MOLECULAR-STRUCTURE OF 6-METHYLENEOXYTETRACYCLINE HYDROBROMIDE

The structure of 4(dimethylamino)-1, 4, 4a, 5, 5a, 6, 11, 12a-octahydr o-3, 5, 10, 12, 12a-pentahydroxy-6-methylene-1, 11-dioxo-2-naphthacene carboxamide hydrobromide salt was determined by an X-ray analysis. One methacycline cation and one bromide anion were found in the asymmetri c unit of an orthorhombic cell, space group P2(1)2(1)2(1), a 9.580(1), b 12.147(2), c 18.735(3) angstrom, V 2180.0(5) angstrom3, Z 4, D(c) 1 .59 g cm-3, mu(MoKalpha) 19.15 cm-1. The structure was solved and refi ned to R(F) 0.062 and R(w)(F) 0.064 by a full matrix least-squares pro cedure. The conformation of the methacycline cation is found to be sim ilar to that reponed for 6-demethyl-7-chlorotetracycline hydrochloride trihydrate.