Synthesis of hydroximoyl chlorides from aldoximes and benzyltrimethylammonium tetrachloroiodate (BTMA ICl4)

Benzyltrimethylammonium tetrachloroiodate (BTMA ICl4) acts as a convenient reagent to convert aldoximes to hydroximoyl chlorides by a simple procedure . When an aldoxime is treated with BTMA ICl4 in dichloromethane, the suspen sion of BTMA ICl4 shortly diasappears as the reaction proceeds. The resulti ng BTMA ICl2 can he precipitated out by adding diethyl ether. Not only stab le aromatic and heteroaromatic hydroximoyl chlorides can be isolated by thi s method but also rather unstable aliphatic hydroximoyl chlorides can be ge nerated in situ. 1,3-Dipole trapping with a dipolarophile is performed in o ne flask and in some cases the chlorination is successfully performed in th e presence of dipolarophile and triethylamine. Effect of MS 4A has been exa mined. (C) 2000 Elsevier Science Ltd. All rights reserved.