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[摘要]：Ethyl 2',3'-dihydro-2-methylthio-2',4-dioxospiro[2-cyclopentene-1,3'-imidazo[ 1,2-a]pyridine]-3-carboxylates were synthesized from the reactions of 3-[bis(methylthio)methylene]-2(3H)-imidazo[1,2-a]pyridinones with ethyl 4-chloroacetoacetate in the presence of a base. The 2-methylthio group in these Spiro compounds was easily replaced with some primary and secondary amines to afford the corresponding 2-amino derivatives. Very interestingly, the proton signals of these Spiro compounds in the H-1-NMR spectra in deuteriochloroform (CDCl3) changed with an increase in the sample concentration, and the analysis for the magnitude and the direction of each proton shift disclosed the conformational change of the cyclopentenone moiety in this molecule. |
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