A Highly Efficient Catalyst for the Suzuki‐Miyaura Cross‐Coupling Reaction of 5‐(5‐chloropyridin‐3‐yl)‐3‐methyl‐1,3,4‐oxadiazol‐2(3H)‐one

Abstract

A highly efficient protocol for the synthesis of diverse aryl (heteroaryl) substituted pyridyl oxadiazol‐2(3H)‐one analogues using Suzuki‐Miyaura cross‐coupling strategy under microwave enhanced conditions is developed. The method is found to be compatible with a wide range of aryl (heteroaryl) boronic acids.

Application of Palladium Based Precatalytic Systems in the Suzuki‐Miyaura Cross‐Coupling Reactions of Chloro‐ Heterocycles

“…The instability of the oxadiazolone nuclei under prolonged basic and heating conditions is well reported. So we decided to utilize the microwave irradiation for the synthesis of diversely substituted analogues [82] (Scheme 13).…”

Electrochemically promoted annulation of aldehydes and carbazates: access to 2-alkoxy/aryloxy-5-substituted 1,3,4-oxadiazole and 1,3,4-oxadiazol-2(3H)-one derivatives

“…1). [3][4][5][6][7][8][9] 1,3,4-Oxadiazol-2(3H)-one has been applied as a backbone for the synthesis of functionally vital compounds, for example, 3,5-disubstituted 1,3,4-oxadiazole-2(3H)-ones. 7,[10][11][12][13] In the case of 1,3,4-oxadiazoles, the 2 and 5 positions of the heterocyclic ring have been substituted with oxygen-and carbon-containing moieties, respectively, eventually forming a plethora of final products.…”

“…Surprisingly, in contrast to its analogs, tert-butyl carbazate produced a minor amount of the expected desired product, 2-(tert-butoxy)-5-phenyl-1,3,4-oxadiazole, when it was reacted with benzaldehyde (1) under standard conditions; instead, 5-phenyl-1,3,4-oxadiazol-2(3H)-one (10a) was obtained as the major product. In view of the important pharmacological activity of 5-substituted-1,3,4-oxadiazol-2(3H)-ones [2][3][4][5][6][7][8][9] and their utility as building blocks for 3,5-disubstituted 1,3,4-oxadiazole-2(3H)-one derivatives, we then investigated the scope of tert-butyl carbazate to form various 5-substituted 1,3,4oxadiazol-2(3H)-ones, as illustrated in Table 4. Various aromatic aldehydes were employed starting with arylaldehydes with para substituents (Me, OMe, CN, CF 3 , Cl, Br) on the benzene ring.…”