In this article it was demonstrated that potassium ethyl carbonate can be successfully utilized within the phenol and its derivatives carboxylation. The optimal reaction conditions for m-cresol were determined: substrate to potassium ethyl carbonate ratio 2:1, temperature 180°C, pressure 10 atmospheres and reaction time 6 hours. Importantly, the carboxylation of m-cresol is selective and resulted in the obtaining of 4-methyl-2-hydroxybenzoic acid in 90% yield.To study the impact of the nature and location of substituents in the phenyl ring on the yield of the desired products, carboxylation reactions of various phenol derivatives were carried out with the use of potassium ethyl carbonate. As a result of the investigation, the optimal carboxylation reaction parameters for each of the phenol derivatives were determined.This study may have practical applications in the development of laboratory and manufacturing approaches for the synthesizing of valuable hydroxybenzoic acids and their derivatives. It was discovered that carboxylation of phenol derivatives by potassium ethyl carbonate occurs via electrophilic substitution of the aromatic ring. The most active in this reaction are p-cresol (84%), mcresol (90%), o-cresol (80%) and resorcinol (73%). It was observed that p-chlorophenol (18%), pbromophenol (48%) and p-fluorophenol (58%) showed less pronounced activity.

Carbon monoxide-based synthesis is an extensive and promising branch of organic synthesis. The interest in this area is primarily due to the wide synthetic capabilities of C1 chemistry, as well as the gradual depletion of traditional sources of hydrocarbon raw materials and the rise in the cost of petroleum products. In this regard, the development of new processes based on alternative sources of raw materials is an urgent task.

This paper presents the results of detailed studies of the possibility of using Lewis acid AlCl3as a promoter of the catalytic three-component system PdCl2(PPh3)2–PPh3–AlCl3in the hydroethoxycarbonylation reaction of cyclohexene at low carbon monoxide pressures (2.5 MPa). As a result a high catalytic activity of the three-component system was established and the reaction proceeds regioselectively with the formation of ethyl ether of cyclohexanecarboxylic acid. The optimal conditions of the process have been elaborated (molar ratio of the starting reagents [Cyclohexene]:[Ethanol] = 1:1; molar ratio of the components of the catalytic system = =[PdCl2(PPh3)2]:[PPh3]:[AlCl3] = 1:6:9; carbon monoxide pressure PCO=2.5MPa; process temperature T=120°C and reaction time τ= 5 h) at which the target product yield reaches 80.7%. To identify the obtained ethyl ester of cyclohexane carboxylic acid gas chromatographic analysis and mass-and IR-spectra were carried out. Based on the data obtained, a possible mechanism of the reaction route of cyclohexene carbonylation with carbon monoxide and ethanol in the presence of the three-component system PdCl2(PPh3)2–PPh3–AlCl3is proposed and discussed.

Carboxylation of o-cresol, m-cresol, and p-cresol with sodium ethyl carbonate (SEC) proceeds regioselectively with the formation of cresotic acids: 2-hydroxy-3-methylbenzoic acid, 2-hydroxy-4-methylbenzoic acid, and 2-hydroxy-5-methylbenzoic acid, respectively. Optimal conditions for conducting the process have been found to be as follows: the reactants ratio of [cresol]: [sodium ethyl carbonate] = (1.5–2): 1, T = 180–185°C, \({P_{C{O_2}}}\) = 10 atm, and t = 6–7 h. Simple and convenient methods for the synthesis of cresotic acids, which can be used for their industrial manufacturing, have been developed.

Hydroalkoxycarbonylation of olefins with carbon monoxide and alcohols under condition of homogeneous –catalysis with transition metal complexes allows facile one-step synthesis of practically useful carbon acid esters. Many of them have biological activity and are constituents of drugs or valuable intermediate products in drug synthesis. Hydroalkoxycarbonylation of isobutylene with carbon monoxide and alcohols in the presence of catalytic system Pd(PPh3)4-PPh3-TsOH was applied for preparing of biological active isovaleric acid esters: 1-menthylisovalerate (main active component of the spasmolytic medicine “Validolum”), ethylisovalerate (intermediate product for obtaining sedative and spasmolytic medicines “Ethyl ester of α-bromisovaleric acid” and “Corvalolum”), cyclohexylisovalerate (bactericide activity) and benzylisovalerate (bactericide and antifungus activity). Hydroalkoxycarbonylation reaction of isobutylene with carbon monoxide and alcohols (ethanol, cyclohexanol, l-menthol, benzyl alcohol) in the presence Pd(PPh3)4-PPh3-TsOH system carried out at conditions: temperature 100 °C; CO pressure 2.0 MPa; reaction time 4 h; reactants and catalyst components ratio [alcohol]:[isobutylene]:[Pd(PPh3)4]:[PPh3]:[TsOH] = 435:550:1:3:12. The yields of the products were 71-95% (on converted alcohols). The selectivity in linear reaction products was 100%. Such a high regioselectivity is apparently provided both by the structure of the starting alkene (isobutylene) and by the reaction mechanism. The most probable is a hydride mechanism. Due to the more advanced technology of production the Medicines will have better qualitative characteristics. The cost of production of the Medicines with the use of new technologies is 2-3 times lower as compared to the medicines produced by existing at the present traditional technologies.

The catalytic activity of the Pd(PPh3)4-TsOH and Pd(PPh3)4-PPh3-TsOH systems in the reaction of isobutylene hydromenthoxycarbonylation with carbon monoxide and l-menthol has been examined. It has been found that the reaction proceeds regioselectively yielding the linear product l-menthyl isovalerate. Optimal conditions have been found for running the process. The spatial structure of l-menthyl isovalerate synthesized via the isobutylene hydromenthoxycarbonylation reaction has been established by 1H and 13C NMR techniques.

High catalytic activity of the Pd(PPh3)-PPh3-TsOH system in the reaction of the isobutylene hydromethoxycarbonylation and hydroethoxycarbonylation of the hexene-1 was estimated. The reactions are running with high selectivity related to liner products.The optimal conditions of the process were determined.

The reaction of isobutylene hydroxycarbonylation with carbon monoxide and an alcohol (ethanol, 1-menthol) in the presence of the palladium acetylacetonate-triphenylphosphine-p-toluenesulfonic acid catalytic system was investigated. It was shown that the reaction proceeds regioselectively with the formation of linear products (ethyl isovalerate, 1-menthyl isovalerate). The optimum conditions for running the process were found, at which the yield of the main products is 67–79%.