L-Pyroglutamic Acid → tetrabutylphosphonium (S)-(-)-2-pyrrolidone-5-carboxylate

Participants

Reaction Steps

At 0° C., 4.2 g of (S)-(−)-2-pyrrolidone-5-carboxylic acid (by Wako Pure Chemical Industry) was added to 21.3 g of tetrabutylphosphonium hydroxide (aqueous 41.4% solution, by Hokko Chemical), and stirred for 10 minutes. Using an evaporator, the pressure was reduced to 40 to 50 mmHg, and this was concentrated at 60 to 80° C. for 2 hours, and then at 90° C. for 3 hours. Thus, 13.3 g of tetrabutylphosphonium (S)-(−)-2-pyrrolidone-5-carboxylate (purity: 94.1%) was obtained as an oily compound. The obtained ionic liquid had the same properties as in Production Example 1.

Provenance & Evidence