The present invention discloses a 2-hydroxy-3-pinone-based
pyrimidine pH-sensitive fluorescent probe and its preparation method and application. The present invention uses 2-hydroxy-3-pinone as a
raw material, and carries out an
aldol condensation reaction with 6-bromo-9-ethyl-9H-
carbazole-3-carbaldehyde to obtain 4-((6-bromo-9-ethyl-9H-
carbazole-3-yl)
methylene)-2-hydroxy-2,6,6-trimethylbicyclo[3.1.1]heptan-3-one; 4-((6-bromo-9-ethyl-9H-
carbazole-3-yl)
methylene)-2-hydroxy-2,6,6-trimethylbicyclo[3.1.1]heptan-3-one and 4-hydroxybenzamidine
hydrochloride to carry out a cyclization reaction to obtain 4-(6-bromo-9-ethyl-9H-carbazole-3-yl)-2-( 4-(9-ethyl-6-(pyridin-4-yl)-9H-carbazol-3-yl)-2-(4-hydroxyphenyl)-6,6,8-trimethyl-5,6,7,8-tetrahydro-5,7-methanoquinazoline-8-ol; 4-(6-bromo-9-ethyl-9H-carbazol-3-yl)-2-(4-hydroxyphenyl)-6,6,8-trimethyl-5,6,7,8-tetrahydro-5,7-methanoquinazoline-8-ol and 4-pyridineboronic acid are coupled to prepare 4-(9-ethyl-6-(pyridin-4-yl)-9H-carbazol-3-yl)-2-(4-hydroxyphenyl)-6,6,8-trimethyl-5,6,7,8-tetrahydro-5,7-methanoquinazoline-8-ol. 4-(9-ethyl-6-(pyridin-4-yl)-9H-carbazol-3-yl)-2-(4-hydroxyphenyl)-6,6,8-trimethyl-5,6,7,8-tetrahydro-5,7-methanoquinazoline-8-ol can specifically recognize acidic and alkaline pH. Under acidic conditions, the
fluorescence color of the solution changes from blue to yellow as the pH value in the
system continues to decrease; under alkaline conditions, the blue
fluorescence of the solution gradually weakens as the pH value in the
system continues to increase. It can be used as a fluorescent probe for measuring pH and has many advantages such as convenient synthesis, good selectivity, and high sensitivity, and has good application prospects.