ADDITION OF AROMATIC CARBOXYLIC ACIDS TO PHENYLACETYLENE IN THE PRESENCE OF ZINC AND COBALT COMPLEX CATALYSTS

The reaction of some aromatic carboxylic acids with phenylacetylene was carried out in the presence of complex catalysts such as diacetato-di (2-amino-5-methylthio-1,3,4-thiadiazolo) cobalt(II) ([Co(C3H5N3S2)2(CH3COO)2]), aqua-tris(2-amino-5-ethyl-1,3,4-thiazole)-zinc(II) dinitrate ([Zn(C4H7N3S)3(OH2)](NO3)2), bis(2-amino-5-ethyl-1,3,4-thiadiazole)-diacetato-zinc(II) ([Zn(C4H7N3S)2(CH3COO)2]) and tetrakis-(2-amino-5-ethylthio-1,3,4-thiadiazole)-zinc(II) dinitrate ([Zn(C4H7S2)4](NO3)2). The influence of temperature, duration of reaction, nature of carboxylic acid, solvent and catalysts, and mole ratio of initial compounds on yield of products was studied. A mixture of Markovnikov and anti-Markovnikov coupling products was formed when the reaction was carried out in toluene solution at 110 °C, the presence of 1 mol% catalyst. The yield of vinyl esters has increased in the order: 4-CH3O-C6H4COOH < 4-CH3-C6H4COOH < C6H5COOH < 4-Cl-C6H4COOH < 4-Br-C6H4COOH < 2-Br-C6H4COOH. A proposed reaction mechanism was suggested. The with increasing of acidity of the carboxylic acid, the formation of the Markovnikov coupling product also has increased. Conversely, a decrease in acidity leads to increasing of yield in the of anti-Markovnikov coupling product. When phenylacetylene reacts with carboxylic acid in the presence of 1 mol% [Zn(C4H7S2)4](NO3)2 catalyst and toluene solvent at 110 °C for 36 hours, the total yield of products in case of 4-methoxybenzoic acid is 44% (62/38), 4-methylbenzoic acid is 50% (66/34), benzoic acid is 45% (81/19), 4-chloro benzoic acid is 83% (82/18), 4-bromo benzoic acid is 86% (83/17) and 2-bromo benzoic acid is 91% (86/14). The structure of the synthesized vinyl esters was proved on the base of the analysis of IR, 1H, 13C NMR and Mass spectrums