Crystalline cholest-4-en-3-one undergoes solid-state dimerization by UV radiation to give two ring A - ring A connected dimers. No dimerization occurs in solution. The first dimer, characterized by a cyclobutane ring, is formed by connection of C-2 and C-3 of a moiety with C-5′ and C-6′ of another. moiety, respectively. The latter dimer has a six-membered ketal ring formed by connection of C-2 with C-5′ and of O, linked to C-3, with C-3′. The structures have been determined by spectroscopic means. X-ray analysis of title compound evidences the proximity of the axial H-2 of a molecule to the C-4′ of a molecule in the upper layer. The transfer of the hydrogen and the connection between C-2 and C-5′ might be the driving force of dimerization.
Solid-state photodimerization of cholest-4-en-3-one
MONACO, Pietro;FIORENTINO, Antonio;
2001
Abstract
Crystalline cholest-4-en-3-one undergoes solid-state dimerization by UV radiation to give two ring A - ring A connected dimers. No dimerization occurs in solution. The first dimer, characterized by a cyclobutane ring, is formed by connection of C-2 and C-3 of a moiety with C-5′ and C-6′ of another. moiety, respectively. The latter dimer has a six-membered ketal ring formed by connection of C-2 with C-5′ and of O, linked to C-3, with C-3′. The structures have been determined by spectroscopic means. X-ray analysis of title compound evidences the proximity of the axial H-2 of a molecule to the C-4′ of a molecule in the upper layer. The transfer of the hydrogen and the connection between C-2 and C-5′ might be the driving force of dimerization.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
