辐照2-烷氧基烟酸烷基酯的苯溶液可得到高产率的笼型光二聚体,其结构通过X射线单晶分析确定。当使用5.0 M(几乎纯净)溶液时,最大量子产率为8.0 x 10(-)(2)。2-甲氧基烟酸酯苯基的光解促进了光-弗里斯重排,得到1,3-和1,5-重排的产物。在77 K下观察到2-甲氧基烟酸甲酯的准分子发射。
辐照2-烷氧基烟酸烷基酯的苯溶液可得到高产率的笼型光二聚体,其结构通过X射线单晶分析确定。当使用5.0 M(几乎纯净)溶液时,最大量子产率为8.0 x 10(-)(2)。2-甲氧基烟酸酯苯基的光解促进了光-弗里斯重排,得到1,3-和1,5-重排的产物。在77 K下观察到2-甲氧基烟酸甲酯的准分子发射。
MULTIPLE PATHS FOR PHOTOALKYLATION OF PYRIDINECARBOXYLIC ESTERS IN ALCOHOLS
作者:Toru Sugiyama、Estuo Tobita、Kyoko Takagi、Michitsugu Sato、Yasuyuki Kumagai、Gen P. Satô、Akira Sugimori
DOI:10.1246/cl.1980.131
日期:1980.2.5
Photochemical substitution of ring hydrogen of pyridinecarboxylic esters by alkyl groups derived from solvent alcohols occurs in several paths: 1) alkylation initiated by the excited carbonyl moiety of the ester group and 2) alkylation initiated by the excitation of the π-electonic system of the pyridine ring. In the photoreaction of methyl 3-pyridinecarboxylate in acidic methanol, three types of excited
containing 2-alkoxynicotinic acid esters (0.02 M) and furan (0.2 M) resulted in the formation of cage-type adducts in 73–84% yield. The structure of the adducts was established by X-ray crystallographic analysis. The mechanism involving 4π+4π photocycloaddition between the pyridine ring and furan was postulated. Two diastereomeric 4π+4π adducts were detected as intermediates in the 1H NMR spectroscopy
辐照含有2-烷氧基烟酸酯(0.02 M)和呋喃(0.2 M)的苯溶液导致形成笼型加合物,产率为73-84%。通过X射线晶体学分析确定加合物的结构。推测了在吡啶环和呋喃之间涉及4π+4π光环加成的机理。当在二烯作为三重态猝灭剂的情况下照射溶液时,在1 H NMR光谱中检测到两个非对映体4π+4π加合物作为中间体。
A Novel Photochemical Reaction of 2-Alkoxynicotinates to Cage-Type Photodimers
the structure of which was established by X-ray single-crystal analysis. The maximum quantum yield was 8.0 x 10(-)(2) when a 5.0 M (almost neat) solution was used. Photolysis of phenyl 2-methoxynicotinate promoted photo-Friesrearrangement to give 1,3- and 1,5-rearranged products. Excimer emission of methyl 2-methoxynicotinate was observed at 77 K.
辐照2-烷氧基烟酸烷基酯的苯溶液可得到高产率的笼型光二聚体,其结构通过X射线单晶分析确定。当使用5.0 M(几乎纯净)溶液时,最大量子产率为8.0 x 10(-)(2)。2-甲氧基烟酸酯苯基的光解促进了光-弗里斯重排,得到1,3-和1,5-重排的产物。在77 K下观察到2-甲氧基烟酸甲酯的准分子发射。