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

• Published in: Journal of heterocyclic chemistry Vol. 38; no. 2; pp. 435 - 441
• Main Authors: Rodriguez-Franco, MI, Dorronsoro, Martinez, A, Castro, A
• Format: Journal Article
• Language: English
• Published: ODESSA HETERO CORPORATION 01.03.2001
• Subjects: Chemistry; Chemistry, Organic; Physical Sciences; Science & Technology; THIADIAZOLOPYRIDINIUM SALTS; DESIGN; THIOUREA; 1,2,4-THIADIAZOLINES; DESULFURIZATION; INHIBITORS; DERIVATIVES
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570380220

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 ' -alkylthioureas and N-aryl-N ' -alkylureas, whereas the heteroarylthioureas tested under similar reaction conditions afforded N-heleroaryl-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.