Methanol → HCID 117925890, compound

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Reaction Steps

Synthetic Scheme 6 is yet another method of regiospecific synthesis of the methyl 3-picolinoylpicolinate 7 and 5-(pyridin-2-yl)pyrido[2,3-d]pyridazin-8(7H)-one 9. N,N-diethylpicolinamide 14, prepared as in Synthetic Scheme 5, is reacted with 1 equiv of sec-butyl lithium, and, without isolation of the lithiated intermediate, a second equivalent of N,N-diethylpicolinamide 14 is added to the reaction mixture, resulting in the condensation reaction yielding lithium 3-picolinoylpicolinate 16. Lithium 3-picolinoylpicolinate 16 is reacted with methanol to yield the methyl ester, methyl 3-picolinoylpicolinate 7, which is then reacted with hydrazine to yield 5-(pyridin-2-yl)pyrido[2,3-d]pyridazin-8(7H)-one 9. The pyridazinone 9 can be converted to the various ketone-Rilyazines 11, and then to the corresponding thione-Rilyazines 13 similarly to the methods shown in Scheme 4.

Provenance & Evidence