing a methyl or a phenyl group in the position γ to the withdrawing groups, were achieved.
Abstract: The syntheses of cinnamylidene malonic or cyanacetic esters, bearing a methyl or a phenyl group in the position γ to the withdrawing groups, were achieved. The configurations of the various isomers were established and the conformations are discussed. Diazomethane adds exclusively to the α,β double bond of these dipolarophiles in only one orientation. The thermolysis of the resulting 1-pyrazoline was studied.
TL;DR: Decafluorocyclohepta and fuming sulphuric acid at 100° gave a bright yellow solution which was decolourised on dilution with water to give 2H,4H-hexafluoro-1,5-dihydroxy-8-oxabicyclo(3,2,1)octan-3-one as discussed by the authors.
TL;DR: In this article, it was shown that the pKa of typical phosphonic acids is around 2.56 and therefore it seemed reasonable that they should be candidates for methylation with 1.56 pKa.
TL;DR: In this article, the structure assignments were based on chemical and spectroscopic data, and the structure assignment was based on 3-hydroxypyrromethenes and 3-hexypyrrole derivatives with trialkyloxoniumtetrafluoborate.
Abstract: Alkylation of 3-hydroxypyrromethenes and 3-hydroxypyrrole derivatives with trialkyloxoniumtetrafluoborate afforded 3-alkoxy-derivatives whereas other methods of alkylation (dimethyl sulfate, methyl fluorosulfonate, diazomethane) led only to N-methylated compounds. The structure assignments were based on chemical and spectroscopic data.
TL;DR: The reaction of chloromethyl(triphenylphosphine) gold with KI and NaCN gave, respectively, triphenylPHosphinegold iodide and methyltriphenyl-phosphonium dicyanoaurate.
Abstract: 1.
We discovered the reaction of inserting the methylene group at the gold-chlorine bond to give chloromethyl (triphenylphosphine) gold.
2.
The triphenylphosphine complexes of acetylacetonate-ferrocenyl-, and acetonylgold react with diazomethane to give vinyl(triphenylphosphine) gold.
3.
The reaction of chloromethyl(triphenylphosphine)gold with KI and NaCN gave, respectively, triphenylphosphinegold iodide and methyltriphenylphosphonium dicyanoaurate.
TL;DR: In this article, the 13C n.m.r. spectra of the major human urinary metabolite of prostaglandin PGE2 and PGE1 are discussed together with some unsaturated precursors.
Abstract: The 13C n.m.r. spectra of the major human urinary metabolite of prostaglandin PGE2 and PGE1 are discussed together with some unsaturated precursors. Δ-2-Pyrazolines, formed by addition of diazomethane to the 11-oxo dienediones in this series, were identified by 13C and 1H n.m.r. and by other physical methods.
TL;DR: In this paper, the parent compound and its dideuterio derivative were obtained from the eight-membered ring ketone by the ring enlargement of 5,10-dihydro-11H-dibenzo[a,d]cyclohepten-11-one with diazomethane.
Abstract: The eight-membered ring 6,6-dicyano-5,6,7,12-tetrahydrodibenzo[a,d]cyclooctene was prepared from 2,2′-bis(bromomethyl)diphenylmethane and sodiomalononitrile. From this dicyano derivative a series of mono- and disubstituted cyclooctenes was synthesized.The corresponding 5,7,12-trihydro-6H-dibenzo[a,d]cycloocten-6-one was obtained by the ring enlargement of 5,10-dihydro-11H-dibenzo[a,d]cyclohepten-11-one with diazomethane. The parent compound and its dideuterio derivative were prepared from the eight-membered ring ketone. A Wittig reaction on the ketone gave the methylene derivative.
TL;DR: The relatively rapid formation of pyrazoline adducts is a serious side reaction in the esterification of 15-oxo-PGF2alpha with ethereal diazomethane under conditions used routinely in the chemical derivatization of prostaglandins.
Abstract: The relatively rapid formation of pyrazoline adducts is a serious side reaction in the esterification of 15-oxo-PGF2alpha with ethereal diazomethane under conditions used routinely in the chemical derivatization of prostaglandins.