Showing papers on "Diazomethane published in 1979"
TL;DR: The in vivo side-chain oxidation of 1 alpha,25-dihydroxyvitamin D3 was investigated by using a double-label radiotracer technique and the trivial name calcitroic acid is proposed for this major side- chain oxidized metabolite.
Abstract: The in vivo side-chain oxidation of 1 alpha,25-dihydroxyvitamin D3 was investigated by using a double-label radiotracer technique. Rats dosed with 1 alpha,25-dihydroxy-[3 alpha-3H]vitamin D3 and 1 alpha,25-dihydroxy[26,27-14C]vitamin D3 produced compounds with a high 3H/14C ratio. These compounds were found in sizable quantities in intestine and liver within 3 h after dosing. The major side-chain oxidized metabolite migrated as an acid on DEAE-Sephadex chromatography and contained no 14C. Methyl esterification of this compound with diazomethane proceeded in good yield and rendered the compound more amenable to chromatographic purification. The metabolite was isolated in several steps from rats dosed with 1 microgram of 1 alpha,25-dihydroxy[3 alpha-3H]vitamin D3. The metabolite was obtained in pure form as the methyl ester and was positively identified as 1 alpha,3 beta-dihydroxy-24-nor-9,10-seco-5,7,10(19)cholatrien-23-oic acid. The trivial name calcitroic acid is proposed for this major side-chain oxidized metabolite of 1,25-dihydroxyvitamin D3.
116 citations
TL;DR: Alcohols including prostaglandins, geraniol, and carbohydrate, can easily be methylated with diazomethane in the presence of silica gel as mentioned in this paper, and the results show that the mixture can be used to synthesize new drugs.
55 citations
TL;DR: In this article, total electronic energies and energies of isomerization have been calculated with STO-3G and 6-31G basis sets for the energy-optimized geometries of the seven isomers of diazomethane.
44 citations
TL;DR: In this paper, the reaction between 2,3-O-isopropylidene-D -glyceraldehyde and diazomethane, dimethylsulfonium methylide and dimethyloxosulfoniam methylide has been studied, with a slight preference for the erythro isomer.
32 citations
TL;DR: In this article, the ratios of the isomeric N-methyl pyrazoles have been determined by N.M.R. and g.l.c. analysis, and explanations for the observed product orientations involve considerations of electronic and steric effects, the possible intermediacy of quaternary salts, and the likelihood that the dominant tautomer is reacting.
Abstract: Unsymmetrical pyrazoles with alkyl, aryl, nitro and carboxyl substituents at C3 or C5 have been methylated with dimethyl sulfate in methanol, dimethyl sulfate in basic medium, and with diazomethane. The ratios of the isomeric N-methylpyrazoles have been determined by N.M.R. and g.l.c. analysis. The modified Ullmann phenylation has also been applied to these pyrazoles. Explanations for the observed product orientations involve considerations of electronic and steric effects, the possible intermediacy of quaternary salts, and, in some instances, the likelihood that the dominant tautomer is reacting.
27 citations
TL;DR: In this article, the presence of PCH3-containing compounds in surface waters can be detected in a sensitive and specific way using an anion-exchange column and subsequently transformed into its dimethyl ester by diazomethane after a clean-up on a microsilica gel column.
25 citations
TL;DR: In this paper, 3-acetyl-2-methoxytropone (2a) and 2acetyl7-mETHO-THO (2b) was synthesized from 3-isopropenyltropolone by treatment with sodium azide in concentrated sulfuric acid.
Abstract: 3-Acetyltropolone (1) was synthesized from 3-isopropenyltropolone by treatment with sodium azide in concentrated sulfuric acid. Methylation of 1 by diazomethane gave two isomers, 3-acetyl-2-methoxytropone (2a) and 2-acetyl-7-methoxytropone (2b). 1, 2a, and 2b reacted with hydrazine to give some 1,8-dihydrocycloheptapyrazol-8-one derivatives.
22 citations
TL;DR: In this article, the insertion of carbon dioxide into the phenyl-manganese σ-bond of 1 gave bis-benzoato manganese complex (PhCOO)2MnPCy3, 2, which on successive treatment with HCl and diazomethane produced methyl benzoate.
