3- Phenylpropynoic acid

When 3-phenylpropynoic acid was combined with perimidine in PPA at 120°C, 6-hydroxy-8-phenylbenzo[g ]per-imidine 939 was obtained <2004RJ0895>. 

Keywords 2-aminothiophenol, cinnamic acid, phenylpropynoic acid, condensation, cyclization, benzothiazepinone, benzothiazole... 

Examples of the use of alcoholic potassium hydroxide are given in Expt 5.23 for the conversion of 10,11-dibromoundecanoic acid (itself prepared from undec-10-enoic acid and bromine), into undec-10-ynoic acid, and of ethyl cinna-mate into phenylpropynoic acid. 

Cognate preparations. Phenylpropynoic acid. Place a solution of 88 g (84 ml,... 

There have been two reports involving gitonic superelectrophiles composed of carboxonium ions and vinylic carbocations in a 1,3-relationship. In the reaction of 3-phenylpropynoic acid (65) with benzene in superacid the novel carboxonium-vinyl dication 66 is generated, followed by reaction with benzene and then cyclization (eq 22).26a Likewise, the unsaturated amide (67) gives the cyclization product in high yields (70-97%) in very strong acids (polyphosphoric acid, CF3SO3H, Nation SAC-13, or HUSY eq 23).30... 

Cognate preparations. Phenylpropynoic acid. Place a solution of 88 g (84 ml, 0.5 mol) of ethyl cinnamate (Expt 6.137) in 50 ml of carbon tetrachloride in a 500-ml round-bottomed flask. Immerse the flask in ice and add 80 g (25.5 ml, 0.5 mol) of bromine from a separatory funnel slowly with frequent shaking. The halogen will disappear rapidly at first, but more slowly towards the end of the reaction no hydrogen bromide is evolved and the time of the addition is about 20-25 minutes. Allow the mixture to stand for 1 hour, pour the solution into a large evaporating dish and permit the excess of bromine and the carbon tetrachloride to evaporate spontaneously in the fume cupboard. The crude ethyl 2,3-dibromo-3-phenylpropanoate will remain as a solid cake this... 

Phenylpropynoic acid (13) can be prepared from cinnamic acid esters by the addition of bromine to the double bond followed by dehy-drobromination with alcoholic potassium hydroxide (Scheme 5.14). 

The Pd-catalysed reaction of phenols with propynoic acids offers an atom-economic and green route to coumarins. Although the reaction with propynoic acid itself is not regioselective, 3-phenylpropynoic acid gives a single product from w-substituted phenols <04S1466>. The synthesis of coumarins both from alkynes, CO and iodophenols and by the reaction of phenols with propiolic esters is facilitated by Co/Rh nanoparticles <04SL2541>. 

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