Vibrational spectroscopic studies, theoretical aspects, and X‐ray analysis of xanthenodiones (1,8‐dioxooctahydroxanthenes)

Compounds containing a pyran moiety fused to two cyclohexen‐2‐one rings are collectively called xanthenodiones (1,8‐dioxooctahydroxanthenes). With the aim of increasing the knowledge about the structures of xanthenodiones, in the present investigation two xanthenodiones, namely 9‐(4‐hydroxy‐3‐methoxyphenyl)‐3,4,5,6,7,9‐hexahydro‐1H‐xanthene‐1,8(2H)‐dione (1) and 9‐(4‐hydroxyphenyl)‐3,6‐diisopropyl 3,4,5,6,7,9‐hexahydro‐1H‐xanthene‐1,8(2H)‐dione (2), were synthesized. Their structures were investigated by nuclear magnetic resonance, single‐crystal X‐ray diffraction, infrared (IR), and Raman spectroscopy techniques along with mass spectrometry. In addition, a computational study was carried out involving vibrational spectroscopy, which allowed us to assign vibrational modes and their shifts as lattice environment. Even though compound 2 has two stereocenters, it crystallized in a centrosymmetric space group (P21/c) as expected from its achiral synthesis. This compound also crystallized as monohydrate and the presence of water molecule did not change the conformation of the target compounds.