Showing papers on "Diazomethane published in 1991"

Synthesis of cyclopropylboronic acid esters by carbene transfer to 1-alkenylboronic acid esters

Abstract: Cyclopropylboronic acid esters 2a-j are prepared conveniently and with high stereoselectivity by cycloaddition of carbenes (or carbenoids) to 1-alkenylboronic acid esters. Methylene transfer is achieved either by the Simmons-Smith reaction or with diazomethane/palladium(II) acetate. The latter procedure is susceptible to steric hindrance, but otherwise, product yields are equally good with both methods. Acyl carbene transfer to vinylboronate 1a succeeds with palladium(II) acetate as catalyst, but not with dirhodium tetraacetate or copper(I) triflate

Modification of Preparation of Diazomethane for Methyl Esterification of Environmental Samples Analysis by Gas Chromatography

Abstract: Pour cette etude le Kit Aldrich de preparation du diazomethane a partir de la N-methy-N'-nitro-N-nitroso-guanidine (MNNG) a ete modifie. On a utilise comme reactif le diazold a la phase de MNNG a cause de sa grande production en diazomethane, son temps de reaction rapide, sa securite et sa stabilite

Chemical amplification type resist material

Abstract: PURPOSE: To obtain a positive type resist material which possesses the high transmissivity for the far infrared light and KrF excimer laser beam, the superior sensitivity for light exposure, heat resistance, and the close adhesion performance with a substrate. CONSTITUTION: A chemical amplification type resist material contains the polymer shown by the formula, photosensitive compound which generates acids through light exposure, and a solvent which dissolves the above-described chemicals. In the formula, R 1 is a methyl group, isopropyl group, tert-butyl group, tetrahydropyranyl group, trimethyl silyl group or tert-butoxy carbonyl group, and each of (k) and (l) is a natural number (k/(k+l)=0.1-0.9). As the polymer, is listed p-tert-butoxystyrene-p-hydroxystyrene polymer, and as the acid generating agent, is listed bis(p-toluene sulfonyl) diazomethane. Further, as the solvent, is listed methyl cellosolve acetate. COPYRIGHT: (C)1992,JPO&Japio

Asymmetric synthesis of cis and trans 2-methyl and 2-ethyl 1-amino cyclopropanecarboxylic acids

Abstract: A new four step asymmetric synthesis of 2-methyl and 2-ethyl 1-amino cyclopropane carboxylic acids resulted from the cycloaddition of diazomethane to the corresponding chirally derivatized dehydro-aminoacid.

Photochemical and acid-catalyzed dienone-phenol rearrangements. The effect of substituents on the regioselectivity of 1,4-sigmatropic rearrangements of the type A intermediate

Abstract: Birch reduction of isophthalic acid and 3-cyanobenzoic acid followed by (1) methylation of the resulting enolate with methyl iodide and (2) esterification with diazomethane provided 2-carbomethoxy- and 2-cyano-6-methyl-6-carbomethoxy-1,4-cyclohexadienes 9 and 25. Type A photorearrangements of a series of 2-carbomethoxy-, 2-cyano-, 2-methoxy-, and 2-methyl-4-carbomethoxy-4-methyl-2,5-cyclohexadien-1-ones 11, 26, 45a, and 45b gave 4-carbomethoxy-3-methyl-2-substituted-phenols 12, 28, 46, and 31. It has been demonstrated that the regioselectivity of type A photorearrangement of C(2) substituted 2,5-cyclohexadien-1-ones is governed by electronic rather than steric effects to give the intermediate C(1) rathen than C(3) substituted bicyclo[3.1.0 1,5 ]hex-3-en-2-ones. Regioselectivities of the acid-catalyzed dienone-phenol rearrangements of C(2) substituted 2,5-cyclohexadienones 11,45a, and 45b appear to be dependent upon the relative stabilities of carbocations resulting from migration of the C(4) carbomethoxy group

Use of 17o nmr in a stereochemical study of the alkaline hydrolysis of cyclic six-membered 2-aryl phosphates

Abstract: The alkaline hydrolysis of the title compounds 1-5 (Chart II) with 17 OH − has been studied. The labeled cyclic phosphate salts produced by hydrolysis of 1-5 were converted to a mixture of the corresponding methyl esters by treatment with diazomethane. The resulting mixture was analyzed by 31 P NMR or GC for the epimeric OCH 3 ratio and by 17 O NMR for the 17 O axial to equatorial ratio in the P= 17 O moiety. Nucleophilic displacement of ArO − by 17 OH − at phosphorus is nonstereospecific. The results can be rationalized by postulating that the direct displacement process involving inversion completes with pseudorotation of pentocoordinate intermediates involving retention

