反应详情

Absolute ethanol (50 mL) was slowly added to a mechanically stirred suspension of finely cut sodium metal (19.3 g; 0.84 mol) in anhydrous ether (500 mL). When most of the metal had dissolved, diethyl oxalate (114 mL; 0.84 mol) was slowly added followed by the slow addition of the N-phenyl-N-formylglycine ethyl ester (130 g; 0.67 mol). The mixture was stirred at room temperature overnight and then ice-water (700 mL) was added. The resulting emulsion was broken by sequential addition of a saturated sodium chloride solution (150 mL) and water (200 mL). The aqueous layer was removed, potassium thiocyanate (114 g; 1.18 mol) was added, then concentrated hydrochloric acid (160 mL), followed by absolute ethanol (900 mL). The resultant mixture was warmed at 60°-65° C. for 1 hour, then at 50° C. for 6 hours and finally allowed to stir at room temperature overnight. The light yellow precipitate was filtered, washed with ethanol and dried to give 103 g (48%) of diethyl 2-mercapto-1-phenyl-4,5-imidazoledicarboxylate (mp 145°-146° C.).

1. dissolutionWhen most of the metal had dissolved
2. customThe aqueous layer was removed
3. waitat 50° C. for 6 hours
4. stirringto stir at room temperature overnight
5. filtrationThe light yellow precipitate was filtered
6. washwashed with ethanol
7. customdried