Method for making Schiff base

Patent metadata

Field	Value
Publication number	US-10106684-B2
Application number	US-201815917274-A
Country	US
Kind code	B2
Filing date	Mar 9, 2018
Priority date	Mar 28, 2016
Publication date	Oct 23, 2018
Grant date	Oct 23, 2018

Abstract

Fluorescent Schiff base compounds comprising a xanthene dye based moiety and an alkyl imidazole moiety. Methods of assessing these fluorescent Schiff base compounds as fluorescent probes for metal ions in Cu 2+ chemosensing applications, methods of preparing the fluorescent Schiff base compounds and methods of detecting Cu 2+ ions with the same are also provided.

First claim

The invention claimed is:

1. A method for making a Schiff base of formula (I)

or a salt, solvate, tautomer, or stereoisomer thereof;
wherein R 1 is an optionally substituted alkyl, optionally substituted cycloalkyl, or optionally substituted aryl;
R 2 an R 3 are independently OH, —NH 2 , —OR 5 , —NHR 5 , —NR 5 R 5 ;
R 4 is H, —F, —Cl, —Br, —CN, —OH, —OR 5 , —NO 2 , —NH 2 , —NHR 5 , —NR 5 R 5 ; and
each R 5 is independently an optionally substituted alkyl, optionally substituted cycloalkyl, or optionally substituted aryl, said method comprising:
refluxing a fluorescein or rhodamine based compound with hydrazine to form a fluorescein or rhodamine based hydrazide; and
refluxing the fluorescein or rhodamine based hydrazide with a N-alkylimidazole-2-carboxaldehyde to form the Schiff base.

2. The method of claim 1 , wherein the compound of formula (I) is

3. The method of claim 1 , wherein the Schiff base has a fluorescence with an emission peak centered at 515-535 nm at an excitation wavelength of 490-510 nm and which has an ultraviolet visible absorption with an absorption peak centered at 330-350 nm.

4. The method of claim 1 , where R 2 in formula (I) is —OR 5 .

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Helal Aasif

Classifications

• C09B26/02 Primary

  Hydrazone dyes (hydrazone-azo dyes C09B56/18) · CPC title

• G01N33/1813

  Specific cations in water, e.g. heavy metals · CPC title

• G01N33/84

  involving inorganic compounds or pH · CPC title

• G01N33/582

  with fluorescent label · CPC title

• C09B11/08

  Phthaleins; {Phenolphthaleins; Fluorescein} · CPC title