Ethyl 2-((benzoxazol-2-yl)thio)acetoacetate (aminocarbonyl)hydrazone

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 苯并恶唑类
• 英文名称: Ethyl 2-((benzoxazol-2-yl)thio)acetoacetate (aminocarbonyl)hydrazone
• 英文别名: ethyl (3Z)-2-(1,3-benzoxazol-2-ylsulfanyl)-3-(carbamoylhydrazinylidene)butanoate
• 化学式: C₁₄H₁₆N₄O₄S
• 分子量: 336.371
• InChiKey: JUKQFIAGZXWCJM-IUXPMGMMSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  2.1
• 重原子数：
  23
• 可旋转键数：
  7
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.29
• 拓扑面积：
  145
• 氢给体数：
  2
• 氢受体数：
  7

反应信息

• 作为反应物：
  描述：

  Ethyl 2-((benzoxazol-2-yl)thio)acetoacetate (aminocarbonyl)hydrazone 在 sodium methylate 作用下， 以 甲醇 为溶剂， 反应 1.0h， 生成 1-(Aminocarbonyl)-3-methyl-4-((benzoxazolyl-2-yl)thio)-1H-pyrazol-5(2H)-one
  参考文献：
  名称：

  Reaction of Heteroaryl Thiols with Conjugated Azoalkenes: Regioselective Preparation of 4-(Heteroarylthio)-1H-pyrazol-5(2H)-ones. X-ray Crystal Structures of Methyl 2-((Pyrimid-2-yl)thio)acetoacetate (Aminocarbonyl)hydrazone and 1-(Aminocarbonyl)-3-methyl-4-((pyrimid-2-yl)thio)-1H-pyrazol-5(2H)-one

  摘要：

  Heteroaryl thiols easily react with conjugated azoalkenes to give alpha-(heteroarylthio)hydrazones, by 1,4-addition to the azo-ene system. The treatment of the latter compounds with sodium methoxide and then with trifluoroacetic acid affords regioisomeric 4-(heteroarylthio)-1H-pyrazol-5(2H)-ones. In general, these reactions can be successfully executed in two as well as one pot procedures. X-ray diffraction studies of methyl 2-((pyrimid-2-yl)thio)acetoacetate (aminocarbonyl)hydrazone unequivocally show that the preliminary 1,4-addition occurs by nucleophilic attack of the thiol function of heteroaryl thiols to the azo-ene system of conjugated azoalkenes. X-ray structure determination of 1-(aminocarbonyl)-3-methyl-4-((pyrimid-2-yl)thio)-1H-pyrazol-5(2H)-one was carried out in order to determine the behavior of alpha-(heteroarylthio) hydrazones in the ring closure and the nature of the heterocycle. In particular, this investigation afforded information about the hydrogen bondings and the stereochemistry of this molecule and clarified some spectroscopic evidence. A detailed H-1 and C-13 NMR study of these compounds in DMSO-d(6) showed separate signals for the ''NH'' and ''OH'' tautomers, as well as a solvent effect on the enol-keto equilibrium. The conversion of the initial keto form to the related enol form was often complete. The equilibration was found to be extraordinarily slow, requiring in some cases 720 h at room temperature and corresponding to Delta G approximate to 25-30 kcal mol(-1). These findings suggest that the regioisomeric structure assignments reported in the literature for some 5- and 3-hydroxypyrazoles in solution should be reconsidered. In order to avoid misunderstandings about the correct nomenclature of heterocycle derivatives, we believe that such assignments should be supported, when possible, by the appropriate X-ray crystal structure determinations.

  DOI：

  10.1021/jo00106a028
• 作为产物：
  描述：

  2-Butenoic acid, 3-[(1E)-(aminocarbonyl)azo]-, ethyl ester, (2E)- 、 2-巯基苯并恶唑 以 甲醇 为溶剂， 以91%的产率得到Ethyl 2-((benzoxazol-2-yl)thio)acetoacetate (aminocarbonyl)hydrazone
  参考文献：
  名称：

  Reaction of Heteroaryl Thiols with Conjugated Azoalkenes: Regioselective Preparation of 4-(Heteroarylthio)-1H-pyrazol-5(2H)-ones. X-ray Crystal Structures of Methyl 2-((Pyrimid-2-yl)thio)acetoacetate (Aminocarbonyl)hydrazone and 1-(Aminocarbonyl)-3-methyl-4-((pyrimid-2-yl)thio)-1H-pyrazol-5(2H)-one

