New thiopyran-4-spiro-2′-(1,3-dithiolane):Formation mechanism and crystal structure

Ethylene trithiocarbonate reacted with dimethyl acetylenedicarboxylate to furnish tetramethyl thiopyran-4-spiro-2＇-（1,3- dithiolane）-2,3,5,6-tetracarboxylate,a new thiopyran-4-spiro-2＇-（1,3-dithiolane） heterocyclic compound,as the minor product together with the major product dimethyl 2-thioxo-1,3-dithiole-4,5-dicarboxylate.The new heterocycle was probably formed through a[2 ＋ 2]cycloaddition between ethylene trithiocarbonate and dimethyl acetylenedicarboxylate followed by a 1,3-dipolar cycloaddition or[4 ＋ 2]cycloaddition.Crystal structure of the new compound revealed that the thiopyran ring and 1,3-dithiolane moiety were perpendicular to each other.

青枯灵在稻田环境中的残留与消解动态

研究了杀菌剂青枯灵的残留分析方法及其在水稻植株、水样和土壤中的消解动态和最终残留。稻株、谷壳、糙米、水样和土壤经丙酮提取、液液分配及中性氧化铝柱净化,用高效液相色谱法测定了残留量。结果表明:青枯灵在稻株和田水中降解迅速,半衰期小于2 d,在土壤中的半衰期5.8 d。