N-Cyano-N-phenyl-p-toluenesulfonamide

Introduction

N-Cyano-N-phenyl-p-toluenesulfonamide (NCTS) is a bench-stable colorless solid (mp 85–87 °C)[1]. It is commercially available and can be readily synthesized by Kurzer’s method[2] on a large scale from inexpensive phenylurea and p-toluenesulfonyl chloride with pyridine as solvent[2] (Scheme [1]). The preparation of NCTS does not require the use of toxic cyanogen halides; thus, comparing to other cyanating reagent, such as p-toluenesulfonyl cyanide,[3] N-cyanobenzimidazole,[4] N-cyanophthalimide[4b] [c] and especially metal cyanide[5], NCTS can be accessed more safely.

Scheme 1

Owing to the N–CN bond, NCTS serves as an electrophilic cyanating reagent. In addition, NCTS is employed in the direct C–H cyanation to a variety of (hetero)arenes. The byproduct for the cyanation using NCTS is N-phenyl-p-toluenesulfonamide, an environmentally benign compound. The cyanation process features the advantages of wide substrate scopes, safe operations, and moderate to excellent yields.

• References

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