2,3-Diphenylpropionic acid

The first 5-isoxazolidinone was synthesized in 1912 by the cyclization of a-hydroxylamino-/3,/3-diphenylpropionic acid (62HC(l7)l,p. 7). The ester (541) underwent an intramolecular Michael cyclization to produce 2-methyl-3-phenyl-5-isoxazolidinone (542) (78TL3985). 

An identical preparation using potassium amide instead of sodium amide gave ,(3-diphenylpropionic acid in 57% yield. 

The present procedure illustrates the use of dianions for alkylation and gives o ,(3-diphenylpropionic acid more conveniently and in better yield than previous preparations. 

M. Raschak, H. Riechers, L. Unger, Discovery and synthesis of (S)-3-[2-(3,4-dimethox-yphenyl)ethoxy]-2- (4,6-dimethylpyrimidin-2-yloxy)-3,3-diphenylpropionic acid (LU 302872), a novel orally active mixed ETa/ETb receptor antagonist, J. Med. Chem. 42(1999) 3026-3032. 

Diphenylpropionic acid Thionyl chloride Diethylaminoethanol Diphen (CIS prep.)... 

After removal of the ether by distillation, the residue is distilled in a vacuum. a,a-Diphenylpropionic acid p-diethylaminoethyl ester is obtained as a thick oil by distilling under 2 mm pressure at 180°-185°C. It is readily soluble in diluted acids. 

To a solution of P,p-diphenylpropionic acid (2 mmol) in CHC13 (8 ml) were added oxalyl chloride (1.5 g) and DMF (one drop). After stirring for 1 h, the solvent and excess oxalyl chloride were removed. The residue was dissolved in CHC13 (6 ml) and then Af-hydroxy-2-thiopyridone (2.2 mmol) was added to the mixture under a nitrogen atmosphere at 0 °C. 

Methoxy-6-methyl-2-pyrimidinyloxy)-3-(2-(3,4-dimethoxyphenyl)-ethoxy)-3,3-diphenylpropionic acid... 

Subsequent industrial processes for preparing tropenol using dimethylformamide, dimethylacetal, meteloidin (3), 2,2-diphenylpropionic acid, and scopine ester-metho-bromide (4) are described. 

Quantification. Gas Chromatography. In urine 3-cyano-3,3-diphenylpropionic acid, sensitivity 600ng/ml, AFID—H. H. van Rooy et al., J. Chromat., 1978,148,447 52. 

Disposition in the Body. Absorbed after oral administration. It is metabolised by hydrolysis to 3-cyano-3,3-diphenylpropionic acid and 1,3-dihydro-1 -(piperidin-4-yl)benzimidazol-2-one which are excreted in the urine. 

A palladium catalyst has been used for the quantitative hydrogenation of /8,/S-diphenyIacrylic acid to /S,yS-diphenylpropionic acid. ... 

A solution of 50 g. (0.34 mole) of cinnamic acid in 600 ml. of benzene is cooled to 10 and stirred while 20 g. (0.15 mole) of powdered anhydrous aluminum chloride is added. The mixture is agitated and held in the temperature range 10-15° for 12 hours, during which time an additional 80 g. (0.60 mole) of aluminum chloride is added in 4 or 5 portions. The mixture is added to a solution of 1 1. of water and 200 ml. of concentrated hydrochloric acid. The excess benzene is removed by steam distillation, and the remaining solid material is Altered off. The solid is mixed with 2 I. of water, heated to boiling, and Altered. The remaining solid is dissolved in aqueous sodium carbonate solution and, after Altration, reprecipitated by the addition of hydrochloric acid. A second treatment with boiling water as above leaves colorless crystals of y8,/8-diphenylpropionic acid, m.p. 154-155°, in 80-90% yield. 

CibH Oj, /3,/3-Diphenylpropionic acid. T37 CieHuOs, /3, 3-Diphenyl-/3-hydroxypro-... 

Cinchonidine modified catalysts, though, have been effectively used for several other enantioselective hydrogenations. Platinum-cinchonidine catalysts have been used for the hydrogenation of the a ketolactone, 36, to D-pantolactone (37) in 35% ee at complete conversion (Eqn. 14.26) while palladium-cinchonidine catalysts have been used for the enantioselective dehydrohalogenation of a,a-dichloro-2-benazapinone (38) (Eqn. 14.27) and the hydrogenation of (E) a phenylcinnamic acid (39) to (S) 2, 3-diphenylpropionic acid (40) in a 44% ee (Eqn. 14.28). ... 

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