In 1970,Tetrahedron included an article by Wamhoff, Heinrich. HPLC of Formula: 29278-09-9. The article was titled 《Heterocyclic β-enamino esters. III. NMR spectroscopic study of the protonation of heterocyclic β-enamino esters》. The information in the text is summarized as follows:
Partially hydrogenated heterocyclic β-enamino esters of the 4,5-dihydrofuran, -thiophene, 5,6-dihydro-4H-pyran and -thiopyran type are protonated in trifluoroacetic acid at position 3 (Cβ-protonation). The course and place of this protonation was studied by means of NMR spectroscopy and the results compared with protonation experiments carried out on unsaturated N-containing heterocyclics of this type. In the part of experimental materials, we found many familiar compounds, such as Ethyl 5-amino-3-phenylisoxazole-4-carboxylate(cas: 29278-09-9HPLC of Formula: 29278-09-9)
Ethyl 5-amino-3-phenylisoxazole-4-carboxylate(cas: 29278-09-9) belongs to anime. Acylation is one of the most important reactions of primary and secondary amines; a hydrogen atom is replaced by an acyl group (a group derived from an acid, such as RCOOH or RSO3H, by removal of ―OH, such as RC(=O)―, RS(O)2―, and so on). Reagents may be acid chlorides (RCOC1, RSO2C1), anhydrides ((RCO)2O), or even esters (RCOOR′); the products are amides of the corresponding acids.HPLC of Formula: 29278-09-9
Referemce:
Isoxazole – Wikipedia,
Isoxazole | C3H3NO – PubChem