作者:Ahmad Basheer、Hiroshi Yamataka、Salai Cheettu Ammal、Zvi Rappoport
DOI:10.1021/jo070877h
日期:2007.7.1
for E and Z isomeric enols. The equilibrium (KEnol) values between the amides and the enols were determined in different solvents by NMR spectra. They decrease on increasing the polarity of the solvent in the order CDCl3 ∼ C6D6 > THF-d8 > (CD3)2CO > CD3CN > DMF-d7 > DMSO-d6. For the R1R2NCOCH(CN)CONHR3 system when R1 = R2 = H, Me or R1 = H, R2 = Me, KEnol for R3 follows the order: C6F5 > Ph ≥ An ≥ i-Pr
制备了二十个开链的单,二和三烷基和芳基-N-取代的氰基马来酰胺R 2 R 1 NCOCH(CN)CONHR 3。在溶液中,尽管有E和Z异构烯醇的潜力,但大多数情况下都能观察到酰胺和单个烯醇的信号。通过NMR光谱在不同溶剂中确定酰胺和烯醇之间的平衡(K Enol)值。它们降低上增加溶剂的极性的顺序CDCL 3〜C ^ 6 d 6 > THF- d 8 >(CD 3)2 CO> CD 3CN> DMF- d 7 > DMSO- d 6。对于R 1 R 2 NCOCH(CN)CONHR 3系统,当R 1 = R 2 = H,Me或R 1 = H,R 2 = Me时,R 3的K Enol遵循以下顺序:C 6 F 5 > Ph≥一个≥我-Pr≥吨-Bu,和对于R 1,R 2:H,H>箱,H>我中,Me在所有的溶剂。当R 1 = R 2时,DMSO- d 6中的烯醇百分含量非常高= H,与带有其他吸电