- On the Silylation of Bifunctional Amidines of Oxalic Acid
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N,N',N'',N'''-Tetraaryl-oxalic amidines react with N-trimethylsilyldiethylamine to yield the activated and open chained derivatives 3a, b.By the use of diorganyldichlorosilanes the new 1,3-diaza-2-sila-cyclopentanes 5a-d were obtained.Cycloacylations of 3
- Beckert, Rainer,Vorwerk, Steffen,Lindauer, Dirk,Doering, Manfred
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p. 1386 - 1390
(2007/10/02)
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- On the Reaction of Oxalic Amidines with Carbonic Acid Derived Heterocumulenes to Imidazolidine-Derivatives
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A useful synthetic route to nonsymmetric derivatives of imidazolidine (derivatives of parabanic acid) is demonstrated by the reaction of tetraarylated oxalic amidines 1 with different alkyl- and aryl substituted isothiocyanates 4, isoselenocyanates 31, and carbodiimides 30.Acylisothiocyanates 9 react differently leading to a mixture of three cycloacylation products 12, 13 and 14.Silylated heterocumulenes such as 25 and 26 react with 1 to give 28 and 29 transsilylation.Based on the 13C-n.m.r. spectroscopic investigation of the reaction between 1a and methyl isothiocyanate and phenyl isothiocyanate respectively a mechanism is proposed.
- Beckert, R.,Gruner, M.
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- Derivatives of Imidazolidines from Oxalic Amidines
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Tetraarylsubstituted oxalic amidines 1 react with acyl chlorides, phosgene, thiophosgene, chlorocarbonylsulfenylchloride, isocyaniddichlorides, and N-aroyl-1-chlorothio-formimidoylchlorides 7 to give the corresponding 5-membered heterocycles 3,4,5 and 8.Isocyanates 9 and isothiocyanates 10 react with oxalic amidines to yield imidazolidines 11, 12 and ureas 13, 14.Hydrolysis of 3-5, 8, 11, 12 leads to the corresponding oxo compounds 15, 16.
- Beckert, R.,Mayer, R.
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p. 227 - 236
(2007/10/02)
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