Advancements in tetronic acid chemistry. Part 1: Synthesis and reactions

The preparation and the properties of the elusive tetronic acid are reviewed, including its synthesis, chemical reactivity and reactions.     

A Concise Diastereoselective Photochemical Synthesis of 3‐Hydroxyfuran‐2(3H)‐ones

The photocycloaddition of alkyl phenylglyoxylates to allylic alcohols leads to oxetanes 3a–h with high to moderate (2R?,4R?)‐diastereoselectivity that can be easily ring‐opened to give 3‐hydroxyfuran‐2(3H)‐ones 4a–b .     

Synthesis and Antimicrobial Activity of New 4-Methyl-2-(3-pyridyl)thiazolyl Chalcones and Pyrazolines

Russian Journal of General Chemistry - In an attempt to develop active antimicrobial agents, a set of new thiazolyl chalcones has been synthesized by the Claisen–Schmidt reaction of...     

Regioselective Synthesis of Some New Pyrazolo[1,5‐a]pyrimidines,Pyrazolo[1,5‐a]quinazoline and Pyrimido[4′,5′:3,4]pyrazolo[1,5‐a] pyrimidines Containing Thiazole Moiety

A regioselective synthesis of novel pyrazolo[1,5‐a]pyrimidines, pyrazolo[1,5‐a]quinazoline and pyrimido[4′,5′:3,4]pyrazolo[1,5‐a]pyrimidines incorporating a thiazole moiety was described via the reactions of the versatile, readily accessible 5‐amino‐3‐(phenylamino)‐N‐(4‐phenylthiazol‐2‐yl)‐1H‐pyrazole‐4‐carboxamide 3 with appropriate 1,3‐biselectrophilic reagents namely, β‐diketones, enaminones, and α,β‐unsaturated cyclic ketone. The newly synthesized compounds were elucidated by elemental analysis, spectral data, and alternative synthetic route whenever possible.     

A Novel Diastereoselective Synthesis of 6‐Aryl‐5‐hydroxy‐2,3‐dihydropyrano[2,3‐c]pyrazol‐4(1H)‐ones

A novel one‐pot diastereoselective synthesis of trans‐6‐aryl‐5‐hydroxy‐2,3‐dihydro[2,3‐c]pyrazol‐4(1H)‐ones 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h is described via the Darzens condensation reaction of 2‐chloro‐1‐(5‐hydroxy‐3‐methyl‐1‐phenyl‐1H‐pyrazol‐4‐yl)ethanone ( 2 ) with different aromatic aldehydes in aqueous basic medium. The structures of the compounds prepared were determined by analytical and spectral analyses.     

Heterocyclic Synthesis with 4-Benzoyl-1-cyanoacetylthiosemicarbazide: Selective Synthesis of Some Thiazole, Triazole, Thiadiazine, Pyrrylthiazole, and Pyrazolo[1,5-a]triazine Derivatives

4-Benzoyl-1-cyanoacetylthiosemicarbazide undergoes coupling reaction with aromatic diazonium chloride to afford (arylhydrazono)thiosemicarbazide, which was reacted with phenacyl bromide regioselectivity to afford the thiazoline. The (arylhydrazono)thiosemicarbazide could be transformed into the pyrazolo[1,5-a]triazine. Heterocyclization of 4-benzoyl-1-cyanoacetylthiosemicarbazide with α-haloketones (bromoacetone and phenacyl bromide), ethyl iodide, and ethyl bromoacetate furnished the pyrrylthiazoles, 1,2,4- triazole, and 1,3,4-thiadiazine. The latter was coupled with aromatic diazonium chloride to give the bis(arylhydrazono)‐thiadiazine. The mechanism for the formation of the title compounds was suggested and discussed.     

Heterocyclic Synthesis with 4-Benzoyl-1-cyanoacetylthiosemicarbazide: Selective Synthesis of Some Thiazole,Triazole, Thiadiazine,Pyrrylthiazole, and Pyrazolo[1,5-<Emphasis Type="Italic">a</Emphasis>]triazine Derivatives

Summary. 4-Benzoyl-1-cyanoacetylthiosemicarbazide undergoes coupling reaction with aromatic diazonium chloride to afford (arylhydrazono)thiosemicarbazide, which was reacted with phenacyl bromide regioselectivity to afford the thiazoline. The (arylhydrazono)thiosemicarbazide could be transformed into the pyrazolo[1,5-a]triazine. Heterocyclization of 4-benzoyl-1-cyanoacetylthiosemicarbazide with α-haloketones (bromoacetone and phenacyl bromide), ethyl iodide, and ethyl bromoacetate furnished the pyrrylthiazoles, 1,2,4- triazole, and 1,3,4-thiadiazine. The latter was coupled with aromatic diazonium chloride to give the bis(arylhydrazono)‐thiadiazine. The mechanism for the formation of the title compounds was suggested and discussed.     

Synthesis and anticancer evaluation of some new pyrazolo[3,4-d][1,2,3]triazin-4-ones,pyrazolo[1,5-a]pyrimidines,and imidazo[1,2-b]pyrazoles clubbed with carbazole

Carbazole represents as a promising template for cancer treatment as it exists in the skeleton of numerous man-made and natural anticancer agents. In this regard, new sets of novel functionalized pyrazolo[3,4-d][1,2,3]triazin-4-ones 6a-e and 10a-e , pyrazolo[1,5-a]pyrimidines 16a,b and imidazo[1,2-b]pyrazoles 20a,b and 23a-c having carbazole moiety were efficiently synthesized, characterized, and mechanistically discussed. They were also evaluated against three human cancer cell lines (HCT-116, HepG-2, and MCF-7) and one standard human cell line (REP1) for their in vitro anticancer activity. The results declared that seven compounds 10d , 10e , 12b , 12d , 12e , 16a , and 23a had potent anticancer activity, having IC₅₀ values in the range 2.97 to 10.31 μM. The most effective compounds 10d and 10e inhibited the growth of all screened cancer cell lines and did not reveal human toxicity.