Showing papers on "Diazomethane published in 1980"
TL;DR: The identity of the isolated compound with the previously synthesized methyl ester of 5 (S)-trans-5,6-oxido-7,9-trans-11,14-cis-eicostatetraenoic acid (leukotriene A), was established by comparing chromatographic and chemical properties of the isolate compound and synthetic leukotrienes.
124 citations
66 citations
TL;DR: In this paper, the authors used trimethylsilyldiazomethane(TMSCHN 2 ) which is a stable and safe substitute for hazardous diazmethane.
57 citations
55 citations
TL;DR: Stable and safe trimethylsilyldiazomethane(TMSCHN2) can be used efficiently for the Arndt-Eistert synthesis in place of highly toxic and explosive diazometHane.
54 citations
TL;DR: In this paper, a gas chromatographie technique based on methylation with diazomethane and specific sulfur detection (FDP) is proposed for the on-filter speciation of add aerosol constituents.
49 citations
46 citations
TL;DR: In this article, competitive oxidations of pairs of 4-monosubstituted diphenyl sulfides by intermediates produced in the photosensitized oxygenation of diethyl sulfide and phenylbenzoyl diazomethane were carried out in methanol and benzene, respectively.
Abstract: — Competitive oxidations of pairs of 4-monosubstituted diphenyl sulfides by intermediates produced in the photosensitized oxygenation of diethyl sulfide and phenylbenzoyl diazomethane were carried out in methanol and benzene, respectively Relative rates of oxidation correlate well with Ham-mett's a, and p values of -061 (oxidation in the presence of diethyl sulfide) and -032 (oxidation in the presence of phenylbenzoyl diazomethane) show that the diphenyl sulfides oxidizing intermediates have electrophilic character In the photosensitized oxygenation of sulfides and diazo compounds, peroxy intermediates (a persulfoxide and a carbonyl oxide, respectively) have been proposed as the most probable intermediates
34 citations
TL;DR: Some simplified and efficient procedures are described for the following chemical modifications of glycophingolipid modifications, which resulted in the release of the intact oligosaccharide under the new conditions.
31 citations
TL;DR: In this article, the IR and NMR data (1H, 13C, 29Si, 119Sn, 207Pb) of the new heterometal-diazoalkanes are reported and discussed in comparison to relevant compounds of the organometallic diazo-alkane series.
20 citations
TL;DR: In this article, a method for the gas chromatographic analysis of a -keto acids in aqueous solution was described, where the keto acids were derivatized with pentafluorobenzyloxylamine to yield the oximes.
TL;DR: In this article, 3-nitrochromone is treated with a diazoalkane in trichloromethane containing ethanol, and one of the products (up to 17%) is formed by the Michael addition of the ethanol to the chromone followed by etherification of the resulting enol.
Abstract: 3-Nitrochromone with diazomethane rapidly gives a derivative (4) of cyclopropa[b][1]benzopyran-7-one which reacts readily with water or alcohols to give 3,4-dihydro-2-hydroxy-4-nitro-1-benzoxepin-5(2H)-one or its ethers. The alcohol is maintained in a particular conformation (9) by hydrogen bonding between the hydroxy- and nitrogroups that makes enolisation impossible, but the ethyl ether (8c) enolises and is easily methylated. With 2-diazopropane the reaction of 3-nitrochromone is extremely vigorous; a derivative (13) of cyclopropa[b][1]benzopyran-7-one is again formed but reacts slowly with ethanol and the ring fission occurs in a different sense so that 2-(1-ethoxy-1-methylethyl)-3-nitrochroman-4-one (14) is formed under what is thought to be stereoelectronic control. With diazoethane the reaction of 3-nitrochromone is more complex and only 2-ethyl-3-nitrochromone (3b) was characterised. If 3-nitrochromone is treated with a diazoalkane in trichloromethane containing ethanol, one of the products (up to 17%) is formed by the Michael addition of the ethanol to the chromone followed by etherification of the resulting enol (17a). In these additions the diazoalkane is regarded as acting as a catalytic nitrogen base.
