Glucose is transformed enzymetically to Pyruvic acid(CH3COCOOH) by the biochemical process called "Glycolysis". The formed pyruvic acid(pyruvate) is reduced in muscules by NADH into the enzyme lactatedehydrogenaze to lactic acid:
C3H4O3 + NADH + H+ ? CO2 + C2H5OH + NAD+
Chemically at lab you may obtain pyruvic acid by thermal pyrolysis of tartaric acid and then you may reduce it to lactic acid by using many reducing agents. Its interesting what such could be proposed