Vilsmeier Haack Acetylation in Micellar Media: An Efficient One Pot Synthesis of 2‐Chloro‐3‐acetyl Quinolines

Abstract

Vilsmeier Haack (VH) acetylations of aromatic hydrocarbons have been carried out by using an N,N‐dimethyl acetamide (DMA)‐POCl₃ system to afford the corresponding acetophenones in good yield with high regioselectivity. These acetylations are dramatically accelerated in micellar media. Further it is of interest to note that cyclizations in micellar media under VH conditions are obtained to afford 2‐chloro‐3‐acetyl quinoline derivatives in good yield. This procedure works efficiently in CTAB (cetyltrimethyl ammonium bromide), SDS (sodium dodecyl sulphate), and TX (Triton‐X100) media under reflux conditions (particularly for deactivated acetanilides).

Keywords:

• Vilsmeier Haack acetylation
• Aromatic hydrocarbons
• (DMA)‐POCl₃
• Quinolines

Acknowledgments

The authors thank Nawab Shah Alam Khan, Chairman, and Nawab Mahboob Alam Khan, Secretary, of Nawab Shah Alam Khan Centre for Post‐Graduate Studies and Research, Mallepally and Prof. T. Navaneeth Rao (former Vice‐Chancellor, Osmania University, Hyderabad) for their constant encouragement.

Notes

^aSelected spectral data. 6‐Bromo‐2‐chloro‐3‐acetyl quinoline (1h): M.P. 122°C, ¹H‐NMR (CDCl₃) δ 2.1 (s, 3H, COCH₃) 7.0–7.4 (m, 4H, Aromatic): IR (KBr), 1590 (C = N), 1670 (C = O); Mass: 283 (M⁺). 2,8‐dichloro‐3‐acetyl quinoline (1i): M.P. 82°C, ¹H‐NMR (CDCl₃) δ2.2 (s, 3H, COCH₃), 7.0–8.4 (m,4H, Aromatic), IR (KBr), 1590 (C = N), 1670 (C = O); Mass: 239 (M⁺). 6‐Nitro‐2‐chloro‐3‐acetyl‐quinoline (1o). M.P. 130°C, ¹H‐NMR (CDCl₃), δ 2.3 (s, 3H, COCH₃), 7.0–7.4 (m, 4H, Aromatic), IR (KBr) 1590 (C = N). 1670 (C = O); Mass: 250 (M⁺).