7267-35-8Relevant articles and documents
Iodine-DMSO mediated conversion of Narylcyanothioformamides to Narylcyanoformamides and the unexpected formation of 2-cyanobenzothiazoles
Ahmed, Saleh A.,Al-Hindawi, Bassam,Al-Masri, Harbi Tomah,Alzamly, Ahmed,Judeh, Zaher M. A.,Moussa, Ziad,Rasool, Faisal,Saada, Sara
, p. 6133 - 6148 (2022/03/31)
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.
Conversion of imino-1,2,3-dithiazoles into 2-cyanobenzothiazoles, cyanoimidoyl chlorides and diatomic sulfur
English, Russell F.,Rakitin, Oleg A.,Rees, Charles W.,Vlasova, Olga G.
, p. 201 - 205 (2007/10/03)
Primary aromatic amines condense with 4,5-dichloro-1,2,3-dithiazolium chloride 1 to give high yields of the N-aryl imines 2 which on heating give 2-cyanobenzothiazoles 3, thus providing a simple two-step route to these heterocycles from the appropriate aniline. This thermolysis is favoured by electron donating substituents in the aniline ring, and retarded by electron withdrawing groups in favour of a second pathway in which both dithiazole sulfur atoms are lost to form cyanoimidoyl chlorides 4. This is the sole pathway when both aniline ortho positions are substituted. Analogous N-alkyl imines 5, prepared from the salt 1 and the bis(trimethylsilyl) derivatives of the amine, also decompose with loss of both sulfur atoms as singlet diatomic sulfur, S2. 4-Chloro-5-methylimino-5H-1,2,3-diathiazole 5a does this at 140-150°C and the S2 generated is intercepted with 2,3-diphenylbutadiene, 2,3-dimethylbutadiene and norbornene to give 16a, 16b and 17 respectively.
