排序方式: 共有43条查询结果,搜索用时 15 毫秒
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以L-酪氨酸为原料,经由羧基、氨基保护后,对其侧链酚羟基进行修饰,得到两个未见文献报道酪氨酸的衍生物Ia,Ib,其总收率分别为74.5%,75.6%,合成方法简便,成本低廉,具有较高的商业应用价值.化合物结构经MS,IR,1H NMR和13C NMR的验证.Abstract: The carboxyl and amino groups of L-tyrosine were protected with methyl esterification for the carboxyl group and with tert-butyloxy carbonylation for the amino group, and then the hydroxyl group was alkylated with n-butyl bromide and methyl-bromoacetate alternatively. Thus two new L-tyrosine derivatives (Ia and Ib) were obtained with an overall yield 74.5% and 75.6%, respectively. The established synthesis technology of L-tyrosine derivatives has advantages over other known ways for its facile operation and low cost. Therefore it has a promising prospect of commercial application. The chemical structures of the compounds were confirmed by MS, IR, 1H NMR and 13C NMR. 相似文献
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微胶囊谷物保护剂“保粮磷”防治储粮害虫研究 总被引:2,自引:0,他引:2
微胶囊杀螟硫磷(单剂)5ppm剂量拌合小麦,一年储藏期中取样作生物测定,对玉米象、赤拟谷盗死亡率100%,对谷蠹死亡率≥80%,超过非微胶囊杀螟硫磷15ppm剂量处理小麦的药效;微胶囊混剂(杀螟松+2%溴氰菊酯)的制剂拌合小麦的药效试验及模拟农户储粮试验证明,杀螟松2.5~3ppm(+溴氰菊酯0.04ppm)就能在一年储存期中保持良好的防虫效果。微胶囊剂拌合小麦,杀螟松在粮食内的残留量在半年存储期内显著低于非微胶囊剂的处理。发芽试验证明,对种子发芽率没有丝毫影响。制剂在54±2℃两周条件下分解损失<10%,储藏稳定性好。 相似文献
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在局部虫害较严重的稻谷仓进行为期8天的局部环流熏蒸,结果表明:07型粮堆局部处理机进行粮堆局部环流熏蒸有效处理面积达20m^2左右(深度5~6m),经一次投药0.8kg,大部分区域PH3浓度100~300mL/m^3可保持6~8天,边沿区域(离中心半径2.6m)的上层及表层PH3浓度稍低。实仓杀虫效果检查:处理区域内表层0.5m以下害虫全部杀死,对表层发现的少许活虫,也提出了相应的对策。 相似文献
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碱性水溶液中,尿嘧啶和多聚甲醛经羟醛缩合反应可直接生成5-羟甲基尿嘧啶.通过对反应物投料比、碱种类、碱液浓度和反应温度的研究,探讨了影响反应收率的主要因素,发现了制备5-羟甲基尿嘧啶的最佳实验条件.放大实验证实了研究结果.合成方法简便,成本很低,收率很高(96%),具有很高的工业应用价值. 相似文献
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采用叔丁氧羰基(Boc)、苄氧羰基(Z)和芴甲氧羰基(Fmoc)这3种保护基保护苯丙氨酸的氨基,顺利得到3个保护的苯丙氨酸(Ⅲa-c);保护的苯丙氨酸与精左氨基物(Ⅱ)进行偶联,较高收率地合成了3个未见文献报道的目标分子(Ⅳa-c),产物的结构通过IR,1H NMR,13C NMR测试得到了验证.对氨基酸的保护及偶联反应的条件进行了优化.Abstract: With butyloxycarbonyl (Boc), benzyloxycarbonyl (Z) and fluorenylmethyloxycarbonyl (Fmoc)as protecting groups, three amino group-protected L-phenylalanines were successfully obtained. Aided by different coupling reagents, three new conjugated products of the amino group-protected L-phenylalanines with chloramphenicolbase were synthesized with a yield of 70%-78%. The chemical structures of the new compounds were confirmed by IR, 1H NMR, and 13C NMR.The conditions for the reactions mentioned above were optimized. 相似文献
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以甲基毒死蜱和防虫磷应用于稻谷储藏生产性试验、并逐月取样进行室内生物测定。试验证明,甲基毒死蜱10ppm 与防虫磷30ppm 相比:对于防治米象、玉米象,谷蠹效果相当;对于米虱类甲基毒死蜱10ppm 明显优于防虫磷30ppm;而对于杂拟谷盗前者略逊于后者。两者应用于实仓稻谷储藏一年均无虫害发生. 相似文献