Simple and convenient routes to new polyheterocycles incorporating pyrazole, thiazole, thiophene, and 1,3,4‐thiadiazole moieties

A convenient route to pyridones, pyrazolo[2,3‐a]pyrimidines and pyrazolo[5,1‐c]triazines incorporating antipyrine moiety

“…In continuation of our interest in the synthesis of heteroatom compounds for biological screening [5][6][7][8], this study was undertaken to utilize 4-aminoantipyrine in the synthesis of a number of pyridone, thiazole, pyrazolo[2,3-a]-pyrimidine, and pyrazolo[5,1-c]-1,2,4-triazine derivatives having an antipyrine moiety.…”

“…The synthesis of 1,2-dihydro-1,5-dimethyl-2-phenyl-3H-pyrazol-3-one (antipyrine) derivatives has attracted a great deal of attention in view of their potent biological and pharmacological importance [1][2][3][4]. In continuation of our interest in the synthesis of heteroatom compounds for biological screening [5][6][7][8], this study was undertaken to utilize 4aminoantipyrine in the synthesis of a number of pyridone, thiazole, pyrazolo[2,3-a]-pyrimidine, and pyrazolo[5,1-c]-1,2,4-triazine derivatives having an antipyrine moiety.…”

Synthesis and Antitumor Activity of New Polysubstituted Thiophenes and 1,3,4‐Thiadiazoles Incorporating 2,6‐Pyridine Moieties

“…Substituted 3‐propanethioamide represents a category of versatile synthetic intermediates. They provide miscellaneous building blocks in the synthesis of polysubstituted thiophenes and thiadiazoles . The required 3‐propanethioamide 3 was prepared in excellent yield by treatment of pyridine‐2,6‐bis(3‐oxopropanenitrile) ( 1 ) with phenyl isothiocyanate in dimethylformamide, in the presence of potassium hydroxide, followed by treatment with cold HCl solution (Scheme ).…”

“…Reactivity of the oxopropanethioamide 3 toward a variety of α‐halo carbonyl compounds 7a , 7b , 7c , as a key step for the synthesis of polysubstituted thiophene derivatives, was investigated . Thus, treatment of the oxopropanethioamide 3 with aryloylcyl bromides 7a , 7b , 7c in refluxing ethanol in the presence of a catalytic amount of triethylamine furnished, in each case, only one isolable product in 65–80% yield.…”

“…Thus, treatment of the oxopropanethioamide 3 with aryloylcyl bromides 7a , 7b , 7c in refluxing ethanol in the presence of a catalytic amount of triethylamine furnished, in each case, only one isolable product in 65–80% yield. The identities of the isolated products were assigned as the thiophene derivatives 9a , 9b , 9c and not the isomeric 1,3‐thiazoles 10 on the basis of the similarity to the well‐established behavior of (2‐cyano‐ N ‐phenyl‐3‐oxopropanethioamide) on the reaction with α‐halo carbonyl compounds and their spectral data (Scheme ). For example, the IR spectra of compounds 9a , 9b , 9c showed, in each case, the presence of NH, nitrile, and carbonyl bands near 3300, 2200, and 1670 cm −1 , respectively.…”