Vilsmeier reagents such as N-methyl-N-phenylchloroiminium chloride are readily deprotonated by tert-amines even in POCl3 solution. The resulting transient intermediates, aminochlorocarbenes, are nucleophilic (ie umpoled Vilsmeier reagents) and are trapped with electrophiles. In this way dimers [1, 2-bis (N-methylanilino)-1, 2-dichloroethanes] 3,'trimers'(indolo [3, 2-b] quinolininium chlorides) 4 and 5,'tetramers'(2, 2′-bis-indoles) 11 ...
