(±)-1-Methyl-7-oxabicyclo[2.2.1]heptan-2-one (1) is a versatile chiral building block for terpenoids. It could be applied in total synthesis of eudesmanes, agarofurans and norcarotenoids. Compound (±)-1 was ...(±)-1-Methyl-7-oxabicyclo[2.2.1]heptan-2-one (1) is a versatile chiral building block for terpenoids. It could be applied in total synthesis of eudesmanes, agarofurans and norcarotenoids. Compound (±)-1 was reduced to alcohol (±)-2. Compound (±)-2 was esterified with commercial available optically pure (S)-(+)-mandelic acid. The diastereomeric ester mixture was separated with preparative HPLC method. After oxidation of the saponified products of diastereomeric ester (+)-4 and (+)-5 respectively, both optically pure enantiomers of compound 1 were prepared for the first time in four steps with an overall yield of 70%. The absolute configurations of (+)-1 and (-)-1 were determined as (+)-(1R,4S)-1-methyl-7-oxabicyclo[2.2.1] heptan-2-one and (-)-(1S,4R)-1-methyl-7-oxabicyclo[2.2.1] heptan-2-one.展开更多
将三(1-氧代-1-磷杂-2,6,7-三氧杂双环[2,2,2]辛烷-4-亚甲基)磷酸酯(trimer)用于阻燃聚碳酸酯(PC),研究了它对 PC 阻燃性能、机械性能、热分解行为及灼烧残炭的影响。将 trimer 用于 PC 时,其质量分数为8%的用量即可使 PC 的阻燃级别达...将三(1-氧代-1-磷杂-2,6,7-三氧杂双环[2,2,2]辛烷-4-亚甲基)磷酸酯(trimer)用于阻燃聚碳酸酯(PC),研究了它对 PC 阻燃性能、机械性能、热分解行为及灼烧残炭的影响。将 trimer 用于 PC 时,其质量分数为8%的用量即可使 PC 的阻燃级别达到 UL 94 V-O(试样厚度为3.2 mm)级,极限氧指数达33%。值得注意的是,加入 trimer 可改善 PC 的拉伸强度,特别是弯曲强度及弯曲模量。热分析数据表明,trimer 可提前并加速 PC 的交联成炭,但不能提高PC 的成炭率。此外,扫描电子最微镜照片显示,trimer 可使炭层轻微发泡膨胀,也可改善炭层质量。展开更多
文摘(±)-1-Methyl-7-oxabicyclo[2.2.1]heptan-2-one (1) is a versatile chiral building block for terpenoids. It could be applied in total synthesis of eudesmanes, agarofurans and norcarotenoids. Compound (±)-1 was reduced to alcohol (±)-2. Compound (±)-2 was esterified with commercial available optically pure (S)-(+)-mandelic acid. The diastereomeric ester mixture was separated with preparative HPLC method. After oxidation of the saponified products of diastereomeric ester (+)-4 and (+)-5 respectively, both optically pure enantiomers of compound 1 were prepared for the first time in four steps with an overall yield of 70%. The absolute configurations of (+)-1 and (-)-1 were determined as (+)-(1R,4S)-1-methyl-7-oxabicyclo[2.2.1] heptan-2-one and (-)-(1S,4R)-1-methyl-7-oxabicyclo[2.2.1] heptan-2-one.
文摘将三(1-氧代-1-磷杂-2,6,7-三氧杂双环[2,2,2]辛烷-4-亚甲基)磷酸酯(trimer)用于阻燃聚碳酸酯(PC),研究了它对 PC 阻燃性能、机械性能、热分解行为及灼烧残炭的影响。将 trimer 用于 PC 时,其质量分数为8%的用量即可使 PC 的阻燃级别达到 UL 94 V-O(试样厚度为3.2 mm)级,极限氧指数达33%。值得注意的是,加入 trimer 可改善 PC 的拉伸强度,特别是弯曲强度及弯曲模量。热分析数据表明,trimer 可提前并加速 PC 的交联成炭,但不能提高PC 的成炭率。此外,扫描电子最微镜照片显示,trimer 可使炭层轻微发泡膨胀,也可改善炭层质量。
