Glycosylated nitrogen mustard derivatives
1951
the range 8–10. The reaction was stirred at room temperature for 8 h while being
monitored by TLC. After reaction completion, the mixture was separated. The
organic layer was washed with HCl (0.1 mmol L-1) and saturated brine, dried over
Na2SO4, and evaporated. The product was further purified by flash chromatography
on silica gel as needed, and a slightly yellowish, fragrant syrup was obtained. MS
m/z: 500.9 [M-18]?. IR (KBr)/cm-1: 3,600–3,400 (mO–H), 2,966 (mC–H), 1,739
(mC=O), 1,441 (mC–N), 1,300–1,041 (mC–O–C), 763 and 670 (mC–Cl).
Synthesis of fructose-nitrogen mustard (FNM)
Fructose (0.5402 g, 3.0 mmol) in water (10 mL) and 0.6120 g (3 mmol) BCC in
CH2Cl2 (20 mL) were mixed in a flask, and triethylamine was added to keep pH in
the range 8–10. The reaction was stirred at room temperature overnight. After
reaction completion, the aqueous solution was removed. The organic layer was
washed with HCl (0.1 mmol L-1) and saturated brine, dried over Na2SO4, and
evaporated. The terminal product was purified by flash chromatography on silica
gel, and a yellowish, fragrant syrup was obtained. MS m/z: 317 [M-CH2OH]?.
IR (KBr)/cm-1: 3,660–3,485 (mO–H), 2,966 (mC–H), 1,731 (mC=O), 1,466 (mC–N),
1,300–1,041 (mC–O–C), 767 and 671 (mC–Cl).
Synthesis of lactose-nitrogen mustard (LNM)
A mixture containing 0.5400 g (1.5 mmol) lactose in water (10 mL) and 0.6120 g
(3 mmol) BCC in CH2Cl2 (20 mL) was adjusted to alkaline (pH in the range 8–10)
using triethylamine. After stirring for 24 h at room temperature, the mixture was
separated. The organic layer was washed with HCl (0.1 mmol L-1) and saturated
brine, dried over Na2SO4, and evaporated. The result was purified like GNM, and a
yellow oil with unpleasant smell was obtained. MS m/z: 680.7 [M]?. IR (KBr)/
cm-1: 3,485 (mO–H), 2,962 (mC–H), 1,748 (mC=O), 1,433 (mC–C, mC–N), 1,300–1,200
(mC–O–C), 767, 661 (mC–Cl).
Interaction of BSA with GNM, FNM, and LNM
Stock solution of BSA (6 lM) in aqueous Tris-HCl buffer solution (100 mL) of pH
7.4 was prepared, while stock solutions of the products were prepared in dehydrated
alcohol because of their lower solubility in water. For interaction studies with
protein, 3.0 mL aqueous solution of BSA (6 lM) was titrated with various
concentrations of the compounds ranging from 0 to 70 lL; the total volume of
alcohol did not exceed 100 lL. The presence of 100 lL alcohol did not induce
major structural changes in BSA. Each solution was mixed thoroughly before
spectral measurements at room temperature.
Fluorescence measurements were taken by exciting the protein solution at
288 nm. An excitation wavelength of 288 nm was applied to selectively excite
tryptophan residues in protein.
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