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Showing papers on "Diazomethane published in 1973"


Journal ArticleDOI
TL;DR: Comparison of C3H3 and 14CH3 labelling showed that the ratio 3H14C in the products was the same and equal to that in the original reagents, in accord with the concept that the methyl group is transferred intact, and not via diazomethane.

72 citations


Journal ArticleDOI
TL;DR: The mass spectra of O(6)-alkyl-2'-deoxyguanosines (methyl and ethyl) and of the corresponding 2-amino-6-alkoxypurines were determined and the reaction of diazomethane with thymidine afforded O(4)-methylthymidine, in addition to the previously detected 3-methylthylidine.
Abstract: The reaction in ether–methanol between 2′-deoxyguanosine and diazomethane or its ethyl or n-butyl homologue gives 1-, O6- and 7-alkyl-2′-deoxyguanosine. N2,O6-Dimethyl-2′-deoxyguanosine was also detected. The hydrolysis of the methyl and the ethyl derivatives gives the corresponding alkylguanines: the O6-alkyl-2′-deoxyguanosines were sequentially hydrolysed, first to 2-amino-6-alkoxypurines, subsequently to guanine. The mass spectra of O6-alkyl-2′-deoxyguanosines (methyl and ethyl) and of the corresponding 2-amino-6-alkoxypurines were determined. The reaction of diazomethane with thymidine afforded O4-methylthymidine, in addition to the previously detected 3-methylthymidine.

59 citations


Journal ArticleDOI
TL;DR: Glutaminase A isolated from Escherichia coli reacts with the glutamine analogue, 6-diazo-5-oxonorleucine, in two ways: (a) it catalyzes hydrolysis of the C5—C6 bond to yield glutamic acid and diazomethane; and (b) a group at the active site of the enzyme becomes irreversibly alkylated by the intact carbon chain of the analogue.

34 citations


Journal ArticleDOI
TL;DR: In this article, a searching theoretical investigation has been carried out on the five structural isomers of diazomethane, CH2N2, and interesting use has been made of electrostatic potential maps in assessing positions of high nucleophilicity in each isomer.
Abstract: A searching theoretical investigation has been carried out on the five structural isomers of diazomethane, CH2N2; the isomers are diazomethane, cyanamide, isocyanamide, nitrilimine, and carbodiimide. The non- empirically calculated structures for the latter three compounds are the first to be reported. Use has been made of localized exclusive orbitals to help explain the bonding and electronic structure in this series of molecules. In addition, interesting use has been made of electrostatic potential maps in assessing positions of high nucleophilicity in each isomer. This information has allowed mechanistic pathways to be postulated for the protonation of diazomethane and cyanamide and for the production of isocyanamide from diazomethane.

30 citations


Journal ArticleDOI
TL;DR: This finding is regarded as additional evidence for a newly conceived conformational structure of bilirUBin and bilirubin dimethyl ester that is maximally stabilized by intramolecular hydrogen bonds.
Abstract: Dimethoxybilirubin dimethyl ester and monomethoxybilirubin dimethyl ester were prepared by treating bilirubin with diazomethane, and the correctness of the assigned structures was proved by elemental analysis as well as by i.r. and n.m.r. spectroscopy. The phenylazo compounds derived from monomethoxybilirubin dimethyl ester were also prepared and characterized spectroscopically. Dimethoxybilirubin dimethyl ester occurs in solution as a single molecular species, unlike bilirubin dimethyl ester, which in non-polar solvents exists as an equilibrium mixture of conformational isomers. This difference in the behaviour of the two compounds is explained by the absence of intramolecular hydrogen bonds in dimethoxybilirubin dimethyl ester, a situation that allows free rotation about the central methylene bridge, whereas in bilirubin dimethyl ester an internally hydrogen-bonded conformation can be distinguished by n.m.r. spectroscopy from a non-bonded family of rotamers. This finding is regarded as additional evidence for a newly conceived conformational structure of bilirubin and bilirubin dimethyl ester that is maximally stabilized by intramolecular hydrogen bonds. This is discussed in detail in the Appendix (Kuenzle et al., 1973), which also includes a description of the molecular mechanism pertaining to the reaction of bilirubin with diazomethane.

30 citations


Journal ArticleDOI
TL;DR: Methods for the separation of these derivatives by argentation thin-layer chromatography and reversed-phase partition thin- layer chromatography are described, finding the procedure is especially advantageous for the analysis of phosphatidylethanolamines that are radioactively labelled in the ethanolamine moiety.

