3-Phenylpropan acid

Preparation 298.—Phenylsulphopropionic Acid [2-Sulphonic acid of Z-phenylpropan acid] (K salt). 

A widespread alkaloid family is made up of phenylalanine-tyrosine derivatives. These amino acids are precursors of a variety of compounds alkaloids, flower pigments, phenylpropane acids, lignins, etc. In most cases, deamination is the first reaction, but sometimes decarboxylation, O-methylation, or A-methylation occurs. The resultant protoalkaloids can be transformed into an impressive number of alkaloids. In closely related orders, e.g., Ranales, Berberidales, Aristolochiales, and Rhoeadales, the commonly synthesized compound is norlaudanosoline, and it acts as a precursor for all alkaloids in these plants. In some orders such as Aristolochiales, the alkaloids can be converted into compounds that do not give an alkaloid-positive reaction. Another group of plants with tyrosine- and phenylalanine-derived alkaloids are the Amaryllidaceae and related taxa. 

Herbicides also inhibit 5- (9/-pymvylshikiniate synthase, a susceptible en2yme in the pathway to the aromatic amino acids, phenylalanine, tyrosine and tryptophan, and to the phenylpropanes. Acetolactate synthase, or acetohydroxy acid synthase, a key en2yme in the synthesis of the branched-chain amino acids isoleucine and valine, is also sensitive to some herbicides. Glyphosate (26), the sulfonylureas (136), and the imida2oles (137) all inhibit specific en2ymes in amino acid synthesis pathways. 

Barton and co workers have explored the aryladon of various nucleophiles inclndmg nitroalkanes using bismuth reagents Reacdon of 2-nitropropane v/ith triphenylbismnth carbonate gives 2-nitro-2-phenylpropane in 80% yield Recently, this aryladon has been used for the synthesis of unusual amino acids Aryladon of ct-nitro esters v/ith triphenylbismnth dichloride followed by redncdon gives unique ct-amino acids fEq 5 68 ... 

To 5.4 mmol of LDA, prepared in 25 mL of diethyl ether from diisopropylamine and 2 M butyllithium in hexane, are added 847 mg (5.00 mmol) of 2-(trimethylsilyloxy)-3-pentenenitrile in 10 mL of diethyl ether at — 78 "C. After stirring for 45 min, 671 mg (5.00 mmol) of 2-phenylpropanal, dissolved in 10 mL of diethyl ether are added. After stirring for 2 h at — 78 X, 1.20 g (10.5 mmol) of trifluoroacetie acid are added carefully to the mixture at below —70CC. 15 mL of sat. aq NH4C1 and then diethyl ether are added and the reaction mixture is allowed to reach r.t. The phases are separated and extracted with aq NH,CI and... 

Hydroxyphenylpyruvic acid plays an important role in the biogenesis of compounds with a phenylpropane skeleton, and it has been used as substrate in several enzyme studies. Published procedures for its preparation are unsatisfactory in many ways. The alkaline hydrolysis of the azlactone of a-bcnzoylamino- -acetoxycinnamic acid 7 makes necessary a tedious separation of the resulting benzoic acid, and the yield is only 34% based on -hydroxybenzaldehyde. The hydrolysis of 5- ( -hydroxybenzal)-3-phenylhydantoin 9 requires a separation of phenylurea. Finally, the two-step cleavage of the azlactone of a-acetamino- -acetoxycinnamic acid 8 does not proceed easily, and impure products are obtained. In applying this procedure to the synthesis of a carboxyl-labeled -hydroxyphenylpyruvic acid, the overall yield was only 9%.u It must be kept in mind that any prolonged isolation procedure will cause some decomposition of this sensitive compound. 

Autoxidation may in some cases be of preparative use thus reference has already been made to the large-scale production of phenol+ acetone by the acid-catalysed rearrangement of the hydroperoxide from 2-phenylpropane (cumene, p. 128). Another example involves the hydroperoxide (94) obtained by the air oxidation at 70° of tetrahydro-naphthalene (tetralin) the action of base then yields the ketone (a-tetralone, 95), and reductive fission of the 0—0 linkage the alcohol (a-tetralol, 96) ... 

