Synthesis of new Organic reagent by Vilsmeier - Haack reaction and estimation of pharmaceutical compounds (Mesalazine) containing aromatic amine groups

In this paper Synthesis new heterocyclic compound from p-phenylenediamine by converting p-diacetanilide (1) and reacting with Vilsmeier-Haack reagent to give (2,7-dicloropyrido[2,3-g]quinoline-3,8-dicarbaldehyde) (2). The two carbaldehydes in compound (2) react with two moles 1-tetralone to give chalcone(3). This chalcone is used as the reagent to estimate the pharmaceutical compounds containing aromatic amino groups. Where a sensitive spectrophotometric method has been developed for the determination of mesalazine by diazotization and coupling reaction of mesalazine with chalcone reagent in basic medium to form a colored water-soluble and stable azo-dye. The product shows maximum absorption at 450 nm. Beer's law was obeyed over the concentration range 0.5-27.5 mu g/ml with molar absorptivity of 9494.37 l.mol(-1).cm(-1). The limit of detection and quantitation is 0.161 and 0.538 mu g.ml(-1). The recovery was 101.48% with a relative standard deviation <= 3.265%. Mesalazine and Chalcone reagent products were formed in the ratio of 2: 1. Full-color development was described and the proposed method was successfully applied to determine mesalazine in the pharmaceuticals preparation. The proposed method was applied to pharmaceutical preparations containing mesalazine derivatives.