The reaction of an aromatic heterocycle with a proton is called a protonation. One of articles about this theory is 《Condensation of aromatic aldehydes with glycine and acetylglycine》. Authors are Dakin, H. D..The article about the compound:cis-Cyclohexane-1,2-dicarboxylic acidcas:610-09-3,SMILESS:O=C([C@H]1[C@@H](C(O)=O)CCCC1)O).HPLC of Formula: 610-09-3. Through the article, more information about this compound (cas:610-09-3) is conveyed.
The condensation referred to in the title is complicated by a competing reaction between CH2(NH2)CO2H and BzH, forming a non-acetylated derivative possibly of a type resembling a Schiff base. The 2 reactions are shown thus: (1) H2NCH2CO2H → AcNHCH2CO2H → MeC:N.C(:CHPh).CO.O → MeCONHC(:CHPh)CO2H, (2) HO2CCH2NH2 + BzH → HO2CCH2N:-CHPh (I) or O.CO.CH2.NH.CHPh. I may be called benzylideneglycine and was isolated and analyzed. Because the 2nd condensation product is a non-acetylated compound its formation can be largely suppressed by acetylating the glycine before the reaction. Correspondingly larger yields of the azlactone of α-acetamidocinnamic acid were obtained. Acetylation was most easily effected by warming glycine suspended in 3 parts of glacial AcOH with the theoretical amount of Ac2O until solution was obtained. A variety of aldehydes was used although the product from salicyl aldehyde was the most interesting. AcOC6H4CH:C.N:CMe.O.CO (II) → HOC3H4CH:C(NHAc)CO2H (III) → O.C6H4.CH:C(NHAc).CO (IV). II on treating with alkali and subsequent acidification forms the transient III which quickly passes over to IV. Detailed exptl. data are given.
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Reference:
Benzisoxazole – Wikipedia,
Benzisoxazole – an overview | ScienceDirect Topics