Methanol aromatic heterocyclics

Synonyms 3-Hydroxymethylpyridine m-Hydroxy-3-picoline Nicotinic alcohol Nic-otinyl alcohol 3-Picolyl alcohol Pyridine-3-carbinol 3-Pyridine methanol Pyridyl-carbinol 3-Pyridylcarbinol 3-Pyridylmethanol Classification 6-membered aromatic heterocyclic Empirical C.H NO... 

The reaction is applicable to the preparation of amines from amides of aliphatic aromatic, aryl-aliphatic and heterocyclic acids. A further example is given in Section IV,170 in connexion with the preparation of anthranilic acid from phthal-imide. It may be mentioned that for aliphatic monoamides containing more than eight carbon atoms aqueous alkaline hypohalite gives poor yields of the amines. Good results are obtained by treatment of the amide (C > 8) in methanol with sodium methoxide and bromine, followed by hydrolysis of the resulting N-alkyl methyl carbamate ... 

The most versatile derivative from which the free base can be readily recovered is the picrate. This is very satisfactory for primary and secondary aliphatic amines and aromatic amines and is particularly so for heterocyclic bases. The amine, dissolv in water or alcohol, is treated with excess of a saturated solution of picric acid in water or alcohol, respectively, until separation of the picrate is complete. If separation does not occur, the solution is stirred vigorously and warmed for a few minutes, or diluted with a solvent in which the picrate is insoluble. Thus, a solution of the amine and picric acid in ethanol can be treated with petroleum ether to precipitate the picrate. Alternatively, the amine can be dissolved in alcohol and aqueous picric acid added. The picrate is filtered off, washed with water or ethanol and recrystallised from boiling water, ethanol, methanol, aqueous ethanol, methanol or chloroform. The solubility of picric acid in water and ethanol is 1.4 and 6.23 % respectively at 20°. 

Nafion is a good membrane for a fuel cell working with H2 but does not work above 80°C or with methanol. An important work on sulfonated aromatic and heterocyclic systems is now involving many teams in North America, Europe,... 

Aromatic and heterocyclic nitro compounds are readily reduced in good yield to the corresponding amines (e.g. o-aminophenol, Expt 6.50) by sodium borohydride in aqueous methanol solution in the presence of a palladium-on-carbon catalyst. In this reduction there is no evidence for the formation of intermediates of the azoxybenzene or azobenzene type, although if the reaction is carried out in a polar aprotic solvent, such as dimethyl sulphoxide, azoxy compounds may sometimes be isolated as the initial products. 

Analytical Properties Has been used to separate aromatic hydrocarbons, heterocyclic compounds, phenols, and aryl amines using methanol/water/phosphate buffer extent of adsorption affects retention times also used as a mobile phase modifier to provide a dynamically modified silica Reference 51-57... 

The resulting alkyl or aryl diethyl phosphates were selectively detected at the 10-25 ng level with the P-mode FPD. Similarly, Jacob et al (36) used dimethyl thiophosphinic chloride in the presence of excess triethylamine to convert primary aliphatic, aromatic and heterocyclic amines to the corresponding N-dimethyl-thiophosphinic amides. The excess reagent was easily removed by treating the reaction mixture with methanol-sodium hydrogen car-... 

All of the common 5-membered aromatic nitrogen heterocycles are quite acidic with pKa s ranging from 16.2 in the case of indole (comparable to methanol) to 5 in the case of tetrazole (comparable to acetic acid). Indoles and pyrroles devoid of electron withdrawing substituents are also very susceptible to electrophilic attack and oxidation whilst imidazole, 1,2,4-triazole and tetr azole are also quite basic. In the case of imidazole, a pKan = 7 corresponds to 50% of the... 

Even poor nucleophiles such as the amides 46 can react with azines in the presence of alkynes as activating agents [59, 60]. Various nucleophiles (including alkoxides, thiols, amines and nitrogen heterocycles) were recently employed in a related process with Ai-oxide azaindoles (Reissert-Henze reaction. Scheme 10). In the process, the oxygen is alkylated with dimethyl sulfate and, after the nucleophilic attack, methanol is released to aromatize the initial adduct [61,62]. Following similar mechanistic trends, V-heteroatom-activated azines afford the corresponding substituted adducts. Likewise, W-tosylated isoquinoline [63, 64] and W-fluoropyridinium salts [65] are also reactive substrates in Reissert-Henze type processes. 

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