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Cyanoformamides are ubiquitous as useful components for assembling key intermediates and bioactive molecules. The development of an efficient and simple approach to this motif is a challenge. Herein, we demonstrate the effectiveness of the I2-DMSO oxidative system in the preparation of Narylcyanoformamides from N-arylcyanothioformamides. The synthetic method features mild conditions, broad substrate scope, and high reaction efficiency. Furthermore, this method provides an excellent entry to exclusively afford 2-cyanobenzothiazoles which are useful substrates to access new luciferin analogs. The structures of all new products were elucidated by multinuclear NMR spectroscopy and high accuracy mass spectral analysis. Crystal-structure determination by means of single-crystal X-ray diffraction was carried out on (4-bromophenyl)carbamoyl cyanide, 5,6-dimethoxybenzo[d]thiazole-2- carbonitrile, 5-(benzyloxy)benzo[d]oxazole-2-carbonitrile, 4,7-dimethoxybenzo[d]thiazole-2-carbonitrile, and (5-iodo-2,4-dimethoxyphenyl)carbamoyl cyanide, a key intermediate with mechanistic implications.

Cyanoformamides are prevalent as versatile building blocks for accessing synthetically useful intermediates and biologically active compounds. The development of a milder, simpler, and more efficient approach to cyanoformamides is nontrivial. Herein, we demonstrate the effectiveness of 4,5-dioxo-imidazolinium cation activation for transforming 1-acyl-1-carbamoyl oximes to cyanoformamides. By making use of the readily available and highly modifiable dichloroimidazolidinediones (DCIDs), this novel method of activation offers reactivity remarkably greater than that of other reported protocols, exhibits a high functional group compatibility with mild conditions, and could be scaled up easily. More than 30 examples are demonstrated with good to excellent yields in short reaction times. This research not only provides a mild and efficient alternative approach to assembling a portfolio of cyanoformamides but also extends the dichloroimidazolidinedione-mediated chemistry to encompass the C-C bond cleavage reaction.

A facile and efficient one-pot synthesis of cyanoformamides was developed from readily available 1-acyl-1-carbamoyl oximes mediated by phosphoryltrichloride (POCl3) under mild conditions in good to high yields.

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