3- -3-phenylpropanoic

In the example of Figure 2-5, the compound has the trivial name phenylalanine but the lUPAC name is 2-amino-3-phenylpropanoic acid, which indicates a carbon... 

Figure 2-5. Phenylalanine, also known by the lUPAC name 2-amino-3-phenylpropanoic acid.

Substitutive nomenclature (Section 4 2) Type of lUPAC nomenclature in which a substance is identified by a name ending in a suffix charactenstic of the type of compound 2 Methylbutanol 3 pentanone and 2 phenylpropanoic acid are examples of substitutive names... 

Cinnamic acid undergoes reactions that are typical of an aromatic carboxyhc acid. Using standard methodology, simple esters are easily prepared and salts are formed upon neutrali2ation with the appropriate base. Hydrogenation of cinnamic acid under mild conditions leads to 3-phenylpropanoic acid [501-52-0] whereas under forcing conditions, such as under high pressure in presence of a nickel catalyst, complete saturation to 3-cyclohexylpropanoic acid [701-97-3] is readily accompHshed (8). 

Copper(Il) complexes 18a-f of methyl or ethyl 3-oxobutanoate la, 2-bromo-3 oxobutanoate lb, 2-(anilinocarbonyl)-3-oxobutanoate Ic, 3-oxo-3- rfienylpro-panoate Id, 2-bromo-3-oxo-3-phenylpropanoate le, or 3-aniHno-2-benzoyl-3-oxopropanoate If were reacted with phenylhydrazine hydrochloride and sodium ( )... 

In the other extreme, ethyl 3-oxohexanoate 75 required fusion with 3-pyridyl-hydrazide 73a or 3-hydrazinocarbonyl-pyridine-l-oxide 73b at 120°C in order to give the corresponding pyrazol-3-ones 76a,b (92AF1350) (Scheme 22). Depending on the reaction conditions, the reaction of ethyl 3-oxo-3-phenylpropanoate 77 and cyanomethylhydrazide 78 gave different products. Thus, fusion at 140°C gave pyrazol-3-one 79 and N,A -bis(cyanoacetyl)hydrazine 80, while heating in ethanol... 

When an optically active carboxylic acid such as (jR)-2-phenylpropanoic acid is brominated under Hell-Volhard-Zelinskii conditions, is the product optically active or racemic Explain. 

One of the first examples of this type of reaction, using a chiral alcohol as an auxiliary, was the asymmetric synthesis of 2-hydroxy-2-phenylpropanoic acid (atrolactic acid, 3, R1 =C6H5 R3 = CH3) by diastereoselective addition of methyl magnesium iodide to the men-thyl ester of phcnylglyoxylie acid4,5 (Table 22). 

A solution of 3.7 g (12 mmol) of the pure (l R)-diastereomer 6 is stirred under nitrogen in 15 mL of iodomethane and 5 mL of dry DMSO for 36 h. The excess iodomethanc is evaporated leaving a viscous red oil which is heated under reflux in 25 mL of 2N KOI for 5 h. After cooling, the amino alcohol is removed from the aqueous phase by extraction with Et20. The alkaline aqueous layer is acidified with 12 N HC1 and extracted with Ei,0. The crude product is recrystallized from benzene/petroleum ether to give enantiomer-ically pure (R)-2-hydroxy-2-phenylpropanoic acid [(-)-(R)-atrolaclic acid] (7) yield 1.4 g (71%) mp U5-116X [x]25 - 38.4 (< = 2.5, EtOH). 

Using oxathiane 11, ( + )-(i )-2-methoxy-2-phenylpropanoic acid was obtained in 97% ee, however, the synthesis contains some inconvenient reaction steps. Thus, reduction of ( + )-10-camphorsulfonic acid (8) leads in low yield to a mixture of 10-mercaptoisoborneol (9 A) and 10-mercaptoborneol (9B) which must be separated by chromatography. The oxathiane 10 resists deprotonation with butyllithium and, therefore,, y -butyllithium had to be employed. Furthermore, after addition of methylmagnesium iodide, cleavage of the oxathiane moiety 12, with iodomethane did not proceed as well as with the simpler oxathianes 3. 

R = Cgll, 1,2,2-triphenyl-2-trimethyhiloxvethyl 3-hydroxy-2-methyI-3-phenylpropanoate yield 90% ( nt/-15/anr/-16/total amount of syn-isomers) 86.6 2.2 11.2... 

Alkaline hydrolysis of the crude adduct formed with benzaldehyde, followed by treatment with diazomethane and column chromatography, affords methyl (2R,3S)-3-hydroxy-2-methyl-3-phenylpropanoate in 96% ee. Reduction of the crude products formed in the reactions with 2-inethylpropanal and 2,2-dimethylpropanal leads to the corresponding 1,3-diols with >96% ee. In both the hydrolysis and the reduction procedures, the chiral auxiliary reagent, 1,1,2-triphenyl-1,2-ethanediol, can be recovered and reused72. 

The major isomer, (1 /L3/t)-2-hydroxy-l, 2,2-triphenylelhyl 3-hydroxy-3-phenylpropanoate is obtained pure after recrystallization (melhanol/water) yield 3.77g (86%) mp 178CC [a] 5 +191.4 (c = 1.1, CHC13). The crude adduct is heated with 5.0 g of potassium hydroxide, 180 mL of water, and 360 mL of methanol... 

Methyl 3-Hydroxy-2-methyl-3-phenylpropanoate Typical Procedurel06a ... 

The aldol addition of deprotonated (3-isopropyl-6-methyl-2-oxo-2-propionyl)-l,3.2-oxazaphos-phorinane 36 to benzaldehyde delivers (2f ,3/ )-3-hydroxy-2-methyl-3-phenylpropanoic acid in 47% ee via the /1-lactone 37, with syn/anti ratio of 94 6106c. 

R = C61I5 methyl 3-(2.2-[Pg.922]

A series of 2-(4-chlorophenoxy)-3-oxoalkanoate were reduced by baker s yeast, and Kluyveromyces marxianus. Yeast reduction of ethyl 2-(4-chlorophenoxy)-3-oxo-3-phenylpropanoate (R=Ph) afforded enantiomerically pure ethyl 2R, 3S)-2-(4-chlorophenoxy)-3-hydroxy-3-phenylpropanoate out of the four possible stereoisomers in >99% de [29h]. Although baker s yeast reduction of butanoate (R = CFl3) was not selective (92% de), the use of K. marxianus afforded (2R, 3S)-isomer selectively [29i]. The products are intermediates for potential peroxisome prolifera-tor-activated receptor isoform a-agonists (Figure 8.39a). 

Figure 13 Temperature effect in lipase PS-C Il-catalyzed resolution of ( )-13 with vinyl acetate ( ), vinyl butyrate ( ), and vinyl 3-phenylpropanoate (A) in...

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