Reacción #1694

Ecuación de reacción

1,4,5,6-tetrahydropyrimidine-5-carboxylic acid hydrochloride

oxalyl chloride

2-butyn-l-ol

→

5-(2-butynyloxycarbonyl)-1,4,5,6-tetrahydropyrimidine

Rendimiento 61.0%

Disolventes

water

benzene

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturaheated
2. 2
   Temperaturaunder reflux for 2.5 h
3. 3
   Otroevaporated to dryness in vacuo
4. 4
   Temperaturaafter cooling
5. 5
   Otroto give an orange-yellow residue
6. 6
   workup.STIRRINGwas stirred at room temperature overnight
7. 7
   workup.STIRRINGAfter stirring overnight
8. 8
   Otrothe solvents were removed in vacuo
9. 9
   Otroto give a brownish residue
10. 10
    workup.STIRRINGstirred at room temperature for 2 h
11. 11
    Filtraciónfiltered
12. 12
    OtroThe brown residue obtained on removal of the solvents in vacuo
13. 13
    Otrowas recrystallized (ethanol/ether)

Procedimiento

1,4,5,6-tetrahydropyrimidine-5-carboxylic acid hydrochloride (1 g, 6 mmol) was suspended in a solution of oxalyl chloride (1.5 mL, 17 mmol) in benzene (10 mL), heated with stirring under reflux for 2.5 h, and then evaporated to dryness in vacuo after cooling, to give an orange-yellow residue. A mixture of the acid chloride (04 g) and 2-butyn-l-ol (20 mL, excess) was stirred at room temperature overnight. After stirring overnight, the solvents were removed in vacuo to give a brownish residue. The residue was taken up in water (100 mL), stirred at room temperature for 2 h and filtered. The brown residue obtained on removal of the solvents in vacuo was recrystallized (ethanol/ether) to give a brown viscous oil (0.3 g, 61%) of 5-(2-butynyloxycarbonyl)-1,4,5,6-tetrahydropyrimidine as the hydrochloride salt. 1H NMR (D2O): δ 1.5 (t, 3H, CH3), 3.1 (m, 1H), 3.5 (d, 4H), 3.9 (q, 2H, OCH2), 7.9 (s, 1H, amidine-H). Anal. (C9H13N2O2Cl) C, H, N.

Fuente