Azine-Hydrazone Tautomerism of Guanylhydrazones: Evidence for the Preference Toward the Azine Tautomer
作者:Sumit S. Chourasiya、Deepika Kathuria、Sampada S. Nikam、Ashok Ramakrishnan、Sadhika Khullar、Sanjay K. Mandal、Asit K. Chakraborti、Prasad V. Bharatam
DOI:10.1021/acs.joc.6b01258
日期:2016.9.2
using quantum chemical methods, whose tautomeric preference toward the azine tautomer is in the range of 3–8 kcal/mol. Twenty new azines were synthesized and isolated in their neutral state. Variable temperature NMR study suggests existence of the azine tautomer even at higher temperatures with no traces of the hydrazone tautomer. The crystal structures of two representative compounds confirmed that the
Ring-chain isomerism in conjugated guanylhydrazones: Experimental and theoretical study
作者:Deepika Kathuria、Sumit S. Chourasiya、Sanjay K. Mandal、Asit K. Chakraborti、Uwe Beifuss、Prasad V. Bharatam
DOI:10.1016/j.tet.2018.04.042
日期:2018.6
first case of ring-chain isomerism in conjugated guanylhydrazones. The acyclic conjugated guanylhydrazone and the corresponding annulated product (4,5-dihydro-1H-pyrazole-1-carboximidamide) could be clearly distinguished by means of UV and NMR spectroscopy. The formation of the ring isomer was further confirmed by single crystal XRD analysis. The time-dependent 1H NMR study indicated the gradual transformation
根据文献报道,在酸性条件下用氨基胍在较短的反应时间(1小时)内处理1,3-二芳基丙烯-2-酮可得到相应的胍。然而,当反应时间增加至12小时时,观察到环环状产物4,5-二氢-1 H-吡唑-1-羧酰亚胺酰胺的形成。这是共轭胍hydr中环链异构的第一种情况。无环共轭和相应的环状产物(4,5-二氢-1 H-吡唑-1-羧酰亚胺)可以通过紫外和核磁共振光谱清楚地区分。通过单晶XRD分析进一步证实了环异构体的形成。时间相关的11 H NMR研究表明开链化合物逐渐转变成环状化合物。使用量子化学方法探索了这两种产物形成的机理见解,结果表明环异构体在热力学上比开链异构体稳定6-11 kcal / mol,发现环化障碍为31.37 kcal /摩尔
Design and synthesis of piezochromic materials exploring intermolecular charge transfer: chalconoids bound to the <i>p</i>-sulfonatocalix[6]arene macrocycle
作者:Sanhita V. Patil、Shridhar P. Gejji、Dipalee D. Malkhede
DOI:10.1039/d2cp01483a
日期:——
complexation. The complex shows partial encapsulation of the guest with one of the phenyl rings of chalcone (guest) is held inside the SCX6 cavity, whilst other phenyl rings that exclude the cavity are hydrogen-bonded to sulfonate portals of the host. The hydrogenbonding conducing such complexation triggers proton transfer engendering a mechanochromic switch. The complexes are further characterized by a variety
由封装在p中的黄酮组成的固态系统已开发出具有机械致变色和热致变色的-sulfonatocalix[6]arene (SCX6) 支架。超分子宿主的引入保证了在不同领域的各种应用,这使它们引人入胜。主要是氢键以及 π···π 相互作用是主客体络合的原因。该复合物显示了客体的部分封装,其中一个查耳酮(客体)的苯环被保持在 SCX6 腔内,而排除腔体的其他苯环与主体的磺酸盐入口氢键合。进行这种络合的氢键会触发质子转移,从而产生机械变色开关。配合物通过各种实验进一步表征,例如循环伏安法 (CV)、稳态荧光、振动光谱和1 H 或 2D NMR (NOESY) 光谱实验。通过 NMR 提供的详细结构显示 Ha-e(客体)质子的去屏蔽,而来自主体的羟基质子经历屏蔽,如1 H NMR 光谱所示。这些推论已通过密度泛函理论得到进一步证实。电化学研究表明在主客体结合中存在不可逆的单电子转移。红外光谱中强烈羰基
DERIVES DE CHALCONE A ACTIVITE ANTIMITOTIQUE
申请人:UNIVERSITE CLAUDE BERNARD - LYON 1
公开号:EP1976818A2
公开(公告)日:2008-10-08
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