Novel diazodisulfone compound

Abstract: PURPOSE: To provide a novel diazodisulfone compound which generates an acid by the irradiation of KrF excimer laser beams, X rays, etc., and which has a large value on the formation of ultrafine patterns in a semiconductor industry, etc. CONSTITUTION: A compound of formula I (R1 is 3-8C branched or cyclic alkyl; R2 is 1-8C linear, branched or cyclic alkyl), e.g. bis(cyclohexyl sulfonyl) diazomethane. The compound has an excellent light transmitting property for far-UV rays, KrF excimer laser beams, ArF excimer laser beams, etc., readily generates an acid on the irradiation of light, electron beams, X rays, etc., and has excellent solution stability in resist materials. The compound of formula I is produced by reacting a compound of formula II with H 2 O 2 and subsequently reacting the produced compound of formula III with tosylazide of formula IV in the presence of a base, the compound of formula II being produced by reacting a compound of formula RISH with CH 2 Cl 2 . COPYRIGHT: (C)1992,JPO&Japio

Gas chromatographic determination of tributyl phosphate, dibutyl phosphate and butyl phosphate in kerosene solutions

Abstract: A gas chromatographic procedure has been developed for the determination of tributyl phosphate (TBP), dibutyl phosphate (HDBP) and butyl phosphate (H2MBP) in kerosene solutions. The last two compounds were converted into their methyl esters by reaction with a solution of diazomethane in diisopropyl ether prior to analysis. The same procedure was applied to the determination of HBDP and H2MBP produced from gamma irradiation of the 30% TBP–kerosene–3 mol dm–3 HNO3 system.

Bis(diisopropylamino)phosphanyldiazomethane: A building block for the synthesis of stable carbene and nitrilimines

Abstract: Thermolysis of [bis(diisopropylamino)phosphanyl](trimethylsilyl)diazomethane 1 affords the corresponding carbene 2, which is stable enough to be spectroscopically characterized. This species possesses a phosphorus–carbon multiple-bond character as shown by the 2 + 3 and 2 + 2 cycloaddition reactions observed with trimethylsilyl azide or N2O and ethyl cyanoformate, respectively. On the other hand, 2 undergoes all the classical reactions of a carbene: cyclopropanation reaction with electron-poor alkenes, carbon–hydrogen bond insertion, and carbene–carbene coupling with isonitriles. Compound 2 reacts with trimethylsilyl triflate affording a stable methylenephosphonium salt 15. Treatment of the lithium salt of the [bis(diisopropylamino)thiophosphoranyl]diazomethane 18 with the bis(diisopropylamino)phosphanyl chloride leads to a stable nitrilimine 3. Thermolysis of 3 affords the isomeric diazo derivative 20, while photolysis gives rise to thiophophoranylnitrile 21 and cyclodiphosphazene 23. Regioselective 2 + 3 cycloadditions are observed with electron-poor dipolarophiles. Addition of trimethylsilyl triflate to 3 leads to a stable electrophilic nitrilimine 29.

Oxoaporphine alkaloids: conversion of lysicamine into liriodendronine and its 2-O-methyl ether, and antifungal activity.

Abstract: Pschorr reaction of diazonium salt 7 in aqueous methanolic sulfuric acid afforded, besides lysicamine 2, the orange colored sulfate of oxodibenzopyrrocoline (8). The structure is fully supported by an X-ray analysis of its picrate salt. Selective ether cleavage of lysicamine (2) with 48% HBr afforded a hydrobromide of 9, and free betaine 9 on treatment with pyridine-water. Both compounds methylated on treatment with etherial diazomethane on nitrogen to give the known 2-O,N-dimethylliriodendronine (11). Liriodendronine (10) was obtained from lysicamine (2) on heating with pyridine HBr at 189 degrees C, and treatment with pyridine-water, as a dark violet betaine. Betaine 12 was obtained by heating 11.HCl to 200 degrees C. The quaternary salts of lysicamine, lysicamine methiodide (3) and lysicamine methosulfate (4) were comparable in anticandidal activity to liriodenine (1), but were not as active as liriodenine methiodide (13).

Strong Base-Induced Cycloaddition Reaction of Homophthalic Anhydride with Aldehydes

Abstract: The reaction of homophthalic anhydride (1) and aldehydes in the presence of a strong base was studied. Reaction of 1 and benzaldehyde in the presence of NaH in anhydrous tetrahydrofuran (THF) at low temperature (0°C-room temperature) followed by treatment with diazomethane gave the cycloadduct, trans-4-methoxycarbonyl-3-phenyl-3, 4-dihydrocoumarin, and the reaction at 50°C gave, after similar work-up, the C-4 methylene condensed product, methyl 2-(2-methoxycarbonylphenyl)-3-phenylacrylate, selectively. Treatment of homophthalic anhydride having a terminal aldehyde group in the side chain at the C-4 position with NaH in anhydrous THF at low temperature resulted in intramolecular cycloaddition in fair yield.

