Cinnamic acids Carboxy

After 15 hours standing, 15.0-16.8 g. of crude o-carboxy-cinnamic acid may be recovered by filtration, washing, and drying. 

The filtrate, either on concentration under reduced pressure or upon dilution with water, fails to yield more o-carboxy cinnamic acid, but a crystalline by-product, presumably 4-(o-carboxy-phenyl)-5,6-benzocoumarin,2 may be encountered in small yield. 

B. (3-(o-Carboxyphenyl)propioniG acid. In an open 1-1. widemouthed round-bottomed flask are placed 18 g. (0.094 mole) of o-carboxy cinnamic acid and 550 ml. of 10% sodium hydroxide solution. The mixture is warmed to 90° (Note 8) on a steam bath and stirred mechanically. The steam bath is then removed while 54 g. (Note 9) of nickel-aluminum alloy (Raney catalyst) powder is added through the open neck of the flask in small portions (from the end of a spatula) at frequent intervals (Note 10). When addition of the alloy is complete (about 50 minutes), the mixture is stirred and maintained at 90-95° for 1 hour by warming on a steam bath. Distilled water is added as needed to maintain the total volume at approximately 550 ml. The hot mixture is filtered with suction, and the metallic residue is washed with 50 ml. of hot 10% sodium hydroxide solution and two 50-ml. portions of hot water in such a manner that the solid is always... 

Using less than 50 g. of the alloy results in the same yield of final product, which, however, contains small amounts of unchanged o-carboxy cinnamic acid. Equally good results are obtained when proportionately smaller quantities of reactants are used. 

Hydroxyamic acids m-Carboxy cinnamic acid bishydroxamic acid (CBHA) Apoptosis, differentiation, and cell cycle arrest... 

In a similar approach, a pretuned glass encased microchip set to emit a unique binary code is placed in a polypropylene tea bag loaded with polystyrene beads. Using a modified split synthesis approach, a 125-membered tripeptide library N-capped as the /r-carboxy-cinnamic acid amide was prepared on Rink resin. Each porous reactor contained a radio frequency transporter which successfully defined the structure of two inhibitors of protein tyrosine phosphatase [37],... 

The olive mesocarp contains a number of phenolic and polyphenolic compounds and their esters, small amounts of which are present in olive oil (35, 43, 44). These include monohydroxy- and dihydroxy-phenylethanol, including tyrosol and other phenols and a series of carboxy-phenols, including caffeic, o-coumaric, p-coumaric, cinnamic, ferulic, gallic, p-hydroxybenzoic, protocatechuic, sinapic, syringic, and vanillic acids. Benzoic and cinnamic acids are produced by hydrolysis of flavonoids. The hydroxyphenyl-ethanols arise from hydrolysis of oleoeuropein. Their esters are responsible for the bitterness and pepperlike sensation occasionally dominant in the taste of olive oils. 

The next higher homologous side-chain carboxyl acid is the one in which the side chain has three carbon groups, CeHs—CH2—CH2— COOH. It is, therefore, beta-phenyl propionic acid or i-carboxy 2-phenyl ethane. It is commonly known as hydrocinnamic acid because of its relation to cinnamic acid as the hydrogenated or reduction product. In the aliphatic series we have two acids, one, propanoic acid or propionic acid, the other propenoic acid or acrylic acid. They are related to each other as corresponding saturated and unsaturated compounds (p. 172). The latter, acrylic acid, yields propionic acid on reduction by the addition of two hydrogen atoms and the conversion of the unsaturated chain into a saturated one. 

The tropane alkaloids commonly occur as esters of tropic acid [as 6.67) and tiglic acid [as 6.75) The former acid arises preferentially from phenylalanine possibly via cinnamic acid and the entire carbon skeleton is involved. The results of C-labelling studies show that, in the rearrangement which occurs during biosynthesis, it is the carboxy group which migrates (see Scheme 6.18). Proof of an... 

The side-chain carboxy acids which we have studied are phenyl acetic, phenyl propionic or hydrocinnamic, phenyl acrylic or cinnamic and phenyl propiolic. Phenol derivatives of all of these are known. Hydroxy phenyl acetic acid is not important. 

The synthesis of pyridazine derivatives from hydrazones includes the thermal cyclization of 2-arylhydrazono-3-oxo-5-phenyl-4-pentenenitriles (readily obtained from ethyl cinnamate by condensation with acetonitrile followed by Japp-Klingemann type reactions) to l-aryl-3-cyano-6-phenyl-5,6-dihydro-4(l//)-pyridazinones (Scheme 85) <86JHC93>, and base-induced cyclization of a hydrazone of a 4-chloro-l-arylbutan-l-one to prepare a 2,3,4,5-tetrahydropyridazine (Scheme 85) <88JHC1543>. An earlier route to 6-carboxy-5-hydroxy-2-phenyl-3(2//)-pyridazinone via condensation of benzenediazonium chloride and dimethyl acetonedicarboxylate has been adapted to give a series of aryl derivatives either as esters (by thermal cyclization) or as acids (by cyclization with hydroxide). Both cyclizations proceed in high overall yield (Scheme 86) and decarboxylation of the acids also proceeds in high yield <89JHC169>. 

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