ChemInform Abstract: RING TRANSFORMATION OF O,N‐HETEROCYCLES. PART 11: SYNTHESIS OF 2‐AMINO‐3‐PHENACYL‐5‐PYRIMIDIN‐2‐YL‐1,3,4‐OXADIAZOLIUM BROMIDES AND THEIR RING TRANSFORMATION WITH HYDRAZINES

Abstract

Die Pyrimidinylcarbonsäurehydrazide (I) cyclisieren mit Phenylcyanat (II) zu den Pyrimidinyloxadiazolen (III), die sich von den Phenacylbromiden (IV) zu den Phenacyloxadiazoliumsalzen (V) alkylieren lassen.

Efficient Synthesis of 3,7-Diaryl-1,4-dihydro[1,2,4]triazolo[5,1-c][1,2,4]triazines

“…Triazolotriazine heterocycles are among the least known in the polyazaindolizine series 7-11 and 3,7-diaryl-1,4dihydro [1,2,4]triazolo [5,1-c] [1,2,4]triazines have been even less studied. Indeed, to the best of our knowledge, only one method for the synthesis of this class of compounds has been described so far; namely, Hetzheim and co-workers [12][13][14] have reported a synthetic pathway from 2amino-5-aryl-3-phenacyl-1,3,4-oxadiazolium bromides by ring transformation with hydrazine. Low yields and the requirement of a multistep synthesis for each building block hamper the use of this approach as a general protocol for the preparation of 3,7-diaryl-1,4-dihydro [1,2,4]triazolo [5,1-c] [1,2,4]triazines.…”

Reaction of esters of 2-substituted 5-pyrimidinecarboxylic acids with hydrazine hydrate

“…lic acids with hydrazine hydrate at 0-5't2 results in the nucleophilic substitution oJ'readiO~ elhninating groups (CI, CHjS) Hydrazides of pyrimidinecarboxylic acids and their derivatives, possessing interesting biological properties [1][2][3][4][5][6], are utilized in organic synthesis [7][8][9][10][11]. The most common method for the synthesis of hydrazides is the acylation of hydrazine by esters [12].…”