title: Crystal structures of thiobarbiturate with N-phenylalkyl group and its photocyclization product.
abstract: The photo-irradiation of thiobarbiturates (1) with an N-phenylalkyl group gives bicyclic fused pyrimidine derivatives (2) through a Norrish type II reaction. The crystal structures of dihydro-1,5,5-trimethyl-3-(3-phenylpropyl)-2-thioxo-4,6(1H,5H)-pyrimidinedione (1a) and the photocyclization product (2b) of dihydro-1,5,5-trimethyl-3-(3-phenylbutyl)-2-thioxo-4,6(1H,5H)-pyrimidinedione (1b) were elucidated by X-ray crystallographic analysis. The photocyclization product (2b) was determined to be 1,6,7,8-tetrahydro-1,3,3-trimethyl-9-phenyl-2H-pyrido[1,2-a]pyrimidine-2,4(3H)-dione.
authors.affiliation: Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Hokkaido, Japan.
authors.forename: Haruko
authors.initials: H
authors.lastname: Takechi
authors.forename: Kanji
authors.initials: K
authors.lastname: Kubo
authors.forename: Hajime
authors.initials: H
authors.lastname: Takahashi
authors.forename: Taisuke
authors.initials: T
authors.lastname: Matsumoto
mesh_terms: D001554:Benzene / Q000737:chemistry*; D018360:Crystallography, X-Ray; D003500:Cyclization / Q000528:radiation effects; D006860:Hydrogen Bonding / Q000528:radiation effects; D008027:Light; D008968:Molecular Conformation; D013858:Thiobarbiturates / Q000737:chemistry*
chemical_list: D013858:Thiobarbiturates; D001554:Benzene