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Article Dans Une Revue Tetrahedron Année : 2021

Diastereoselective synthesis of new Thiazolyl-Indazole derivatives from R-carvone: A combined experimental and theoretical study

Résumé

The reaction of (R)-carvone and (R)-pulegone thiosemicarbazones with phenacyl bromide yields two new thiazoles: (R)-2-(2-(5-isopropyl-2-methylcyclohex-2-enylidene) hydrazinyl)-4-phenylthiazole, I and (3aR,6R)-3,3,6-trimethyl-2-(4-phenylthiazol-2-yl)-3,3a,4,5,6,7-hexahydro-2H-indazol-3a-ol, II, respectively. While HRMS and NMR spectroscopic data confirm the expected structure of I, they show that the product from (R)-pulegone undergoes rearrangement and oxidation to give II. The orientation of the OH group in II produces two possible diastereoisomers; (3aR,6R) and (3aS,6R). X-Ray analysis was used to assign the (3aR,6R) configuration to II. Energetic analysis with the M052-X functional with 6-31+G(d,p) basis set showed that the (3aR,6R) is more stable than the (3aS,6R) diatereoisomer by approximately 4.5 kcal/mol. The dimerization of the (3aR,6R) isomer of II was studied computationally via two types of hydrogen bonding interactions: (OH⋯O), as the conventional hydrogen bonding, and the interaction of the OH group with the aromatic ring (OH⋯Ar). We find that these two modes of polymerization are approximately isoenergetic.

Dates et versions

hal-03551192 , version 1 (01-02-2022)

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Citer

A. N’ait Ousidi, M.Y. Ait Itto, A. Auhmani, M. Loubidi, A. Riahi, et al.. Diastereoselective synthesis of new Thiazolyl-Indazole derivatives from R-carvone: A combined experimental and theoretical study. Tetrahedron, 2021, 78, pp.131830. ⟨10.1016/j.tet.2020.131830⟩. ⟨hal-03551192⟩
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