On US4672121 4-cyanopyridine is quaternized with acrylamide and hcl in isopropanol (no water).
Obtained N-(2-carbamoylethyl)-4-cyanopyridinium chloride.
EXAMPLE 1 N-(2-carbamoylethyl)-4-cyanopyridinium chloride Isolation of title compound
The following procedure was also applied to the preparation of the 3-cyanopyridine quaternization salt and also to mixtures of 3-cyano/4-cyanopyridine quaternization salts.
A five liter, three-necked round bottom flask was fitted with a mechanical stirrer, thermometer, dropping funnel and a beating mantle. The flask was charged with 637 g of 98% 4-cyanopyridine followed by one liter of isopropanol. Stirring was initiated and 426 g of acrylamide followed by another one liter portion of isopropanol was charged to the flask. The temperature was 6° C. at this point. The dropping funnel was charged with a solution of hydrogen chloride in isopropanol (21.12% w/v) and 1033 ml of this solution was added to the reaction flask over a one hour period. The reactor temperature was 46° C. at this point and a white precipitate had developed.
Heat was applied--the dropping funnel was replaced by a reflux condenser and the mixture which became thicker was refluxed for one hour, then allowed to cool overnight. The heavy precipitate was collected on a Buchner funnel by vacuum filtration. This was washed with cold isopropanol and dried in a vacuum oven for two hours at 60° C., affording 1172 g of the title compound with melting point 188°-189° C. Yield 92.6%.
How its works? Its possible to use alkenes? Why acrylamide does not forms acrylic acid and nh4cl?
I think, first stage - 4-cyanopyridinium chloride is formed. CN remains unchanged with low temperature?
Then, under heat, hydrogen is substituted by acrylic residue like in Zeisel–Prey ether cleavage?
But why amide is not transformed to acid?