作者:Chicheng Ma、Mark G. Steinmetz、Erica J. Kopatz、Rajendra Rathore
DOI:10.1021/jo050246s
日期:2005.5.1
H2CC(OH)CON+(R)C(R‘)CH35a−c, cyclize intramolecularly to 3b or undergo intermolecular addition of water followed by tautomerization and cyclization to give 2a,c. These inter- or intramolecular trapping reactions of 5 release protons that decrease the pH and cause bleaching of the 620 nm band of the pH indicator, bromocresol green. Determination of the bleaching kinetics by laser flash photolysis methods in the case
在水性介质中,α-酮酰胺LGCH 2 COCON(R)CH(R')CH 3(1a,R = Et,R'= H; 1b,R = iPr,R'= Me; 1c中,R =苯基,R” = H)与在C-3位置上的各种羧酸酯的离去基团(LG)经历光裂解,并用形成非对映5- hydroxyoxazolidin -4-酮的羧酸的释放2A,Ç在的情况下在1b的情况下,为1a,c或5-亚甲基恶唑烷丁-4-酮3b。对于1a,b,Φ(光解)= 0.24-0.38,而Φ(光解)= ca. 0.05 1C。拟议的机制涉及将氢从N-烷基转移至酮氧以生成两性离子中间体4a - c消除羧酸根阴离子。生成的亚胺离子H 2 C C(OH)CON +(R)C(R')CH 3 5a - c分子内环化成3b或在分子间加水,然后互变异构化和环化生成2a,c。这些5个分子间或分子内的捕获反应释放质子,这些质子降低pH值并导致pH指示剂溴甲酚绿的620