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Showing papers on "Diazomethane published in 1983"


Journal ArticleDOI

88 citations


Journal ArticleDOI
TL;DR: In this paper, a method for the chemical synthesis of 1-O-hexadecyl dihydroxyacetone-3-phosphate is described, which can be used to prepare different acyl and alkyl derivatives of dihydroxacetone phosphate in good yield.

35 citations


Journal ArticleDOI
TL;DR: In this article, a 16-step synthesis of methylpallidinine from 1,4-cyclohexanedione and 3-bromoveratrole was described.

31 citations




Journal ArticleDOI
TL;DR: The structure of these sugar analogs were effectively established on the basis of the mass and 400-MHz, 1 H-n.m.r. spectra of the four title compounds, derived by treatment with diazomethane and then acetic anhydride in pyridine.

20 citations


Journal ArticleDOI
TL;DR: In this paper, a base-promoted formylation followed by methylation with methyl iodide forms methyl 2.3-O-isopropylidene-5.O-trityl-β-D-ribofuranosyl)methyl]-3methoxyacrylate.
Abstract: Lithium aluminium hydride reduction of methyl (2,3-O-isopropylidene-5-O-trityl-β-D-ribofuranosyl) acetate gives 2-(2,3-O-isopropylidene-5-O-trityl-β-D-ribofuranosyl)ethanol. Subsequent tosylation, displacement by cyanide ion, nitrile hydrolysis, and diazomethane methylation afford methyl 3-(2,3-O-isopropylidene-5-O-trityl-β-D-ribofuranosyl)propionate. The base-promoted formylation followed by methylation with methyl iodide forms methyl 2-[(2,3-O-isopropylidene-5-O-trityl-β-D-ribofuranosyl)methyl]-3-methoxyacrylate. Base-catalyzed condensation of the methoxyacrylate and urea followed by deprotection produces 5-[(β-D-ribofuranosyl)methyl]uracil. In a like manner, condensation of the methoxyacrylate with thiourea or guanidine gives, after deblocking, 5-[(β-D-ribofuranosyl)methyl]-2-thiouracil and 5-[(β-D-ribofuranosyl)methyl]isocytosine, respectively. Ozonolysis of the methoxyacrylate yields methyl 3-(2,3-O-isopropylidene-5-O-trityl-β-D-ribofuranosyl)pyruvate, which undergoes condensation with carbamoylmethy...

17 citations


Journal ArticleDOI
TL;DR: In this paper, the reaction of diazomethane with several (Z)-2-substituted-4-benzylidene-5(4H)-thiazolones (1) under two different conditions, has been studied.

15 citations


Journal ArticleDOI
TL;DR: In this paper, the reactions of 3-acetyl-4-ethoxycarbonyl- or 3,4-diethoxy carbonylpyrrolo[1,2-a]pyrimidine derivatives 7a,b, which were prepared by condensation of the 2-aminopyrrole (4) with ethyl 3-ethoxymethylene-2, 4-dioxovalerate (5a) or ethyl ethoxyethyleneoxaloacetate (5b), with diazomethane are described.

12 citations



Journal ArticleDOI
TL;DR: In this article, reaction of a 6-sulfeniminopenicillanic acid ester with diazomethane induces a β-lactam ring expansion rearrangement which proceeds via methylene insertion into the C(6)-C(7) bond.

Journal ArticleDOI
TL;DR: In this article, the authors showed that 4-[1-acetamido-3-(3,4,5-trimethoxyphenyl)propyl]-5-aminotropolone with ethereal diazomethane gave the 6-and 4-substituted title compounds in 51 and 38% yields, respectively.
Abstract: The treatment of 4-[1-acetamido-3-(3,4,5-trimethoxyphenyl)propyl]tropolone with ethereal diazomethane gave the 6- and 4-substituted title compounds in 51 and 38% yields, respectively. The 270-MHz 1H-NMR spectral analysis performed on these compounds, colchicine, and two methyl ethers of hinokitiol permits unequivocal assignment of the position of the C-substituent on these 2-methoxytropone rings. Attempts were made to effect the direct B-ring closure of these intermediates and 4-[1-acetamido-3-(3,4,5-trimethoxyphenyl)propyl]-5-aminotropolone using various oxidizing reagents.

Journal ArticleDOI
TL;DR: The use of strong mineral acids, expecially hydrochloric acid, on polyhydroxy steroids, such as bile acids, can often cau se the formation of undesirable side products.

