Hydrogen Sulfide → 2-Chloro-6-fluorobenzene-1-carbothioamide

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

2-Chloro-6-fluorobenzonitrile, (99.1%, 62.2 g, 0.40 mol) was weighed into a 1-L three-necked roundbottom flask equipped with a condenser and an overhead electric stirrer, along with Et3N (78 mL, 56.6 g, 0.56 mol) and 180 mL (176.04 g, 2.23 mol) of pyridine. The reactor was purged with a slow stream of N2 and vented to a 13% bleach solution. The stirring solution was cooled to −19° C. in a CCl4/dry ice bath, and H2S gas (33.6 g, 0.99 mol) was sparged below the liquid surface at a rate of 0.4 g/min over a period of 82 min. During the gas addition, the solution temperature rose to −11° C. The yellow-green solution was allowed to gradually warm to 25° C. and stir overnight with a slow N2 purge of the reactor head space into bleach solution. The solution was poured into 1.6 L of ice water, stirred, and the resulting white crystals were collected on a buchner funnel and rinsed with additional water. After 2 h of air drying, the moist filter cake was vacuum oven dried for 5 h at 65° C. to give 54.5 g of 2-Chloro-6-Fluorobenzthioamide (72% wt. % yield), mp 155-160° C., having a GC area % purity of 98.8% and containing 1.2% 2-Chloro-6-fluorobenzonitrile.

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