Hydrochloric Acid → 6-[[[4-[(1-Oxo-2-propen-1-yl)oxy]butoxy]carbonyl]oxy]-2-naphthalenecarboxylic acid

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Reaction Steps

The pH of a solution of 100 g (0.53 mol) of 6-hydroxy-2-naphthoic acid in a solvent mixture of 600 ml of water and 500 ml of DMF was adjusted to 10 with 10 percent sodium hydroxide solution at 0° C. 132 g (0.61 mol) of 4-acryloyloxybutyl chloroformate (prepared according to WO 97/00600 A2) was subsequently added dropwise over a period of 2 h, in the course of which the temperature was kept between 0 and 5° C. and the pH at 10 (±0.2 pH unit) by means of 10 percent sodium hydroxide solution. The resulting solution was subsequently diluted with 3 l of water/ice mixture and the pH was adjusted to 5 with concentrated hydrochloric acid. The resulting suspension was filtered, the resulting filtercake was washed with 3 l of water and, after drying, 165.8 g (87% of theory based on the pure acrylate derivative) of a beige-colored powder were obtained, which comprises the compound NAPA shown above and the corresponding acrylate/HCl adduct.

Provenance & Evidence