engleski

Unusal Cleavage of Alkyl Heteroaryl Ehthers Group of 2-Chloromethyl-3, 5-dimethyl-4-methoxypyridine

Heating of 2-chloromethyl-3, 5-dimethyl-4-methoxypyridine (1) in neat or in a solution lead to cleavage of methoxy group under subsequent methyl chloride evolution and dimerisation to the very low soluble 6, 12-dihydro-1, 3, 7, 9-tetramethyl-5H, 11H-dipyrido[1, 2-a:1', 2'-d]pyrazine-2, 8-dione (2). To the our knowledge this is the first example of such thermal cleavage of alkyl heteroaryl ethers. Recrystallisation of 2 from hydrochloric acid furnished 6, 12-dihydro-2, 8-dihydroxy-1, 3, 7, 9-tetramethyl-dipyrido[1, 2-a:1', 2'-d]pyrazinediylium dichloride (3), neutralisation of which give back pyrazine-2, 8-dione (2). While 3 crystallised from aqueous methanol as dihydrate, confirmed by a single crystal X-ray structure analysis, from the same solvent 2 formed hexahydrate. Details of chemistry, possible mechanisms of formation and the single crystal X-ray structure analysis of 2 will be discussed.

methoxypyridine derivative; ether

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