Structure of naproxen, C14H14O3

An effective inhibitor of cyclo-oxygenase. Mr=230.25 , monoclinic, P21, a= 13.3150(10), b = 5.7765 (4), c= 7.8732 (4)A, fl= 93.88 (1) °, V= 604.2 (1)A 3, Z= 2, Din= 1.25 (2) (flotation), D~= 1.265 Mg m -3, 2(Mo Ka 1) = 0.70926/~, #(Mo Ka) = 0.095 mm -1, F(000) = 244, T= 296 K, final R(F) = 0.061 for 1037 observed reflections. The rotation of the carboxyl group with respect to the benezene ring, which seems to be connected with anti-inflammatory potential, is similar to the other two substituted propionic acids already reported. The benzene rings in the naphthyl group are inclined at an angle of 5.2 (2) °. Introduction. The title compound, an effective inhibitor of the cyclo-oxygenase responsible for biosynthesis of prostaglandins, was obtained from Dr Natarajan, Institute of Basic Medical Sciences, Madras. It exhibits anti-inflammatory, analgesic and antipyretic activity in man (Goodman & Gilman, 1980). The analysis of its structure was undertaken to help to establish the structure-activity relationship in propionic acid derivatives.