I₂‐Promoted [3+2] Cyclization of 1,3‐Diketones with Potassium Thiocyanate: a Route to Thiazol‐2(3H)‐One Derivatives

Abstract

An I2‐promoted strategy has been developed for the synthesis of thiazol‐2(3H)‐one derivatives from 1,3‐diketones with potassium thiocyanate. This [3+2] cyclization reaction involves C−S and C−N bond formation and exhibits good functional group tolerance. A series of thiazol‐2(3H)‐one derivatives are obtained in moderate to good yields.

Iodine‐Mediated Three‐Component Strategy to Synthesize 2‐Aminothiazoles from β‐Diketones/β‐ketoesters, Arylamines and Ammonium Thiocyanate

“…In order to support the reaction mechanism, the progress of the reaction was analyzed by mass spectrometry at 2 mins. Based on the mass data and previous literature report, [9b] herein we proposed the plausible formation of intermediates B or B’ and C or C’ along with product 3 aa during the course of the reaction (Scheme 2f, see ESI for Mass spectrum).…”

“…Next, Yan et al. (2021) demonstrated an I 2 ‐promoted annulation reaction for synthesizing thiazol‐2(3 H )‐ones using 1,3‐diketones and potassium thiocyanate (Scheme 1c) [9b] . In the same year, Retailleau and Nguyen disclosed a base‐catalyzed reaction of chalcones, isothiocyanates, and elemental sulfur to produce thiazole‐2‐thiones (Scheme 1d) [10] .…”

Preparation of 4-Arylthiazol-2(3H)-ones and the Three-Component Synthesis of Multidentate 5,5′-Methylenebis[4-arylthiazol-2(3H)-one] Ligands

“…1,2 The preparation of general thiazoles includes several routes and approaches, 2 but, particularly, the family of thiazol-2(3H)-one heterocycles can be synthesized from -thiocyanatoacetophenones under acidic conditions (Scheme 1a), 3 using metal-mediated terminal alkynes and isocyanate deriva-tives (Scheme 1b), 4 or by hydrolysis of the previously obtained 2-imino precursors (Scheme 1c), 5 or even from the corresponding 2-(3H)-thiones (Scheme 1d). 6,7 Scheme 1 Previous synthesis of thiazol-2(3H)-ones 2…”

“…Paper Synthesis 1 H NMR (300 MHz, DMSO-d 6 ):  = 11.52 (br s, 2 H), 7.49 (d, J = 5.1 Hz, 1 H), 7.05 (d, J = 8.4 Hz, 4 H), 6.98 (dd, J = 13.4, 4.2 Hz, 2 H), 6.80 (d, J = 8.4 Hz, 4 H), 5.59 (s, 1 H), 3.75 (s, 6 H). 13 C NMR (75 MHz, DMSO-d 6 ):  = 170.9 (2 × CO), 160.…”

Selective Thiocyanation and Aromatic Amination To Achieve Organized Annulation of Enaminone with Thiocyanate

“…We speculate that if thiazole could be first constructed and then followed by further cyclization via regioselective aromatic C–N bond formation to build a benzimidazole moiety, isomerization might be avoided. Thiocyanate-involved reactions have provided the possibility for the above hypothesis . Various initiators such as persulfate, N -halosuccinimide, visible light, and electricity have been employed to promote thiocyanation of various nucleophiles, leading to sulfur-containing compounds.…”