Réaction #1694

Équation de réaction

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

oxalyl chloride

2-butyn-l-ol

→

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

Rendement 61.0%

Solvants

water

benzene

Conditions de réaction

Traitement

1. 1
   Températureheated
2. 2
   Températureunder reflux for 2.5 h
3. 3
   Autreevaporated to dryness in vacuo
4. 4
   Températureafter cooling
5. 5
   Autreto give an orange-yellow residue
6. 6
   workup.STIRRINGwas stirred at room temperature overnight
7. 7
   workup.STIRRINGAfter stirring overnight
8. 8
   Autrethe solvents were removed in vacuo
9. 9
   Autreto give a brownish residue
10. 10
    workup.STIRRINGstirred at room temperature for 2 h
11. 11
    Filtrationfiltered
12. 12
    AutreThe brown residue obtained on removal of the solvents in vacuo
13. 13
    Autrewas recrystallized (ethanol/ether)

Mode opératoire

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.

Source