排序方式: 共有86条查询结果,搜索用时 15 毫秒
81.
Ramana CV Baquer SM Gonnade RG Gurjar MK 《Chemical communications (Cambridge, England)》2002,(6):614-615
Synthesis of tetrakis(cyclopropylmethyl)methane, a new symmetric product has been described using the radical mediated gem-diallylation of cyclopropylmethyl xanthate as a key step and its single crystal X-ray analysis established its C2-symmetry. 相似文献
82.
Rohit Kumar Sandeep Yadav Kritika Gour Ekta Sangtani Soumya Ranjan Dash Abhishekram Raja Kumar Vanka Rajesh G. Gonnade Sakya S. Sen 《化学:亚洲杂志》2020,15(6):820-827
In this paper, we have used two N,O‐ketiminato ligands ( L1 and L2 ) with biphenyl and terphenyl substituent on the nitrogen atom. Deprotonation of L1 with KN(SiMe3)2 and subsequent reaction with MgI2 led to a homoleptic dinuclear magnesium complex ( 1 ) with a Mg2O2 four‐membered ring. Deprotonation with nBuLi and subsequent reaction with MgI2 afforded a unusual dinuclear magnesium complex ( 2 ) with a Mg2O2 ring. Extension of the ligand for calcium resulted in a trinuclear calcium complex ( 3 ) with six four‐membered Ca2O2 rings. We could not isolate any chelating complex when L2 was used as a ligand, and only oxygen bound magnesium ( 4 ) and calcium ( 5 ) adducts were isolated. DFT studies were performed to understand this dissimilar behavior. More diverse results were obtained when lithiated L1 and L2 were treated with germanium dichloride. We were able to stabilize a monomeric germylene monochloride ( 7 ) with L1 . However, with L2 , an unusual ligand scrambling, and a C?C coupling take place, leading to the formation of a secondary carbocation with GeCl3‐ as a counter‐anion ( 8 ). Besides, a germanium dichloride adduct ( 9 ) bound to the oxygen center of the ligand was obtained as the minor product. 相似文献
83.
Subrata Bhattacharjee Anjali Raju Rahul N. Gaykar Rajesh G. Gonnade Tony Roy Akkattu T. Biju 《化学:亚洲杂志》2020,15(14):2203-2207
A mild and easy to perform multicomponent coupling involving phosphines, arynes generated from 2‐(trimethylsilyl)aryl triflates, and CO2 allowing the transition‐metal‐free synthesis of zwitterionic phosphonium benzoates has been developed. The reaction proceeds via the generation of 1 : 1 zwitterionic intermediates from phosphines and arynes followed by the interception with CO2 to deliver the carboxylates in moderate to good yields instead of the anticipated benzooxaphosphol‐3(1H)‐ones. 相似文献
84.
Srinivas D Gonnade R Ravindranathan S Sanjayan GJ 《The Journal of organic chemistry》2007,72(18):7022-7025
In this note, we describe the design, synthesis, and structural studies of novel hybrid foldamers derived from Aib-Pro-Adb building blocks that display repeat beta-turn structure motif. The foldamer having a conformationally constrained aliphatic-aromatic amino acid conjugate adopts a well-defined, compact, three-dimensional structure, governed by a combined conformational restriction imposed by the individual amino acids with which it is made of. Conformational investigations by single-crystal X-ray and solution-state NMR studies were undertaken to investigate the conformational preference of these foldamers with a hetero-backbone. Our findings suggest that constrained aliphatic-aromatic amino acid conjugates would offer new avenues for the de novo design of hybrid foldamers with distinctive structural architectures. 相似文献
85.
C.V. Ramana Mangesh P. DushingSradhanjali Mohapatra Rosy MallikRajesh G. Gonnade 《Tetrahedron letters》2011,52(1):38-41
A rapid access to the central 4,5,6-tricyclic core of 4,5,6-trinems has been achieved by employing the alkyne [2+2+2]-cyclotrimerization as the key and final reaction in the synthesis. 相似文献
86.
Padmini Sahoo Purva Chibde Satyabrata Das Subhrashis Banerjee Bhupendra P. Mali Dr. Kumar Vanka Dr. Rajesh G. Gonnade Prof. Dr. Cem. B. Yildiz Dr. Moumita Majumdar 《欧洲无机化学杂志》2023,26(29):e202300249
A 12-membered zwitterionic tetrastanna(II) cycle 1 having a crown ether-like topology has been isolated from the deprotonation of 1,1′-methylenediimidazole ( B ) with two equivalents of Sn[N(SiMe3)2]2 ( A ). The solid-state structure and NMR analysis confirms the tetrastanna(II) cycle 1 to be comprised of two stannate(II) and two stannyliumylidene ion pairs in alternating positions of the heterocycle. Computational analysis shows greater nucleophilicity at the proximally located stannate(II) centers. Nonetheless, the tetrastanna(II) cycle 1 remains poorly reactive due to engagement of SnII lone pair electrons in intramolecular donor-acceptor interactions. Simple deprotonation reaction between Sn[N(SiMe3)2]2 ( A ) and N-(diisopropylphenyl)imidazole ( C ) in equimolar ratio has led to a stannylene 2 , involving the formation of a Sn−C covalent bond with the anionic imidazol-2-yl carbon center along with the release of NH(SiMe3)2. Compound 2 exists as a dimer, where the unsubstituted ring nitrogen atom coordinated intermolecularly to the other stannylene center. 相似文献