Abstract: Treatment of Mn(acac)3 (acac=acetylacetonato ligand) with AlPh3·Et2O in the presence of PCy3 (Cy=cyclo-C6H11) gave a new diphenylmanganese(II) complex, Ph2MnPCy3 (1). Complex 1 reacted with allylic compounds, CH2=CHCH2X (X=Br, OPh, OCH2CH=CH2, and OCOCH3), to give allylbenzene. Carbon dioxide was found to be inserted into the phenyl-manganese σ-bond of 1 to give bis(benzoato)manganese complex, (PhCOO)2MnPCy3, 2, which on successive treatment with HCl and diazomethane produced methyl benzoate. Complex 1 reacted with aldehydes, ketones, and esters having no active α-hydrogen atom to give alkoxomanganese species in solution, indicating that the insertion of C=O double bond into the phenyl-manganese σ-bond occurred. On the other hand, acetone and acetophenone reacted with Ph2MnPCy3 to give benzene and 2-oxoalkyl complexes, (RCOCH2)2Mn(PCy3)m (R=Me, Ph), 3. Reaction of alcohols with 1 afforded alkoxomanganese compounds which catalyze the Tishchenko type and Meerwein-Pondorf type reactions as well as transester...
21 citations
TL;DR: In this article, it was shown that certain amides and thioamides can be methylated with diazomethane in the presence of silica gel, which can be used to synthesize amides.
21 citations
TL;DR: In this paper, the cycloadditions of diazoacetic, diazomalonic and diaz(phenylsulfonyl)acetic esters show U-shaped activity functions when log k 2 is plotted versus the lowest IP of the dipolarophiles.
20 citations
TL;DR: In this article, the reaction with diazomethane of methyl 4,6-O benzylidene-3-O-methyl-α-d -arabino-hexopyranosid-2-ulose (2), its 3-epimer (3), its β anomer (5), and the corresponding 3-Obenzoyl derivative (4) have been examined in comparison with those in the Grignard reaction and in reduction with sodium borohydride.
TL;DR: In this article, a tricyclic system with 1,3-butadienes and cyclopentadiene was synthesized using double Diels-Alder reaction.
Abstract: Thermal reaction of coumalic acid with 1,3-butadienes gave after diazomethane treatment dimethyl tricyclo[32102,7]oct-3-ene-2,4-dicarboxylate via double Diels-Alder reaction This represents the simplest synthesis of such a tricyclic system The reaction with cyclopentadiene was also studied
Journal Article•
TL;DR: The results show that the proportion of the imino forms of these compounds is of the same order of magnitude as for 1-substituted cytosines, and hence is unlikely to account for the observed mutagenic effects of 1- substituting 5-halogenocytosines.
Abstract: 1. Methylation and thiation of 5-fluorouracil led to 1,3-dimethyl-5-fluoro-4-thiouracil, the amination of which was examined under various conditions. At high dilution, and in the presence of a large excess of NH3, 1,3-dimethyl-5-fluoro-4-thiouracil was converted to 1,3-dimethyl-5-fluorocytosine in 60% yield. 2. Two procedures were employed for methylation of 5-fluoro-1-methylcytosine and 5-fluorocytidine. Treatment of each of these with diazomethane in alcohol-ether gave a complex mixture of products, the major one of which was the desired 3-methyl derivative. By contrast, treatment with methyl iodide in dimethylsulphoxide led exclusively to the 3-methyl derivatives in much better yeilds. 3. Ultraviolet absorption spectra and pKa values are presented for 1-substituted N-methyl-5-fluoro- and 5-bromo-cytosines. The basicity method was applied to determine the tautomeric equilibrium constants of the 1-substituted 5-halogenocytosines. The results show that the proportion of the imino forms of these compounds is of the same order of magnitude as for 1-substituted cytosines, and hence is unlikely to account for the observed mutagenic effects of 1-substituted 5-halogenocytosines.
TL;DR: In this article, the corresponding β-glycosides of D-chalcose were obtained in good yield by dechlorination with tributyltin hydride, selective benzoylation with benzoyl cyanide at O 2, methylation at O 3, and acid hydrolysis.
