Thiourea → Methyl 5-(2-aminothiazol-4-yl)valerate

Temperature

20 °C

Thiourea (15.7 g) and methyl 7-chloro-6-oxoheptanoate (39.7 g) are mixed in ethanol (200 cc). The mixture is stirred for 20 hours at a temperature of about 20° C.; gradual dissolution of the reactants is observed. The solution is concentrated to dryness under reduced pressure (25 mm Hg; 3.3 kPa) at 40° C. The residue is stirred in a mixture of methylene chloride (250 cc) and N sodium hydroxide solution (250 cc). The insoluble product is filtered off, washed with water and recrystallised by dissolving it in boiling water (350 cc) and cooling to 5° C. The resulting crystals are washed with water (3×30 cc), ethanol (3×30 cc) and diethyl ether (2×50 cc) and dried at 20° C. under reduced pressure (0.1 mm Hg; 0.013 kPa) to yield methyl 5-(2-aminothiazol-4-yl)valerate (31 g), as a white solid, m.p.=131° C.

1. dissolutiongradual dissolution of the reactants
2. concentrationThe solution is concentrated to dryness under reduced pressure (25 mm Hg; 3.3 kPa) at 40° C
3. stirringThe residue is stirred in a mixture of methylene chloride (250 cc) and N sodium hydroxide solution (250 cc)
4. filtrationThe insoluble product is filtered off
5. washwashed with water
6. customrecrystallised
7. dissolutionby dissolving it
8. temperaturecooling to 5° C
9. washThe resulting crystals are washed with water (3×30 cc), ethanol (3×30 cc) and diethyl ether (2×50 cc)
10. customdried at 20° C. under reduced pressure (0.1 mm Hg; 0.013 kPa)

ORD record

ord-7da61c55bb01422cb73892c494c0e771

Source dataset

uspto-grants-1982_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04363909