1-(2-Methylpropyl)-1H-imidazo[4,5-c]quinoline

Uses

Desamino Imiquimod is a pharmacologically active compound related to Imiquimod (I475000), an immune response modifier. It stimulates the production of Interferon-a.

Synthesis

Example 1 Preparation of 1-isobutyl-1H-imidazo[4,5-c]quinoline (II): 3-amino-4-isobutylaminoquinoline (215 g, 1.0 mol) was dissolved in formic acid (1000 ml), and the reaction mixture was heated to reflux at 110-115°C. The reflux reaction was maintained for 8-10 hours. Upon completion of the reaction, the excess formic acid was removed by distillation under reduced pressure and the residue was diluted with 3.5 liters of water. Subsequently, the pH was adjusted to 10-11 with 30% sodium hydroxide solution at 20 °C. The reaction mixture was cooled to 100 °C and stirring was continued for 3 h. The solid product was precipitated. The solid was collected by filtration, washed with water and dried to give 1-isobutyl-1H-imidazo[4,5-c]quinoline (221 g, 98% yield) as a white solid. Melting point: 91-94°C. Mass spectrum (m/z): M+ 226. 1H NMR (200 MHz, DMSO-d6): δ-value see attached.

References

[1] Patent: WO2006/70379, 2006, A1. Location in patent: Page/Page column 8
[2] Patent: WO2006/70408, 2006, A2. Location in patent: Page/Page column 7; 11
[3] Patent: US6348462, 2002, B1. Location in patent: Page column 22
[4] Patent: WO2014/120995, 2014, A2. Location in patent: Page/Page column 174-175