نتایج جستجو برای: cyclic carbodiimides

تعداد نتایج: 98478  

Journal: :Organic & biomolecular chemistry 2012
Fei Zhao Yang Wang Wen-Xiong Zhang Zhenfeng Xi

The one-pot sequential reaction of various amines, carbodiimides, and acyl dichlorides has been achieved for the first time under metal-free conditions to provide symmetric cyclic di-oxoguanidines via an unexpected 2,2-dichloro-imidazolidindione intermediate. Acyl dichlorides have a dual function: to serve as the third component and to activate carbodiimides. In sharp contrast, the AlMe(3)-cata...

Journal: :journal of physical & theoretical chemistry 2004
issa yavari vahideh hadigheh-rezvan mohsen dadgar

ab initio calculations at hf/6-31g* level of theory for geometry optimization and mp2/6-31g*//hf/6-31g* for a single point total energy calculation are reported for the importantenergy-minimum conformations and transition-state geometries of 1, 3-diazacyclohepta-1, 2-diene (2) and 1, 3-diazacycloocta-1, 2-diene (3). the c2 symmetric twist-chair (2-tc)conformation of 2 is calculated to be 7.4 kj...

2008

1 Chemistry 2 Liquid-phase synthesis 3 Solid-phase synthesis 3.1 Boc SPPS 3.2 Fmoc SPPS 3.3 BOP SPPS 4 Solid supports 4.1 Polystyrene resin 4.2 Polyamide resin 5 Protecting groups 5.1 Fmoc protective group 5.2 Boc protective group 5.3 Benzyloxy-carbonyl (Z) group 5.4 Alloc protecting group 5.5 Lithographic protecting groups 6 Activating groups 6.1 Carbodiimides 6.2 Aromatic oximes 7 Synthesizin...

Journal: :Acta Chemica Scandinavica 1975

Journal: :Dalton transactions 2013
Kazumasa Hayasaka Kozo Fukumoto Hiroshi Nakazawa

Dehydrogenative desulfurization of thiourea derivatives (RNHC(S)NHR') has been achieved, to give carbodiimides (RN=C=NR'), in the reaction with hydrosilane and (η(5)-C5H5)Fe(CO)2Me. The obtained carbodiimide reacted with (η(5)-C5H5)Fe(CO)(SiR3) formed in the reaction to give an N-silylated η(2)-amidino iron complex, which was isolated and then characterized by X-ray analysis.

Journal: :Dalton transactions 2016
David R Carbery Michael S Hill Mary F Mahon Catherine Weetman

Reactions between magnesium 1,4-dihydropyridide or 1,2-dihydro-iso-quinolide derivatives and carbodiimides, RN[double bond, length as m-dash]C[double bond, length as m-dash]NR, generally result in Mg-N insertion and formation of guanidinate complexes. More sterically perturbed systems with N-aryl carbodiimide substitution, however, follow a divergent course of reaction initiating heterocyclic r...

2016
Anup Rana Mehmet Emin Cinar Debabrata Samanta Michael Schmittel

The mechanism of the thermal cyclization of enyne-carbodiimides 7a-c has been studied computationally by applying the DFT method. The results indicate that enyne-carbodiimides preferentially follow the C(2)-C(6) (Schmittel) cyclization pathway in a concerted fashion although the Myers-Saito diradical formation is kinetically preferred. The experimentally verified preference of the C(2)-C(6) ove...

Journal: :Dalton transactions 2015
J Niemeyer M J Kelly I M Riddlestone D Vidovic S Aldridge

Correction for 'Iminoborylene complexes: evaluation of synthetic routes towards BN-allenylidenes and unexpected reactivity towards carbodiimides' by J. Niemeyer et al., Dalton Trans., 2015, DOI: 10.1039/c5dt00131e.

2016
Alexander Hinz Jose M Goicoechea

The synthesis and isolation of the 2-arsaethynolate anion, AsCO(-) , and its subsequent reactivity towards heteroallenes is reported. Reactions with ketenes and carbodiimides afford four-membered anionic heterocycles in formal [2+2] cycloaddition reactions. By contrast, reaction with an isocyanate yielded a 1,4,2-diazaarsolidine-3,5-dionide anion and the unprecedented cluster anions As10 (2-) a...

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