反应详情

Fluorophores [6,7]-benzo-4-oxo-4H-quinolizine-3-carboxylic acid (3a) (FIG. 16), 1-[N,N-di(carboxymethyl)]-4-oxo-4H-quinolizine-3-carboxylic acid (11a) (FIG. 17), 8-(naphth-1-yl)-4-oxo-4H-quinolizine-3-carboxylic acid (23a) and 8-(benzo[b]furyl)-4-oxo-4H-quinolizine-3-carboxylic acid (24a), show an increase of the fluorescence emission when binding to Mg2+, and are sensitive to changing Mg2+ levels. The triacid 1-[N,N-di(carboxymethyl)]-4-oxo-4H-quinolizine-3-carboxylic acid (11a) exhibits a fluorescence maximum at 552 nm, making this compound an attractive fluorescent magnesium indicator. The presence of the amino group at the 1-position gave a hypsochromic shift of 117 nm with respect to 4-oxo-4H-quinolizine-3-carboxylic acid (1a). The introduction of an aromatic moiety at the 8-position (e.g., 8-(4-methoxyphenyl)-4-oxo-4H-quinolizine-3-carboxylic acid [22a]; 8-(naphth-1-yl)-4-oxo-4H-quinolizine-3-carboxylic acid [23a]; and 8-(benzo[b]furyl)-4-oxo-4H-quinolizine-3-carboxylic acid [24a]), or extension of the 7-system as in [6,7]-benzo-4-oxo-4H-quinolizine-3-carboxylic acid (3a) are believed to result in a hypsochromic shift to longer wavelengths, although it is not necessary to understand the mechanism in order to practice the present invention and it is not intended that the present invention be so limited. However, the hypsochromic shifts of these compounds are smaller in comparison to the hypsochromic shift exhibited by 1-[N,N-di(carboxymethyl)]-4-oxo-4H-quinolizine-3-carboxylic acid (11a).

1. temperaturean increase of the fluorescence emission when binding to Mg2+