6-Nitro-2-mercaptobenzothiazole Reagent for the Identification of Alkyl Dihalides HAROLD B. CUTTER' AND ALGIRD KREUCHUNAS Grasselli Chemical Department, E . I . d u Pont de Nemours & Co., Inc., Wilmington, Del. mole, is dissolved in a mixture of 30 ml. of Butyl Carbitol [2(2butoxyethoxy)ethanol] and 5 ml. of 2 X sodium hydroxide. The alkyl dihalide (0,005 mole) is added, and the mixture is refluxed. Table I gives t.he time of refluxing for the different dihalides. has n o x been extended t o include certain alkyl dihalides. The When the refluxing is completed, the mixture is cooled and reagent reacts ieadily with all primary dihalides and iTith some poured over 500 xnl. of ice Kate?. The derivatives usually secondary dihalides to r ield 2.2'-(alkvlenedithio)bi~(6-nitrosolidify under these conditions. The derivative is collected by benzothiazoles). filtration, and iyashcd Kith dilute sodium hydroxide (approsimately 1 S ) until the filtrate becomes .. . colorless or only slightly yellow, then with water, and finally with 95% ethyl Table I. Data for Derivatives Prepared alcohol. The crude product is dried, ?'i oft:ie recrystallized from acetic anhydride M.P., Sulfur, "0 Reflllu, Yield. using decolorizing charcoal, and dried Halide C.' Formula Calcd. Found Hours Vc in a vacuum desiccator over potassium 2 1.1-Dichloromethane 232-233 CijTIsX v , moderately strong. Optic Axial Plane. 100. Sign of Double Refractlon. Xegative. Acute Bisectri.;. CY = e. Extinction. Parallel and symmetrical.
CRYSTAL MORPHOLOGY
Crystal System. Orthorhonihic.
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