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.
Keywords: aromatic carboxylic acids, phenylacetylene, Markovnikov's rule, anti-Markovnikov's rule, complex catalysts, 1-phenylvinyl benzoate, styrylbenzoate.
doi.org/10.32737/0005-2531-2025-2-114-125
.png)