Studies on Photocleavage Reaction of Arylmethyl and Diarylmethyl Carboxylates

1.除芳香族羧酸盐外，二芳基甲基羧酸盐在Ar气氛下的光解反应一般都会产生一个二芳基酮和一个二芳基甲醇二芳甲基自由基，这些自由基是由C-0CO键均相裂解形成的(β-裂解)，非常有效地捕获了反应介质中存在的微量氧，从而得到酮和醇。同时，氧与由酰氧基脱羧基产生的烷基反应得到醛或酮。没有发生O-CO键的断裂(α-断裂)。通过对几种二芳甲基羧酸盐光解产物的研究表明，二芳基甲基自由基的高效捕氧作用与其稳定性和体积大小有关。α-(1-萘基)苯基和3，4-苯并荧基首先是最有效的捕氧剂。将这种氧捕获反应应用于从羧酸合成醛的反应并不成功。详细研究了2-(1-吡喃基)对氰基苯甲酸乙酯荧光猝灭激基络合物的形成，特别是首次系统地研究了溶剂极性的影响。建立了高效、方便的氨基和磷酸基团保护程序。用这种方法制备了各种受保护的氨基酸、多肽和磷酸盐，并对它们的辐照脱保护进行了研究。(1-吡喃基)甲基被发现不利于生物应用，因为它降低了在水中的溶解度。在Leu-Leu-ome和cAMP中引入了更多的水溶性肉桂酰基和4-Chmarinyl甲基作为笼状基团，并研究了它们的体外光解行为。

1. Photolysis under Ar of diarylmethyl carboxylates, except for aromatic carboxylates, generally gives a diaryl ketone and a diarylmethanol Diarymethyl radicals formed by homolytic cleavage of C-0CO bond (beta-cleavage) quite efficiently trap trace amount of oxygen present in the reaction media under Ar to give the ketone and alcohol. At the same time, the reaction of oxygen with the alkyl radical derived from decarboxylation of the acyloxy radical gives an aldehyde or ketone. Cleavage of O-CO bond (alpha-cleavage) is concluded not to take place. High efficiency of oxygen trapping by diarylmethyl radicals is related to their stability and bulkiness by the product studies of photolysis of several diarylmethyl carboxylates. alpha- (1-Naphthyl) benzyl and 3,4-benzofluorenyl radicals are above all most efficiently trap oxygen.2. Application of this oxygen trapping reaction to the synthesis of an aldehyde from a carboxylic acid has not been successful.3. Fluorescence quenching exciplex formation in 2- (1-pyrenyl) ethyl p-cyanobnzoate was studied in detail, especially the effect of solvent polarity has been studied systematically for the first time.4. Efficient and convenient procedure for the protection of amino and phosphate groups has established. Various kinds of protected amino acids, peptides and phosphates are made by this procedure and their deprotection by irradiation was examined. (1-Pyrenyl) methyl was found not to be good for biological application because it decreases the solubility in water. More water soluble cinnnamoyl and 4-chmarinylmethyl are introduced to Leu-Leu-OMe and cAMP as caged groups and their in vitro photolytic behavier was studied.