Journal ArticleDOI
TL;DR: In this paper, the reactivity of the carboxylic group was studied for 3-formyl-2,2,5,5-tetramethyl-thiazolidine-4-carboxyric acid.
Abstract: DL-Penicillamine-hydrochloride was condensed with various aldehydes (1–22) and ketones (23–28) to the corresponding 5,5-dimethyl-thiazolidine-4-carboxylic acid hydrochlorides and the free bases respectively. Their methylesters were obtained with diazomethane or methanol (29–35). Various 5,5-dimethyl-thiazolidine-4-carboxylic acids were formylated in position 3 (36—39). The reactivity of the carboxylic group was studied for 3-formyl-2,2,5,5-tetramethyl-thiazolidine-4-carboxylic acid. SubstitutedN-penicillaminamides were obtained for the first time (40–53). Also some S-alkylated penicillamines were prepared (54–60). By diazotation of 2,2,5,5-tetramethyl-thiazolidine-4-carbonamide or of penicillaminamide itself, 2-carbamyl-3,3-dimethyl-ethylenesulfide was obtained.

Journal ArticleDOI
TL;DR: In this paper, Meldrum's acid was used to synthesize monomethyl malonates (IIIa-c and Va) by treating with an excess of diazomethane in the corresponding alcohols and piperidine.
Abstract: Monomethyl malonates (IIIa-c and Va) were synthesized from Meldrum's acid (Ia) by treating with an excess of diazomethane in the corresponding alcohols and piperidine, respectively, in quantitative yields. In a similar manner, 5-p-chlorobenzyl Meldrum's acid (Ib) afforded the corresponding monomethyl malonate derivatives (IIIe, f, and Vb). The mechanism proposed for this reaction is described.

Journal ArticleDOI
TL;DR: A 1H n.m.n.r. study of some methoxy-, methylthio- and chloro-N-methyl-purines and imidazo[4,5-c]-pyridines revealed that the signal due to the N-methyl group when present in the six-membered ring occurred at lower field than when presented in the imidazole ring as mentioned in this paper.
Abstract: A 1H n.m.r. study of some methoxy-, methylthio- and chloro-N-methyl-purines and imidazo[4,5-c]-pyridines revealed that the signal due to the N-methyl group when present in the six-membered ring occurred at lower field than when present in the imidazole ring. The methylation of 2-,6-and 8-methoxypurines with diazomethane, and metatheses of chloro-N-methylpurines each to methoxy-N-methylpurines are described.

Journal ArticleDOI
01 Oct 1983-Steroids
TL;DR: The mass spectra of a representative group of the mono- and diglucosiduronic acids and esters were determined by utilizing fast atom bombardment and monitoring ions in both positive and negative modes of operation.

Journal ArticleDOI
TL;DR: In this article, X-ray crystallographic analysis was employed in the characterization of 1,6-dimethyl-1-H-indazole-4,7-dione (4a), which was the major 1-N-methyl regioisomer in the methylation of the cycloaddition mixture 2 with diazomethane.

Journal ArticleDOI
TL;DR: In this article, it was shown that 2-chloro-4-nitro-imidazole can be converted to 4-chlorosulphonyl-2-IMIDazolidinone in four steps, either with dimethyl sulphate or with diazomethane.
Abstract: Methylation of 2-chloro-4-nitroimidazole (6), obtained from imidazole in four steps, either with dimethyl sulphate or with diazomethane affords a mixture of 2-chloro-l-methyl-5-nitroimidazole (10) and the 4-nitro-isomer (7). The corresponding dinitro compounds 11 and 8 are formed in the methylation of 2,4-dinitroimidazole (5), 8 being converted to 7 by the action of POCl3. Reaction of 10 with the sodium salt of N-methanesulphonyl-2-imidazolidinone provides the potent amoebicide, 1-methylsulphonyl-3-(1-methyl-5-nitroimidazol-2-yl)-2-imidazolidinone (2). The isomer 14 is synthesised from 7 in low yield. Ethylation of 5 leads to preponderant N-alkylation, providing a mixture of l-ethyldinitroimidazoles (9) and (12), but a small amount of N,C-diethyl derivative 15 is also obtained. The formation of 15 from 5 is rationalised. The diiodination product of imidazole is shown to be 4,5-diiodoimidazole (19), nitric acid transforming it to 4-iodo-5-nitroimidazole (20). Methylation of 20 affords a mixture of isomeric 1 -methyliodonitro derivatives (21) and (22). The structures of 21 and 22 are established by 13C NMR data as well as by conversion into morpholine derivatives 26 and 24 respectively which also arise from 1-methylchloronitroimidazoles (25) and (23). A mechanism is proposed for the reported conversion of 5 into 4-chloro-5-nitroimidazole (32) in boiling 2-chloroethanol.