TL;DR: In this article, the stereoisomers of monocrotalic acid have been synthesized and their stereochemistry was assigned respectively as S- and R-configuration by correlation to the known (R)-(−)-2-phenylpropanoic acid.
Abstract: All stereoisomers (3a, b–6a, b) of monocrotalic acid have been synthesized. Methylation of (±)-cis-2,3,4-trimethyl-2-pentenedioic acid with diazomethane followed by cis-hydroxylation with potassium permanganate afforded two epimeric γ-lactone esters in a ratio of ca. 1:5. These esters were then hydrolyzed with dilute hydrochloric acid to the corresponding acids, (±)-3 and racemic monocrotalic acid (4). Optical resolution of (±)-3 with brucine afforded 3a (2R,3R,4S) and 3b (2S,3S,4R). The racemic monocrotalic acid was also resolved by means of brucine to give natural monocrotalic acid (4a: 2R,3R,4R) and its enantiomer (4b: 2S,3S,4S). Subsequently, (±)-trans-2,3,4-trimethyl-2-pentenedioic acid was resolved with cinchonidine to give 8a and 8b, whose stereochemistry was assigned respectively as S- and R-configuration by correlation to the known (R)-(−)-2-phenylpropanoic acid. Methylation of 8a followed by cis-hydroxylation and hydrolyses afforded γ-lactone acids, 5a (2R,3S,4S) and 6b (2S,3R,4S). Similarly, th...
TL;DR: In this paper, a 12-step synthetic route to (±)-daunomycinone was described, which uses Friedel-Crafts reactions to assemble the ring system; (−)-carminomycinones reacts with diazomethane to give (+)-Daunomycinone.
Abstract: A 12-step synthetic route to (±)-daunomycinone is described which uses Friedel–Crafts reactions to assemble the ring system; (–)-carminomycinone reacts with diazomethane to give (+)-daunomycinone.
TL;DR: In this article, the interconversions of isomeric esters of 3-methylcatechol and 1-hydroxyphosphetan 1-oxides were studied by variable temperature 1H n.m. spectroscopy.
Abstract: The interconversions of isomeric esters of 3-methylcatechol and 1-hydroxyphosphetan 1-oxides (phosphetinic acids) have been studied by variable temperature 1H n.m.r. spectroscopy (ΔG*ca. 17–18 kcal mol–1) and the intermediate hydroxyspirophosphoranes trapped as methoxyspirophosphoranes on treatment with diazomethane. The more stable ester from 3-methylcatechol and diphenylphosphinic acid has been obtained essentially pure; it isomerises to the less stable isomer with ΔG* 24.4 ± 0.2 kcal mol–1. No methoxyphosphorane was detected on treatment with diazomethane. The corresponding phosphinothioate esters have higher free energies of activation for interconversion and the intermediate hydrothiospirophosphoranes are not trapped with diazomethane. P-Hydroxy-2,2′-spirobi-(1,3,2-benzodioxaphosphole) has been obtained in solution in THF by treatment of the corresponding P-chloro-compound with one mole equivalent of water. With chlorotrimethylsilane and triethylamine it gave the P-trimethylsilyloxyphosphorane; with o-hydroxyphenyl o-phenylene phosphite (36) in DMF it gave the tris-(o-phenylene) phosphate anion (37) and o-phenylene phosphonate.
TL;DR: In this article, the reaction of methyl isocyanoacetate with nitrophthalic anhydrides in the presence of 1, 8-diazabicyclo [5. 4. 0] undec-7-ene (DBU), followed by esterification with diazomethane and hydrolysis with HCl.
Abstract: Nitro-1, 2-dihydro-1-oxoisoquinoline-3-carboxylate compounds (5a, b and 9a, b) were synthesized by the reaction of methyl isocyanoacetate with nitrophthalic anhydrides in the presence of 1, 8-diazabicyclo [5. 4. 0] undec-7-ene (DBU), followed by esterification with diazomethane and hydrolysis with HCl. In these reactions, the methylidenephthalide compound (10) was also obtained by hydrolysis of the oxazole-4-carboxylate compound (8b) due to the presence of the bulky ortho nitro group. Moreover, 1, 2-dihydro-4-hydroxy-1-oxoisoquinoline-3-carboxylic acid (16) was prepared via the oxazole dicarboxylic acid compound (15) in good yield.
