942227-99-8Relevant articles and documents
Transition Metal-Free Synthesis of Substituted Isothiazoles via Three-Component Annulation of Alkynones, Xanthate and NH4I
Li, Jian,Li, Jiaming,Ji, Xiaoliang,Liu, Qiang,Chen, Lu,Huang, Yubing,Li, Yibiao
, p. 1059 - 1068 (2020/12/15)
A protocol was described to access diverse isothiazoles with functionalization potential via transition metal-free three-component annulation of alkynones, potassium ethylxanthate (EtOCS2K) and ammonium iodide (NH4I). A sequential regioselective hydroamination/thiocarbonylation/intramolecular cyclization cascade achieved the efficient formation of consecutive C?N, C?S and N?S bonds in a one-pot process. (Figure presented.).
3,4,5-Triarylisothiazoles via C-C coupling chemistry
Christoforou, Irene C.,Koutentis, Panayiotis A.
, p. 1381 - 1390 (2008/01/03)
The regiocontrolled preparation of triarylisothiazoles is presented. 3-Halo-5-phenylisothiazole-4-carbonitriles, 1 (hal = Cl) and 18 (hal = I), are converted into the corresponding 4-bromo derivatives 5 (3-hal = Cl) and 24 (3-hal = I) via a Hunsdiecker strategy while the 4-iodo analogues 7 (3-hal = Cl) and 22 (3-hal = I) are prepared via a Hoffmann and Sandmeyer strategy. Regioselective Suzuki, Stille and Negishi reactions occur at C-4 with both the 4-bromo- and 4-iodoisothiazoles 5 and 7, the latter being more reactive than the former. 3-Iodoisothiazoles 22 and 24 fail to give regiocontrolled Suzuki, Stille or Negishi couplings, however, 4-bromo-3-iodo-5-phenylisothiazole 24 gives the regiospecific palladium catalysed Ullmann-type reaction product 3,3′-bi(4-bromo-5-phenylisothiazole) 25. Alkali hydrolysis of 3-chloro-4,5-diphenylisothiazole 8 gives the 3-hydroxy analogue 12 which is converted into 3-bromo-4,5-diphenylisothiazole 13 with POBr3. 3-Bromoisothiazole 13 reacts with phenylzinc chloride to give 3,4,5-triphenylisothiazole 17 but fails to undergo effective Suzuki or Stille couplings. 3,5-Diphenylisothiazole-4-carbonitrile 26 is converted into the 4-bromo- and 4-iodo-3,5-diphenylisothiazoles 30 and 34 both of which are effective for Suzuki and Stille couplings. A series of triarylisothiazoles are prepared in this manner and fully characterised. This journal is The Royal Society of Chemistry.
