Synthesis and Characterization of Photolabile <i>o</i>-Nitrobenzyl Derivatives of Urea
作者:Raymond Wieboldt、Doraiswamy Ramesh、Evelyn Jabri、P. Andrew Karplus、Barry K. Carpenter、George P. Hess
DOI:10.1021/jo0201373
日期:2002.12.1
N-(alpha-methyl-2-nitrobenzyl)urea, and 0.56 for N-(alpha-carboxy-2-nitrobenzyl)urea. The caged N-(alpha-carboxy-2-nitrobenzyl)urea is not a substrate of the enzyme urease, while the photolytically released urea is. Also, neither this caged urea nor its photolytic side products inhibit hydrolysis of free urea by urease. Thus, the alpha-carboxy-2-nitrobenzyl derivative of urea is suitable for mechanistic investigations
我们在这里介绍了尿素的四个光不稳定衍生物的合成和表征,其中α-取代的2-硝基苄基基团共价连接到尿素氮上。这些衍生物易于在水溶液中光解以释放出游离尿素。2-硝基苄基的α-取代基强烈影响通过瞬态吸收光谱法测量的光解反应速率。N-(2-硝基苄基)脲,N-(α-甲基-2-硝基苄基)脲,N-(α-羧甲基-2-硝基苄基)脲在pH 7.5和室温(约22摄氏度)下的光解速率和N-(α-羧基-2-硝基苄基)脲分别为1.7 x 10(4),8.5 x 10(4),4.0 x 10(4)和1.1 x 10(5)s(-) (1)。在308 nm的单个激光脉冲照射下,通过测量游离尿素确定的量子产率为0。N-(2-硝基苄基)脲为81,N-(α-甲基-2-硝基苄基)脲为0.64,N-(α-羧基-2-硝基苄基)脲为0.56。笼状的N-(α-羧基-2-硝基苄基)脲不是脲酶的底物,而光解释放的脲则是。同样,这种笼形尿素或其光