Malonic Acid → 3-Methyl-2-nitrocinnamic acid

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Reaction Steps

3-Methyl-2-nitrobenzaldehyde, prepared according to Berichte, 47, 406, is reacted with malonic acid in pyridine with the addition of piperidine to give 3-methyl-2-nitrocinnamic acid; yield 64% of theory; m.p. 230°-235° C., after recrystallisation from methanol. After hydrogenation thereof in aqueous sodium hydroxide solution in the presence of palladium catalyst, 2 mole of acetic anhydride are added thereto and the reaction product is purified on an Amberlite IR-120 column (H+ form). There is thus obtained, in a yield of 75% of theory, 3-(2-acetylamino-3-methyl-phenyl)-propionic acid; m.p. 110° C. sinters, 117°-120° C. This is then reacted with phosphorous acid/phosphorus trichloride analogously to Example 16.

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