Table 15: 13C NMR Data for 7a; chemical shifts in ppm relative to TMS(1%) at room temperature in CDCl3.

      Piperazine Piperazine      
No. X Aromatic I II CH2(Ⅰ) CH2(Ⅱ) X
    153.6,139.5,          
7a p-CO2CH3 130.1, 128.2 51.4 (a) 59.6 33.2 51.9(OMe)
    127.9,126.7,         166.5(C=O)
    125.7, 119.9        

(a) not detected