Methylation reaction

The methylation of secondary amines tvorks better than for primary amines because there is no competition bettveen the formation of mono- or di-methylated products. The best results for the microtvave-enhanced conditions were obtained when the molar ratios of substrate to formaldehyde to formic acid were 1 1 1, so that the amount of radioactive waste produced is minimal. The reaction can be carried out in neat form if the substrate is reasonably miscible with formic acid-formaldehyde or in DMSO solution if not. Again the reaction is rapid - it is complete within 2 min at 120 W microwave irradiation compared to longer than 4 h under reflux. The reaction mechanism and source of label is ascertained by alternatively labeling the formaldehyde and formic acid with deuterium. The results indicate that formaldehyde contributes two deuterium atoms and the carbon, whilst formic acid contributes one deuterium atom there is no exchange between the formaldehyde and formic acid. 

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It is important in the body as, except for methionine, it is the only substance known to take part in methylating reactions. Sometimes regarded as a member of the vitamin B group. 

It IS important to note that although methyl and primary alcohols react with hydro gen halides by a mechanism that involves fewer steps than the corresponding reactions of secondary and tertiary alcohols fewer steps do not translate to faster reaction rates Remember the order of reactivity of alcohols with hydrogen halides is tertiary > sec ondary > primary > methyl Reaction rate is governed by the activation energy of the slowest step regardless of how many steps there are... 

The antiviral activity of (5)-DHPA in vivo was assessed in mice inoculated intranasaHy with vesicular stomatitis vims ( 5)-DHPA significantly increased survival from the infection. (5)-DHPA did not significantly reduce DNA, RNA, or protein synthesis and is not a substrate for adenosine deaminase of either bacterial or mammalian origin. However, (5)-DHPA strongly inhibits deamination of adenosine and ara-A by adenosine deaminase. Its mode of action may be inhibition of Vadenosyl-L-homocysteine hydrolase (61). Inhibition of SAH hydrolase results in the accumulation of SAH, which is a product inhibitor of Vadenosylmethionine-dependent methylation reactions. Such methylations are required for the maturation of vital mRNA, and hence inhibitors of SAH hydrolase may be expected to block vims repHcation by interference with viral mRNA methylation. 

Methyl bromide slowly hydrolyzes in water, forming methanol and hydrobromic acid. The bromine atom of methyl bromide is an excellent leaving group in nucleophilic substitution reactions and is displaced by a variety of nucleophiles. Thus methyl bromide is useful in a variety of methylation reactions, such as the syntheses of ethers, sulfides, esters, and amines. Tertiary amines are methylated by methyl bromide to form quaternary ammonium bromides, some of which are active as microbicides. 

Benzimidazole, IV-aryl-reactions, 5, 448-449 Benzimidazole, 2-aryl-1-methyl-reactions,... 

Benzo[b]furan, 3-acetoxy-6-methoxy-4-methyl-reactions, 4, 650 Benzo[b]furan, 2-acetyl-oxime... 

Benzothiazolylium salts, 2-alkoxy-3-methyl-reactions, 6, 289 Benzothiazolylium salts, 3-alkyl-deprotonation, 6, 262 Benzothiazolylium salts, 2,3-dimethyl-anhydro base structure, 6, 238 reactions... 

Chromone, 2-amino-3-chloro-synthesis, 3, 713 diacetate, 3, 714 Chromone, 3-aroyl-photochemistry, 3, 695 Chromone, 2-benzhydryl-3-benzoyl-photoenolization, 3, 695 Chromone, 3-benzoyl-2-benzyl-photoenolization, 3, 695 Chromone, 3-benzoyl-2-methyl-synthesis, 3, 823 Chromone, 2-benzyl-in photochromic processes, 1, 387 Chromone, 3-benzyl-photolysis, 3, 695 Chromone, 3-bromo-synthesis, 3, 828 Chromone, 3-bromoacetyl-ring opening, 3, 713 Chromone, 3-bromo-2-methyl-reactions... 

Chromone, 2,3-dichloro-7-methoxy-synthesis, 3, 825 Chromone, dihydromass spectra, 2, 23 Chromone, 3,5-dihydroxy-2-methyl-selective methylation, 3, 716 Chromone, 5,7-dihydroxy-2-methyl-prenylation, 3, 716 Chromone, 3,7-dimethoxy-2-methyl-reactions... 

Chromone, 5-hydroxy-2-methyl-biosynthesis, 3, 876 Chromone, 6-hydroxy-2-methyl-reactions... 

