Solid-state photodimerization of cholest-4-en-3-one.
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.
DellaGreca
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Dipartimento di Chimica dell'Università Federico II and Centro di Biocristallografia CNR, Via Mezzocannone 4, 80134 Napoli, Italy.
Monaco
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Previtera
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Zarrelli
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A
Fiorentino
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A
Giordano
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Mattia
C A
CA