  摘要：

  Heteroaryl thiols easily react with conjugated azoalkenes to give alpha-(heteroarylthio)hydrazones, by 1,4-addition to the azo-ene system. The treatment of the latter compounds with sodium methoxide and then with trifluoroacetic acid affords regioisomeric 4-(heteroarylthio)-1H-pyrazol-5(2H)-ones. In general, these reactions can be successfully executed in two as well as one pot procedures. X-ray diffraction studies of methyl 2-((pyrimid-2-yl)thio)acetoacetate (aminocarbonyl)hydrazone unequivocally show that the preliminary 1,4-addition occurs by nucleophilic attack of the thiol function of heteroaryl thiols to the azo-ene system of conjugated azoalkenes. X-ray structure determination of 1-(aminocarbonyl)-3-methyl-4-((pyrimid-2-yl)thio)-1H-pyrazol-5(2H)-one was carried out in order to determine the behavior of alpha-(heteroarylthio) hydrazones in the ring closure and the nature of the heterocycle. In particular, this investigation afforded information about the hydrogen bondings and the stereochemistry of this molecule and clarified some spectroscopic evidence. A detailed H-1 and C-13 NMR study of these compounds in DMSO-d(6) showed separate signals for the ''NH'' and ''OH'' tautomers, as well as a solvent effect on the enol-keto equilibrium. The conversion of the initial keto form to the related enol form was often complete. The equilibration was found to be extraordinarily slow, requiring in some cases 720 h at room temperature and corresponding to Delta G approximate to 25-30 kcal mol(-1). These findings suggest that the regioisomeric structure assignments reported in the literature for some 5- and 3-hydroxypyrazoles in solution should be reconsidered. In order to avoid misunderstandings about the correct nomenclature of heterocycle derivatives, we believe that such assignments should be supported, when possible, by the appropriate X-ray crystal structure determinations.

  DOI：

  10.1021/jo00106a028

文献信息

• Reaction of Heteroaryl Thiols with Conjugated Azoalkenes: Regioselective Preparation of 4-(Heteroarylthio)-1H-pyrazol-5(2H)-ones. X-ray Crystal Structures of Methyl 2-((Pyrimid-2-yl)thio)acetoacetate (Aminocarbonyl)hydrazone and 1-(Aminocarbonyl)-3-methyl-4-((pyrimid-2-yl)thio)-1H-pyrazol-5(2H)-one
  作者：Orazio A. Attanasi、Elisabetta Foresti、Zhiyuan Liao、Franco Serra-Zanetti

  DOI：10.1021/jo00106a028

  日期：1995.1

  Heteroaryl thiols easily react with conjugated azoalkenes to give alpha-(heteroarylthio)hydrazones, by 1,4-addition to the azo-ene system. The treatment of the latter compounds with sodium methoxide and then with trifluoroacetic acid affords regioisomeric 4-(heteroarylthio)-1H-pyrazol-5(2H)-ones. In general, these reactions can be successfully executed in two as well as one pot procedures. X-ray diffraction studies of methyl 2-((pyrimid-2-yl)thio)acetoacetate (aminocarbonyl)hydrazone unequivocally show that the preliminary 1,4-addition occurs by nucleophilic attack of the thiol function of heteroaryl thiols to the azo-ene system of conjugated azoalkenes. X-ray structure determination of 1-(aminocarbonyl)-3-methyl-4-((pyrimid-2-yl)thio)-1H-pyrazol-5(2H)-one was carried out in order to determine the behavior of alpha-(heteroarylthio) hydrazones in the ring closure and the nature of the heterocycle. In particular, this investigation afforded information about the hydrogen bondings and the stereochemistry of this molecule and clarified some spectroscopic evidence. A detailed H-1 and C-13 NMR study of these compounds in DMSO-d(6) showed separate signals for the ''NH'' and ''OH'' tautomers, as well as a solvent effect on the enol-keto equilibrium. The conversion of the initial keto form to the related enol form was often complete. The equilibration was found to be extraordinarily slow, requiring in some cases 720 h at room temperature and corresponding to Delta G approximate to 25-30 kcal mol(-1). These findings suggest that the regioisomeric structure assignments reported in the literature for some 5- and 3-hydroxypyrazoles in solution should be reconsidered. In order to avoid misunderstandings about the correct nomenclature of heterocycle derivatives, we believe that such assignments should be supported, when possible, by the appropriate X-ray crystal structure determinations.