Amberlite IR-12O(H) ion-exchange resin (0-5 g., dried) was added to a mixture of redistilled 2 : 3-dihydropyran (17 g.) and ethyl glycollate (10 g.). The temperature rose slowly from 22" to 26". The mixture was kept for 20 hr. at room temperature, then filtered, and the filtrate was distilled as before.The amide was prepared by treatment of the ester with an excess of ammonia solution (d 04380) overnight. It crystallised after removal of solvent under reduced pressure and recrystallised from benzene as prisms, m.