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0 °C

A single-necked flask containing 80 ml of ethanol is cooled down to 0° C. by an ice bath, 4 g (55.6 mmoles) of sodium ethylate and 3.8 g (27.8 mmoles) of tert-butylcarbamidine hydrochloride are added. The reaction mixture is left to return to ambient temperature, then 5 ml (27.8 mmoles) of diethyl ester methylmalonate is added dropwise. Stirring is maintained at ambient temperature overnight. The ethanol is then condensed under reduced pressure (2 kPa). The crude product obtained is solubilized in a minimum amount of water (approximately 40 ml), then acidified at 0° C. with pure acetic acid until a pH comprised between 4 and 5 is achieved. The white precipitate formed is filtered, rinsed successively with water, ethyl ether and with pentane. Then the white powder obtained is dried over P2O5 under reduced pressure (0.2 kPa). 2.4 g of expected product is obtained.

1. waitThe reaction mixture is left
2. customto return to ambient temperature
3. temperatureis maintained at ambient temperature overnight
4. customcondensed under reduced pressure (2 kPa)
5. customThe crude product obtained
6. customThe white precipitate formed
7. filtrationis filtered
8. washrinsed successively with water, ethyl ether and with pentane
9. customThen the white powder obtained
10. dry with materialis dried over P2O5 under reduced pressure (0.2 kPa)