22 citations


Journal ArticleDOI
TL;DR: Stereoselectivities in diazomethane and nitromethane reaction of methyl 2-O-benzoyl-4,6-Obenzylidene-α-D-ribo-hexopyranosid-3-ulose were examined as discussed by the authors.
Abstract: Stereoselectivities in diazomethane and nitromethane reaction of methyl 2-O-benzoyl-4,6-O-benzylidene-α-D-ribo-hexopyranosid-3-ulose were examined. Reduction of the epoxidation product (2) gave an epimeric 3-C-methyl derivative in contrast with that obtained by the Grignard reaction. Comparison of NMR spectra of the corresponding di-O-acetate of the both epimers proved that 2 has the gluco-configuration. Ring-opening of the epoxide with alkali, methanolic ammonia, and acid gave the corresponding 3-C-hydroxymethyl, 3-C-aminomethyl (17), and de-O-benzylidenated product, respectively. Hydrogenation of the 3-C-nitromethyl derivative (21) obtained by nitromethane condensation, in the presence of Raney nickel, accompanied with benzoyl-migration to give 3-C-benzamidomethyl derivative (22). De-benzoylation of 22 with methanolic potassium hydroxide gave 3-C-aminomethyl derivative (26) and an orthoester-type compound. Comparison of 26 with 17 and their derivatives indicated that 21 has the allo-configuration. The b...

20 citations


Journal ArticleDOI
TL;DR: The cyclo-addition reaction of diazomethane with α,β-unsaturated sulfones was described in this article, where the reaction was shown to lead to substituted pyrazoles.

19 citations


Journal ArticleDOI
TL;DR: The photoelectron spectra of 2-diazopropane (3) and diazocyclopentadiene (4) show that the highest occupied molecular orbital in 3 and thus in diazomethane (1) is the non-bonding orbital b2(π) as discussed by the authors.
Abstract: Die Photoelektronen-Spektren des 2-Diazopropans (3) und des Diazocyclopentadiens (4) zeigen, das das oberste besetzte Molekulorbital in 3 und somit im Diazomethan (1) ein nicht-bindendes b2(π)-Orbital ist. The Orbital Sequence in Aliphatic Diazo Compounds The photoelectron spectra of 2-diazopropane (3) and diazocyclopentadiene (4) show that the highest occupied molecular orbital in 3 and thus in diazomethane (1) is the non-bonding orbital b2(π).

18 citations


Journal ArticleDOI
TL;DR: The first evidence for the existence of 3-acyl-2-methoxybenzo-furan-2(3H)-ones in the tautomeric form was provided by as discussed by the authors.
Abstract: Methylation of 3-acylbenzofuran-2(3H)-ones with diazomethane generally led to a mixture of 3-acyl-2-methoxybenzofuran and 3-(α- methoxy)alkylidenebenzofuran-2(3H)-one. These reactions provided the first evidence for the existence of 3-acylbenzo- furan-2(3H)-ones in the 3-acyl-2-hydroxybenzofuran tautomeric form as well as the widely accepted 3-(or-hydroxy)alkylidenebenzofuran-2(3H)one form. In general, methylation of the title compounds with methanol and sulphuric acid gave initially the corresponding 3-(α-methoxy)alkylidenebenzofuran- 2(3H)one while prolonged reaction led to the formation of methyl 2- alkylbenzofuran-3-carboxylates. The mechanism of this acid-catalysed rearrangement and the rearrangement of 3-acetyl-2-methoxybenzo- furan were studied. The reaction of 3-acetylbenzofuran-2(3H)-one with methyl iodide and potassium carbonate gave a mixture of 3,3-dimethylbenzo-furan-2(3H)-one and 3-methylbenzofuran-2(3H)-one. These products were also obtained by methylating benzofuran-2(3H)-one under similar conditions.

18 citations


Journal ArticleDOI
TL;DR: The reaction of hydrogen atoms with diazomethane was used as a source of methyl radicals to study the reaction of oxygen atoms with methyl radicals as discussed by the authors, and it was shown that formaldehyde is a major product and that the rate constant is greater than 3×10−11cm3 molecule−1 sec−1.
Abstract: The reaction of hydrogen atoms with diazomethane was used as a source of methyl radicals to study the reaction of oxygen atoms with methyl radicals. This investigation verifies directly the earlier results that formaldehyde is a major product and that the rate constant is greater than 3×10−11cm3 molecule−1 sec−1.

