Sodium Hydroxide → HCID 20319604, compound

Participants

Reaction Steps

2-[2-(3,4-dichlorobenzyl)-5-benzoxazolyl]propionic acid. (g) 2N-Sodium hydroxide solution (30 ml.) was added to the ethyl ester (5.8 g.) prepared in Example 1(g) in ethanol (40 ml). After 2 hours stirring at room temperature the volume was reduced by evaporation at 40° C and the solution diluted with water (120 ml.). It was then extracted with ether (x2) acidified with concentrated hydrochloric acid and then extracted with chloroform (x3). The combined chloroform extracts were washed with water, dried over anhydrous sodium sulphate and evaporated to give an oil. This oil was purified using prep. tlc plates to give 2-[2-(4-chlorobenzyl)-5-benzoxazolyl]propionic acid, m.p. 135°-7° C, which was characterised by IR, UV and NMR spectroscopy and by micro analysis which gave C 64.41% H 4.71% N 4.57% C17H14Cl NO3 requires C 64.66% H 4.44% N 4.44% (h) A mixture of ethyl 3-amino-4-hydroxy-phenyl-propionate (4 g.), 4-fluoro-phenyl-acetic acid (3 g.), p-toluene sulphonic acid (0.1 g.) and xylene (50 ml.) was heated under reflux for 20 hours and the water which formed was removed using a Dean and Stark apparatus. The solution was evaporated to dryness and the residue dissolved in ether. The solution was washed with 2N-sodium hydroxide solution (x2) and water, then stirred with charcoal and anhydrous sodium sulphate, filtered and evaporated to dryness. The residual oil (3.7 g., ND22.5 1.5469) was dissolved in ethanol (30 ml.) and 2N-sodium hydroxide solution (30 ml) was added with stirring over 15 minutes. The reaction mixture was stirred for 21/2 hours during which time water (250 ml) was slowly added. The solution was extracted with ether (x2), acidified with concentrated hydrochloric acid and then extracted with ether (x3). These ethereal extracts were washed with water, dried over anhydrous sodium sulphate and evaporated to give an oil. This oil was purified using prep. tlc plates to give 2-[2-(4-fluorobenzyl)-5-benzoxazolyl]propionic acid as a white solid, mpt 91°-93° C, which was characterised by IR UV and NMR spectroscopy and by microanalysis which gave C68.40% H 3.86% N 4.64% C17H14FNO3 requires C 68.23% H 4.68% N 4.68% (i) 2,6-Dichloro-phenyl-acetic acid (15.1 g.) was added portionwise with warming to thionyl chloride (30 ml.). The solution was heated on a steam bath for half an hour then allowed to stand at room temperature for 21/2 hours. The excess of thionyl chloride was removed by distillation under reduced pressure and the residue was distilled to give the acid chloride as a colourless oil, bpt 149°-150°/15 mm.

Provenance & Evidence