67-56-1
甲醇
+
762-42-5
丁炔二酸二甲酯
29108-09-6
ethyl 5-amino-2,3-dihydrofuran-4-carboxylate
→
59909-63-6
3a-O-ethyl 4-O-methyl 7a-methoxy-6-oxo-3,7-dihydro-2H-furo[2,3-b]pyridine-3a,4-dicarboxylate