Preparation and characterization of naphthoquinone derivatives and isomers / Norzafneza Mohd Arriffin

Pyridinium salt 30 was prepared by reaction of pyridine with bromoketone. The bromoketone used was 4-phenylphenacylbromide 29. The percentage yield of the pyridinium salt obtained was 66.137%. The pyridinium salt was then reacted with menadione to form compound 33. There are two possible stereoisomers of the compound 33 as can be seen in predicted mechanisms of reaction and formation. This possible pathway occurs due to the tautomerisation of the menadione. The expected stereoisomers occur in compound 33 since it consists of two colours; yellow and red colours but the properties are the same in 1H NMR and 13C NMR. This result was obtained by comparing the NMR and IR results of the mixture from the previous study, red and yellow compound, with NMR and IR of pure yellow compound obtained.