P-Benzoylpropionic acid

Y-Phenylbutyric acid. Prepare amalgamated zinc from 120 g. of zinc wool contained in a 1-litre rovmd-bottomed flask (Section 111,50, IS), decant the liquid as completely as possible, and add in the following order 75 ml. of water, 180 ml. of concentrated hydrochloric acid, 100 ml. of pure toluene (1) and 50 g. of p benzoylpropionic acid. Fit the flask with a reflux condenser connected to a gas absorption device (Fig. II, 8, l,c), and boil the reaction mixture vigorously for 30 hours add three or four 50 ml. portions of concentrated hydrochloric acid at approximately six hour intervals during the refluxing period in order to maintain the concentration of the acid. Allow to cool to room temperature and separate the two layers. Dilute the aqueous portion with about 200 ml. of water and extract with three 75 ml. portions of ether. Combine the toluene layer with the ether extracts, wash with water, and dry over anhydrous magnesium or calcium sulphate. Remove the solvents by distillation under diminished pressure on a water bath (compare Fig. II, 37, 1), transfer the residue to a Claisen flask, and distil imder reduced pressure (Fig. II, 19, 1). Collect the y-phenylbutyric acid at 178-181°/19 mm. this solidifies on coohng to a colourless sohd (40 g.) and melts at 47-48°. 

Friedel-Crafts Acylation. The Friedel-Crafts acylation procedure is the most important method for preparing aromatic ketones and thein derivatives. Acetyl chloride (acetic anhydride) reacts with benzene ia the presence of aluminum chloride or acid catalysts to produce acetophenone [98-86-2], CgHgO (1-phenylethanone). Benzene can also be condensed with dicarboxyHc acid anhydrides to yield benzoyl derivatives of carboxyHc acids. These benzoyl derivatives are often used for constmcting polycycHc molecules (Haworth reaction). For example, benzene reacts with succinic anhydride ia the presence of aluminum chloride to produce P-benzoylpropionic acid [2051-95-8] which is converted iato a-tetralone [529-34-0] (30). 

Beckmann rearrangement of, 729,741 p-Benzoquinone, 745 Benzoylacetone, 865 o-Benzoylbenzoic acid, 728, 739 Benzoyl chloride, 791, 792 Benzoyl glycine, 584 Benzoyl peroxide, 807 determination of, 809 Benzoyl piperidine, 489, 492 P-Benzoylpropionic acid, 728, 737 P-Benzoylpropionitrfle, 911, 912 Benzoyl-p-toluidide, 582, 583 Benzyl acetate, 780, 783 Benzylacetophenone, 726, 734 Benzyl alcohol, 706,711, 811,812,884 N-Benzylamid es 394 table of, 395 ... 

Problem 16.73 Give steps for the following preparations (phenylpropionic acid, (6) p benzoylpropionic acid from benzene and succinic acid. -4... 

Blocking of OH-groups fi-Benzoylpropionic acid. p-Nitrophenyl chloroformate. 

Hydroxyl group Adamantane-l-carboxylic acid chloride. 0-Benzoylpropionic acid. Ethyl vinyl ether. 4-Methoxy-5,6-dihydro-2H-pyrane. p-Nitrophenyl chloroformate. 

Leaflets -f- IILO. M.p. 64°, anhyd. 99°. Sol. EtOH, EtjO, hot HjO. Hot alkalis —> acetophenone +.glyoxylic acid. Red. —2-benzoylpropionic acid. 

See Styrylglyc c Acid, p-Hydro3 tyryl-acetic Acid and 2-Benzoylpropionic Acid. 3-Hydroxyphthalic Acid... 

Preparation of N-Hydroxysuccinimide Esters. For the synthesis of the iV-hydroxysuccinimide esters of 3-(4-benzoylphenyl)propionic acid and 3-benzoyIpropionic acid, the method of Rappaport and Lapidot has been modified. 3-(4-Benzoylphenyl) propionic acid (765 mg, 3 mmoles) or 3-benzoylpropionic acid (534 mg, 3 mmoles) and Af-hydroxysuccinimide (345 mg, 3 mmoles) are suspended in dry ethyl acetate (6 ml) and cooled in ice. Dicyclohexylcarbodiimide (618 mg, 3 mmoles), dissolved in ethyl acetate (2 ml), is added under stirring. After 15 min in ice, the mixture is allowed to warm to room temperature and stirring is continued for 2 hr. Dicyclohexylurea is removed by filtration with suction and washed with ethyl acetate (20 ml). The combined filtrate is evaporated to dryness under reduced pressure (under 40°). The residue is crystallized from methanol. Yield 3-(4-benzoylphenyl)propionic acid A -hydroxysuccini-mide ester 810 mg (72%), m.p. 114°-115° 3-benzoylpropionic acid N-hydroxysuccinimide ester 540 mg (65%), m.p. 132°-134°. 

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