Showing papers on "Diazomethane published in 1984"
TL;DR: In this paper, the synthesis and biological activity of γ-lactam analogues of penicillanic and carboapenicillanic acids, and the sodium periodate mediated rearrangement of pyrrolidine-2,3-diones are described.
43 citations
TL;DR: Phenyltrifluoromethylacetylene (4a) was synthesized by the pyrolysis of triphenylphosphonium α-(triffluoroacetyl) benzylide (3a), which was easily derived from benzyl halide (1a) as mentioned in this paper.
Abstract: Phenyltrifluoromethylacetylene (4a) was synthesized by the pyrolysis of triphenylphosphonium α-(trifluoroacetyl) benzylide (3a), which was easily derived from benzyl halide (1a). This method can be used for the synthesis of 4-substituted-phenyltrifluoromethylacetylenes (4). The 1, 3-dipolar reaction of 4 with diazomethane and phenyl azide proceeds readily to give trifluoromethylated pyrazoles and triazoles.
40 citations
TL;DR: A new very simple assay using HPLC and direct injection of urine led to a very precise and reproductible determination of tienilic acid and its hydroxylated metabolite in urine, the first example of metabolic hydroxYLation of the thiophene ring.
39 citations
TL;DR: In this paper, a mass spectrometric method for monitoring 2-oxoglutarie acid (an essentially nonvolatile compound) in aqueous solutions is described; the acid is esterified with methanol.
21 citations
TL;DR: A detailed analysis of the reaction of alpha-oxo acids with diazomethane revealed that, besides the already known oxirane methyl esters, homologous esters are also produced by an insertion reaction.
17 citations
TL;DR: In this paper, Z/E methyl (ou phenyl)-5 phenyl-1 oxa-6aza-4spiro [2•4] heptene-4ones-7 et al.
Abstract: Obtention de Z/E methyl (ou phenyl)-5 phenyl-1 oxa-6aza-4spiro [2•4] heptene-4ones-7 et de Z/E methyl (ou phenyl)-2 «α»-methylbenzylidene-4 oxazoline-2ones-5
16 citations
TL;DR: Results suggest that OPNU undergoes base-catalyzed decomposition and NAMOPA undergoes enzymatic hydrolysis to yield the same intermediate, 2-oxopropyldiazotate, which then collapses to form acetate and the methylating agent diazomethane.
16 citations
TL;DR: In this article, an approach based on considering frontier orbitals (F.O.) leads to a model for reactivity towards diazomethane in these systems, which is suggested as an alternative approach to accounting for reactions involving nucleophilic attack on fluorinated alkenes.
Abstract: Additions of diazomethane to fluorinated alkenes have established the reactivity order (RF)2CC(RF)2 > (RF)2CCFRF (RF)2CCF2, RFCFCFRF(RF= perfluoroalkyl). Highly regioselective addition occurs with the carbon of the dipole becoming attached preferentially to the site in the alkene most susceptible to nucleophilic attack. An approach based on considering frontier orbitals (F.O.) leads to a model for reactivity towards diazomethane in these systems. Also, consideration of F.O. is suggested as an alternative approach to accounting for reactions involving nucleophilic attack on fluorinated alkenes.
15 citations
TL;DR: In this paper, a chiral dimethylcyclopropane derivatives, useful for the synthesis of casbane, lathyrane, and ingenane-type diterpenoids, from easily available (+)-3-carene is described.
Abstract: A synthesis of chiral dimethylcyclopropane derivatives, useful for the synthesis of casbane, lathyrane, and ingenane-type diterpenoids, from easily available (+)-3-carene is described. The silyl enol ether (8) was derived from (-)-cis-4-caranone (7b), which was obtained from (+)-3-carene (6). Ozonolysis of 8 gave 9a and 10. The right half segment (11b) for a synthesis of crotonitenone (3) was formed from 9a in three steps. The epoxide (12) was isomerized to a mixture of the allylic alcohols (13a) and (14a), which was transformed to the ketone (20) in five steps. Methylation of 20 followed by phosphorylation and reduction gave (+)-cis-4-caranone (23) in about 40% overall yield from 12. The methylester (+)-(32b) and its enantiomer (-)-(34b) were synthesized from (+)-6. Ozonolysis of a mixture of the silyl enol ether (30) and (31) followed by methylation with diazomethane gave 32a, which was hydrolyzed to give the desired (+)-32b. The enantiomer (-)-34b was derived from 32a in five steps.
13 citations
TL;DR: The cyclopropanation of olefins proceeds through a step involving the reaction of diazomethane with a Π-olefinic complex of zero-valent palladium formed upon the reduction of the palladium compounds introduced as the catalyst by diazmethane as discussed by the authors.
Abstract: 1.
In the cyclopropanation of mono- and polyolefins by diazomethane in the presence of palladium compounds, strained intracyclic and terminal double bonds are initially cyclopropanated with high selectivity.
2.
The cyclopropanation of olefins proceeds through a step involving the reaction of diazomethane with a Π-olefinic complex of zero-valent palladium formed upon the reduction of the palladium compounds introduced as the catalyst by diazomethane.