TL;DR: Some 7-melhyl-substituted-2,1-benzisoxazoles and cyclopropanobenzofurazan oxides are synthesized and characterized by their elemental and spectral analyses.
TL;DR: The metabolic aromatic hydroxylation of oxprenolol in rats was examined and metabolites obtained from a human urine treated in the same manner gave similar results with both 4a and 5a present.
Abstract: The metabolic aromatic hydroxylation of oxprenolol [1-(isopropylamino)-3-[2'-(allyloxy)phenoxy]-2-propanol] in rats was examined. Synthesis of the isomeric ring methoxyoxprenolols (3b-6b) was accomplished from the isomeric methoxysalicylaldehydes by O-allylation, followed by Baeyer-Villiger oxidation. The propanolamine side chain was elaborated by O-alkylation of the Bayer-Villiger product with epichlorohydrin and subsequent oxirane opening with isopropylamine. Gas chromatography-mass spectra of the trifluoroacetyl derivatives of these standards was compared with urinary metabolites obtained from the rat, after methylation with diazomethane and derivatization with trifluoroacetic anhydride. Both 4'- and 5'-hydroxyoxprenolol (4a and 5a) were present in an approximate 4:1 ratio. No 3'- or 6'-hydroxyoxprenolol (3a and 6a) was detected. The metabolites obtained from a human urine treated in the same manner gave similar results with both 4a and 5a present.
TL;DR: A gas chromatographic chemical ionization mass spectrometric assay has been developed to measure carprofen in blood that features the addition of either a structural or stable isotope analog internal standard to plasma prior to a simple benzene extraction.
Abstract: A gas chromatographic chemical ionization mass spectrometric assay has been developed to measure carprofen in blood. The method features the addition of either a structural or stable isotope analog internal standard to plasma prior to a simple benzene extraction at pH 4.5. The residue, after removal of the benzene, is methylated with ethereal diazomethane. Following evaporation of the methylating solvents, a portion of the reconstituted residue is analyzed by gas chromatography mass spectrometry. The mass spectrometer is set to monitor in the gas chromatographic effluent the [MH]+ ions of carprofen methyl ester and the methyl ester of the internal standard generated by isobutane chemical ionization. Assay sensitivity is 5 pmol ml-1. When 200 pmol ml-1 samples are analyzed using a stable isotope analog as the internal standard, the precision and accuracy are both 4%. Using a structural analog as the internal standard, the assay was neither as precise nor as accurate.
TL;DR: In this paper, both anomers of 1-O-[N-(tert-butoxy-carbonyl)-L -α-glutamyl]- d -glucopyranose (2) were converted into the unprotected 1-esters, characterised as the trifluoroacetate salts 3α and 3β.
TL;DR: A superior method for generation of diazomethane and several other gaseous diazoalkanes has been provided by alkali treatment of N-[(N-nitrosoalkylamino) methyl]-carbamates, especially their isopropyl esters, which react smoothly in high yields as mentioned in this paper.
Abstract: A superior method for generation of diazomethane and several other gaseous diazoalkanes has been provided by alkali treatment of N-[(N-nitrosoalkylamino) methyl]-carbamates, especially their isopropyl esters, which react smoothly in high yields (81-82% for diazomethane).
TL;DR: In this paper, it was shown that C,N-dimethylated homologues of 2-methylthiopurine can be identified as 7,8- and 8,9-dimdimethyl-2- methylthiopuronine, which represents an additional alkylation pathway for purine derivatives.
Abstract: Diazomethane treatment of 2-methylthiopurine gives the expected 9- methyl-2-methylthiopurine as the main product together with a smaller amount of the 7-methyl isomer An unexpected feature of this reaction, however, is the formation also, in smaller but significant yields, of C,N-dimethylated homologues, identified as 7,8- and 8,9-dimethyl-2- methylthiopurine Subsequent methylation studies point towards the 8-methyl group in the latter derivatives being introduced prior to the N-methylation step, thus representing an additional alkylation pathway for some purine derivatives
TL;DR: Trifluoronitrosomethane and heptafluoro-1-nitrosopropane rapidly attack diphenyldiazomethanes in diethyl ether at -78 °C to yield, quantitatively, benzophenone and perfluoro -azoxymethane or -1,1′-azoxypropane respectively as mentioned in this paper.
