O-(Mesitylsulfonyl)hydroxylamine

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[36016-40-7] C9H13NO3S (MW 215.2) InChI = 1S/C9H13NO3S/c1-6-4-7(2)9(8(3)5-6)14(11,12)13-10/h4-5H,10H2,1-3H3 InChIKey = CHKQALUEEULCPZ-UHFFFAOYSA-N (reagent for electrophilic aminations, NH2 transfer to nucleophiles) Physical Date: mp 93–94 °C.1 Solubility: very sol diethyl ether, chloroform, dichloromethane, benzene, ethanol, THF; insol water and petroleum ether. Analysis of Reagent Purity: IR (KCl) ν(cm−1) 3340, 3250, 1600, 1350, 1190, 1180.1 1HNMR (CDCl3, 300 MHz): 6.75 (2H, s, 2CH), 2.15 (9H, s, 3CH3).29 Preparative Methods: to a solution of 89 g (330 mmol) O-(mesitylsulfonyl)acetohydroxamate 1 in dioxane is added with stirring 30 mL perchloric acid (70%) at 0 °C within 10 min, and then stirred for another 10 min. After about 20 mL of the acid has been added, the reaction mixture becomes pasty. The crude reaction mixture is poured into ice-water to give a white solid of O-(mesitylsulfonyl)hydroxylamine 2 (eq 1) which is collected, washed with cold water (500 mL), then with cold petroleum ether (300 mL), and dried by maintaining suction for about 1 h; yield 55–65 g (77–92%).1 (1) The product should be stored in a refrigerator below 0 °C. Iodometric titration indicates that 2 thus prepared contains 20–30% water. It can be used for most applications. A further purification can be achieved by dissolution of a small amount in diethyl ether at room temperature and precipitation with petroleum ether. N-Boc-O-mesitylenesulfonylhydroxylamine (Boc-MSH, 1).29 2-Mesitylenesulfonyl chloride (1200 g 1.00 equiv, 5.43 mol) and tert-butyl N-hydroxycarbamate (738 g, 1.00 equiv, 5.43 mol) were dissolved in methyl tert-butyl ether (12.5 L). The mixture was purged with nitrogen and cooled to 0°C. Triethylamine (772.27 mL, 560.67 g, 5.54 mol) was added dropwise with stirring at 1 °C (time of addition: 1h 30 min, final temperature: 10 °C). The mixture was stirred for 2 h after addition. The reaction was monitored by TLC (n-hexane:ethyl acetate 7:3). After 2 h, the internal temperature was 4 °C. Et3NHCl was filtered and washed with MTBE (4 L). The liquid phase was concentrated under vacuum at 20 °C and 760 mmHg. After 5 min stirring a solid appeared, and it was filtered and n-hexane (2 L) was added to the solution to produce a second crop of solid that was combined with the first crop to give carbamic acid, N-Boc-O-mesitylenesulfonylhydroxylamine (1) (1706 g, 99% yield) as a white solid. O-Mesitylenesulfonylhydroxylamine (MSH, 2).29 Trifluoroacetic acid (5 L) was cooled to 2 °C. Carbamic acid, N-Boc-O-mesitylenesulfonylhydroxylamine (1) (1696 g, 5.37 mol) was added portionwise over 1 h. Reaction was stirred at 2 °C for 90 min and monitored by TLC (n-hexane: ethyl acetate 8:2). After 90 min, TLC showed total conversion. Crushed ice was added (2 kg) followed by water (4 L), increasing the internal temperature to 2 °C. A white solid appeared while the internal temperature increased to 8 °C. Additional ice/cold water was added (6 L). After 15 min, the solid was filtered, washed with water (20 L) until pH 7, and dried of excess water for 15 min. O-Mesitylenesulfonylhydroxylamine (MSH, 2) (1747 g, of apparent yield 151%) was isolated as a white solid. This material contained 33% of water and was stored in plastic bottles in the freezer for 2 h. Handling, Storage, and Precautions: caution: O-(mesitylsulfonyl)hydroxylamine 2 must be handled with care. A first report about a rapid decomposition when standing at room temperature appeared in 1977.2 After an explosion of 2 during storage below 0 °C,3 as suggested above,1 it is strongly recommended that 2 be prepared immediately prior to use, and that it not be stored.3 After evaluation of the stability of this high-energy reagent, it can be concluded that the use of a wet batch increases its stability, providing the possibility to use it safely up to more than 1.7 kg scale.29 Thermal hazard evaluation of this reagent has been done using ARC and DSC techniques where the onset observed for the material strongly depends on the water content. Typically, water contents ranging from 15 to 40% allow the material to be stored in kilogram quantities in the freezer over 2 h. In contrast, rigorous drying of the filtrated reagent must always be avoided.2, 30 Due to the demonstrated hazard potential of the reagent and the difficulty to manage larger amounts of compound quickly, the authors29 do not recommend the preparation of the reagent in larger than kilogram scale.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.