反应详情

Pyridine-2-carboxamidine (1 eq, 24.8 mmol, 5.69 g) is dissolved in EtOH (60 ml). After addition of NaOMe (30% in MeOH, 1.5 eq, 37 mmol, 6.9 ml) the mixture is stirred for 3 h at r.t. and then filtered. The filtrate is added to 2-cyano-4,4-diethoxy-butyric acid ethyl ester (see Journal of Heterocyclic Chemistry (2006), 43 (6), 1523-1531) (1 eq, 24.8 mmol, 3.01 g) and the resulting mixture is heated at 80° C. for 18 h. The solvents are evaporated, then water (50 ml), EtOH (50 ml) and aqueous HCl solution (2M, 50 ml) are added and the mixture is stirred at 0° C. for 2 h. The mixture is adjusted to pH 8 using aqueous NaOH solution (8 M) and the resulting precipitate is filtered and washed with cold water. The crystals are dried in vacuo giving the title compound; [M+H]+=213.

1. filtrationfiltered
2. temperaturethe resulting mixture is heated at 80° C. for 18 h
3. customThe solvents are evaporated
4. additionwater (50 ml), EtOH (50 ml) and aqueous HCl solution (2M, 50 ml) are added
5. stirringthe mixture is stirred at 0° C. for 2 h
6. filtrationthe resulting precipitate is filtered
7. washwashed with cold water
8. customThe crystals are dried in vacuo