Studies on the reactivity of some N-aryl- and N-heteroaryl-N'-alkylthioureas towards electrophilic reagents. Synthesis of new N-pyridylthioureas and thiazolines maría

✍ Scribed by Isabel Rodríguez-Franco; Isabel Dorronsoro; Ana Martínez; Ana Castro

• Publisher: Journal of Heterocyclic Chemistry
• Year: 2001
• Tongue: English
• Weight: 117 KB
• Volume: 38
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570380220

✦ Synopsis

Abstract

Here in we describe our findings about the behaviour of some N‐aryl‐ and N‐heteroaryl‐N'‐alkylthioureas towards electrophilic reagents. In acid medium, the treatment of thioureas bearing aryl groups with 4‐chloropyridine in 2‐propanol yielded N‐aryl‐N‐(4‐pyridyl)‐N'‐alk;ylthioureas and N‐aryl‐N'‐alkylureas, whereas the heteroarylthioureas tested under similar reaction conditions afforded N‐heteroaryl‐N'‐alkyl‐O‐(2‐propyl)isoureas. The reaction of N‐(5,6,7,8‐tetrahydronaphth‐1‐yl)‐ and N‐(2‐benzimidazolyl)‐N'‐butyl‐thiourea with propargyl bromide in acid medium led to the formation of 2‐butylimino‐3‐arylthiazolines, in a regioselective way. However, when this reaction was carried out in basic conditions the regioselectivity failed and a mixture of isomeric thiazolines was obtained. The Z‐ or E‐configuration of the imino group of the synthesized thiazolines was studied by molecular modelling and by selective nuclear Overhauser experiments in nuclear magnetic resonance.