Hydrochloric Acid → 2-[3-(4-Chlorophenyl)-1,2-benzoxazol-7-yl]propanoic acid

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Reaction Conditions

Reaction Steps

n-Butyl lithium (31ml, 46m Mole of 1.5M) was cooled to -30°C under nitrogen with stirring and treated with a solution of diisopropylamine (6.25 ml. 4.65g., 46m Mole) in tetrahydrofuran (38ml) keeping the temperature at -30° to -50°C. A solution of the acetic acid of Example 35 (4.5g, 15.64m Mole) in THF (38ml) and hexamethylphosphoramide (38ml) was added dropwise to the Bu Li solution and the solution stirred at -30° to -40°C for 1.5 hours. It was then transferred to a solution of methyliodide (150ml) which was stirred and had been cooled to 5° C. in an ice bath. The mixture was stirred in the melting ice bath for 1.5 hours, acidified with a little conc. HCl, evaporated to small bulk and treated with water (500ml). The mixture was extracted with chloroform which was dried (Na2SO4) and evaporated to leave the α-methyl acetic acid as a mixture with its methyl ester. This was refluxed with conc. HCl (60ml) and acetic acid (30ml) for four hours, diluted with water, extracted with chloroform, which was dried (Na2SO4), evaporated to leave a gum which was purified on preparative thin layer chromotography to give the α-methyl acetic acid (0.85g), m.p. 136°-138°C.

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