3-isopropyl-6(E)-(1-bromoethylidene)tetrahydro-2-pyranone | 136358-17-3

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 内酯类
• 英文名称: 3-isopropyl-6(E)-(1-bromoethylidene)tetrahydro-2-pyranone
• 英文别名: (6E)-6-(1-bromoethylidene)-3-propan-2-yloxan-2-one
• CAS: 136358-17-3
• 化学式: C₁₀H₁₅BrO₂
• 分子量: 247.132
• InChiKey: ZAMIZDLDSUXLBT-VQHVLOKHSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  3
• 重原子数：
  13
• 可旋转键数：
  1
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.7
• 拓扑面积：
  26.3
• 氢给体数：
  0
• 氢受体数：
  2

反应信息

• 作为反应物：
  描述：

  3-isopropyl-6(E)-(1-bromoethylidene)tetrahydro-2-pyranone 在 Hg(II) trifluoroacetate 作用下， 以 二氯甲烷 为溶剂， 反应 10.0h， 生成 6-[1-Bromo-eth-(Z)-ylidene]-3-isopropyl-tetrahydro-pyran-2-one
  参考文献：
  名称：

  Stereoselective Z- and E-bromoenol lactonization of alkynoic acids

  摘要：

  We have found that treatment of the silver salt of a 4- or 5-terminal alkynoic acid with bromine results in clean formation of the corresponding Z-bromo enol lactone, the result of a formal cis addition of carboxylate and bromine across the triple bond. This Z-bromo enol lactonization is highly stereoselective and gives good yields in systems that bear substituents on the internal methylene groups; yields with unsubstituted or terminally substituted alkynoic acids are modest. The E-bromo enol lactonization reaction, reported by us previously (Krafft, G. A.; Katzenellenbogen, J. A. J. Am. Chem. Soc. 1981, 103, 5459), has a broader scope and, with modifications, can be performed with high reliability. Mercury(II) salts equilibrate the Z- and E-bromo enol lactones, presumedly by a mercuric ion addition-elimination mechanism. These three reactions provide access to an array of stereoisomeric bromo enol lactone systems.

  DOI：

  10.1021/jo00024a035
• 作为产物：
  描述：

  异戊酸乙酯 在 盐酸 、 N,N-二甲基丙烯基脲 、 氢氧化钾 、 N-溴代丁二酰亚胺(NBS) 、 正丁基锂 、 potassium tert-butylate 、 氨 、 水 、 溴 、 碳酸氢钠 、 sodium amide 、 二异丙胺 、 lithium diisopropyl amide 作用下， 以 二氯甲烷 、 水 为溶剂， 反应 10.0h， 生成 3-isopropyl-6(E)-(1-bromoethylidene)tetrahydro-2-pyranone
  参考文献：
  名称：

  New approaches to the synthesis of alkyl-substituted enol lactone systems, inhibitors of the serine protease elastase

  摘要：

  We have synthesized a series of alkyl-substituted enol lactones designed to act as mechanism-based inhibitors of human neutrophil elastase (HLE). General methods were developed for the preparation of alpha- and beta-alkyl-substituted 5-hexynoic acids by the bromoform reaction on the corresponding alkynoic methyl ketone, prepared by an Eschenmoser-Tanabe fragmentation sequence from a suitably substituted cyclohexenone. By this method, beta-methyl- and beta,beta-dimethyl-5-hexynoic acids were synthesized from commercially available isophorone and 3,5-dimethyl-2-cyclohexen-1-one, respectively. Alpha-Substituted 5-hexynoic acids were prepared from 3-ethoxy-2-cyclohexen-1-one, using a novel ZnCl2-mediated alkylation that we developed; this method gives high yields of alpha'-alkylation products, even with secondary halides. The most efficient method for the preparation of alpha-substituted 5-hexynoic acids involved a four-reaction sequence-alkylation of the alpha-substituted ester with 1,4-dibromobutane, elimination, bromination and bisdehydrobromination-that proceeded in high overall yield. Protio enol lactonizations were performed with mercury(II) catalysis in CH2Cl2 or CH2Cl2-H2O. Stereo-selective Z-bromo enol lactonization was carried out by Br+-induced lactonization in the presence of Ag+. E-Bromo enol lactonization with N-bromosuccinimide in CH2Cl2 in the presence of a small amount of water gave better yields and shorter reaction times than the traditional anhydrous conditions. In studies of the inhibitory activity of these lactones toward several proteases (reported in full elsewhere), we found that the alpha-alkyl-substituted protio and bromo enol lactones 1-3 were very good inhibitors of HLE, with k(a)/K(i) values ranging from 14 500 to 37 500 M-1 s-1; the beta-alkyl-substituted enol lactones 5-8 showed only moderate inhibition of HLE.

