DRX-400 MHz spectrometer (400 and 101 MHz, respectively) using CDCl3 or DMSO-d6 as solvents with TMS
as an internal standard. Chemical shifts were reported as d (ppm),
and spin–spin coupling constants were reported as J (Hz) values. The mass spectra (MS) were recorded on a Finnigan MAT-95
mass spectrometer. Column chromatography was performed with silica
gel (200–300 mesh).
SAHA was synthesized before. SN-38
was purchased from Shanghai Puyi Chemical Co., Ltd. Di-tert-butyl dicarbonate ((Boc)2O), 4-dimethylaminopyridine
(DMAP), 1,1′-carbonyl-diimidazole (CDI), and N,N′-diisopropylcarbodiimide (DIC) were all
purchased from Energy Chemical Reagent Co. ( Shanghai, China). The
different amino acids were purchased from Meryer Chemical Reagent
Co. (Shanghai, China). CH2Cl2 was dried and
redistilled before use. All chemical reagents used were of analytical-grade
quality. Mouse plasma was taken from KM mouse (male, 6 weeks old).
Human plasma was donated by an adult man.