Synthesis of heterocycles from arylation products of unsaturated compounds: XVIII. 5-Arylfuran-2-carboxylic acids and their application in the synthesis of 1,2,4-thiadiazole, 1,3,4-oxadiazole, and [1,2,4]triazolo[3,4-b][1,3,4]thiadiazole derivatives

• Published in: Russian journal of organic chemistry Vol. 45; no. 4; pp. 541 - 550
• Main Authors: Gorak, Yu. I., Obushak, N. D., Matiichuk, V. S., Lytvyn, R. Z.
• Format: Journal Article
• Language: English
• Published: Dordrecht SP MAIK Nauka/Interperiodica 01.04.2009; Springer Nature
• Subjects: Chemistry; Chemistry and Materials Science; Chemistry, Organic; Organic Chemistry; Physical Sciences; Science & Technology; EtOH; Azimilide; Phosphoryl Chloride; Thiadiazole; Meerwein Reaction; ANTIVIRAL ACTIVITY; INHIBITION; POSSIBLE ANTICANCER AGENTS; 2-FUROIC ACID
• ISSN: 1070-4280; 1608-3393
• DOI: 10.1134/S1070428009040125

Arylation of furan-2-carboxylic acid or its methyl ester with arenediazonium chlorides in the presence of copper(II) chloride gave the corresponding 5-arylfuran-2-carboxylic acids or methyl 5-arylfuran-2-carboxylates. 5-Arylfuran-2-carbonyl chlorides reacted with potassium thiocyanate and then with 5-methyl-1,2-oxazol-3-amine to give 5-aryl- N -[3-(2-oxopropyl)-1,2,4-thiadiazol-5-yl]furan-2-carboxamides as a result of recyclization of intermediate isoxazolylthiourea derivatives. The reactions of 5-arylfuran-2-carbonyl chlorides with 5-(2-furyl)-1 H -tetrazole involved opening of the tetrazole ring with elimination of nitrogen molecule and led to the formation of 2-(5-arylfuran-2-yl)-5-(2-furyl)-1,3,4-oxadiazoles. 3-Substituted 6-(5-arylfuran-2-yl)-[1,2,4]triazolo[3,4- b ][1,3,4]thiadiazoles were obtained by condensation of 5-arylfuran-2-carboxylic acids with 5-substituted 4-amino-4 H -1,2,4-triazole-3-thiols in phosphoryl chloride.