Carbonyl chemistry of tetrafluorocyclopentadienone

Abstract: In order to control the Diels-Alder reactivity of the very labile title compound 1, experiments designed to modify the carbonyl group have been carried out. Diazomethane reacts with 1 in cold methanol to give a spirooxirane which undergoes Diels-Alder dimerization orders of magnitude slower than dienone 1 at room temperature. Trimethylsilyl cyanide yields a trimethylsilyl cyanohydrin, a stable derivative of 1 that dimerizes only at elevated temperatures, yet retains reactivity as a Diels-Alder diene

Analytical methods for the determination and mass spectrometric confirmation of 1‐methyl‐2‐nitroso‐1,2,3,4‐tetrahydro‐β‐carboline‐3‐carboxylic acid and 2‐nitroso‐1,2,3,4‐tetrahydro‐β‐carboline‐3‐carboxylic acid in foods

Abstract: A method is described for the determination of the two title compounds that is based on: (a) extraction of the acidified sample with methanol, (b) removal of fats and lipids by partitioning of the extract with n-hexane, (c) clean-up on acidic alumina extraction cartridge, and (d) determination by a post-HPLC column chemical denitrosation-thermal energy analyser (TEA) technique or by conventional HPLC-TEA analysis after derivatization of the compounds with diazomethane. Confirmation was carried out by HPLC-mass spectrometry of the free acids and also by gas chromatography-mass spectrometry of the methyl esters. The formation of both 1-methyl-2-nitroso-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid and 2-nitroso-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid in nitrosated samples of several Japanese and Chinese pickled vegetables, one soy sauce, and two cheeses was demonstrated.

Synthesis and antifungal activity of 2-(4-aryl-2-pyrazolin-3-yl)-3-aryl-4 (3h)-quinazolinones.

Abstract: The title compounds (III) have been prepared by cycloaddition of diazomethane to 3-aryl-2-styryl-4 (3H)-quinazolinones (II) in dry ether. Their structures have been elucidated on the basis of elemental analysis and spectral data (IR, PMR and mass). Some of these compounds have been found to exhibit good antifungal activity.

Novel quinoxaline derivative and determination method for carboxylic acid with same compound

Abstract: NEW MATERIAL:A quinoxalinone derivative of formula I [R1, R2, R3 are 1-6C lower alkyl; R4 is -(CH2)nCONHNH2; n is 0-6]. EXAMPLE:A compound of formula II. USE:The compound is useful for the high performance liquid chromatography fluorescent quantitative analysis of biologically important carboxylic acids, especially thermally unstable carboxylic acids such as the metabolite product of arachidonic acid. The compound of formula I can selectively label the carboxylic acid in an aqueous solution. The compound is highly sensitive and can detect the carboxylic acid in a concentration of several femto mole order at room temperature. PREPARATION:For example, a compound of formula III prepared from alpha- ketoglutaric acid and 1,2-diamino-4,5-dimethoxybenzene is treated with an etheric diazomethane solution in anhydrous methanol to prepare a compound of formula IV. The compound of formula IV is reacted with the aqueous solution of hydrazine hydrate under heating to provide the compound of formula II among the compound of formula I.

The regioselectivity of cycloaddition reactions between diazomethane and 3-vinylcephalosporins

Abstract: Diphenylmethyl (6R,7R)-7-phenylacetamido-3-vinylceph-3-em-4-carboxylate 1 undergoes regioselective addition of diazomethane to give the 1-pyrazoline 7, which readily undergoes thermolysis to give the cyclopropyl analogue 10. The regioselectivity is reversed, however, when one or more electron withdrawing ester substituents are attached to the 3-vinyl group.

Synthesis of (19E)-3,20-dioxopregn-4-en-19-al 19-(O-carboxymethyl)oxime

Abstract: Hydride reduction of the ketone I gave the (20 R )-hydroxy derivative II . Cleavage of the diacetate III with zinc dust, followed by mild Jones’ oxidation led to the aldehyde V . Oximation with (O-carboxymethyl)hydroxylamine hemihydrochloride and methylation with diazomethane afforded the ester VI . Alkaline hydrolysis to the acid catalyzed rearrangement afforded the dione IX . Mild hydrolysis gave the desired hapten X derived from progesterone.