Furan, 2-alkenyl-3-hydroxytetrahydro-synthesis, 4, 677 Furan, alkyl-reactions, 4, 644 synthesis, 4, 710 Furan, 2-alkyl-mass spectra, 4, 21-22 synthesis, 4, 666 Furan, 3-alkyl-mass spectra, 4, 21-22 synthesis, 4, 665, 710 Furan, 5-alkyl-2-phenylthio-reactions, 4, 80 Furan, 2-alkyltetrahydro-synthesis, 4, 675, 711 Furan, 3-amido-synthesis, 4, 665 Furan, 2-amino-synthesis, 4, 74, 121, 661 tautomerism, 4, 38 Furan, 3-amino-tautomerism, 4, 38 Furan, 2-amino-3-cyano-synthesis, 4, 661, 689, 712 Furan, 3-amino-2-methyl-reaction, 4, 74 Furan, 2-aryl-reactions... 

Furan-2(3H)-one, 4,5-dihydro-5-methyl-dipole moments, 4, 556 Furan-2(3H)-one, 5-methyl-reactions, 4, 648 Furan-2(5H)-one, 5-alkoxy-synthesis, 4, 135 Furan-2(5H)-one, 5-ethyl-synthesis, 4, 135... 

Imidazole, 4-acetyl-5-methyl-2-phenyl-synthesis, 5, 475 Imidazole, 1-acyl-reactions, 5, 452 rearrangement, 5, 379 Imidazole, 2-acyl-synthesis, 5, 392, 402, 408 Imidazole, 4-acyl-synthesis, 5, 468 Imidazole, C-acyl-UV spectra, 5, 356 Imidazole, N-acyl-hydrolysis rate constant, 5, 350 reactions, 5, 451-453 synthesis, 5, 54, 390-393 Imidazole, alkenyl-oxidation, 5, 437 polymerization, 5, 437 Imidazole, 1-alkoxycarbonyl-decarboxylation, 5, 453 Imidazole, 2-alkoxy-l-methyl-reactions, 5, 102 thermal rearrangement, 5, 443 Imidazole, 4-alkoxymethyl-synthesis, 5, 480 Imidazole, alkyl-oxidation, 5, 430 synthesis, 5, 484 UV spectra, 5, 355 Imidazole, 1-alkyl-alkylation, 5, 73 bromination, 5, 398, 399 HNMR, 5, 353 synthesis, 5, 383 thermal rearrangement, 5, 363 Imidazole, 2-alkyl-reactions, 5, 88 synthesis, 5, 469... 

Imidazole, 1 -hydroxy-2,4,5-triphenyl-3-oxides reactions, S, 455 Imidazole, iodo-nitrodehalogenation, 5, 396-397 Imidazole, 1-iodo-reactions, S, 454 stability, S, 110 Imidazole, 2-iodo-synthesis, S, 401 Imidazole, N-iodo-, S, 393 reactions, 5, 454 Imidazole, 4-iodo-5-methyl-iodination, 5, 400 Imidazole, 2-isopropyl-4-nitro-N-nitration, 5, 351 Imidazole, 2-lithio-reactions, S, 106, 448 Imidazole, 2-mercapto-l-methyl-as antithyroid drug, 1, 171 mass spectra, 5, 358 Imidazole, 1-methoxymethyl-acylation, S, 402 Imidazole, 5-methoxy-l-methyl-reactions... 

Imidazo[4,5-c]pyridine-2(3f7)-thione, 1-methyl-reactions with acrylonitrile, 5, 620 Imidazo[l,2-a]pyridine-2(3H)-thiones synthesis, 5, 632... 

Isothiazole, 4-bromo-5-hydroxy-3-methyl-methylation, 6, 160 Isothiazole, 5-bromo-3-methyl-reactions... 

Claisen condensation, 6, 156 reactions, S, 92 IsothiazoIe-3-carboxyIic acids decarboxylation, 6, 156 Isothiazole-4-carboxylic acids decarboxylation, 6, 156 Isothiazole-5-carboxylic acids decarboxylation, S, 92 6, 156 IR spectroscopy, 6, 142 Isothiazole-3-diazonium borofluoride decomposition, 6, 158 IsothiazoIe-4-diazonium chloride, 3-methyl-reactions with thiourea, 6, 158 Isothiazole-5-diazonium chloride, 4-bromo-3-methyl-halogen exchange, 6, 163 Isothiazole-5-diazonium chloride, 3-methyl-reactions... 

Naphthothiazole-2-carboxylic acid decarboxylation, 6, 279 Naphthothiene nomenclature, 1, 21 Naphthothiete, S-methyl-reactions... 

Naphtho[ 1,2-h]thiophene-2-carboxylic acid synthesis, 4, 893 Naphthothiophenes synthesis, 4, 881, 907, 914 Naphthothiophenes, dihydrosynthesis, 4, 113 Naphtho[ 1,2-c]thiophenes synthesis, 4, 891 Naphtho[2, l-h]thiophenes synthesis, 4, 907 Naphtho[2,3-h]thiophenes synthesis, 4, 905, 908-909 Naphtho[ 1,8-de][l,2,3]triazine, 2-methyl-reactions... 

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