A Fluorogenic Aldehyde Bearing a 1,2,3-Triazole Moiety for Monitoring the Progress of Aldol Reactions
作者:Hai-Ming Guo、Fujie Tanaka
DOI:10.1021/jo900013w
日期:2009.3.20
We have developed a new type of fluorogenic aldehyde bearing a 1,2,3-triazole moiety that is useful for monitoring the progress of aldol reactions through an increase in fluorescence. Whereas 6-methoxy-2-naphthaldehyde was highly fluorescent, the fluorogenic aldehyde, 4-formylbenzene connected to the 6-methoxy-2-naphthyl group through a 1,2,3-triazole moiety, was essentially nonfluorescent in aqueous solutions. We suggest that the 4-formylphenyl group acts as a quencher to suppress the fluorescence of the 6-methoxy-2-naphthyltriazole moiety. The product of the aldol reaction of this aldehyde does not have a quenching moiety and showed more than 800-fold higher fluorescence than the aldehyde. Assay systems using the fluorogenic aldehyde were validated by screening of aldol catalysts, ranking of the activities of the catalysts, and evaluation of reaction conditions.
Substituent-dependent reactivity in aldehyde transformations: 4-(phenylethynyl)benzaldehydes versus simple benzaldehydes
作者:Isamu Katsuyama、Pandurang V. Chouthaiwale、Hai-Lei Cui、Yuji Ito、Ayumi Sando、Hiroaki Tokiwa、Fujie Tanaka
DOI:10.1016/j.tet.2013.03.056
日期:2013.5
Effects of substituents on transformations of 4-(phenylethynyl)benzaldehydes and related benzaldehydes were analyzed in aldol and thiazolidine formation reactions. The aldol reaction of 4-cyanobenzaldehyde was 54-fold faster than that of 4-methoxybenzaldehyde. In contrast, the aldol reaction of 4-(4-cyanophenylethynyl)benzaldehyde was only 1.4-fold faster than that of 4-(4-methoxyphenylethynyl)benzaldehyde