Water → HCID 18943088, compound

Participants

Reaction Steps

The ester of Example 15, tris(8-methoxycarbonyl-2,2,6,6-tetramethyl-benzo[1,2-d:4,5-d']bis(1,3)dioxole-4-yl)methanol (0.30 g, 0.34 mmol) was dissolved in MeOH (10 mL), and NaOH (0.041 g, 1.02 mmol) dissolved in MeOH/H2O (2.32M NaOH solution) was added until pH reached 7. In total 0.44 mL of the basic solution was used. The MeOH was evaporated in vacuum due to solubility problems and THF (3.5 mL) was added. The reaction mixture cleared with this treatment. After 12 h the reaction mixture was turbid and a precipitate had formed. This precipitate dissolved with the addition of water (10 mL). The THF was evaporated under reduced pressure and water (10 mL) was added and the aqueous phase was extracted with ether (10 mL). The organic phase was separated and the aqueous phase was acidified (pH 3.5) with 2M HCl. A yellow precipitate was formed and the aqueous phase was extracted with ether (3×20 mL) and CH2Cl2 (30 mL). The organic phases were collected, dried (Na2SO4) and the solvent was evaporated to yield the product tris(8-carboxy-2,2,6,6-tetramethyl-benzo[1,2-d:4,5-d']bis(1,3)dioxole-4-yl)methanol as a slightly tanned residue (0.25 g, 87%). The product contained a small impurity (appreciated to about 2% at the same extinction) according to HPLC (C18, ion pair (tetrabutyl-ammonium acetate) chromatography, CH3CN:H2O) with UV (254 nm) detection.

Provenance & Evidence