Ethanol → ethyl 3,3,3-trifluoro-2-hydroxypropanoate

The step (b) of the present invention was conducted as follows. At first, 2.84 g of the crude product obtained by Example 1 (containing 16.07 mmol (1.00 eq.) of 3,3,3-trifluoro-2-hydroxypropionic acid) and 19.6 mg (0.20 mmol, 0.01 eq.) of 98% sulfuric acid were added to 20 ml of ethanol, followed by stirring for 43 hr with heating under reflux. The resulting reaction liquid itself was subjected to a vacuum distillation (52° C./3,500 Pa), thereby obtaining 1.87 g of white, needle-like crystals of ethyl 3,3,3-trifluoro-2-hydroxypropionate of the following formula 8. The yield was 68%. The obtained crude product (the white, needle-like crystals) was used in the following step (c) of Example 3 without conducting a further purification.