Ketene N,S-acetals reacted with b-ketoesters in the presence of Zn(NO 3 ) 2 Á 6H 2 O as catalyst, in ethanol solvent, giving 6-alkylsulfanylpyridines 4 in good yields without complicated purification procedures. Oxidization of compounds 4 with aqueous hydrogen peroxide in the presence of catalytic sodium wolframate led to the formation of 6-alkylsulfonylpyridine derivatives 5, which could be further derivatized in the 6-position by nucleophilic reactions with phenols or amines to give multisubstituted pyridine compounds 8. Bioassays indicated that some of the compounds of the type 8 have good herbicidal activity at a dose of 100 mg/L on the roots of oil rape and barnyard grass.

In this study, solid solution ceramics of (1−x)Bi0.5K0.5TiO3–xCaTiO3 (BKT‐CT, x = 0, 0.12, 0.15, 0.18, 0.21, and 0.25) were prepared. A phase transition from the tetragonal symmetry to the pseudocubic symmetry is discovered near x = 0.25. The reasons for the appearance of the pseudocubic phase were discussed. The compositions of x ≤ 0.21 show the ferroelectric ordering at room temperature. The remnant polarization (Pr) is 22.4 μC/cm2 for the x = 0.15 composition. The temperature dependence of the relative permittivity suggests two dielectric anomalies for x ≤ 0.18. The dielectric anomaly in the low‐temperature range is related to a spontaneous transition between the ferroelectric and relaxor states. The temperature (TF‐R) for the transition decreases with the CT addition, falling from 211°C for x = 0.12‐134°C for x = 0.18. Only one relaxor‐like dielectric anomaly was observed for x ≥ 0.21. The thin double ferroelectric hysteresis loops have been observed during the ferroelectric‐relaxor transition process for x ≥ 0.21. The maximum electrostrain (Sm) reaches 0.155% at 100°C for x = 0.21. The low‐temperature Raman measurement suggests the intrinsic tetragonal distortions for x = 0.25.

The compounds Hf1−xMnxO 2−δ (x = 0 ∼ 0.5) have been synthesized by conventional solid state reaction method in Ar. Rietveld analysis of X-ray diffraction data has shown that the Mn-doped HfO2 undergoes a structural transformation from monoclinic to cubic phases, which is significantly dependent on the Mn content under current synthesis conditions. The stabilized cubic structure by multivalent Mn ion doping can transform to the monoclinic structure when annealed at high temperature in air. Transmission electron microscopy and electron diffraction investigations have also confirmed the existence of the high-temperature cubic structure. A mechanism of stabilizing the high-temperature cubic phase in the Hf1−xMnxO 2−δ system has been analyzed based on considerations of manganese substitution effect for hafnium ions and oxygen vacancy formation.