TL;DR: In contrast to the 4-Diazoacetyithianthren, 7-diazoacetyl-2-methylbenzo[b]thiophen with acetonitrile and perchloric acid cyclised in an alternative mode to give a new synthesis of 2-methyl-4-substituted oxazolium perchlorates as discussed by the authors.
Abstract: 4-Diazoacetylthianthren with perchloric acid in acetonitrile gave 2-oxo-1,2-dihydrothieno[3,2,1 -de]-thianthrenium perchlorate which gave the corresponding enol ether with diazomethane. This ether was compared with 3-methoxy-1-methylbenzo[b]thiophenium perchlorate, prepared from 3-methoxythiophen, and which was much more stable to solvolysis than the demethoxy-analogue. In contrast to the 4-diazoacetyithianthren, 7-diazoacetyl-2-methylbenzo[b]thiophen with acetonitrile and perchloric acid cyclised in an alternative mode to give a new synthesis of 2-methyl-4-substituted oxazolium perchlorates.
TL;DR: The aerial parts of P. canadensis afforded a new germacran-8,12-olide and several diterpenic acids as discussed by the authors, but the stereochemistry of the lactone could be established only by careful 1 H NMR investigations of corresponding pyrazolines formed by addition of diazomethane, while the natural compound and its acetate only show very uncharacteristic NMR spectra.
TL;DR: In this paper, the preparation of eighteen epoxy diazomethyl ketones was described, and two general methods were developed: mixed anhydrides of glycidic acids and carbonic acid ester with diazmethane led to the title compounds in yields ranging from 17-74%.
TL;DR: In this paper, 1,3-Dipolar additions of diazomethane, diazoethane, ethyl diazacetate, phenyldiazomethsane and phenyl azide to 7-methylthieno[2,3c]pyridine 1,1-dioxide have been examined.
Abstract: 1,3-Dipolar Additions to 7-Methylthieno[2,3-c]pyridine 1,1-dioxide
1,3-Dipolar additions of diazomethane, diazoethane, ethyl diazoacetate, phenyldiazomethane and phenyl azide to 7-methylthieno[2,3-c]pyridine 1,1-dioxide have been examined. The structures of the primary products e.g.2, 8, 18, 25 have been established and their behaviour towards elevated temperatures and/or basic conditions was investigated. Under these conditions the primary products lost SO2 or N2 to yield e.g.4, 11, 19, 21, 23, 27, 28.
TL;DR: In this article, the reactions of diazomethane and dimethyloxo-sulfonium methylide with 1,2-dideoxy-4,5- O -isopropylidene- d - glycero -3-pentulose were studied.
TL;DR: In this article, the diazomethane was incorporated into carbonylmanganese and -rhenium complexes, and the reaction of the diazoalkane to the novel complexes Mn3(CO)12 (N2CH3) (3) and M2( CO)10 (N 2CH2) (4a: MMn; 4b: MRe) was analyzed.
Abstract: Die Reaktionen von Pentacarbonylhydridomangan (1a) bzw. -rhenium (1b) mit Diazomethan fuhren unter Einbau des Diazoalkans zu den neuartigen Komplexverbindungen Mn3(CO)12 -(N2CH3) (3) sowie M2(CO)10 (N2CH2) (4a: MMn; 4b: MRe), in denen Diazomethan bzw. die Methandiazo-Gruppierung komplexstabilisiert sind.
Complex Chemistry of Reactive Organic Compounds, XXXIV. Incorporation of Diazomethane into Carbonylmanganese and -rhenium Complexes
Reaction of pentacarbonylhydridomanganese (1a) and -rhenium (1b) with diazomethane leads via incorporation of the diazoalkane to the novel complexes Mn3(CO)12 (N2CH3) (3) and M2(CO)10 (N2CH2) (4a: MMn; 4b: MRe), resp., which contain coordinatively stabilized diazomethane or the methanediazo moiety.