Abstract: Trifluoronitrosomethane and heptafluoro-1-nitrosopropane rapidly attack diphenyldiazomethane in diethyl ether at –78 °C to yield, quantitatively, benzophenone and perfluoro-azoxymethane or -1,1′-azoxypropane respectively; an analogous reaction occurs between the former nitrosoalkane and dimethyldiazomethane. Use of an equimolar mixture of the nitrosoalkanes provides the azoxy-compounds CF3[graphic omitted](Ō):NC3F7-n and n-C3F7[graphic omitted](Ō):NCF3.
TL;DR: In this article, four gas-chromatographic methods are proposed; the first and the second involve derivatisation of the mercaptoacetic acid with diazomethane to the methyl ester, methyl thioether derivative.
Abstract: Identification of mercaptoacetic acid in hair waving and depilatory products containing other mercapto acids is possible by using thin-layer chromatography.However, gas-chromatographic methods are to be preferred for accurate quantitative determination. Four gas-chromatographic methods are proposed; the first and the second involve derivatisation of the mercaptoacetic acid with diazomethane to the methyl ester, methyl thioether derivative. In the third method, the mercaptoacetic acid is converted into its methyl ester by use of p-toluenesulphonic acid. The last method involves the direct chromatography of underivatised mercaptoacetic acid.
TL;DR: The title compound (1) reacts with methyl iodide and allyl bromide to give [(cp)2ReMe2]+(5)(cp =η5-C5H5) and [(cp2Re(C3H6)]+(8) respectively; the dihydrido cation [(cp(2ReH2]+6)]+9] reacts with diazomethane and excess of RCN to give the metallocarbene cations [(cp'2ReC(NHMe)R](11) as discussed by the authors ).
Abstract: The title compound (1) reacts with methyl iodide and allyl bromide to give [(cp)2ReMe2]+(5)(cp =η5-C5H5) and [(cp)2Re(C3H6)]+(8) respectively; the dihydrido cation [(cp)2ReH2]+(10) reacts with diazomethane and excess of RCN to give the metallocarbene cations [(cp)2ReC(NHMe)R](11).
Patent•
05 Nov 1979
TL;DR: A 5-substituted indazole derivative of formula I: [R is H, CH3, or OCH3; X is O or two groups R2 and R3 (R isH or CH3; R is OH, CH, or oCH3 group)]..
Abstract: NEW MATERIAL:A 5-substituted indazole derivative of formula I: [R is H, CH3, or OCH3; X is O or two groups R2 and R3 (R is H or CH3; R is OH, CH , or OCH3 group)]. EXAMPLE:4,5,6,7-Tetrahydro-1-phenylindazole-5-carboxylic methyl ester. USE:Safe medicines having improved anti-inflammatory, analgesic, and antipyretic actions with slight toxicity and side effects. PROCESS:A compound of formula II is esterified with diazomethane to give the objective compound of formula I wherein R is OCH3 and X is O. The ester group is selectively reduced to form the desired compound of formula I wherein R and R are hydrogens and R is OH group. The compound thus obtained in then oxidized, methylated, oxidized, and methylated twice to give the objective compound of formula I wherein R and X are different.
TL;DR: In this paper, a gas chromatographic determination of traces of alkali metal O,O-diethyl phosphorodithioates is described, where the salts were converted into a volatile derivative by alkylation with diazomethane.
Abstract: A gas Chromatographic determination of traces of alkali metal O,O-diethyl phosphorodithioates is described. The salts were converted into a volatile derivative by alkylation with diazomethane. The product was identified by gas chromatography-mass spectrometry. With aqueous samples a linear relationship of peak height to amount of salt was obtained in the range 0.04–1 ng and for urine samples a calibration curve was constructed. The detection limit (signal to noise ratio 4/1) was 40 pg of salt. The procedure was successfully used for monitoring phosalone absorption by occupationally exposed persons.