Synthesis and crystal structure of 7,7a,8,9,11,11a-Hexahydro-7,7,10-trimethyl-1,10-epoxy-10H-benz[de]anthracen-6-ol

Abstract

3-Methyl-3-(4?-methylpent-3?-enyl)-3H-naphtho[2,1-b]pyran-9-ol and -8- ol were prepared by condensation of citral with naphthalene-2,7-diol and -2,6-diol respectively. The 8-hydroxy compound sublimed unchanged but on heating the 9-hydroxy isomer cyclization occurred yielding 7,7a,8,9,11,11a-hexahydro-7,7,10-trimethyl-1,10-epoxy-10H- benz[de]anthracen-6-ol. Crystals of the cyclization product were found to be monoclinic [C2/c, a = 21.934(5), b = 8.713(2), c = 19.849(4) Ǻ; β = 127.78(2)°; Z = 81. The crystal structure was determined at 295 K from diffractometer data [1350 reflections with I > 2σ(I)] and refined to a residual of 0.052.