RT Journal Article
T1 Reaction of unsymmetrical -bromo-1,3-diketones with N-substituted thioureas: regioselective access to 2-(N-arylamino)-5-acyl-4-methylthiazoles and/or rearranged 2-(N-acylimino)-3-N-aryl-4-methylthiazoles.
A1 Aggarwal, Ranjana
A1 Sharma, Shilpa
A1 Sanz, Dionisia
A1 Claramunt, Rosa M.
A1 Delgado, Patricia
A1 Torralba, M. Carmen
A1 Torralba Martínez, María Del Carmen
AB The present study reports some fascinating results of Hantzsch's [3 + 2] cyclic condensation of α-bromo-1,3-diketones, a tri-electrophilic synthon generated in situ by bromination of 1,3-diketones using the mild brominating reagent NBS with trinucleophilic N-substituted thioureas. Interestingly, out of a total of 20 combinations, 10 resulted in the exclusive formation of the desired 2-(N-arylamino)-5-acyl-4-methylthiazoles regioselectively, seven led to the formation of unexpected 2-(N-acylimino)-3-N-aryl-4-methylthiazoles through an interesting C–N acyl migration, and three furnished a mixture consisting of both products. The regioselectivity pattern of the two products may be attributed to a greater electrophilicity of the carbonyl carbon of the acetyl group than that of the acyl group towards both nitrogens of thiourea. The structures of the thiazole derivatives were unambiguously assigned using 1H-NMR, 13C-NMR, and rigorous heteronuclear 2D-NMR [(1H–13C) HMQC and (1H–13C) HMBC] spectroscopic techniques. The outcomes of the spectroscopic experiments were further concurred through X-ray crystallographic studies, and a plausible mechanism for acyl migration was proposed for the formation of the unexpected rearranged product.
PB Royal Society of Chemistry
YR 2024
FD 2024-11-08
LK https://hdl.handle.net/20.500.14352/115833
UL https://hdl.handle.net/20.500.14352/115833
LA eng
NO RSC Adv., 2024,14, 35585
NO Council of Scientic and Industrial Research (CSIR), New Delhi, India
NO Haryana State Council for Science and Technology (HSCST)
NO Spanish Ministerio de Economia, Industria y Competitividad
DS Docta Complutense
RD 22 abr 2025