(Raw Data Set) An efficient synthesis of 4-Thiocyanato anilines using benzyltrimethylammonium dichloroiodate and ammonium thiocyanate in DMSO:H2O

Abstract

Treatment of a variety of 2(3)- mono-substituted anilines with benzyltrimethylammonium dichloroiodate (1.2 equiv) and ammonium thiocyanate (1.2 equiv) in DMSO:H2O (9:1) at 70 degrees C gave the corresponding 4-thiocyanato-2(3)-substituted anilines in excellent isolated yields (60-99%; ave. yield for all anilines = 90%). The reaction worked well for substrates with 2-halo, 2-alkoxy, 2-aryloxy, 2-alkyl, 2-dialkylamino, 2-N-sulfonylamino, 2-alkyn-1-yl, 2-cyano, 2-acyl, 2-sulfonyl, and 2-heteroaryl substitution. 3-Substituted, 3,5- or 2,6-disubstituted anilines and substituted phenols were also well tolerated. 4-Substituted anilines gave the corresponding 2-aminobenzothiazole products, whereas 4-, 5-, 6-, or 7-substituted indoles were not reactive. Regioselective thiocyanation of 2-quinoline, 3-amino1-methylpyrazole, 2-amino-4-phenylthiazole, and 2-phenylimidazo[1,2-a] pyridine was achieved in 93-99% yield, thus demonstrating the broad-substrate scope for this thiocyanation reaction. (c) 2022 Elsevier Ltd. All rights reserved.