反应详情

A suspension of guanylthiourea (2.36 g) and ethyl 3-bromopyruvate (4.8 g) in dry ethanol (50 ml) is refluxed under stirring for 2.5 hours. The reaction mixture is concentrated in vacuum to dryness, and the residue is dissolved in water (about 100 ml). The aqueous solution is washed with ethyl acetate and made alkaline with 5% sodium hydrogencarbonate solution. The precipitated crystals are filtered, washed with water and dried to give 2-guanidino-4-ethoxycarbonylthiazole (3.6 g) as crystals. The yield is 84%.

1. temperatureis refluxed
2. concentrationThe reaction mixture is concentrated in vacuum to dryness
3. dissolutionthe residue is dissolved in water (about 100 ml)
4. washThe aqueous solution is washed with ethyl acetate
5. filtrationThe precipitated crystals are filtered
6. washwashed with water
7. customdried