A facile synthesis of some new pyrazolo[1,5-a]pyrimidine heterocyclic disazo dyes and an evaluation of their solvatochromic behaviour

Synthesis and Antioxidant Activity of New Pyrazolo[1,5‐a]Pyrimidine Derivatives Incorporating a Thiazol‐2‐yldiazenyl Moiety

“…The suggested synthetic plans to obtain the target compounds are shown in Schemes –3. The versatile hitherto reported starting material, 4‐(thiazol‐2‐yldiazenyl)‐1 H ‐pyrazole‐3,5‐diamine ( 2 ) could be easily obtained via cyclization of 2‐thiazolylazomalononitrile ( 1 ) with hydrazine hydrate in boiling ethanol following a procedure described by Tsai and Wang .…”

“…The fused heterocyclic compound, pyrazolo[1,5‐ a ] pyrimidine and its derivatives are known to possess pharmacological activity, anxiolytic properties, and used as intermediates in the dyestuff industry . While a large number of arylazopyrazole dyes have been reported in the literature, very few condensed pyrazole derivatives carrying an arylazo function on the pyrazole ring have been reported .…”

A Facile Synthesis of New Monoazo Disperse Dyes Derived from 4-Hydroxyphenylazopyrazole-5-amines: Evaluation of Microwave Assisted Dyeing Behavior

“…While a large number of arylazopyrazole dyes have been reported in the literature, very few condensed pyrazole derivatives carrying an arylazo function on the pyrazole ring have been reported [8,9,10,11,12,13]. The present study reports the synthesis of novel condensed 4-hydroxyphenylazopyrazolo[1,5-a]pyrimidine dyes, and their application as disperse dyes for polyester fabrics by a method using microwave irradiation as an energy source [14,15].…”

A synthesis of some new 4-arylidene-5(4H)-oxazolone azo dyes and an evaluation of their solvatochromic behaviour

“…Of more general importance is the tertiary phosphane/tetrachloromethane system, as chlorinating and dehydrating agent for sensitive substrates to the aggressive and readily hydrolyzed acid chlorides such as PCl 5 , P(O)Cl 3 , thionyl chloride and sulfonyl chloride. A great advantage can also be seen in its ability to the demands made by the various donor strengths of the substituents chosen for attachment to the phosphorus atom.…”

“…On the other hand, they are very important in applications such as disperse dyes for polyester fibers, reprography, functional dye and nonlinear optical systems, photodynamic therapy, and lasers. [3][4][5][6][7][8][9] The 5(4H)-oxazolones are important synthons for the synthesis of several biologically active molecules. Also, they are precursors of amino acids containing an aromatic side chain.…”