Refinement of the structure of naproxen, (+)-6- methoxy-$\alpha$-methyl-2-naphthaleneacetic acid

The molecular structure of naproxen determined by X-ray diffraction technique was refine to the final R-value geing 0.042. The compound was recrystallized from ethanol solution in monoclinic crystal system, space group $P2_1$ , with Z = 2, a = 13.375(5) $\AA$, b = 5.793(2) $\AA$, c = 7.914 $\AA$, $\beta$=93.91(3)$\AA$ and $d_{obs}$ = 1.26, $d_{calc}$ = 1.25 g/cm$^{3}$. The structure was solved by direct method and refined by block diagonal least squares procedure for 747 relfections (F .leq. 6.sigma.(F)). The molecules are connected by two intermolecular OH--O type hydrogen bonds.