Felbinac Synthesis Lab Report

Introduction
Chemists often find a method to determine the level of “greenness” of a chemical reaction, or its “atom economy”. A higher atom economy is preferable because a greater amount of the reactants will be present in the product as opposed to the byproduct.1 A Suzuki reaction is classified as an organic, coupling reaction that includes boronic acid and a halide that are catalyzed by a palladium complex under basic conditions. Other palladium- catalyzed coupling mechanisms include the Heck and Stille reactions. Palladium typically exists in the oxidation states of 0, +2, and +4. PdCl2 is usually the starting compound for several other heterogeneous palladium catalysts such as Pd/C and Pd/BaSO4.1 Suzuki coupling is an efficient way to
As shown in the balanced chemical reaction in figure 1, Felbinac is synthesized from 4-bromophenyl acetic acid, phenylboronic acid, and 10% Pd/C. Figure 1: The balanced chemical reaction showing the synthesis of felbinac.
It functions by inhibiting cyclooxygenase-1, which releases prostaglandins that cause pain as a response to injury. In a study conducted by Moore et al., 160 patients were subject to various topical NSAIDS to determine their effectiveness. Out of the six drugs tested, the results indicated that felbinac, ibuprofen, and piroxicam were the most useful in relieving pain due to acute and chronic conditions.3 Figure 2: The four steps involved in the catalytic cycle of a Suzuki coupling
The reaction was carried out specifically with water and heterogeneous palladium (10% Pd/C) that made this reaction relatively safe and simple to isolate. First, phenylboronic acid, sodium bicarbonate, and 10% Pd/C were added to a 25 mL round bottom flask with distilled water and stirred at room temperature until it homogenized, which was about 10 minutes. Next, 4- bromophenylacetic acid was added to the flask and the mixture was refluxed for about 50 minutes at about 80°C. TLC was used to monitor the reaction progress every 15 minutes. A relatively non-polar solvent system of 25% ethyl acetate/ 75% hexanes was used as the mobile phase. Each plate contained a starting material (4-bromophenylacetic acid), a reaction mixture spot, and a co-spot. The TLC at 15 minutes showed the starting material to have an Rf of about 0.12 and reaction mixture lane had only one spot at an Rf of 0.07, which was probably the starting material. At 30 minutes, the reaction lane showed one spot at Rf of 0.13 and another spot at Rf of 0.03. The starting material standard was seen to have an Rf of about 0.14. At 45 minutes, the reaction lane had a dark spot around 0.26 and a faint spot around 0.15 which indicates the starting material. At 60 minutes, the reaction lane only contained one spot which had an Rf of about 0.28. This means that the reaction had completed