Afterwards, the target product dyes BPI-P and BPI-T were obtained through a Knoevenagel condensation reaction between 5 and cyanoacetic acid
in the presence of piperidine.
A mixture of 2 (100 mg, 0.27 mmol) and cyanoacetic acid (30 mg, 0.36 mmol) was vacuum dried, and CH[Cl.sub.3] (50 ml) and piperidine were added.
The Knovenagel condensation of compound 2 with cyanoacetic acid afforded the final fluorescent probe (3).
Summary: A monobasic bidentate ligand (H2L) was prepared from the reaction of cyanoacetic acid hydrazide with 1-(4-((1H-imidazol-2-yl)sulfonyl)phenyl)ethanone (ISE) in ethanol.
Firstly, the vibrational modes of the azomethine group, (-C=N-), were identified by comparing the infrared spectra of (ISE) and cyanoacetic acid hydrazide, in which (C=O) and (NH2) in cyanoacetic acid hydrazide were obscured.
Condensation of cyanoacetic acid hydrazide (1) with 4-methoxyacetophenone and 4-chlorobenzaldehyde(2a,b) in hot 1,4-dioxane afforded hydrazone derivatives (3a,b).
El-Demellawy, "Cyanoacetic acid hydrazones of 3-(and 4)acetylpyridine and some derived ring systems as potential antitumor and anti-HCV agents," Archiv der Pharmazie, vol.
N-alkylation of phenothiazine followed by Vilsmeier-Haack formylation and then Knoevenagel condensation between the carbaldehyde and cyanoacetic acid in the presence of ammonium acetate affords the desired dyes.
Knoevenagel condensation between 2a-c and cyanoacetic acid in the presence of ammonium acetate produced the desired phenothiazine dyes PT1-3.
Tetraphenylbenzidine, triphenyl phosphine, PO[Cl.sub.3], cyanoacetic acid
, and piperidine are purchased from Aldrich.