关键词: 光化学反应, 二聚体, 红外分光光度法, Ｘ射线衍射分析, 核磁共振谱法, 香精油, 甲氧基, 香豆素 P, 结构分析, 佛手, 柠檬

Two photochem. products, cis-head-to-tail-limettin dimer (I) and cis-head-to-head-limettin dimer, were isolated from the fruit of fingered citron (Citrus medica sarcodactylis), a traditional Chinese medicine. The structures of these dimers were elucidated by the data from IR, NMR, and x-ray diffraction. I and the trans-head-to-head-limettin dimer (II) were synthesized from limettin upon UV irradiation

Key words: PHOTOCHEMICAL REACTION, DIMER, INFRARED SPECTROPHOTOMETRY, X-RAY DIFFRACTION ANALYSIS, NMR SPECTROMETRY, ESSENTIAL OIL, METHOXY GROUP, COUMARIN P, STRUCTURAL ANALYSIS, CISTUS MEDICA VAR SARCODACT, CITRUS LIMON