Ahmed F. Khattab

An unprecedented study of the rearrangement of 5,5-diazidobarbituric acids under various conditions

The unexpected parabanic acid derivatives 6a,b were obtained via unprecedented rearrangement of 5,5-diazidobarbituric acids 2a,b upon stirring in water at 50-60°C. Themolysis of diazides 2a,b in benzyl alcohol at 120–130°C afforded the tetrazole derivative 11 and/or benzyl allophanate 14.

Formation of novel pyrido[3‘,2‘:4,5]thieno [2,3-e][1,2,4]triazolo[4,3-c]pyrimidines and their acyclic C-nucleosides analogues: synthesis of 3-(Alditol-1-yl)pyridothienotriazolopyrimidines

A series of the hydrazones were prepared by the reaction of 4-hydrazino-7,9-dimethylpyrido[3′,2′:4,5]thieno [2,3-d]pyrimidine (1) with monosaccharides, and their acetylation was studied. The oxidative cyclisation of the hydrazones 3a–c gave 3-(Alditol-1-yl)-pyridothienotriazolopyrimidenes 5a–c, whose acetylation was carried out. Also, oxidative cyclisation of arylidenes 7a,b gave the pyridothienotriazolopyrimidines 8a,b.

Synthesis of Functionalized Pyrano[3,2‐c]pyridines and Their Transformations to 4‐Hydroxy‐3[(1E)‐N‐hydroxyalkanimidoyl]pyridones

Abstract Reaction of 4‐hydroxy‐6‐methyl‐2(1H)‐pyridones 1a and 4‐hydroxy‐1,6‐dimethyl‐2(1H)‐pyridones 1b with diethyl malonates 2a–e leads to the formation of pyrano[3,2‐c]pyridines 4a–j. Degradation of 4a–i affords the corresponding ketones 6a–i. Condensation of ketones 6a–i with hydroxyl amine or phenyl hydrazine hydrochloride is described.