Background: Due to the importance of carbonylation reactions, many studies have been carried out in the field of these reactions. The first transition-metal catalyzed carbonylation reaction by carbon monoxide gas was reported in 1963 by Hack et al. Despite the high use of carbon monoxide gas in industrial processes, in organic synthesis, it is not desirable to carry out the reactions in the presence of this gas. Carbon monoxide is a very poisonous gas that has no specific color and smell. Its affinity with blood hemoglobin is about 200 times higher than that of oxygen gas. In addition to carbon monoxide toxicity, these reactions require high gas pressure and high temperatures, as well as special tools for using, storing and transporting gas. In this way, it is important to develop methods to carry out carbonylation reactions without direct use of gas and to find suitable alternatives for it. So far, several sources of carbonylation have been introduced as a substitute for carbon monoxide gas, including formic acid and its derivatives, aldehydes, carbamoylsilane, carbamoylstannane, and metal carbonyls.
Aim: Metal carbonyls are solid and stable carbonyl sources that can be easily used. These compounds are much more desirable than other carbonyl sources because cleavage of a carbon–carbon bond in organic carbonyls requires much more energy than removing the carbonyl ligand from the complexes. Therefore, the aim of this study is to use chromium hexacarbonyl as a carbonylating source in the one-pot synthesis of pyrido[2,3-d] pyrimidines. In the second part, pyrimidine derivatives were synthesized in a one-pot and two-step method, without the need for a catalyst, in water and ethanol solvents.
Methodology: In the first part, the multicomponent reaction between aryl iodides, phenylacetylene, chromium hexacarbonyl and uracil or enaminone derivatives in the presence of palladium acetate as catalyst and sodium acetate as base was investigated for the one-pot synthesis of pyri