Several Pd11 complexes with thiolate or thioether derivative ligands have been studied to be applied in the hydroxycarbonylation reaction.394 Aminothiolate complexes of palladium with PPh3 catalyze the conversion of styrene to 2-phenylpropionic acid in high yield and excellent regioselectivity.644 Under mild conditions and in the presence of a catalytic amount of an S, TV-chelated palladium or//zo-amino-arenethiolate complex, styrene reacts with CO and oxalic acid or water to selectively give 2-phenylpropanic aid in high yield.645... 

Chemat et al. have reported several microwave reactors, including systems that can be used in tandem with other techniques such as sonication [68], and ultraviolet radiation [69]. With the microwave-ultrasound reactor, the esterification of acetic acid with n-propanol was studied along with the pyrolysis of urea. Improved results were claimed compared with those from conventional and microwave heating [68]. The efficacy of the microwave-UV reactor was demonstrated through the rearrangement of 2-benzoyloxyacetophenone to l-(2-hydroxyphenyl)-3-phenylpropan-l,3-dione [69]. 

Lignin may be defined as the incrusting material of the plant which is built up mainly, if not entirely, of phenylpropane building stones it carries the major part of the methoxyl content of the wood it is unhydrolyzable by acids readily oxidizable, soluble in hot alkali and bisulfite, and readily condenses with phenols and thio compounds (14). 

Acetohydrazide, 0912 Acetone oxime, 1258 Acetylenedicarboxylic acid, 1405 Acrylaldehyde, 1145 f Allyl acetate, 1912 A-Ally lthiourca. 1600 4-Aminophenylazobenzene, 3487 Ammonium dichromate, 4246 Ammonium peroxodisulfate, 4576 4-Azidobenzaldehyde, 2697 2-Azido-2-phenylpropane, 3159 f Aziridine, 0863 Azobenzene, 3483 Azoformamide, 0816 Azoisobutyronitrile, 3011 Azoxybenzene, 3485 Benzaldehyde oxime, 2760... 

Examples of the so-called chaperon effect involving interaction between the electrophile and an appropriate substituent at the a-position in an alkyl chain prior to ring substitution at the ortAo-position have been explored in nitrations involving dilute solutions of nitric acid in dichloromethane. Aldehydic or ketonic carbonyl groups are most effective, but carboxyl, alkoxycarboxyl, and amide groups also work well. l-Phenylpropan-2-one, for example, forms 85% of l-(2-nitrophenyl)propan-2-one (5). 

Phomopsis sp. strain endophytes of the medicinal plant Erythrina crista-galli continue to yield novel compounds (Table 1). New phenyl-propane, pyronol, benzoic acid, phenylpyran, macrocyclic, and alkene compounds were discovered, as well as the known compounds clavatol, 4-hydroxymellein, mellein, mevalonolactone, mevinic acid, nectriapyrone, phomol, scytalone, and tyrosol. The new compounds were phomopy-ronol (101), 3-phenylpropane-l,2-diol (102), 4-(2,3-dihydroxypropoxy) benzoic acid (103), 2-(hydroxymethyl)-3-propylphenol (104), 2-... 

Dextroamphetamine Dextroamphetamine, D-2-amino-l-phenylpropane (8.1.2.2), is synthesized by various methods. One of them consists of uses of the Leucart reaction, in particular, the reaction between methylbenzylketone and ammonium formate, giving the formamide (8.1.2.1), which is hydrolyzed to 2-amino-1-phenylpropane (8.1.2.2) by hydrochloric acid [1]. An analogous method has been suggested using formamide instead of ammonium formate [2]. 

Amino-l-phenylpropane (8.1.2.2) is also synthesized in a Hofmann reaction from a-benzylpropionic acid amide [4,5]. 

No loss of optical purity was observed in the mild acidic hydrolysis of the enantiomerically pure 6-alkoxy -phenyl-5,6-dihydro-4/7-l,3-oxazine 132, which resulted in formation of (R)-3-benzoylamino-3-phenylpropanal 133 in excellent yield (Scheme 20). Hydrolysis of the analogous tetrahydro-l,3-oxazin-2-one 134 to 133 required a stronger acidic medium and took place only in poor yield, but without any decrease in the optical purity <20000L585, 2003JOC4338, 2004TL9589>. 

---