d,l-3,4-diisopropylhexane-2,5-dione | 99902-11-1

• 分子结构分类: 有机化合物 - 有机氧化合物
• 英文名称: d,l-3,4-diisopropylhexane-2,5-dione
• 英文别名: d,l-3,4-Diisopropyl-2,5-hexanedione；2,5-Hexanedione, 3,4-bis(1-methylethyl)-, (R*,R*)-；(3R,4R)-3,4-di(propan-2-yl)hexane-2,5-dione
• CAS: 99902-11-1
• 化学式: C₁₂H₂₂O₂
• 分子量: 198.305
• InChiKey: YNJBURGZLQLQNE-RYUDHWBXSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  2.3
• 重原子数：
  14
• 可旋转键数：
  5
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.83
• 拓扑面积：
  34.1
• 氢给体数：
  0
• 氢受体数：
  2

反应信息

• 作为反应物：
  描述：

  d,l-3,4-diisopropylhexane-2,5-dione 在 对甲苯磺酸 作用下， 以 苯 为溶剂， 生成 2,5-dimethyl-3,4-diisopropylfuran
  参考文献：
  名称：

  Intermediates in the Paal-Knorr Synthesis of Furans

  摘要：

  New experimental evidence for the mechanism of the Paal-Knorr reaction involving the acid-catalyzed cyclization of a 1,4-diketone to form a furan is reported. In aqueous or alcoholic solutions containing hydrochloric acid and in chloroform containing boron trifluoride-etherate d,l- and meso-3,4-diethyl-2,5-hexanediones (2r and 2m) cyclize at unequal rates; the stereochemical configuration of the unchanged done is preserved during the reaction. This disagrees with the commonly accepted mechanism involving the ring closure of the rapidly formed monoenol (11b) followed by loss of water. A pathway involving the rapid protonation of one of the carbonyls followed by the electrophilic attack on the protonated carbonyl by the enol being formed at the other carbonyl group (10c) is proposed to account for the difference in reaction rates between the diastereomers of 3,4-disubstituted 2,5-hexanediones (1-3). The following results also seem to support the intermediacy of 10c. The presence of two isopropyl groups in 3,4-diisopropyl-2,5-hexanedione (3) considerably reduces the rate of cyclization, The catalytic constants k(H)(+) for the cyclization of 2r and 2m are larger than the constants for enolization of methyl ketones. The diastereomers of 2,3-dimethyl-and 2,3-diethyl-1,4-diphenyl-1,4-butanediones (4 and 5), which could enolize only toward the center of the molecule, also react at different rates. The d,l and meso dideuterio analogs (d(2)-4r and d(2)-4m) exhibit a primary isotope effect during cyclization. The order of cyclization of 1,4-diphenyl-1,4-butanedione (6) and its analogs (7-9) reveals that the presence of electron-donating groups facilitate the reaction.

  DOI：

  10.1021/jo00107a006
• 作为产物：
  描述：

  4-甲基-2-戊酮 、 二氧化铅 以29%的产率得到
  参考文献：
  名称：

  SZAKAL-QUIN, GYOENGYI;GRAHAM, D. G.;MILLINGTON, D. S.;MALTBY, D. A.;MCPHA+, J. ORG. CHEM., 1986, 51, N 5, 621-624

  摘要：

  DOI：

文献信息

• Stereoisomer effects on the Paal-Knorr synthesis of pyrroles
  作者：Gyongyi Szakal-Quin、Doyle G. Graham、David S. Millington、David A. Maltby、Andrew T. McPhail

  DOI：10.1021/jo00355a010

  日期：1986.3
• Intermediates in the Paal-Knorr Synthesis of Furans
  作者：Venkataraman Amarnath、Kalyani Amarnath

  DOI：10.1021/jo00107a006

  日期：1995.1

  New experimental evidence for the mechanism of the Paal-Knorr reaction involving the acid-catalyzed cyclization of a 1,4-diketone to form a furan is reported. In aqueous or alcoholic solutions containing hydrochloric acid and in chloroform containing boron trifluoride-etherate d,l- and meso-3,4-diethyl-2,5-hexanediones (2r and 2m) cyclize at unequal rates; the stereochemical configuration of the unchanged done is preserved during the reaction. This disagrees with the commonly accepted mechanism involving the ring closure of the rapidly formed monoenol (11b) followed by loss of water. A pathway involving the rapid protonation of one of the carbonyls followed by the electrophilic attack on the protonated carbonyl by the enol being formed at the other carbonyl group (10c) is proposed to account for the difference in reaction rates between the diastereomers of 3,4-disubstituted 2,5-hexanediones (1-3). The following results also seem to support the intermediacy of 10c. The presence of two isopropyl groups in 3,4-diisopropyl-2,5-hexanedione (3) considerably reduces the rate of cyclization, The catalytic constants k(H)(+) for the cyclization of 2r and 2m are larger than the constants for enolization of methyl ketones. The diastereomers of 2,3-dimethyl-and 2,3-diethyl-1,4-diphenyl-1,4-butanediones (4 and 5), which could enolize only toward the center of the molecule, also react at different rates. The d,l and meso dideuterio analogs (d(2)-4r and d(2)-4m) exhibit a primary isotope effect during cyclization. The order of cyclization of 1,4-diphenyl-1,4-butanedione (6) and its analogs (7-9) reveals that the presence of electron-donating groups facilitate the reaction.
• SZAKAL-QUIN, GYOENGYI;GRAHAM, D. G.;MILLINGTON, D. S.;MALTBY, D. A.;MCPHA+, J. ORG. CHEM., 1986, 51, N 5, 621-624
  作者：SZAKAL-QUIN, GYOENGYI、GRAHAM, D. G.、MILLINGTON, D. S.、MALTBY, D. A.、MCPHA+

  DOI：——

  日期：——