Ethyl Acetate → HCID 53771611, Verbindung

Beteiligte Stoffe

Reaktionsschritte

A solution of 14.3 g. of 3-(4-chlorobenzoyl)-2-methylpropionic acid (Example 47), 7.26 g. of N-hydroxysuccinimide and 13 g. of dicyclohexylcarbidiimide in 150 ml. of dioxane is allowed to stir at room temperature overnight and is then filtered. The filtrate is concentrated at reduced pressure and taken up in 100 ml. of water containing 7.25 g. of L-proline and 10.58 g. of sodium bicarbonate. The mixture is stirred at 25°-35° overnight and filtered through celite. The filtrate is concentrated to remove the ethanol. Concentrated hydrochloric acid is added and the mixture is extracted several times with dichloromethane. The extracts are washed with water and dried (Na2SO4). Evaporation of the solvent yields an amber gum which is dissolved in ethylacetate. Hexane is added, causing white crystals to separate. Recrystallization from ethylacetate gives colorless needles, m.p. 177.5-179.5, labeled isomer A. The preceding compound is brominated as in Example 20 and the product reacted with potassium thioacetate in ethanol-water as in Example 21 to give the product of the Example as a glass.

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