racem. 3,4-dimethyl-hexane-2,5-dione | 28895-03-6

• 分子结构分类: 有机化合物 - 有机氧化合物
• 英文名称: racem. 3,4-dimethyl-hexane-2,5-dione
• 英文别名: racem.-3,4-Dimethyl-hexan-2,5-dion；(3S,4S)-3,4-Dimethylhexane-2,5-dione；(3S,4S)-3,4-dimethylhexane-2,5-dione
• CAS: 28895-03-6
• 化学式: C₈H₁₄O₂
• 分子量: 142.198
• InChiKey: GECZPGNLQXZLFU-WDSKDSINSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  0.7
• 重原子数：
  10
• 可旋转键数：
  3
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.75
• 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：

  racem. 3,4-dimethyl-hexane-2,5-dione 在 氨 作用下， 以 氯仿 为溶剂， 生成 2,3,4,5-四甲基吡咯
  参考文献：
  名称：

  Intermediates in the Paal-Knorr synthesis of pyrroles

  摘要：

  The mechanism of Paal-Knorr reaction between a 1,4-dicarbonyl compound and ammonia or a primary amine to form a pyrrole is explored. In aprotic solvents and in aqueous solutions near neutrality, d,l diastereomers of 3,4-dimethyl- and 3,4-diethyl-2,5-hexanediones (1r and 2r) formed pyrroles 1.3-57.0 times faster than the corresponding meso diastereomers (1m and 2m). This contradicts any intermediate, such as the enamine 15, which does not remain saturated at both the 3- and 4-positions through the rate-determining step. The demonstrated stereoisomeric difference in reactivity coupled with the following results support the hemiaminal (9) as the intermediate undergoing cyclization in the rate-limiting step of the Paal-Knorr reaction: (1) The reaction rate was adversely affected by increase in the size of the alkyl substituents on the dione. (2) Racemic 2,3-dimethyl-1,4-diphenyl-1,4-butanedione (3r) was more reactive toward ammonium acetate (2.2:1) and 2-aminoethanol (11.2:1) than the meso isomer (3m), ruling out the involvement of the less substituted enamine 14. (3) The relative rate of pyrrole formation of 1,4-diphenyl-1,4-butanedione (5) and its dimethoxy (6) and dinitro (7) derivatives (1:03:6) does not support cyclization of the imine (11) to the pyrrolinium ion (12). (4) The rates of reaction of 2,2,3,3-tetradeuterio-1,4-diphenyl-1,4-butanedione (5D) and perdeuterio-2,5-hexanedione (4D) were very close to those of unlabeled diketones, indicating the absence of a primary isotope effect in the reaction. (5) Neither the isomerization of the unreacted diastereomers of 1, 2, and 3 nor hydrogen exchange of 4D and 5D was detected during the reaction.

  DOI：

  10.1021/jo00024a040
• 作为产物：
  描述：

  丁酮 在 lead dioxide 作用下， 生成 racem. 3,4-dimethyl-hexane-2,5-dione
  参考文献：
  名称：

  六甲基双环[2.2.0]己烷的热诱导骨架转化和开环

  摘要：

  六甲基双环[2.2.0]己烷经过内切，外切异构化（骨架倒置）和立体选择性同上，在140–250°裂解antara。研究了动力学，分离并鉴定了产物。关于反应的一般的1，4-π键中间体进行了讨论，该中间体演变为反相异构体或旋旋地与甲基取代的己二烯敞开。

  DOI：

  10.1016/0040-4020(76)85145-9

文献信息

• Bone Morphogenetic Protein Signals Are Required for Cartilage Formation and Differently Regulate Joint Development During Skeletogenesis
  作者：Noriyuki Tsumaki、Takanobu Nakase、Takahiro Miyaji、Masaaki Kakiuchi、Tomoatsu Kimura、Takahiro Ochi、Hideki Yoshikawa

  DOI：10.1359/jbmr.2002.17.5.898

  日期：——

  The bone morphogenetic protein (BMP) family consists of a large number of members and has diverse biological activities during development. Various tissues express pleural BMP family members, which seem to cooperatively regulate developmental events. Here, multiple BMP signals were inactivated in chondrocytes to clarify the function of BMPs during skeletogenesis. To obtain tissue‐specific inactivation, Noggin gene (Nog) was overexpressed in cartilage under the control of α2(XI) collagen gene (Col11a2) promoter/enhancer sequences. The resultant transgenic mice lacked most of their cartilaginous components, suggesting that cartilage does not develop without BMP signals. These effects seem to be mediated through down‐regulation of Sox9 expression. Conversely, specific BMP signals were activated in the skeleton by targeted expression of Bmp4 in cartilage and the resultant phenotype was compared with that of transgenic mice expressing growth and differentiation factor‐5 (GDF‐5), another BMP family member. Overactivity of Bmp4 in the skeleton caused an increase of cartilage production and enhanced chondrocyte differentiation, as GDF5 expression did, but it did not disturb joint formation as GDF5 did. During skeletogenesis, unique roles of each BMP may reside in the regulation of joint development. Together with the common effect on the cartilage overproduction by Bmp4 and GDF5 overactivation, loss of cartilage by inactivation of multiple BMPs in Noggin transgenic mice indicates that signals for cartilage production are reinforced by multiple BMPs exclusively. These conclusions may account for the reason why multiple BMPs are coexpressed in cartilage.

  骨形态发生蛋白（BMP）家族由大量成员组成，在发育过程中具有多种生物活动。不同组织表达多种BMP家族成员，它们似乎协同调控发育事件。在这里，研究人员在软骨细胞中失活了多条BMP信号通路，以阐明BMP在骨骼发生过程中的功能。为了实现组织特异性失活，研究者在软骨内过表达了Noggin基因（Nog），该基因在α2（XI）胶原基因（Col11a2）启动子/增强子序列的控制下进行表达。结果转基因小鼠缺乏大部分软骨成分，表明没有BMP信号软骨无法发育。这些效应似乎是通过下调Sox9的表达来介导的。相反，特定BMP信号在骨骼中通过靶向在软骨中表达Bmp4而被激活，结果表型与表达生长与分化因子5（GDF-5）的转基因小鼠进行了比较，后者是另一个BMP家族成员。Bmp4在骨骼中的过度活性导致软骨生成增加，并增强了软骨细胞分化，类似于GDF5的作用，但并未如GDF5那样干扰关节形成。在骨骼发育过程中，各个BMP在关节发育调控中的独特作用可能存在。Bmp4和GDF5的过度激活共同对软骨过度生成产生影响，而在Noggin转基因小鼠中失活多条BMP信号则表明，软骨生成的信号是由多条BMP独立增强的。这些结论可能解释了为什么多种BMP在软骨中共同表达的原因。
• DE876237
  申请人：——

  公开号：——

  公开（公告）日：——
• Criegee; Noll, Justus Liebigs Annalen der Chemie, 1959, vol. 627, p. 1,8
  作者：Criegee、Noll

  DOI：——

  日期：——
• 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.