11 citations
TL;DR: The authors showed that substituted arylazides, as well as p -tosylazide, when allowed to react at room temperature with THF previously treated with n -butyllithium, undergo a rapid decomposition affording the corresponding amines and fomamides, together with diazomethane.
TL;DR: The long-period reaction of heparin with excess diazomethane at 20° resulted in cleavage at the β-position of the uronic acid carboxyl group to give a mixture of methyl α- and β-glycosides of N,O-methylated di-, tetra-, and hexa-saccharides having a 4,5-unsaturated URonic acid, nonreducing end-group as mentioned in this paper.
TL;DR: In this article, a method was developed to prepare 1 -methyl, 3-methyl, and 4-0-methyl-ψ-isocytidine by selective methylation.
TL;DR: In this article, the minor component of 7-dehydrocholesterol was treated with trimethylsilylmethylpotassium in tetrahydrofuran, dry ice, mineral acid and diazomethane to give a regioisomerically pure, homoconjugated ester.
TL;DR: Birch reduction of a dibenzazonine base with sodium produced the desired diene in a good yield as discussed by the authors, which was then converted by treatment with excess diazomethane to the known base, cis-15, 16-dimethoxyerythrinan-3-one.
Abstract: Birch reduction of a dibenzazonine base (1) with sodium produced the desired diene (2) in a good yield. The diene (2) was heated with 10% sulfuric acid and cyclized readily to provide the erythrina base (3) as a sole product, which was subsequently converted by treatment with excess diazomethane to the known base, cis-15, 16-dimethoxyerythrinan-3-one (4).
TL;DR: The reaction of 2-chloro-3-methyl-1,4-naphthoquinone (3) with the anion of ethyl cyanoacetate led to a mixture of two epimeric fused-ring cyclopropane compounds, characterised as exo- and endo-1-cyano-1 -ethoxycarbonyl-1a-methyl -1a,7a-dihydro-1H-cyclopropa[b]-naphthalene-2,7-dione (8
Abstract: The reaction of 2-chloro-3-methyl-1,4-naphthoquinone (3) with the anion of ethyl cyanoacetate led to a mixture of two epimeric fused-ring cyclopropane compounds, characterised as exo- and endo-1-cyano-1 -ethoxycarbonyl-1a-methyl-1a,7a-dihydro-1H-cyclopropa[b]naphthalene-2,7-dione (8) and (9). Various hydrolysis products of these were prepared and an X-ray crystallographic analysis was carried out on one of them, 1-carbamoyl-1 -carboxy-1a-methyl-1a,7a-dihydro-1H-cyclopropa[b]-naphthalene-2,7-dione (17). The reaction of 2-methyl-1,4-naphthoquinone (1) with ethyl diazoacetate gave a fused pyrazoline derivative, 3-ethoxycarbonyl-4-hydroxy-9a-methyl-1,9a-dihydro-benz[f]indazol-9-one (22), while reaction of 2-methyl-3-nitro-1,4-naphthoquinone (5) with diazomethane led to a fused Δ2-isoxazoline N-oxide, 3a-methyl-3,3a-dihydroisoxazolo[3,4-b]naphthalene-4,9-dione 1-oxide (26).
TL;DR: Azomethine ylides (methyl 3-oxido-2-[3,4-dihydroisoquinolinio]-acrylate, 3-methyl-2,4diphenyloxazolium-5-olate), thiocarbonyl ylide (thiofluorenone S-methylide, thiobenzophenone Smethylide) as well as diazomethane undergo 1,3-dipolar cycloadditions to the NN-bond of 4-nitroben
TL;DR: The reaction of 1 with hydrazines provided hydrazinium-4,7-dioxo-4 7-dihydroindazol-3-olates 2a-e and 4 7-indazolequinones 3f,g depending upon the nature of the substituent present in the reactants as mentioned in this paper.
Patent•
15 Oct 1984
TL;DR: In this paper, a solution containing the diazomethane derivative of formula (R1 and R2 are substituted or unsubstituted aromatic group) and an orgnaic solvent (e.g. methylene chloride) is subjected to the continuous thin-layer evaporation concentration process under a vacuum of >=37cmHgG at <=35 deg.
Abstract: PURPOSE:To obtain the titled compound useful as a carboxyl-protecting group of organic compounds, in high yield and purity, by subjecting the solution containing a diazomethane derivative and an organic solvent to the continuous thin-layer evaporation concentration process under specific pressure and temperature condition. CONSTITUTION:A solution containing the diazomethane derivative of formula (R1 and R2 are substituted or unsubstituted aromatic group) and an orgnaic solvent (e.g. methylene chloride) is subjected to the continuous thin-layer evaporation concentration process under a vacuum of >=37cmHgG at <=35 deg.C to obtain the diazomethane derivative. Diazomethane derivative is easily decomposable and the lowering of the purity and yield is unavoidable when the derivative is to be separated as a crystal in an industrial scale. According to the theoretical analysis of the rate of the decomposition reaction, it has been found that the rate of decomposition increases remarkably in molten state. Accordingly, the decomposition reaction can be suppressed by concentrating the solution under the above condition in vacuum. The scraping concentrator is preferable in view of the quality and yield of the product.
