2-Isopropyl-5-methylcyclohexyl quinoline-2-carboxylate

In the title compound, C20H25NO2, the cyclohexyl ring adopts a slightly disordered chair conformation. The dihedral angle between the mean planes of the quinoline ring and the carboxylate group is 22.2 (6)°. In the crystal, weak C—H⋯N interactions make chains along [010].

In the title compound, C 20 H 25 NO 2 , the cyclohexyl ring adopts a slightly disordered chair conformation. The dihedral angle between the mean planes of the quinoline ring and the carboxylate group is 22.2 (6) . In the crystal, weak C-HÁ Á ÁN interactions make chains along [010].

Comment
Quinoline-2 carboxylic acid derivatives are a class of important materials as anti-tuberculosis agents, as fluorescent reagents, hydrophobic field-detection reagents, visualisation reagents, fluorescent labelled peptide probes and as antihyperglycemics. Quinoline derivatives represent a major class of heterocycles and are found in natural products (Morimoto et al., 1991;Michael, 1997), numerous commercial products, including fragrances, dyes (Padwa et al., 1999) and biologically active compounds (Markees et al., 1970;Campbell et al., 1988). Quinoline alkaloids such as quinine, chloroquin, mefloquine and amodiaquine are used as efficient drugs for the treatment of malaria (Robert & Meunier, 1998). Quinoline as a privileged scaffold in cancer drug discovery is published (Solomon & Lee, 2011).  Table 1).

Experimental
The title compound was prepared by the following procedure: To a mixture of 1.73 g (10 mmol) of quinaldic acid and 1.56 g (10 mmole) of 2-isopropyl-5-methylcyclohexanol in a round-bottomed flask fitted with a reflux condenser with a drying tube is added phosphorous oxychloride (0.150 g, 10 mmol). The mixture is heated with occasional swirling, and temperature is maintained at 348-353 K. At the end of 8 h the reaction mixture is poured in to a solution of sodium bicarbonate (2 g) in water (25 mL). The precipitated ester is collected on a filter and washed with water. The yield of crude, air dried 2-isopropyl-5-methylcyclohexyl quinoline-2-carboxylate is isolated in 1.71 to 1.85 g (65-70 %) yield. Xray quality crystals were obtained by recrystallization from absolute ethanol by slow evaporation (M.pt: 414-416 K).

Refinement
All of the H atoms were placed in their calculated positions and then refined using the riding model with C-H lengths of 0.95-1.00 Å, and with U iso (H) = 1.2-1.5U eq (C). Two reflections, i.e.

Figure 1
ORTEP drawing of (I) showing the labeling scheme with 50% probability displacement ellipsoids.