Synthesis And Application Of Pyrazoline Fluorescent Probes

The research of fluorescent probes has been promoted in the field of medicine,chemistry and many others,and it is of great significance to find new probes with high value.Due to the many advantages of pyrazoline compounds and high practical value,pyrazoline fluorescent probes have been received more and more attention Although research in this area has been extensively,there are still many practical applications that require development and research.We have designed and synthesized three new pyrazoline fluorescent probes,which are expected to provide certain value for industry(medicine,pesticides,etc.).Chapter 1:Fluorescent probes have a good role in photochemistry detection technology in the fields of chemistry,environment and life sciences.At present,pyrazoline fluorescent probes have been received extensively attention and many research advances have been made.Some of them have good luminescence properties and are applied as fluorescent probes to identify metal ions.In this paper,three pyrazolines were synthsized and the application were studiedChapter 2:A pyrazoline fluorescent probe were designed with its structure 1-(5-(Anthracene-9-yl)-3-(pyridin-2-yl)-4,5-dihydro-1H-Pyrazol-1-yl)ethan-l-one(A1).First,(E)-3-(indol-10-yl)-1-(pyridin-2-yl)propane was synthesized by reacting 9-furfural and 2-acetylpyridine with ethanol solution and 10%sodium oxide as a catalyst.2-keto-l-one chalcone(A2).Next,the pyrazoline compound A1 was prepared by reacting chalcone A2 with hydrazine hydrate in glacial acetic acid.The structure was confirmed by 1H NMR,13C NMR and HRMS.To investigate the optical respons,the UV absorption and fluorescence were done to detect ions(such as titration curve,selectivity,reversibility,etc.)in CH3CH2OH:H2O(V:V= 1:1),the results showed that the 1-(5-(Anthracene-9-)3-(pyridin-2-yl)-4,5-dihydro-lH-pyrazol-l-yl)ethan-1-one(Ai)is particularly selective for Cu2+ and has a high selectivity sensitivity.Chapter 3:A pyrazoline fluorescent probe were designed with its structure 1-(5-(3-phenyl?2H_chromen-2-yl)-3-(pyridin-2-yl)-4,5-dihydropyrazol-1-yl)ethanone(B1).First,2-methyl-2H-chromene-3-carbaldehyde were synthesized using salicylaldehyde and cinnamaldehyde by Michael addition and intramolecular aldol condensation.After completion of the reaction,a bright yellow solid was obtained with yield was 85%.Next,we carried out the synthesis of chalcone.2-Ethyl-2H-chromene-3-carbaldehyde and 2-acetylpyridine are reacted in ethanol,and 10%NaOH was used to obtain(E)-3-(3-phenyl-2H-chromen-2-yl)-1-(pyridin-2-yl)prop-2-en-l-one(B2),the structure was confirmed by 1H NMR,13C NMR and HRMS.Finally,The 1-(5-(3-phenyl-2H-chromen-2-yl)-3-(pyridin-2-yl)-4,5-dihydropyrazol-l-yl)ethanone(B1)was obtained by(E)-3-(3-phenyl-2H-chromen-2-yl)-1-(pyridin-2-yl)prop-2-en-1-one reacted with hydrazine hydrate under reflux of ice glacial acetic acid,the 1-(5-(3-phenyl-2H-chromen-2-yl)-3-(pyridin-2-yl)-4,5-dihydropyrazol-l-yl)ethanone(Bi)has good selectivity and high sensitivity and anti-interference in buffer CH3CH2OH:H2O(V:V=1:1).Using the Benesi-Hildebrand program and the Job's Plot curve,the results indicated that the complex forms a 1:1 complex with Fe3+shows fluorescent quenching.Further experiments with EDTA proved that the process of recognition is reversible.Chapter 4:A pyrazoline fluorescent probe were designed with its structure 1-(5-(indol-10-yl)-3-(6-methoxynaphthalen-2-yl)-4,5-dihydropyrazol-l-yl)one(C,).((E)-3-(Indol-10-yl)-1-(6)-Methoxypyridin-2-yl)prop-2-en-1-one(C2)was obtained using 2-(Ethyl-6-methoxynaphthalene)reacted with 9-furaldehyde in ethanol solution.Further(E)-3-(indol-10-yl)-1-(6-methoxypyridine-2-yl)prop-2-en-1-one(C2)reacted with hydrazine hydrate in glacial acetic acid and obtained a crude product,the pyrazoline 1-(5-(Indol-10-yl)-3-(6-methoxynaphthalen-2-yl)-4,5-dihydropyrazol-1-yl)one(Ci)was obtained by column chromatography with its yield 82%.The optical properties were tested by UV absorption and fluorescence emission spectroscopy.The emission intensity reduced significantly with the Cu2+addition.Therefore,the probe C1 can be used to detect the Cu2+.In addition,the addition of PPi can restore the fluorescence,indicating that Ci is a reversible probe.