A Safe and Facile Route to Imidazole-1-sulfonyl Azide as a Diazotransfer Reagent

Abstract

A facile approach to the diazotransfer reagent of imidazole-1-sulfonyl azide was reported. The procedure was well optimized to clarify potential explosion risks. A high production yield as well as small batch variation was achieved even without careful pretreatment of reagents and solvents. HPLC and NMR methods to monitor the process were provided. These features made this protocol suitable for large scale preparation in academia and industry as well.

Metabolic labelling of the carbohydrate core in bacterial peptidoglycan and its applications

“…2 and Supplementary Methods). First, we modified conditions42 to produce high gram quantities of the 2-azido intermediate 4 from commercially available glucosamine HCl (Fig. 2 and Supplementary Methods).…”

Modern Organic Synthesis with α-Diazocarbonyl Compounds

“…39 However, in addition to the putative relative stability of the hydrochloride 1, serious concerns were raised regarding the safety of its preparation. 40 The first step involves the addition of sodium azide to sulfuryl dichloride to form intermediate 4 ( Scheme 14). Sulfuryl dichloride can generate hydrogen chloride upon exposure to moisture, which in turn may react with sodium azide to form the highly explosive hydrazoic acid.…”

“…They also recommend that compound 5 (free base, not the hydrochloride salt) be used as the final diazo transfer reagent and that this compound should be prepared in situ. 40 While this new protocol has been safely scaled up to 100 g, reagent 5 may not be as attractive as the widely used, and commercially available, acetamidobenzenesulfonyl azide. Another recent diazo transfer reagent is benzotriazole-1-sulfonyl azide (7) developed by Katritzky and co-workers (Scheme 16).…”

Selective Protection of Secondary Amines as the N-Phenyltriazenes. Application to Aminoglycoside Antibiotics

“…13 Work-up and silica gel chromatography then gave the azido triazenes in moderate to good yield as reported in Table 1. Yields are not improved by the use of excess benzenediazonium tetrafluoroborate as this leads to complications in isolation arsing from decomposition of the reagent.…”