O-p-Toluenesulfonylhydroxylamine

[52913-14-1] C7H9NO3S (MW 187.22) InChI = 1S/C7H9NO3S/c1-6-2-4-7(5-3-6)12(9,10)11-8/h2-5H,8H2,1H3 InChIKey = OAIJQSLFIIMPOI-UHFFFAOYSA-N (powerful aminating reagent which is used for aminating five-and six-membered heterocycles; source of nucleophilic nitrogen; used in aziridination reactions) Alternate Name: tosyloxyamine, TSH. Physical Data: mp 40 °C (dec.); IR (nujol): 1353, 1176 cm−1.1 Solubility: soluble in DCM; insoluble in H2O. Form Supplied in: colorless crystals; very unstable in the pure state. The compound should be immediately dissolved in DCM and used in such solutions. Solutions in DCM can be kept for about 1 week. Preparative Methods: TSH can be generated from ethyl acetohydroximate,3 tert-butyl N-hydroxycarbamate,1 or N,N-bis(trimethylsilyl)hydroxylamine by tosylation.4 All the three procedures are completed by hydrolysis with aqueous HClO4 or HF (eq 1). The first method seems to be the most convenient. Ethyl iminoacetate hydrochloride5 was treated with hydroxylamine to give ethyl acetohydroximate,6 which was then tosylated to give O-p-toluenesulfonylacetohydroximate.3 The latter compound was finally treated with 60% aq HClO4 at 25 °C. Aqueous work-up and extraction with DCM afforded TSH.3, 7 All steps proceeded in good yields. (1) Purification: is capricious and not necessary. Dioxane solution is poured very slowly into water under vigorous mechanical stirring to obtain the material as large crystals which can be filtrated quickly before decomposition takes place. The contents of TSH in solution can be established by iodometric titration.2 TSH can be characterized by its acetone oxime1 or its N-acylated derivatives.2 Handling, Storage, and Precautions: the neat compound is very unstable and deflagrates sometimes in minutes to a black tar. Used in DCM solution. Such solutions can be kept for about 1 week. No toxicity data are available. The compound should be used only in a well-ventilated fume hood. The neat compound should be handled with great care due to its instability.