Journal ArticleDOI
TL;DR: The reaction of diazomethane with 6-phenyl-3-thioxo-5-oxo-2,3,4,5-tetrahydro-1,2,4-triazine 3a and 3-methyl-mercapto-4,6-diphenyl-1.
Abstract: The reaction of diazomethane with 6-phenyl-3-thioxo-5-oxo-2,3,4,5-tetrahydro-1,2,4-triazine 2a, and with 6-phenyl-3-methylmercapto-5-oxo-4,5-dihydro-1,2-triazine 3a effected N-methylation to 2b and 3b, respectively. Compound 3a and 3-methyl-mercapto-5, 6-diphenyl-1,2,4,-triazine 4a react with amines to give 3-N-substituted-amino-triazines 5a–h and 6a–h, respectively. 3-Mercapto-5,6-diphenyl-1,2,4-triazine 4b underwent S-alkylation with ethyl monobromoacetate and with tetra-O-acetyl-α-D-glucopyraosyl bromide.

Journal ArticleDOI
TL;DR: Elution patterns on three different columns, quantitative data, and mass spectra are presented, and the mass spectrum of 8-methoxy-1,3,8-trimethylxanthine may be useful for studies of incorporation of [ 13 C]glycine and other stable isotope precursors into uric acid.

Journal ArticleDOI
TL;DR: Hippuric acid can be determined, after conversion to its methyl ester with diazomethane, by gas chromatography on cyclohexane dimethanol succinate as discussed by the authors.

Journal ArticleDOI
TL;DR: Diazomethane reacted with methyl 3,6-dideoxy-3,nitro-α- l -glucopyranoside (1) under catalysis by boron trifluoride to give the 2,4-di- O -methyl derivative as discussed by the authors.

Journal ArticleDOI
TL;DR: On heating, penicillin S-oxides form equilibrium mixtures with the corresponding sulphenic acids, which can be trapped intermolecularly with a variety of reagents, including thiols.
Abstract: On heating, penicillin S-oxides form equilibrium mixtures with the corresponding sulphenic acids. The sulphenic acids can be trapped intermolecularly with a variety of reagents, including thiols. The disulphides (3) so obtained react with trialkyl phosphites to produce the corresponding sulphides, the alkyl residue arising from the phosphite reagent. Cleavage of the nitrogen-containing substituent from the disulphides or sulphides was effected by addition of diazomethane across the double bond of the unsaturated ester to give an epimeric mixture of pyrazolines, which was then treated with base or reduced. The pyrazolines could also be reduced with NN′-dihydrobenzo[c]-cinnoline, a new, mild reducing agent.

Journal ArticleDOI
TL;DR: In this article, the MANNICH reaction was used to obtain the N-morphilinomethyl derivatives of 5-arylidene, 2-thiazolidinone-4-thiones.
Abstract: Treatment of 5-arylidene-2-thiazolidinone-4-thiones 1 with diazomethane in etherchloroform mixture effects N-methylation beside S-methylation to give the products 2 and 3 respectively. The S-alkylated derivatives 2 and 4 are obtained exclusively by the treatment of 1 with ethereal diazomethane or with ethyl bromoacetate, respectively. The N-piperidinomethyl and N-morphilinomethyl derivatives 5 were obtained by the MANNICH reaction on 1. The reaction of 1 with acrylonitrile or ethylacrylate in pyridine medium at room temperature yields the products 6. Subjecting 5-arylazo-2-thiazolidinone-4-thiones 7 to the action of ethereal diazomethan gives both the S- and N-methylated derivatives 8 and 9, respectively. Subjecting 5-arylazo-4-methylmercapto-3-thiazolin-2-ones 8 to the action of aniline yields 5-arylazo-4-phenylimino-2-thiazolidinones 10.

Journal ArticleDOI
TL;DR: The Ritter reaction of cyano- and chlorocyanoacetylene with appropriate substrates provided a facile one step synthesis of 4,4-dimethyl-2-ethynyloxazoline (5), 4, 4,6-trimethyl- 2-ethylynyl (7) and -2-chloro-1-methyl)-pyrazolyl]-1-pyrroline (11) in 42 and 40% yields respectively as mentioned in this paper.
Abstract: The Ritter reaction of cyano- and chlorocyanoacetylene with appropriate substrates provided a facile one step synthesis of 4,4-dimethyl-2-ethynyloxazoline (5), 4,4,6-trimethyl-2-ethynyl (7) and -2-chloroethynyl-5,6-dihydro-1,3-oxazine (8), 5,5-dimethyl-3-isopropylidene-2-ethynyl- (10) and -2-chloroethynyl-1-pyrroline (11). On treatment with diazomethane, 7 gave 4,4,6-trimethyl-2-(4-1H-pyrazolyl)- (13) and -2-(3-1H-pyrazolyl)-5,6-dihydro-1,3-oxazine (14) in 42 and 40% yields respectively, while 8 afforded only 4,4,6-trimethyl-2-[3-(4-chloro-1-methyl)-pyrazolyl]-5,6-dihydro-1,3-oxazine (15) in 52% yield. On the other hand, 10 gave 5,5-dimethyl-3-isopropylidene-2-(3-1H-pyrazolyl)-1-pyrroline (16) in 64% yield and 11, 5,5-dimethyl-3-isopropylidene-2-[3-(4-chloro-1-methyl)-pyrazolyl]-1-pyrroline (17) in 16% yield.

