2,3-Butanediol, 2,3-dimethyl- 2,3-Dimethyl-2,3-butanediol 76-09-5 NSC25943 Pinacol Pinacone Tetramethylethylene glycol WLN: QX1&1&XQ1&1 meso-2,3-Dimethyl-2,3-butanediol