2,2,6,6-tetramethylpiperidine-1-yl | 38951-81-4

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 哌啶类
• 英文名称: 2,2,6,6-tetramethylpiperidine-1-yl
• 英文别名: 2,2,6,6-Tetramethylpiperidyl-radikal
• CAS: 38951-81-4
• 化学式: C₉H₁₈N
• 分子量: 140.249
• InChiKey: YJQARMKRSNORQZ-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  2.1
• 重原子数：
  10
• 可旋转键数：
  0
• 环数：
  1.0
• sp3杂化的碳原子比例：
  1.0
• 拓扑面积：
  1
• 氢给体数：
  0
• 氢受体数：
  0

反应信息

• 作为产物：
  描述：

  2,2,6,6-四甲基哌啶 在 二苯甲酮 作用下， 以 苯 为溶剂， 生成 2,2,6,6-tetramethylpiperidine-1-yl
  参考文献：
  名称：

  N−H and α(C−H) Bond Dissociation Enthalpies of Aliphatic Amines

  摘要：

  Bond dissociation enthalpies (BIDES) of a large series of aliphatic amines (21) were measured by means of photoacoustic calorimetry. Despite the different structures studied in the primary, secondary, and tertiary amine series, the a(C-H) BIDES were found to be very similar for unconstrained amines with values very close to 91 kcal/mol. alphaC- and N-alkylation or introduction of an hydroxy group only slightly affect the BDEs, a fact in perfect agreement with calculations performed at different CBS levels. This demonstrates the predominance of the two-orbital-three-electron interaction involving the N and alphaC(.) orbitals. On the other hand, the N-H BIDE decreases when going from primary to secondary amines. This result is interpreted in term of a hyperconjugation in sigmaC-C bonds, which leads to a stabilization of the aminyl radical. For cyclized amines, the BIDES depend on the relative geometry of the singly occupied alphaC(.) orbital with respect to that of the N atom, disfavoring the two-orbital-three-electron interaction. However, such structures can exhibit through-bond interaction. For a crowded structure such as triisopropylamine, for which the alphaC(.) orbital is not coplanar with the nitrogen one, the relaxation of a strain energy allows the BIDE to be comparable to flexible structures.

  DOI：

  10.1021/ja0204168
• 作为试剂：
  描述：

  2-氯-3-己基噻吩 在 2,2,6,6-tetramethylpiperidine-1-yl 、 四甲基乙二胺 、 sodium 、 碘 作用下， 以 正己烷 、 mineral oil 、 乙醚 为溶剂， 反应 1.01h， 以85%的产率得到2-chloro-3-hexyl-5-iodothiophene
  参考文献：
  名称：

  有机钠交叉偶联聚合合成聚噻吩

  摘要：

  在己烷中用 2,2,6,6-四甲基哌啶-1-基钠 (TMPNa) 处理 2-氯-3-己基噻吩导致 5-位去质子化，得到噻吩-钠物质，其形成由用碘淬灭，产生 2-chloro-3-hexyl-5-iodothiophene，产率为 85%。将带有 N-杂环卡宾 (NHC) 的镍催化剂添加到环戊基甲基醚中由此形成的噻吩-钠物质中，在 -20°C 下引发了交叉偶联聚合。将反应混合物搅拌24小时后，以56%的产率获得聚(3-己基噻吩-2,5-二基)。平均分子量M n为 9700，接近理论分子量（M = 8500) 基于单体进料/催化剂负载比 (2.0 mol %)，发现分子量分布为 2.1。

  DOI：

  10.1021/acs.organomet.1c00508

文献信息

• One-Electron Oxidation of Sterically Hindered Amines to Nitroxyl Radicals:  Intermediate Amine Radical Cations, Aminyl, α-Aminoalkyl, and Aminylperoxyl Radicals
  作者：O. Brede、D. Beckert、C. Windolph、H. A. Göttinger

  DOI：10.1021/jp980089j

  日期：1998.2.1

  Sterically hindered amines (2,2,6,6-tetramethyl-substituted piperidines) are easily oxidized (i) by electron transfer to parent cations in n-butyl chloride solution, (ii) by the sulfate radical anion in aqueous solution, and (iii) by sensitized electron transfer to carbonyl triplets. In nonpolar surroundings in the nanosecond time range, the radical cations of the tertiary piperidines have been directly observed by optical spectroscopy to exhibit absorption maxima below lambda = 300 nm and; around 550 nm. Subsequently, they deprotonate to alpha-alkylamine radicals, which are also the first observable products of oxidation with sulfate radical anions in water. In the case of secondary piperidines, the amine radical cations deprotonate to aminyl radicals in times < 10 ns. The triplet-sensitized electron transfer to the benzophenone as well as cyclohexanone triplet results in amine-derived and ketyl-type radicals formed at a nearly diffusion-controlled rate, which suggests an electron- and subsequent proton-transfer mechanism. In the presence. of oxygen, the amine-derived radicals are oxidized to nitroxyl radicals by different pathways for secondary and tertiary piperidines. For the reaction of the nitroxyl radicals with other radicals, rate constants are found to be quite similar (about 5 x 10(8) M-1 s(-1)) for several alkyl radicals and for the tert-butyloxyl radical and less than 10(5) M-1 s(-1) for alkylperoxyl radicals. Because of the minor importance of radical reactions with the sterically hindered amines (HALS), the antioxidant effect of these compounds ought to be explained by oxidation, primarily via cationic and subsequently radical intermediates to the persistent nitroxyl radicals, which scavenge other radicals very efficiently.