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

4-Chloro-1-(2-methylpropyl)-1H-imidazo[4,5-c]quinoline is a chemical product that has been used as a photosynthetic activator in weed science and pest control. It has been shown to significantly increase the growth rate of wheat, soybean, and oilseed crops. It is also effective at controlling weeds by inhibiting their ability to produce chlorophyll, thereby preventing them from photosynthesizing. 4-Chloro-1-(2-methylpropyl)-1H-imidazo[4,5-c]quinoline has also been shown to be an effective herbicide for agricultural use.

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

4-Chloro-1-(2-methylpropyl)-1H-imidazo[4,5-c]quinoline is prepared by the reaction of 2-chloro-N⁴-(2-methylpropyl)quinoline-3,4-diamine and orthoformic acid triethyl ester. The specific synthesis steps are as follows:
A suspension of 2-chloro-N4 -(2-methylpropyl)-3,4-quinolinediamine (35 g) and triethylorthoformate (52.3 g, 2.5 eq) was heated at 145° C. for 10 h, during which time ethanol was removed by distillation. The resulting mixture was cooled to room temperature and the solid was removed by filtration. The solid was dissolved in hydrochloric acid (100 mL, 4N). The resulting solution was added to a solution of sodium hydroxide. The precipitate was filtered and washed with water to afford the product 4-chloro-1-(2-methylpropyl)-1H-imidazo[4,5-c]quinoline in 92% yield.

[1] Patent: WO2006/70379, 2006, A1. Location in patent: Page/Page column 9-10
[2] Patent: WO2006/70408, 2006, A2. Location in patent: Page/Page column 7; 12-13