A mild one-pot synthesis of 2-iminothiazolines from thioureas and 1-bromo-1-nitroalkenes

Abstract

A mild method to access functionalized 2-iminothiazolines in a facile and efficient manner has been developed.

Developments and applications of α-bromonitrostyrenes in organic syntheses

“…The synthesis of 2-iminothiazolines 59 can be obtained from the cyclization of 1,3-disubstituted thioureas 58 with 1-bromo-1-nitroalkenes 1 ( Scheme 26 ). 56 At first, Michael addition between 1-bromo-1-nitroalkenes 1 and 1,3-diphenylthiourea 58 produced intermediate II, which then underwent a tautomerism and nucleophilic substitution to afford the five-membered ring intermediate III. The deprotonation of III by bromide anion, followed by the oxidation yielded product 59.…”

Bromonitroalkenes as efficient intermediates in organic synthesis

“…The method provides a mild, metal-free synthesis of 2-iminothiazolines from easily accessible starting materials under mild conditions and short reaction times. 54…”

“…The method provides a mild, metalfree synthesis of 2-iminothiazolines from easily accessible starting materials under mild conditions and short reaction times. 54 The authors' proposed mechanism reveals that the first event is the aza-Michael addition of thiourea to bromonitroalkene in the presence of Et 3 N to afford 148. Then, nucleophilic substitution of bromide with the sulfur atom provides the intermediate 149, followed by deprotonation with Et 3 N to afford the intermediate 150.…”

Cascade Reaction of Tertiary Enaminones, KSCN, and Anilines: Temperature-Controlled Synthesis of 2-Aminothiazoles and 2-Iminothiazoline

“…Thus, considerable attention has been paid to the development of efficient strategies for the preparation of a 2-aminothiazole derivative with structural diversity . The most common methods for the synthesis of polysubstituted 2-aminothiazoles are mainly based on the direct condensation of α-halocarbonyl compounds with substituted thiourea (Hantzsch reaction, Scheme , eq 1) . Although the Hantzsch method has substantially contributed to the construction of 2-aminothiazoles, new and concise methods still need to be developed to afford 2-aminothiazole derivatives from other different readily available starting materials.…”