Journal ArticleDOI
TL;DR: Recovery of OA as OA-Me2 from chicken kidney homogenates and human plasma was quantitative following simple extraction and cleanup procedures, reaction with diazomethane, and HPLC analysis.
Abstract: The mycotoxin ochratoxin A (OA) was derivatized to an O-methyl,methyl ester (Me2) with diazomethane and then determined by high pressure liquid chromatography (HPLC). Both OA and OA-Me2 were chromatographed by reverse phase HPLC with a mobile phase of acetonitrile-water (60 + 40). An increase in retention time of 309 s was observed with OA-Me2 which was detectable at 254 nm at levels as low as 3 ng. Recovery of OA as OA-Me2 from chicken kidney homogenates and human plasma was quantitative following simple extraction and cleanup procedures, reaction with diazomethane, and HPLC analysis. The novel method described should prove useful for measuring and confirming OA in tissues and in further studies on the biological fate of this mycotoxin.

Journal ArticleDOI
TL;DR: The reaction between diazomethane and chlorothalonil produced a major compound identified as 4methoxy-2,5,6-trichloroisophthalonitrile as mentioned in this paper.

Journal ArticleDOI
TL;DR: In this paper, a tentative mechanism for complexation, and a possible model of a tin(II)chloride-methyl glycoside intermediate complex, have been established largely from analysis of methyl ethers formed on methylation of methyl α- l -rhamnopyranoside and its monomethyl ethers by diazomethane in the presence of a catalytic amount of tin (II) chloride in selected solvents.

Journal ArticleDOI
TL;DR: On effectue la nitration de la dimethyl-5,5 cyclohexene-2 one and de l'isophorone, qui conduit respectivement au dimethyl5, 5 nitro-2 cyclochexadiene-1,3 ol et a la trimethyl-3, 5,5,1,5 n-cyclohexane-1.
Abstract: On effectue la nitration de la dimethyl-5,5 cyclohexene-2 one et de l'isophorone qui conduit respectivement au dimethyl-5,5 nitro-2 cyclohexadiene-1,3 ol et a la trimethyl-3,5,5 nitro-2 cyclohexene-2 one. Les reactions de ces deux derniers composes sont etudiees

Journal ArticleDOI
TL;DR: In this article, the reaction of 1,4-bishomocubanone with ethereal diazomethane leads to a mixture of the homologous ketone (2)(37%) and the aldol-type dimer (3)(32%).
Abstract: The reaction of 1,4-bishomocubanone (1) with ethereal diazomethane leads to a mixture of the homologous ketone (2)(37%) and the aldol-type dimer (3)(32%). In the presence of methanol the reaction yields predominantly the ketone (2)(70%). Other constrained ketones are shown to react with diazomethane in an analogous way. The mechanism is discussed in terms of the influence of ring strain.

Journal ArticleDOI
TL;DR: In this paper, a mixture of two enol ethers, the 2methoxy and the 4methoxide isomer, with a product ratio which depends upon reaction temperature, is shown to isomerize to the corresponding (E)-conformers.
Abstract: Methylation of ethyl 2, 4-dioxopentanoate with diazomethane gives a mixture of two enol ethers, the 2-methoxy and the 4-methoxy isomer, with a product ratio which depends upon reaction temperature. Both enol ethers, initially (Z)-configurated, isomerize to the corresponding (E)-conformers, the 4-methoxy compound with particular ease.


Journal ArticleDOI
TL;DR: Some new 4,5-dihydro-5-oxoisoxazole derivatives were synthesized as part of a study to prepare potential antiinflammatory agents.

Journal ArticleDOI
TL;DR: In this article, le produit de la reaction du diazomethane avec l'oxo-4 tetrahydro-4,5,6,7 tetramethyl-5',5',6,6 spiro [benzooxaselenole-1,3-2:2'-cyclohexanedione-1',3'] is described.
Abstract: Le produit de la reaction du diazomethane avec l'oxo-4 tetrahydro-4,5,6,7 tetramethyl-5',5',6,6 spiro [benzooxaselenole-1,3-2:2'-cyclohexanedione-1',3'] est une octahydro tetramethyl dibenzo [b, g] dioxaselenocinne-1,4,6dione. Deseleniation et reaction avec une base de ce compose