G. F. Smith, “Indoles. Part I. The Formylation of Indole and Some Reactions of 3-Formylindole,” Journal of the Chemical Society, Vol. 1, 1954, pp. 3842-3846

has been cited by the following article:

• TITLE: Ultrasonically Assisted Synthesis of Aromatic Sulfonic Acids under Vilsmeier Haack Conditions in Acetonitrile Medium

  AUTHORS: Kamatala Chinna Rajanna, Purugula Venkanna, Mukka Satish Kumar, Soma Ram Gopal

  KEYWORDS: Vilsmeier Haack (VH) Reagent; Sulfonation; NaHSO3; Sonication; Aromatic Compounds

  JOURNAL NAME: International Journal of Organic Chemistry, Vol.2 No.4, December 27, 2012

  ABSTRACT: Sulfonation of aromatic compounds (Phenols, Anilines) is triggered by Vilsmeier Haack (VH) reagent (DMF/POCl3) or (DMF/SOCl2) in the presence of NaHSO3 under Sonication and conventional stirred conditions at room temperature. The reactions afforded corresponding Sulfonic acid derivatives in very good yields. The results obtained under Sonication were enhanced when compared with the yields of the conventional method.