Pyridine methiodide

Pyridine methiodide and ethiodide. Place 2 drops of dry pyridine in a test-tube, add 2 drops of methyl iodide and mix. A vigorous reaction occurs and on cooling, a colourless crystalline mass of pyridine methiodide, CjHjN.Mel, is formed cf. p. 377) when recrystallised from methylated spirit, the methiodide has m.p. 117. ... 

Methiodide formation. Place 2 drops of dry pyridine in a dry test-tube, add 4-5 drops of methanol, and 2 -3 drops of methyl iodide. 

B) Methiodi s. Members of Classes (i), (ii) and (iv) combine wdth methyl iodide (some very vigorously) to form quaternary methiodides. It is best to add the amine to an excess of methyl iodide dissolved in about twice its volume of methanol, allow any spontaneous reaction to subside, and then boil under reflux for 30 minutes (extend to 1 hour for Class (iv) except pyridine and quinoline). The methiodide may crystallise when the reaction-mixture cools if not, evaporate the latter to small bulk or to dryness, and recrystallise, (M.ps., pp. 553-554 )... 

Pyridine, 4-methoxy-3-styryl-photoelectron spectroscopy, 2, 137 Pyridine, 2-methyI-alkylation, 2, 176 amination, 2, 233, 236 carboxylation, 2, 53 chlorination, 2, 201, 331 Claisen condensation, 2, 51 methiodide... 

The formation of cotar none from cotar nine methine methiodide by the action of potash (IX—X) led Roser to represent cotarnine and its salts by the following formulae, the loss of a molecule of water in the formation of cotarnine salts being explained by the production of a partially reduced pyridine ring, which is fully hydrogenated in the reduction of cotarnine to hydrocotarnine. In the reverse process, oxidation of liydrocotarnine to cotarnine, Roser assumed the scission of the ring at the point indicated, with the formation of a hydration product, and oxidation of the latter to cotarnine thus —... 

Of the four possible oxazolopyridines, two have been studied with respect to quatemization reactions. Frazer and Tittensor prepared 2-alkyl- and 2-aryl-oxazolo[4,5-c]pyridines (105 Y = H) and converted them into methiodides, the structures of which have not been determined. Subsequently Takahashi et al. prepared the corresponding 5-methyl (105 Y = Me) and 2-methyl-5-nitro compounds and... 

Work on the thiazolopyridines has been centered on the 2-methyl derivatives and their conversion into cyanine dyes. Takahashi et al. prepared a number of substituted thiazolo[5,4-6]pyridines (109 Y =.MeO,i6 EtO, Cl,i6 and EtgNi ), all of which form methiodides (110) as evidenced by the high reactivity of the 2-methyl group. A parallel will be seen between these compounds and the l,4-diaza-3fi -indenes. Kiprianov reports the interesting observation that the etho-toluene- -sulfonate of 109 (Y = H) does not contain a reactive methyl group presumably when Y is H the steric and electronic... 

Paudler and Helmick515 have measured half-lives for deuteration of some heterocycles by deuterated sulphuric acid at 100 °C. The equivalent first-order rate coefficients (lO ) are as follows imidazo[l, 2-a]pyridine, 427(3-H) imidazo[l,2-a]pyridine-N-methiodide, 62(3-H) imidazo[l,2-a]pyrimidine, 123-(3-H) imidazo[l,2-a]pyrimidine-N-methiodide, < 6.4 (3-H, 5-H) 1,2,4-tri-azolo [1,5-a]pyridimidine, 128(5-H) 1,2,4-triazolo [1,5-a]pyrimidine-N-methiodide, 11.7 (5-H). The lower reactivity in each case of the corresponding methiodides shows that the bases react as such and not as the conjugate acids. 

Reactivators of phosphorylated ChE. Pyridine aldoxime methiodide (PAM) and related compounds are the best known. They reactivate the phosphorylated enzyme so long as aging has not occurred. They do not, however, reactivate the aged enzyme. ChE which has been phosphorylated by certain nerve gases ages rapidly ... 

Irreversible anticholinesterases include the organophosphorus inhibitors and ambenonium, which irreversibly phosphorylate the esteratic site. Such drugs have few clinical uses but have been developed as insecticides and nerve gases. Besides blocking the muscarinic receptors with atropine sulphate in an attempt to reduce the toxic effects that result from an accumulation of acetylcholine, the only specific treatment for organopho-sphate poisoning would appear to be the administration of 2-pyridine aldoxime methiodide, which increases the rate of dissociation of the organophosphate from the esteratic site on the enzyme surface. 

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