TL;DR: The Michael reaction of 3-(carboethoxy-cyano) methyleneoxindole (Ia) with active methyl groups, e.g., acetophenone and acetone, afforded, the corresponding normal Michael adducts (IIa-c).
Abstract: The Michael reaction of 3-(carboethoxy-cyano) methyleneoxindole (Ia) or 3-dicyanomethyleneoxindole (Ib) with active methyl groups, e.g., acetophenone and acetone, afforded, the corresponding normal Michael adducts (IIa-c). The reduction of IIa with NaBH4 gave the spiro [oxindole-3, 4'-(2', 3'-dihydro-4'H-pyran)] compound (III), which on reaction with diazomethane afforded two methoxy derivatives (IVa, b) diastereomeric at C-2' of the 2', 3'-dihydropyran ring. The reduction of IIb, c with NaBH4 gave similar spiro compounds (V-VI), which gave similar diastereoisomers, Va, b and VIa, b, respectively. Refluxing of IIc with NH2OH gave the spiro [oxindole-3, 4'-(1', 4'-dihydropyridine)] compound (X). When the same reaction was carried out at 0°, compound (IX), the precursor of X, was obtained.
TL;DR: The rate of hydrolysis of N-methyl-N-nitrosoamides by aqueous alkalis varies greatly as mentioned in this paper, depending on the concentration and strength of the base and temperature.
Abstract: The rate of hydrolysis of N-methyl-N-nitrosoamides by aqueous alkalis varies greatly. Methylnitrosourea (1) is hydrolyzed rapidly by aqueous KOH-solutions at low temperatures to give a high yield of diazomethane. Under similar conditions, N,N′-dimethyl-N,N′-dinitroso-oxamide (3) is hydrolyzed more slowly, but also gives a good yield of diazomethane. N,N′-Dimethyl-N,N′-dinitrosoterephthal-amide (4), and (N-methyl-N-nitroso)-4-amino-4-methyl-2-pentanone (5) are less easily hydrolyzed by aqueous KOH-solutions. N-Methyl-N-nitroso-p-toluenesulfonamide (2) was the least reactive out of those tested. The hydrolysis of diazomethane in toluene with aqueous bases follows first order kinetics. The hydrolysis rate is greatly influenced by the concentration and strength of the base and temperature.
TL;DR: The proposed gas chromatographic method permits simple, rapid and reliable determination of the two above named acids in human urine and is used with success in biological monitoring of industrial styrene exposure.
Abstract: A new gas chromatographic method is proposed for the simultaneous determination of mandelic and phenylglyoxylic acids in human urine. The two acids are extracted into ethyl acetate from acidified and ammonium sulphate-saturated urine, converted into methyl esters with diazomethane and chromatographed in this form. Gaseous diazomethane is generated in a simple apparatus and introduced by a mild nitrogen flow into the extract of the investigated urine. Completion of esterification is indicated by an external indicator (chloroform solution of iodine). When the pink colouring of the indicator disappears, further supply of diazomethane is stopped. Since only the exact amount of diazomethane needed enters the reaction, any adverse effects of its excess cannot assert themselves. Phenylglyoxylic acid is transformed quantitatively into the corresponding methyl ester without formation of any secondary products. The method permits simple, rapid and reliable determination of the two above named acids in human urine. It is used with success in biological monitoring of industrial styrene exposure.
TL;DR: In this paper, 2-Dichloracetamido-1,3-dimethyl-5-nitroimidazoline undergoes novel cycloaddition with diazomethane to form 5-dichloracetylimino-tetrahydroimidine-opyrazoles via
TL;DR: In the case of the reaction 4c + 8, the regiospecifity is lost, with formation of the cycloadducts 9b and 10b All diazomethane-adducts as discussed by the authors, and all the diazoalkanes can be transformed thermally into the allyl(phosphoryl)diazomethsanes 13a - d, but only 13c and d could be isolated.
