Cyclohexylamine → Dicyclohexylamine

Temperature

20 °C

Sodium azide (52.2 g, 0.803 mol) was added to water (200 mL) in a 2 L three-neck flask fitted with a mechanical stirrer and a reflux condenser. A gas outlet tube from the condenser was connected to the sidearm of a 4 L filter flask containing bleach (3 L) in order to destroy the methanethiol evolved during the reaction. A rubber stopper was placed lightly on the top of the filter flask, and the stirred bleach was cooled in an ice bath. Compound 3 (185 g, 0.730 mol) and isopropanol (400 mL) were added to the NaN3 solution, and the thick slurry stirred and slowly heated to reflux. A clear solution was obtained and the evolution of gaseous methanethiol become vigorous before reflux was reached. The heating was discontinued for several minutes to allow the rate of methanethiol evolution to diminish. The solution was then gently refluxed for 1.5 h, after which the light yellow solution was cooled to room temperature. To the solution was added 50% aqueous NaOH solution (73 g, 0.91 mol), raising the solution temperature to 55° C. After 10 min the light orange solution was cooled to 10° C. The solution was acidified with concentrated hydrochloric acid (140 mL); the resulting pH was 3. Another 10 mL of concentrated hydrochloric acid was added, and the separated oil was extracted with dichloromethane (400 and 2×100 mL). The extract was dried (MgSO4), filtered, and evaporated in vacuo to give an oil (170 g). The oil was dissolved in acetone (450 mL) and cooled in an ice bath to 20° C. Cyclohexyl amine (145 g, 1.46 mol) was added with stirring; a precipitate quickly formed. After cooling 0.5 h the solid was filtered and washed with acetone to give the bis-cyclohexylamine salt (4) (209 g, 66%), mp 205° C. (dec).

1. customa precipitate quickly formed
2. temperatureAfter cooling 0.5 h the solid
3. filtrationwas filtered
4. washwashed with acetone

ORD record

ord-0bce119566b1494d96e345f46e367f86

Source dataset

uspto-grants-2000_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06043013