Journal ArticleDOI
TL;DR: The reaction of 5-arylidene-4-arylimino-2-thiazolidinones with GRIGNARD reagents effected 1,4-addition to the exocyclic CC bond with the formation of 5.
Abstract: The reaction of 5-arylidene-4-arylimino-2-thiazolidinones 4 with GRIGNARD reagents effected 1,4-addition to the exocyclic CC bond with the formation of 5. Alkylation of the arylidene derivatives 4 with diazomethane or methyl iodide results in the formation of the N-methyl derivatives 6. Treatment of 6 with phenylmagnesium bromide effects addition of the reagent to the double bond of the lateral chain to yield products, proved to have structure 8. The 5-arylazo derivatives 9 of 4-arylimino-2-thiazolidinones were obtained by coupling 4 with aromatic diazonium chlorides. Compounds 9 were N-methylated with diazomethane to yield 10.


Journal ArticleDOI
TL;DR: In this paper, the treatment of β-trimethylsilyl-α,β-unsaturated esters with diazomethane results in a stereospecific homolgation to the corresponding α, β-uns saturated esters.

Journal ArticleDOI
TL;DR: Iodomethyl sulphoxides may be synthesized in good yields by the reaction of diazomethane with sulphinyl chlorides in the presence of alkali metal iodides as mentioned in this paper.
Abstract: Iodomethyl sulphoxides may be synthesized in good yields by the reaction of diazomethane with sulphinyl chlorides in the presence of alkali metal iodides.

Journal ArticleDOI
TL;DR: In this paper, the product ratios of the mechanistically similar diazomethane and Tiffeneau-Demjanov homologations of 17β-hydroxy-5α-androstan-3-one and 5α-cholestan-3,one were compared.

Journal ArticleDOI
TL;DR: A procedure is described to separate and detect an hydroxylated PCB from a mixture of PCB isomers and recovery of PCBOH when six replicated solutions of the compound were carried through the procedure.
Abstract: Polychlorinated biphenyls (PCB's) are now known to be major environmental contaminants. PCB's can induce hepatic hydroxylating enzymes (RISEBROUGH et al. 1968; STREET et al. 1969; LINCER and PEAKALL 1970). Although knowledge of the metabolism of PCB's is speculative, it is possible that hydroxylated derivatives may be produced in biological systems. In the work reported a procedure is described to separate and detect an hydroxylated PCB from a mixture of PCB isomers. Experimental Two, 2',6,6'-tetraehloro-p,p'-biphenol (PCBOH) was used as a model compound. A mixture of this compound (0.2~ug/ml) and PCB isomers (Aroclor 1254, 2.44 ~g/ml) was prepared in 50 ml of hexane. The solution was extracted successively with a 15 ml and a i0 ml portion of 2% sodium bicarbonate solution. The combined aqueous extracts were extracted with i0 ml of hexane. The pH of the aqueous solution was adjusted to i with hydrochloric acid and extracted with two, 50 ml portions of diethyl ether. The combined ether extracts were dried over anhydrous sodium sulfate for 20 minutes, decanted and 0.2 ml of water was then added to the solution. The solution was evaporated with air to 0.5 ml in a graduated centrifuge tube. The volume was adjusted to 4 ml with a solution of 10% methanol in diethyl ether. The solution was methylated with diazomethane by the procedure of SCHLENK and GELLERMAN (1960) to convert PCBOH to 2,2',6,6'-tetrachloro-4,4'-dimethoxybiphenyl for gas chromatography. After removal of excess diazomethane the solution was diluted to I0 ml with ether and finally to 50 ml with hexane. The solution was analyzed by electron affinity gas chromatography using a Varian Aerograph Model 705 gas chromatograph equipped with a nickel-63 detector. The column was glass, 1/8" inside diameter, 4 feet long and packed with 10% DC-200 on 100/120 mesh Gas Chrom Q. The temperatures of the column, flash heater and detector were 185 ~ , 235 ~ and 300~ and nitrogen (24 ml/min.) was the carrier gas. Results and Discussion The recoveries of PCBOH when six replicated solutions of the compound (0.22ug/ml) in the presence of 2.4 ug/ml of Aroclor 1254 in hexane were carried through the procedure were 59.5, 63.7, 68.3, 83.3, 86.1 and 65.0. Phenols are notably volatile and loss of PCBOH during evaporation probably accounts for the recoveries

