engleski

One Pot Synthesis of 6, 12-Dihydro-1, 3, 7, 9-teramethyl-5H, 11H-dipyrido [1, 2-a:1', 2'-d]pyrazine-2, 8-dione by Hilbert-Johnson Reaction of 2-Chloro-3, 5-dimethly-4-methoxypyridine

By heating 2-chloromethyl-3, 5-dimethyl-4-methoxypyridine (1) in neat or in a solution the methoxy group cleavage was achieved, followed by dimerisation to poorly soluble 6, 12-dihydro-1, 3, 7, 9-tetramethyl-5H, 11H-dipyrido[1, 2-a:1', 2'-d]pyrazine-2, 8-dione (3) in almost quantitative yield and methyl chloride evolution. To our knowledge this is the first example of such Hilbert-Johnson preparation of dipyridopyrazinediones. Recrystallization of 3 from the hydrochloric acid yielded 6, 12-dihydro-2, 8-dihydroxy-1, 3, 7, 9-tetramethyl-dipyrido[1, 2-a:1', 2'-d]pyrazinediylium dichloride (4), neutralization of which gave back the pyrazine-2, 8-dione 3. The molecular structures of both compounds 3 and 4 have been unambiguously confirmed by single crystal X-ray structure analysis.

pyrazinediylium derivative; X-ray

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