5,6-dihydro-5,5-dimethyl-7H-thieno<3,4-b>pyran-7-one | 129969-35-3

• 分子结构分类: 有机化合物 - 有机氧化合物
• 英文名称: 5,6-dihydro-5,5-dimethyl-7H-thieno<3,4-b>pyran-7-one
• 英文别名: 2,2-dimethyl-3H-thieno[3,4-e]pyran-4-one；2,2-dimethyl-3H-thieno[3,4-b]pyran-4-one
• CAS: 129969-35-3
• 化学式: C₉H₁₀O₂S
• 分子量: 182.243
• InChiKey: WTJWALNMNVFFMA-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  1.7
• 重原子数：
  12
• 可旋转键数：
  0
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.44
• 拓扑面积：
  54.5
• 氢给体数：
  0
• 氢受体数：
  3

反应信息

• 作为反应物：
  描述：

  5,6-dihydro-5,5-dimethyl-7H-thieno<3,4-b>pyran-7-one 在 sodium tetrahydroborate 、 N-溴代丁二酰亚胺(NBS) 、 对甲苯磺酸 作用下， 以 乙醇 、 苯 为溶剂， 反应 6.0h， 生成 3-Bromo-5,5-dimethyl-5H-thieno<3,4-b>pyran
  参考文献：
  名称：

  Thiophene systems. 16. Interesting contrasts in electrocyclic reactions for thieno[3,2-b]- and -[2,3-b]pyrans with chromenes

  摘要：

  Thienopyrans 3, 4, and 5 were synthesized and found to have remarkable differences in stability. Systems 3 and 5 undergo electrocyclic ring-opening to 8 and 18, respectively. In acid milieu at room temperature, system 5 exists in an equilibrium with ring-opened thienopyranone 18. Ground state and activation parameters for the open and closed forms of thienopyrans 3 and 5 as well as the isosteric chromene 2 were calculated using the AM1 Hamiltonian. The Gibbs' free energy differences between the open and closed isomers in each system were found to be predictive of the observed equilibria. The mechanism for ring-opening in both thienopyran systems is proposed to be acid-catalyzed based on the calculated temperatures required for ring-opening as well as experimentally determined results.

  DOI：

  10.1021/jo00069a026
• 作为产物：
  描述：

  3-t-butoxy-4-(3-methyl-1-oxo-2-buten-1-yl)thiophene 在 对甲苯磺酸 作用下， 以 甲苯 为溶剂， 反应 2.0h， 以63%的产率得到5,6-dihydro-5,5-dimethyl-7H-thieno<3,4-b>pyran-7-one
  参考文献：
  名称：

  McNally, James J.; Sanfilippo, Pauline J.; Fitzpatrick, Louis, Journal of Heterocyclic Chemistry, 1992, vol. 29, # 1, p. 247 - 250

  摘要：

  DOI：

文献信息

• McNally, James J.; Sanfilippo, Pauline J.; Fitzpatrick, Louis, Journal of Heterocyclic Chemistry, 1992, vol. 29, # 1, p. 247 - 250
  作者：McNally, James J.、Sanfilippo, Pauline J.、Fitzpatrick, Louis、Press, Jeffery B.

  DOI：——

  日期：——
• Thiophene systems. 16. Interesting contrasts in electrocyclic reactions for thieno[3,2-b]- and -[2,3-b]pyrans with chromenes
  作者：Ignatius J. Turchi、Jeffery B. Press、James J. McNally、Mary Pat Bonner、Kirk L. Sorgi

  DOI：10.1021/jo00069a026

  日期：1993.8

  Thienopyrans 3, 4, and 5 were synthesized and found to have remarkable differences in stability. Systems 3 and 5 undergo electrocyclic ring-opening to 8 and 18, respectively. In acid milieu at room temperature, system 5 exists in an equilibrium with ring-opened thienopyranone 18. Ground state and activation parameters for the open and closed forms of thienopyrans 3 and 5 as well as the isosteric chromene 2 were calculated using the AM1 Hamiltonian. The Gibbs' free energy differences between the open and closed isomers in each system were found to be predictive of the observed equilibria. The mechanism for ring-opening in both thienopyran systems is proposed to be acid-catalyzed based on the calculated temperatures required for ring-opening as well as experimentally determined results.