Hydrochloric Acid → (Z)-3-(4-bromophenyl)-2-[[2-chloro-4-[[(3-hydroxybenzyl)amino]carbonyl]benzoyl]amino]propenoic acid methyl ester

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Reaction Steps

1,1,3,3-Tetramethylguanidine (0.047 g, 0.41 mmol) was added to a solution of rac.-N-[2-chloro-4-[[(3-hydroxybenzyl)amino]carbonyl]benzoyl]-2-(dimethoxyphosphinyl)glycine methyl ester (Example 141; 0.10 g, 0.21 mmol) and 4-bromobenzaldehyde (0.076 g, 0.412 mmol) in tetrahydrofuran (1.5 mL). Dioxane (1.5 mL) was added to bring everything into solution and the reaction mixture was stirred at room temperature for 15 h. The solution was then poured into 1N hydrochloric acid solution and the aqueous phase was extracted with ethyl acetate. The organic layer was concentrated in vacuo and the residual material was chromatographed over silica gel (45% ethyl acetate/hexanes) to give (Z)-3-(4-bromophenyl)-2-[[2-chloro-4-[[(3-hydroxybenzyl)amino]carbonyl]benzoyl]amino]propenoic acid methyl ester (69 mg, 62% yield).

Provenance & Evidence