Journal ArticleDOI
TL;DR: In this article, the structures and configurations of the products have been established and some aspects of the stereochemical course of the reactions are discussed, as well as the structural and structural properties of the resulting products.
Abstract: Epoxidation of methyl 4,6-O-benzylidene-2-deoxy-α-D-erythro-hexopyranosid-3-ulose (1) and of 5-O-benzoyl-1,2-O-isopropylidene-α-D-erythro-pentofuranos-3-ulose (12) by treatment with diazomethane in methanol–ether has been shown to be accompanied by ring expansion (methylene insertion). The structures and configurations of the products have been established. Some aspects of the stereochemical course of the reactions are discussed.

Journal ArticleDOI
TL;DR: In this article, the possibility of the presence of an open-chain non-hydrated alde-hyde-form of aldotetrose in water was investigated using ORD and CD spectra of L-threose and D-erythrose.
Abstract: Reduction of methyl hydrogen di-O-acetyl-dextro-tartrate (I) with sodium borohydride in water afforded L-threono-γ-lactone (II). L-Threose (IV) was obtained on treatment of the γ-lactone (II) with an excess of disiamylborane. Reduction of ester chloride of di-O-acetyl-dextro-tartaric acid (VI) with tri-n-butyltin hydride yielded methyl di-O-acetyl-L-threuronate (VII). Attempts to reduce 2-deoxy-pentarate ester (X) derived from ester chloride (VI) via diazoketone (VIII) with sodium borohydride to give 2-deoxy-threo-pentono-γ-lactone (XI) gave unsatisfactory results. Formation of methyl L-threo-2,3-di-O-acetyl-5-chloro-5-deoxy-4-C-hydroxymethyl-4,4′-anhydropentonate (IX) in addition to diazoketone (VIII) was observed when ester chloride (VI) was treated with an excess of diazomethane. On the basis of the observed (−)-Cotton effect in the 290 nm region of ORD and CD spectra of L-threose (IV) and D-erythrose, possibility of the presence of an open chain non-hydrated alde-hyde-form of aldotetrose in water was ...

Journal ArticleDOI
J.M.H. Daemen1, W. Dankelman1
TL;DR: In this paper, a gas chromatography method was applied to a sample of phosphated pure n-dodecanol and to the alkylphosphoric acid part of the commercial surfactants Tallopol ZN and Zelec NE.

Journal ArticleDOI
TL;DR: In this paper, the synthesis of the 4-methyl, the 2,4-dimethyl, and 2,3,6-trimethyl ethers of methyl α-D -mannopyranoside has been accomplished by the use of selective, benzoyl protecting groups, the 1-ethoxyethyl protecting group, and methylation with diazomethane.

Journal ArticleDOI
TL;DR: In this article, the synthesis of macromerine from normetanephrine by a two-step methyl-ation, using diazomethane and formaldehyde-formic acid mixture, is also reported.

Journal ArticleDOI
TL;DR: In this paper, the CF:CF double bond of 2-methoxypentafluorobicyclo [2.2.0] and exo-5,6-dibromohexa-fluorobicycleclo was shown to react with 1,3-dipoles phenyl azide.
Abstract: Hexafluorobicyclo[2.2.0]hexa-2,5-diene is an active dipolarophile, reacting with the representative 1,3-dipoles phenyl azide. diazomethane, 2,2,2-trifluorodiazoethane. 2,4,6-trimethylbenzonitrile oxide, and benzonitrile N-phenylimide to give 1 : 1 adducts, and mixtures of 1 : 2 adducts. Related compounds are similarly reactive, addition to the CF:CF double bond of 2-methoxypentafluorobicyclo [2.2.0]hexa-2,5-diene, and of exo-5,6-dibromohexa-fluorobicyclo [2.2.0]hex-2-ene, occurring with phenyl azide and with 2,4,6-trimethylbenzonitrile oxide, respectively. 19F N.m.r. studies indicate that reaction occurs by exo-addition to the bicyclo-compounds.The phenyl azide adducts, 1,2,3,4,5,6-hexafluoro-9-phenyl-7,8,9-triazatricyclo[4.3.0.02,5]nona-3,7-diene and 1,2,3,5,6,7-hexafluoro-4,10-diphenyl-4,8,9,10-tetra-azatetracyclo[5.3.0.02,6.03,5]dec-8-ene, lose nitrogen upon u.v. photolysis in acetone solution, to give the derived aziridines.