Reaction #2779

Reaction equation

HCl

7-(tetraacetyl-β-galactosyl)-4-methylcoumarin-3-acetic acid, ethyl ester

7-(Tetraacetyl-β-galactosyl)-4-methylcoumarin-3-acetic acid, ethyl ester

KOH

→

4

Yield 60.4%

7-(β-galactosyl)-4-methylcoumarin-3-acetic acid

Yield 60.4%

Solvents

methanol

Conditions

Workup

1. 1
   Otherevaporated to dryness under reduced pressure
2. 2
   workup.DISSOLUTIONThe residue was dissolved in water (10 mL)
3. 3
   WashThe C18Sep Pack Cartridge (Waters Part No. 65910) was washed with methanol (3 mL) and water (3 mL) before the sample
4. 4
   WashThe cartridge was then washed with water (3 mL)
5. 5
   Otherto remove any salt
6. 6
   Washeluted the desired product
7. 7
   Otherevaporated under reduced pressure
8. 8
   Otherthe while solid obtained
9. 9
   Otherwas recrystallized from ethanol/water

Procedure

To a stirred solution of 7-(tetraacetyl-β-galactosyl)-4-methylcoumarin-3-acetic acid, ethyl ester (3) (422 mg, 0.712 mmol) in methanol was added 6.8M KOH (5 mL) and the solution was stirred overnight at room temperature. The solution was neutralized by the addition of 1N HCl and evaporated to dryness under reduced pressure. The residue was dissolved in water (10 mL) and desalted using C18Sep Pack Cartridges in 10×1 mL portions. The C18Sep Pack Cartridge (Waters Part No. 65910) was washed with methanol (3 mL) and water (3 mL) before the sample was applied in 1 mL. The cartridge was then washed with water (3 mL) to remove any salt followed by metahnol (3 mL) which eluted the desired product as determined by TLC (silica gel, acetone:20 mM NaOAc 9:1). The methanol washes were pooled and evaporated under reduced pressure and the while solid obtained was recrystallized from ethanol/water to give 170 mg (0.43 mmol, 60%) of 4 as white crystals: m.p. 186°-188° C.

Source