O-Nitrobenzenesulfonyl chloride

A stirred solution of 5.0 gm (0.077 mole) of sodium azide in 75 ml of acetone is cooled to —10°C while 15 gm (0.66 mole) of o-nitrobenzenesulfonyl chloride dissolved in 75 ml of acetone is added dropwise. The reaction mixture is stirred for 1 hr at —10°C and for 1 hr at room temperature. The solution is filtered and diluted with 500 ml of ice water. The yellow product is removed by filtration, washed with water and dried. The product is dissolved in 150 ml of warm ethanol and freed from any insoluble material by filtration. The clear filtrate is cooled to afford 12.0 gm (80%), m.p. 71°-73°C. 

Desulfuration.1 The reaction of K02 with o-nitrobenzenesulfonyl chloride results in a peroxysulfur reagent that converts thioureas, thioamides, and thiocar-bamates in CH3CN at -30° into the corresponding carbonyl compounds. Example ... 

The reaction of o-nitrobenzenesulfonyl chloride with aminotetrazole (93) in an attempt to make 94 gave instead the ring-opened isomeric sulfonylcarbamimidic azide 95 (76%). Treatment of 95 with sodium dithio-nite in aqueous potassium hydroxide solution yielded benzothiadiazine 96 in quantitative yield—possibly by ring closure of the first-formed o-aminobenzenesulfonylcarbamimidic azide (87JHC1531). 

A) o-Nitrobenzenesulfonyl Chloride.—A 3-I. three-necked, round-bottomed flask is fitted with an efficient liquid-sealed stirrer, a reflux condenser, and an inlet tube for introducing chlorine well beneath the surface of the liquid. A glass outlet tube leads from the reflux condenser to the hood. In the flask are placed 200 g. (0.65 mole) of di-o-nitrophenyl disulfide (Org. Syn. Coll. Vol. 1, 215) 1 1. of concentrated hydrochloric acid (sp. gr. 1.18), and 200 cc. of concentrated nitric acid (sp. gr. 1.42). A stream of chlorine is passed into the mixture at the rate of about two bubbles per second, and the solution is warmed on a steam bath to 70°. In about thirty minutes the disulfide melts and the solution becomes orange-red in color. After the disulfide has melted, the heating and addition of chlorine are continued for one hour. The sulfonyl chloride is separated immediately from the supernatant liquid by decantation, washed with two 300-cc. portions of warm water (70°) and allowed to solidify. The water is drained from the solid mass as completely as possible. 

Key i) o-Nitrobenzenesulfonyl chloride, ii) Trimethylsilyl quinine, /-Pr2NEt. iii) PdCl2, CUCI2, CO. 

A suspension of 4-nitro-l-(o-nitrobenzenesulfonyl)imidazole (made from 4-nitroimidazole, o-nitrobenzenesulfonyl chloride, and triethylamine) (0.745 g, 2.5mmol) and aniline (l.Og, 11 mmol) in aqueous methanol (1 1 20ml) is stirred and heated at 70°C (2h). The mixture is then steam distilled, and the hot undistilled residue is filtered to give the above product (0.41 g, 87%), m.p. 185-187°C. Cooling of the filtrate results in separation of... 

Chlorination has been carried out also in hydrochloric acid solution containing nitric acid, e.g., for preparation of o-nitrobenzenesulfonyl chloride.623 Also, thiophenols624 and heterocyclic thiols625 can be converted into sulfonyl chlorides by chlorination. 

DEHYDRATION Diethoxyaluminum chloride. Lithium n-propylmercaptide. N-Methyl-N,N -di-r-butylcarbodiimidium tetrafluoroborate. o-Nitrobenzenesulfonyl chloride. Potassium acetate. Thiobenzoyl chloride. Triphenylphosphine ditriflate. Triphenyl-phosphine methiodide. 

A solution of 67.0 g o-nitrobenzenesulfonyl chloride (0.3 mol) in 400 mL anhydrous ether was added gradually with stirring to a cooled solution of 80.0 g 1,2,3,4-tetrahydroquinoline (0.6 mol) in 120 mL anhydrous ether. After the addition was complete, the cooling bath was removed, and the mixture was refluxed for 1 h. The cooled reaction mixture was filtered, and the precipitate was washed with hot water to remove the amine hydrochloride. The residue was combined with the ether filtrate, and the solvent was stripped to give " 50 g crude product. The product was dissolved in ethanol, decolorized, and recrystallized to give 43 g l-(phenylsulfonyl)-1,2,3,4-tetrahydroquinoline as a pale yellow solid, in a yield of 47%, m.p. 131-132 C. 

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