Elektronenstruktur und physikalisch-chemische Eigenschaften von Azo-Verbindungen Teil III: Dipolmomente substituierter Phenyl-azo-azulene
作者:F. Gerson、T. Gäumann、E. Heilbronner
DOI:10.1002/hlca.19580410605
日期:——
The dipole moments of α-naphthyl-azo-azulene, β-naphthyl-azo-azulene, phenyl-azo-azulene, and substituted derivatives of the latter have been determined in benzene solution. A discussion of these moments under the assumption that partial moments add vectorially suggests that phenyl-azo-azulene has the trans configuration with the azulene nucleus in the s-trans constellation relative to the azo-bond
<sup>77</sup>Se NMR Chemical Shifts of 9-(Arylselanyl)triptycenes: New Standard for Planar Structures of ArSeR and Applications to Determine the Structures in Solutions
作者:Takashi Nakamoto、Satoko Hayashi、Waro Nakanishi
DOI:10.1021/jo801786j
日期:2008.12.5
that of 1-(arylselanyl)anthraquinones (3 (pd)). Sets of delta(Se) of 1 and 2 must serve as the standard for pl and that of 3 does for pd in solutions. Structures of various ArSeR in solutions are determined from the viewpoint of the orientational effect based on the standard delta(Se) of 1-3. While the structure of 2-methyl-1-(arylselanyl)naphthalenes is concluded to be all pl in solutions, those of 8-chloro-
should supply the planar structure (pl) around the p-YC6H4Se (ArSe) group in the ground state, irrespective of the p-Y substituents. 1 with Y = H (a), NMe2 (b), OMe (c), Cl (d), CN (e) and NO2 (f) are prepared. Structures of 1a–d and 1f are determined by X-ray analysis and dynamic 1H NMR spectroscopy is applied to 1a, 1c, 1e and 1f. For convenience of discussion, the structure of 1 is defined as follows:
9-(芳基杂戊基)三联烯(1:p -YC 6 H 4 SeTpc)应在基态下围绕p -YC 6 H 4 Se(ArSe )基团提供平面结构(pl),而与p -Y取代基无关。1与Y = H(一),NME 2(b),OME(Ç),CL(d),CN(ë)和NO 2(˚F)制备。的结构图1A-d和1F是通过X射线分析和动态确定的1 H NMR光谱适用于1a, 1c, 1e和1f。为了便于讨论,将1的结构定义如下:将1中的三联基周围的构象体称为A,其中Se–C Ar键位于三联基的两个苯基平面之间的等分区域中,它为B其中键在三苯甲基的苯基平面上。Ar基团的构象异构体称为pl,其中Se–C Tpc键位于Ar平面上,而如果键垂直于该平面则为pd。的结构通过X射线分析确认1为基态(A:pl)。1(A:pl)通过过渡状态1(B:pd)转换为等效齿轮(换档过程)。活化能是通过测定动态1 H NMR光谱:值是36
Efficient Synthesis of 1-Aryl-4-[(ethoxycarbonyl)oxy]-1<i>H</i>-pyrazole-3-carboxylates
作者:Sergei M. Korneev、Valery A. Polukeev、Peter G. Jones
DOI:10.1002/jhet.1787
日期:2013.7
Two‐step synthesis of N‐aryl 4‐[(ethoxycarbonyl) oxy]‐1H‐pyrazole‐3‐carboxylates is achieved starting from the commercially available ethyl 4‐chloroacetoacetate and aromatic amines. Azo coupling followed by cyclization with ethyl chloroformate–DMAP pair resulted in the formation of new 4‐oxy‐1H‐pyrazole derivatives in high yields.