Methylation, exhaustive

Chemical Properties. Reactions of quaternaries can be categorized iato three types (169) Hoffman eliminations, displacements, and rearrangements. Thermal decomposition of a quaternary ammonium hydroxide to an alkene, tertiary amine, and water is known as the Hoffman elimination (eq. la) (170). This reaction has not been used extensively to prepare olefins. Some cycHc olefins, however, are best prepared this way (171). Exhaustive methylation, followed by elimination, is known as the Hoffman degradation and is important ia the stmctural determination of unknown amines, especially for alkaloids (qv) (172). 

Exhaustive Methylation. As in the lobeline group it is the diketo-bases, lelobanines (p. 30) in the lelobine series and lobinanines (p. 31) in the lobinine group, which give methiodides amenable to this mode of degradation. They are decomposed by alkali yielding an unsaturated neutral oil, which is hydrogenated and then, if necessary, oxidised to the saturated open chain diketone, e.g., see under lelobanine. 

On hydrogenation at 80°, or on electrolytic reduction, aphyllidine is converted into d-sparteine (p. 133). On exhaustive methylation one nitrogen atom is eliminated in three stages, leaving a product, b.p. 235-255°/ll mm., as a viscous, yellow, alkaline oil of uncertain composition. Aphylline, on similar treatment, yields hemiaphylline, CjgH jON, b.p. 217-220°, as a viscous, yellow oil, not markedly basic. 

This formula for 0-pelIetierine received confirmation from the results of the exhaustive methylation of A -methylgranatanine, produced by the... 

The exhaustive methylation of sparteine was reinvestigated by Karrer,. Shibata, Wettstein and Jacubowitz. At each stage they reduced the unsaturated product formed and so ended up with a pentadecane, C15H32 (b.p. 242°/729 mm., D] 0-7740, 1-43351). The object of this work... 

Proof of formula (VI) for dehydrolaudanosoline salts was provided by a study of its exhaustive methylation, the products at the first and second stages of the application of this process being 5 6-dimethoxy-2-(3 4 -dimethoxy-6 -vinylphenyl)-l-methyldihydroindole (VIII) and 6-dimethyl-amino-3 4 3 4 -tetramethoxy-6 -vinylstilbene (IX) respectively. 

When the Hofmann process of exhaustive methylation is followed and -methylmorphimethine methohydroxide is heated in water, a decomposition similar to the foregoing takes place with the production of methylmorphenol, trimethylamine and ethylene thus — ... 

EtOH), is insoluble in benzene or ether, and sparingly in chloroform, but dissolves readily in alkali, the solution darkening in air. The salts are crystalline but unstable. The base forms a crystalline metbiodide and contains two methoxyl and two phenolic hydroxyl groups. On methyla-tion it yields a mixture of corydine and fsocorydine. On exhaustive methylation corytuberine yields eventually trimethylamine and 3 4 5 6-tetramethoxy-8-vinylphenanthrene, m.p. 69°. 

The indolinol character of eseretholemethine is indicated by the fact that the methiodide on treatment with picric acid yields a diquaternary pierate (m.p. 170°) with the loss of the hydroxyl group. More definite proof is afforded by the oxidation of eseretholemethine with ammoniaeal silver nitrate or potassium ferricyanide, when a dehydroeseretholemethine (oxyeseretholemethine of Polonovski), pierate, m.p. 199°, is produced which is assumed to have formula (VI), since on exhaustive methylation it yields trimethylamine and an unsaturated product (deep-red pierate, m.p. 103°), which absorbs two atoms of hydrogen, forming 5-ethoxy-l 8-dimethyl-S-ethyl-2-indolinone (VII), colourless cubes, m.p. 68°. The... 

Exhaustive Methylation. (Parts I, XXII, XXVIII>) This process applied to vomicine has developed difficulties like those met with in the case of strychnine (p. 575). The Emde process used with vomicine metlio-sulphate, C22H24O4N2. MeHS04, m.p. 272° (dec.), produced two methyl-vomicihes, I and II, C23H28O4N2. 

Vomicidine and derivatives, 591, 592 oxidation, 594 Vomicine, 553, 586, 589, 592 constitution, 586 exhaustive methylation, 592 oxidation, 594 pharmacological action, 596 reduction products, 589 and derivatives, formhlae, 587, 593, 595... 

A 0.2-g sample of amylopectin was analyzed to determine the fraction of the total glucose residues that are branch points in the structure. The sample was exhaustively methylated and then digested, yielding 50 /tmol of 2,3-dimethylglucose and 0.4 /tmol of 1, 2, 3, 6-tetramethylglucose. 

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