  DOI：

  10.1021/jo00059a049

文献信息

• New approaches to the synthesis of alkyl-substituted enol lactone systems, inhibitors of the serine protease elastase
  作者：Wei Dai、John A. Katzenellenbogen

  DOI：10.1021/jo00059a049

  日期：1993.3

  We have synthesized a series of alkyl-substituted enol lactones designed to act as mechanism-based inhibitors of human neutrophil elastase (HLE). General methods were developed for the preparation of alpha- and beta-alkyl-substituted 5-hexynoic acids by the bromoform reaction on the corresponding alkynoic methyl ketone, prepared by an Eschenmoser-Tanabe fragmentation sequence from a suitably substituted cyclohexenone. By this method, beta-methyl- and beta,beta-dimethyl-5-hexynoic acids were synthesized from commercially available isophorone and 3,5-dimethyl-2-cyclohexen-1-one, respectively. Alpha-Substituted 5-hexynoic acids were prepared from 3-ethoxy-2-cyclohexen-1-one, using a novel ZnCl2-mediated alkylation that we developed; this method gives high yields of alpha'-alkylation products, even with secondary halides. The most efficient method for the preparation of alpha-substituted 5-hexynoic acids involved a four-reaction sequence-alkylation of the alpha-substituted ester with 1,4-dibromobutane, elimination, bromination and bisdehydrobromination-that proceeded in high overall yield. Protio enol lactonizations were performed with mercury(II) catalysis in CH2Cl2 or CH2Cl2-H2O. Stereo-selective Z-bromo enol lactonization was carried out by Br+-induced lactonization in the presence of Ag+. E-Bromo enol lactonization with N-bromosuccinimide in CH2Cl2 in the presence of a small amount of water gave better yields and shorter reaction times than the traditional anhydrous conditions. In studies of the inhibitory activity of these lactones toward several proteases (reported in full elsewhere), we found that the alpha-alkyl-substituted protio and bromo enol lactones 1-3 were very good inhibitors of HLE, with k(a)/K(i) values ranging from 14 500 to 37 500 M-1 s-1; the beta-alkyl-substituted enol lactones 5-8 showed only moderate inhibition of HLE.
• Stereoselective Z- and E-bromoenol lactonization of alkynoic acids
  作者：Wei Dai、John A. Katzenellenbogen

  DOI：10.1021/jo00024a035

  日期：1991.11

  We have found that treatment of the silver salt of a 4- or 5-terminal alkynoic acid with bromine results in clean formation of the corresponding Z-bromo enol lactone, the result of a formal cis addition of carboxylate and bromine across the triple bond. This Z-bromo enol lactonization is highly stereoselective and gives good yields in systems that bear substituents on the internal methylene groups; yields with unsubstituted or terminally substituted alkynoic acids are modest. The E-bromo enol lactonization reaction, reported by us previously (Krafft, G. A.; Katzenellenbogen, J. A. J. Am. Chem. Soc. 1981, 103, 5459), has a broader scope and, with modifications, can be performed with high reliability. Mercury(II) salts equilibrate the Z- and E-bromo enol lactones, presumedly by a mercuric ion addition-elimination mechanism. These three reactions provide access to an array of stereoisomeric bromo enol lactone systems.