Methylation of 3-methyl- and 3-phenyl-4-arylhydrazonoisoxazol-5-ones with methyl iodide and dimethyl sulfate

Chromatography and electrophoresis of the reaction products from B12s and methyl iodide yield the known Co-methyl-cobalamin and a new light sensitive corrinoid compound. The latter is very probably Co-methyl-cobalamin a with the methyl group “down”. The absorption spectrum of this yellow corrinoid differs only slightly from that of Co-methyl-cobalamin in acid media and does not depend on pH at wavelengths higher than 300 nm. The new corrinoid is thermolabile and on heating at 95°C for several hours in O2-free aqueous medium changes nearly quantitatively to Comethyl-cobalamin. The last corrinoid, on the contrary, yields at 95 cC several per cents of Comethyl-cobalamin a. The reaction of B12s with dimethyl sulfate yields beyond the mentioned products Co-methyl-cobalamin Nm (yellow; the absorption spectrum does not depend on pH and is identical with that of Co-methyl-cobalamin in acid media) and B12Nm (both corrinoids have a methyl group on N-3 of the 5,6-dimethylbenzimidazole moiety). The thermal isomerization of both Co-methyl-cobalamins is in accord with the observed formation of Co-14CH3-cobinamide on heating of Co-14CH3-cobalamin with Co-CH3-cobinamide.

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Thiazoloisoquinolines. III. Structure and methylation of 2-hydroxythiazolo[4,5-c]- and -[5,4-c]isoquinolines

Canadian Journal of Chemistry ◽

10.1139/v68-117 ◽

1968 ◽

Vol 46 (5) ◽

pp. 691-694 ◽

Cited By ~ 5

Author(s):

Catherine E. Hall ◽

Alfred Taurins

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Methyl Iodide ◽

Dimethyl Sulfate ◽

The Other ◽

Thiazole Ring ◽

Spectral Evidence ◽

Other Hand ◽

Methylating Agents ◽

Nuclear Magnetic

2-Hydroxythiazolo[4,5-c]isoquinoline (1) and 2-hydroxythiazolo[5,4-c]isoquinoline (2) were both found to exist predominantly in the lactam form (1b and 2b respectively) from infrared, nuclear magnetic resonance, and ultraviolet spectral evidence. Various methylating agents methylated compound 1 exclusively on the N-3 atom in the thiazole ring. Compound 2 on the other hand, gave a mixture of O-and N-3 methylated products with diazomethane and a mixture of N-1 and N-4 methylated products with either methyl iodide or dimethyl sulfate.

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Single-Step Methylation of Chitosan Using Dimethyl Carbonate as a Green Methylating Agent

Molecules ◽

10.3390/molecules24213986 ◽

2019 ◽

Vol 24 (21) ◽

pp. 3986 ◽

Cited By ~ 2

Author(s):

Ellen B. Hemming ◽

Anthony F. Masters ◽

Alvise Perosa ◽

Maurizio Selva ◽

Thomas Maschmeyer

Keyword(s):

Ionic Liquid ◽

Reaction Time ◽

Nmr Spectroscopy ◽

Methyl Iodide ◽

1H Nmr ◽

1H Nmr Spectroscopy ◽

Dimethyl Carbonate ◽

Dimethyl Sulfate ◽

Single Step ◽

Chitosan Derivative

N,N,N-Trimethyl chitosan (TMC) is one chitosan derivative that, because of its improved solubility, has been studied for industrial and pharmaceutic applications. Conventional methods for the synthesis of TMC involve the use of highly toxic and harmful reagents, such as methyl iodide and dimethyl sulfate (DMS). Although the methylation of dimethylated chitosan to TMC by dimethyl carbonate (DMC, a green and benign methylating agent) was reported recently, it involved a formaldehyde-based procedure. In this paper we report the single-step synthesis of TMC from chitosan using DMC in an ionic liquid. The TMC synthesised was characterised by 1H NMR spectroscopy and a functionally meaningful degree of quaternisation of 9% was demonstrated after a 12-h reaction time.

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Study of methylation reactions of 2-phenylquinazoline-4-tion with “soft” and “hard” methylation agents and determination of its biological activity

E3S Web of Conferences ◽

10.1051/e3sconf/202125804023 ◽

2021 ◽

Vol 258 ◽

pp. 04023

Author(s):

B Sapaev ◽

F.E Saitkulov ◽

A.A Tashniyazov ◽

OU Normurodov

Keyword(s):

Biological Activity ◽

Reaction Time ◽

Methyl Iodide ◽

Dimethyl Sulfate ◽

Reaction Centers ◽

Reaction Proceeds ◽

Alkylation Reactions ◽

Isomeric Product

Alkylation reactions of 2-phenylquinazoline-4-thion with methylation agents “soft” (methyl iodide) and “hard” (dimethyl sulfate, methyltozylate) were studied. It was found that the reaction proceeds with the formation of alkyl products at the N3 - and S4 - reaction centers, depending on the methylation agent, solvent and temperature. This indicated the ambivalent nature of the 2-phenylquinazoline-4-tion anion. Prolongation of the reaction time leaded to the formation of a second isomeric product (VII). A slight increase in phenyl N3-product (VII) yield was noted when dimethyl sulfate and methylfolate were used as methylation agents. In non-polar proton-free solvent DMF and dipolar proton-free solvent acetonitrile, only N-methyl product (VII) was formed because of the reaction. An increase in the polarity of the solvent and the “hardness” of the methylation agent leads to an increase in the yield of N3 products.

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Reactions of 1-Phenyl-1,2,3-triazolyllithium Compounds; Formation of Ketenimines, Alkynylamines, and Heterocycles from the Ambident (N-Phenyl)phenylketenimine Anion

Canadian Journal of Chemistry ◽

10.1139/v71-295 ◽

1971 ◽

Vol 49 (11) ◽

pp. 1792-1798 ◽

Cited By ~ 50

Author(s):

R. Raap

Keyword(s):

Methyl Iodide ◽

Heterocyclic Compound ◽

Room Temperature ◽

Dimethyl Sulfate ◽

Phenyl Isocyanate ◽

Ambident Anion ◽

Membered Heterocyclic Compound

At room temperature 1,4-diphenyl-1,2,3-triazolyllithium rapidly undergoes fragmentation to nitrogen and lithium (N-phenyl)phenylketenimine anion 8c, [Formula: see text]. Some of the reactions of this ambident anion have been studied. Reaction of 8c with methyl iodide results in C-methylation to a mixture of (N-phenyl)methylphenylketenimine and 3-methyl-1,3-diphenyl-4-(2′-phenylethylene)-2-phenyliminoazetidine. A six-membered heterocyclic compound, 6-anilino-1,3,5-triphenyluracil, results from the reaction between 8c and phenyl isocyanate. With dimethyl sulfate and methyl chloroformate N-alkylation and N-acylation takes place predominantly, forming N-methyl-N-phenyl-2-phenylethynylamine and N-carbomethoxy-N-phenyl-2-phenylethynylamine respectively. Reaction of 8c with methanol and ethanethiol gives an iminoester and an iminothioester respectively.1-Phenyl-1,2,3-triazolyllithium and 4-methyl-1-phenyl-1,2,3-triazolyllithium undergo fragmentation at somewhat higher temperatures.

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