Premixed ethyl carbamate, thionyl chloride and pyridine (which generate thiazyl chloride, N [triple bond, length as m-dash] SCl) in boiling benzene or toluene convert 2, 5-and 2, 3, 5- substituted furans into 5-acylisothiazoles regiospecifically. The reactions are much faster and generally higher yielding in boiling chlorobenzene with more thionyl chloride and with pyridine or isoquinoline as base. Under the more vigorous conditions, even fully ...