TL;DR: Condensation of naphthalene-2,7-diol with 2,4-dioxo-4-phenylbutanoic acid gives 6-hydroxy-1-oxo-9 -phenyl-1H-phenalene-7-carboxylic acid which is readily converted into the lactone and on treatment with diazomethane forms only methyl 6-methoxy-1.
Abstract: Condensation of naphthalene-2,7-diol with 2,4-dioxo-4-phenylbutanoic acid gives 6-hydroxy-1-oxo-9-phenyl-1H-phenalene-7-carboxylic acid which is readily converted into the lactone and on treatment with diazomethane forms only methyl 6-methoxy-1-oxo-9-phenyl-1H-phenalene-7- carboxylate. Analogous reactions of other 4-aryl-2,4-dioxobutanoic acids with naphthalene-2,7-diol or with 3,6-dimethoxynaphthalene-2,7- diol give easy access to arylphenalenones and naphthoxanthenones related to natural pigments.
TL;DR: Acylation of 4-carbamoylimidazolium-5-olate (2) with a variety of acid chlorides produced 4(5)-CARBAMOYL-1H-IMIDZol-5-(4)yl acid carboxylates (3a-j) as discussed by the authors, which demonstrated the complete lack of antitumor activity against Lewis lung carcinoma or sarcoma 180 in mice.
TL;DR: By the reaction of unsymmetrically substituted carbodiimides with diazomethane the corresponding 1,2,3-triazoles have been obtained.
Abstract: By the reaction of unsymmetrically substituted carbodiimides with diazomethane the corresponding 1,2,3-triazoles have been obtained. The structure of the adducts was elucidated by IR, UV,1H-NMR and high resolution mass spectrometry.
TL;DR: When terephthalic acid was chemisorbed on an alumina surface, was esterified in a stream of diazomethane, monomethyl Terephthalate was obtained quantitatively as discussed by the authors.
Abstract: When terephthalic acid, which had been chemisorbed on an alumina surface, was esterified in a stream of diazomethane, monomethyl terephthalate was obtained quantitatively
TL;DR: In this article, the regiochemistry of diazomethane cycloadditions with simple alkylethylenes, heretofore not reported, was investigated in the simplest case, and the products were 3-and 4-methylpyrazolines in 7.4/1 ratio, in accord with the diradical mechanism.
TL;DR: In this paper, two 14-and 12-membered ring lactones were synthesized from the metasternal secretion of the eucalypt longicorn Phoracantha synonyma using racemic mixtures.
Abstract: Synthesis of Phoracantholide K, O and M
Two 14membered ring lactones 3 and 4 and a 12membered ring lactone 5 isolated from the metasternal secretion of the eucalypt longicorn Phoracantha synonyma have been synthesized as racemic mixtures by the following method. Reaction of the dilithium derivative of 5-hexynoic acid (6) with threo-8-bromo-2,4-isopropylidenedioxyoctane (7), followed by removal of the protecting group and esterification with diazomethane gave methyl-threo-11, 13-dihydroxy-5-tetradecy-noate (8) (s. Scheme 2). Partial hydrogenation of the triple bond in 8 with Lindlar Pd-catalyst, followed by saponification lead to (threo, Z)-11, 13-dihydroxy-5-tetra-decenoic acid (10). The dihydroxy acid 10 was converted into the S-(2-pyridyl) thioate and cyclized in diluted benzene solution under the influence of silver ions to yield the corresponding 12- and 14-membered lactones in approximately equal amounts. Isomerization of the mixture with p-toluenesulfonic acid in methylene chloride yielded the 14-membered lactone (cis-11, 13–5Z)-11-hydroxy-5-tetradecen-13-olide almost exclusively. It proved to be identical in its properties with natural phoracantholide K (3). With 5-hexynoic acid and 7-tetrahydropyranyloxy-octyl bromide or 5-tetrahydropyranyloxy-hexyl bromide as starting materials (±)-phoracantholide O (4) and M (5) have been synthesized in an analogous manner.