反应详情

A mixture of 11.62 g (77.5 mmol) of isopropyl-guanidine hydrogen sulfate, 32 ml (5 eq; 0.37 mol) of freshly distilled pyrrolidine in 230 ml of anhydrous methanol is refluxed for twenty minutes. A methanolic solution (60 ml) of methoxymalonaldehyde (1 eq; 77.5 mmol; 10 g) is added to the above solution at 0° C. as well as 140 g of molecular sieve (4 A°). The reaction medium is stirred under argon and under reflux for 24 hours. The molecular sieves are removed by filtration and then rinsed with methanol. Evaporation of the filtrate gives a residue which is taken up with ethyl acetate and then acidified with a 1N hydrochloric acid solution. The organic phases are washed with a saturated sodium chloride solution, dried over sodium sulfate, evaporated and purified on silica gel under 200 mb (eluent: 50 ethyl acetate/50 heptane).

1. temperatureis refluxed for twenty minutes
2. temperatureunder reflux for 24 hours
3. customThe molecular sieves are removed by filtration
4. washrinsed with methanol
5. customEvaporation of the filtrate
6. customgives a residue which
7. washThe organic phases are washed with a saturated sodium chloride solution
8. dry with materialdried over sodium sulfate
9. customevaporated
10. custompurified on silica gel under 200 mb (eluent: 50 ethyl acetate/50 heptane)