Polystyrene-Supported Tosyl Azide

Abstract

[941-55-9]P (a cross-linked polystyrene (1% divinylbenzene) used as a reagent for diazo transfer to activated methylene groups) Alternate Name: polystyrene-supported benzenesulfonyl azide, PS-TsA. Physical Data: white polymer beads, 100–200 mesh, loading of 1.0–1.5 mmol/g, initiation temperature is 130 °C, onset temperature is 165.98 °C, peak exotherm is 192.72 °C, heat of decomposition is 0.27 cal/s/g, and BAM friction > 360 N. Solubility: this is an insoluble polymer. Form Supplied in: polystyrene-supported beads of 100–200 mesh and 1.0–1.5 mmol/g loading. Analysis of Reagent Purity: Fourier transform infrared spectroscopy (FTIR), combustion analysis. Preparative Methods: the title reagent1 can be prepared in one step by the reaction of polystyrene-supported benzenesulfonyl chloride (100–200 mesh, available from Aldrich, 51,623-6 [163894-16-4], as 1% DVB cross-linked polystyrene resin with a loading of 1.5–2.0 mmol/g) with sodium azide (1.5 equiv) in DMF/H2O (reaction complete at rt in 16 h). Purification: filter and wash with H2O, DMF, and finally with CH2Cl2. Dry under vacuum at 40 °C. Handling, Storage, and Precautions: PS-TsA is a relatively safe alternative to existing azide reagents; the reagent appears to be stable at room temperature (rt) over an indefinite period of time. Due to the toxicity and potentially explosive nature of diazo alkanes, proper precaution should be taken when using this and any other azide reagents. Disposal of azide-containing material was done in accordance with safe laboratory procedures.2