The regioselective addition-elimination of 3-acetyl-4-methoxy-2-butenolide and 3-(1-methoxy ethylidene)furan-2,4-dione having enol ether with different amines yielded novel stable enaminone derivatives in ethanol solution. Their structures were elucidated by 1 H NMR, 13 C NMR, HRMS and X-ray diffraction data. Among of them, the Z/E isomers were observed for 3-(1-aminoethylidene)-furan-2,4-dione. The structures of byproducts for preparing intermediates and title compounds were also characterized.
The α-D-ribose and α-D-xylose C(5)-aldehyde derivatives (1 and 2) were prepared through four and two steps using 1,2:5,6-di-O-isopropylidene-α-D-glucofuranose as raw material. Then 1 and 2 reacted with hydantoin phosphonate and 2-thiohydantoin by Wittig-Horner and Knoevenagel reaction to afford 3 pairs of E and Z isomers of target products 3~5. Their structures were elucidated by 1 H NMR, 13 C NMR, IR, MS and X-ray diffraction. The preliminary bioassay results showed that some of them have certain fungicidal activities against 7 plant pathogens at the concentration of 50 μg/mL.
The total synthesis of 3,7-dimethyl-7-hydroxy-2-octen-1,6-olide and (E)-6,7-dihydroxy-3,7-dimethyl-2-octenic acid were carried out though Wittig reaction, hydrolyzation, epoxidation and intramolecular cyclization or ring-opening in overall yields of 6.4% and 23.7% using 6-methyl-5-hepten-2-one as raw materials, and their structures were characterized by 1 H NMR, 13 C NMR and ESI-MS spectral data.
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