Acetic Anhydride → 4-Ethoxy-3-(4-pyridyl)-3-buten-2-one

Participants

Reaction Steps

One aspect of the invention resides in the process which comprises reacting pyridinylmethyl lower-alkyl ketone of the formula ##STR1## (I) with tri-(lower-alkyl) orthoformate, acetic anhydride and acetic acid to produce 2-(lower-alkoxy)-1-(pyridinyl)-ethenyl lower-alkyl ketone of formula II, ##STR2## and reacting said ketone (II) with malononitrile in a lower-alkanol to produce 1,2-dihydro-6-R-2-oxo-5-PY-nicotinonitrile of formula III, ##STR3## where R and R' are each lower-alkyl and PY is 4- or 3-pyridinyl or 4- or 3-pyridinyl having one or two lower-alkyl substituents. In a preferred embodiment 4(or 3)-pyridinylmethyl methyl(or ethyl) ketone is first reacted with triethyl or trimethyl orthoformate, acetic anhydride and acetic acid to produce 2-ethoxy(or methoxy)-1-(4- or 3-pyridinyl)ethenyl methyl(or ethyl) ketone and then said ketone is reacted with malononitrile in ethanol to produce 1,2-dihydro-6-methyl(or ethyl)-2-oxo-5-[4(or 3)-pyridinyl]nicotinonitrile. In a particularly preferred embodiment 4-pyridinylmethyl methyl ketone is first reacted with triethyl orthoformate, acetic anhydride and acetic acid to produce 2-ethoxy-1-(4-pyridinyl)ethenyl methyl ketone and then said ketone is refluxed with malononitrile in ethanol to produce 1,2-dihydro-6-methyl-2-oxo-5-(4-pyridinyl)nicotinonitrile.

Provenance & Evidence