Potassium Sodium Tartrate → 4-Thiazoleethanol, 2-(4-chlorophenyl)-

Participants

Reaction Conditions

Reaction Steps

Dissolve [2-(4-chloro-phenyl)-thiazol-4-yl]-acetic acid ethyl ester (107.4 g, 381.2 mmol) in THF (800 mL) and cool to 0-5° C. Add DIBAL (1.0 M in THF, 800 mL, 800 mmol) slowly over approximately 3.5 h (somewhat exothermic) keeping the temp. <5° C. Allow the reaction to warm to room temperature with mechanical stirring overnight. Cool the reaction to 0-5° C. and slowly add more DIBAL (150 mL) over approximately 15 min keeping the temperature <5° C. Stir the reaction solution at room temperature for 2.5 b. Cool to 0-5° C. and slowly add over 5 h aqueous saturated Rochelle's salt (2900 mL, very exothermic at first, minor gas evolution) keeping the temperature <10° C. The mixture solidifies after approximately 150 mL has been added. It becomes more fluid and then solidifies again as the addition continues. Extract the mixture with EtOAc (2×3300 mL). Combine the organic layers and concentrate in vacuo to give an oil weighing 112.9 g. Take the oil up in toluene (600 mL), concentrate in vacuo and repeat. Dry the residue on a vacuum pump for 6 h to give a residue weighing 107.4 g (110% yield). MS (ES+) 240.1 (M)+. 1H NMR (400 MHz, CDCl3): δ 7.84 (dt, J=8.4, 2.2 Hz, 2H), 7.39 (dt, J=8.4, 2.2 Hz, 2H), 6.98 (s, 1H), 3.98 (m, 2H), 3.44 (bs, 1H), 3.02 (t, J=5.5 Hz, 2H).

Provenance & Evidence