反应详情

Ethyl chloroformate (10.5 ml, 0.11 mol) was added dropwise over 20 minutes to a stirred solution of 2-butylamino-4-methyl oxazole (15.4 g, 0.10 mol) and triethylamine (15.3 ml, 0.11 mol) in dry ether (100 ml) cooling to 5°-10° C. The mixture was stirred for a further 2 hours at ambient temperature, the white solid was filtered off and the filtrate evaporated under vacuum to a pale oil (22.4 g) NMR (CCl4) 6.3 δ (oxazole 5-H). This 3-acylated compound was dissolved in xylene and the solution was heated under reflux for 2 hours, cooled, washed with dilute HCl, saturated NaCl solution, dilute Na2CO3 and NaCl solution again, dried and evaporated. The residue was distilled under vacuum, b.p. 85°-90° C./0.6 mm NMR (CCl4) 7.12 δ (oxazole 5-H).

1. temperaturecooling to 5°-10° C
2. filtrationthe white solid was filtered off
3. customthe filtrate evaporated under vacuum to a pale oil (22.4 g) NMR (CCl4) 6.3 δ (oxazole 5-H)
4. dissolutionThis 3-acylated compound was dissolved in xylene
5. temperaturethe solution was heated
6. temperatureunder reflux for 2 hours
7. temperaturecooled
8. washwashed with dilute HCl, saturated NaCl solution, dilute Na2CO3 and NaCl solution again
9. customdried
10. customevaporated
11. distillationThe residue was distilled under vacuum, b.p. 85°-90° C./0.6 mm NMR (CCl4) 7.12