Pyridine → Octylisothiazolon

참여 물질

반응 조건

반응 단계

To a 500 ml flask fitted with a mechanical stirrer, nitrogen inlet, and an outlet to a 10% sodium hydroxide trap was charged 20g(0.095M) of 3,3'-dithiodipropionic acid, 200 ml of chlorobenzene and 0.25 ml of pyridine. An addition funnel containing 24.9 g (0.21 M) of thionyl chloride was added and the thionyl chloride was added dropwise. The mixture was warmed to 45° C. and stirred for 2.5 hours. The mixture was not homogeneous and was stirred overnight. (The reaction was still not quite homogeneous but was carried on at this point.) The mixture was reheated to 45° C. and sparged for 15 min with nitrogen. The remaining thionyl chloride was removed by stripping under house vaccuum for 1 hr and then 50 ml of chlorobenzene was charged. The mixture was cooled to -20° C. and 6.8 g (0.096 M) of chlorine was added over 16 min. After stirring 0.5hr the mixture was warmed to 0°-5° C. and a solution of 24.6 g (0.188 M) of n-octyl amine and 9.2 g (0.188 M) of triethyl amine in 100 ml of chlorobenzene was added dropwise such that the reaction temperature remained below 5° C. (addition time 1.75 hr). The solution was allowed to warm and then heated to 35° C. During this time the reaction thickened and then thinned out. Chlorine (13.5 g, 0.19 M) was then fed over 40 min at 35° C. and the mixture was stirred for an additional 1 hr. The reaction mixture was washed with 3×400 ml of water and then the solvent was removed under vaccuum to yield 36g of 3-n-octylisothiazolone as a dark oil. Analysis by capillary gas chromatography indicated a yield of 21.8 g (53.7%) of 3-n-octylisothiazolone.

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