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| Synthesis of Novel Chiral Thioureas Derived from D-mannitol and Their Application in Henry Reaction |
| LIU Miao-xi1a, WANG Xiao-gang1b, HE Wei1a, LIU Peng1a |
| a. School of Pharmacy; b. Company 19, Battalin 5, Cadet Brigade, 1.Fourth Military Medical University, Xi’an 710032, China |
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Abstract An intermediate of chiral amine with 1,3-dioxane structure(4) was obtained by a four-step reaction of condensation, alcoholysis, azidation and reduction, using D-mannitol as material. Three novel chiral thioureas(6a~6c) were synthesized by the reaction of 4 with 3,5-bis(trifluoromethyl)phenyl isothiocyanate, epiquinine isothiocyanate and quinidine isothiocyanate, respectively. The structures were characterized by 1H NMR, 13C NMR, IR and HR-MS. The catalytic performances and selectivities of 6 were investigated by Henry reaction of nitrocarbol with benzaldehyde. The results showed that the yield and enantioselectivity of (S)-2-nitrophenylethan-1-ol were 69% and 78%, respectively, using Et3N as base, toluene as solvent, 5 mol% 6b as catalyst at -30 ℃ for 24 h.
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Received: 08 October 2015
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2016, Vol. 24 