TL;DR: In this paper, the synthesis of 2H-1,2,4,6-thiatriazin-3(4H)-one 1-oxides and 1,1-dioxides is described.
TL;DR: Two dihydroxybenzofuroquinolinones, 3,9-dihydroxy-5H-bensofuro[3,2-c]quinolin-6-one (V) and 3,8-dhedroxy-6H-benzofturo[2,3-b]-quinolinone (VI), were obtained by the demethyl-cyclization of 3-(2,4-dimethoxyphenyl)-4-hydroxy-7-methoxy-1H-quinolone-2
TL;DR: In this paper, an efficient synthesis of 1,1-dimethoxynaphthalen-2(1H)-one has been achieved, using bis-p-nitrobenzoyl peroxide.
Abstract: An efficient synthesis of 1,1-dimethoxynaphthalen-2(1H)-one (13) has been achieved. Oxidation of 2-naphthol with bis-p-nitrobenzoyl peroxide gave the known derivative (5). Methylation with diazomethane and hydrolysis afforded 1-methoxy-2-naphthol which was oxidised in methanol to the enone (13) in high yield. The synthesis could also be carried out with benzoyl peroxide, but with lower yields.
TL;DR: In this paper, the mixture of hexafluorotropone with sodium methoxide under mild conditions gave a mixture, but with predominant formation of the 3methoxide or the 3,6-dimethoxide: exhaustive methoxylation gave hexamethoxytropone.
TL;DR: The structures of these sugar analogs were effectively established on the basis of the mass and 400-MHz, 1H-n.r.m. spectra of the title compounds, derived by treatment with diazomethane and then acetic anhydride in pyridine.
TL;DR: In this paper, cycloadditions of diazomethane and N-methyl nitrone with α,β, unsaturated F-hexyl sulfones substituted on C β by an aromatic group were investigated.
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 title compounds, derived by treatment with diazomethane and then acetic anhydride in pyridine as discussed by the authors.
TL;DR: In this paper, 1,3-Dipolar cycloadditions of diazomethane to exo-2-methylenecephalosporins are described and a structural study of the products shows that the initially formed 2-spiropyrazolinocephems form cyclopropanes by the spontaneous loss of nitrogen.
Abstract: 1,3-Dipolar cycloadditions of diazomethane and diphenyldiazomethane to exo-2-methylenecephalosporins are described. A structural study of the products shows that the initially formed 2-spiropyrazolinocephems form cyclopropanes by the spontaneous loss of nitrogen. ASIS and NOE measurements reveal that the products with different C-2 configurations are in two different conformations.
TL;DR: Homoursodeoxycholic acid and [11,12-3H]homoursode Oxycholic Acid were synthesized from ursodeoxyCholic Acid and homocholic acid, respectively by means of the Wolff rearrangement of the Arndt-Eistert synthesis.
Patent•
04 Sep 1984
TL;DR: In this paper, a 2-hydroxypropiophenone derivative shown by the formula I (Q is imidazolyl, or triazolyls; X, X, Y, and Y are H, halogen, alkyl, trifluoromethyl, alkoxy, or nitro) or its acid addition salt.
Abstract: NEW MATERIAL:A 2-hydroxypropiophenone derivative shown by the formula I (Q is imidazolyl, or triazolyl; X , X , Y , and Y are H, halogen, alkyl, trifluoromethyl, alkoxy, or nitro) or its acid addition salt. EXAMPLE:2',4'-Dichloro-2-( 2,4-dichlorophenyl )-2-hydroxy-3-( 1H-imidazol-l-yl )propiophenone. USE:Useful as an antifungal agent. Showing improved antifungal action, useful as a drug or drug for animals. Having high value for internal use and injection. PREPARATION:For example, when R' is oxo, a compound shown by the formula II(R' is oxo, or methylene) is subjected to oxolane formation reaction wherein it is reacted with diazomethane in an organic solvent of ether. The prepared ethylene oxide shown by the formula III is reacted with 1H-imidazole or 1H- triazole shown by the formula IV, to give a compound shown by the formula I .
Journal Article•
TL;DR: Arteannuin (1) on treatment with 10% H 2SO_4 in glacial acetic acid at room temperature for 19 h afforded eight products as mentioned in this paper, which were characterized previously as norsesquiterpenoid lactone.
Abstract: Arteannuin (1) on treatment with 10% H_2SO_4 in glacial acetic acid at room
temperature for 19 h afforded eight products. The major neutral product(～55%)
has been characterized previously as norsesquiterpenoid lactone (2). In addition, three
compound 3a～b(～16%) and 4(～9.8%) were isolated. Their structures were tenta-
tively assigned from IR, ~1H and ~(13)C NMR and mass spectroscopic studies. The minor
acidic products after being esterified with diazomethane were identified with GC-MS
as 5a～d(～6. 7%). The mechanisms of formation of 3a～b and 4 were proposed.