Кафедра "Органічна хімія, біохімія, лакофарбові матеріали та покриття"

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Зараз показуємо 1 - 6 з 6

Acyloxy group exchange in N-acyloxy-N-alkoxyamides
(Elsevier Inc., 2004) Shtamburg, V. G.; Tsyhankov, A. V.; Klots, E. A.; Kostyanovsky, R. G.
Synthesis, structure and properties of N-alkoxy-N-(1-pyridinium)urea salts, N-alkoxy-N-acyloxyureas and N,N-dialkoxyureas
(Elsevier Inc., 2007) Shtamburg, V. G.; Shishkin, O. V.; Zubatyuk, R. I.; Kravchenko, S. V.; Tsygankov, A. V.; Shtamburg, V. V.; Distanov, V. B.; Kostyanovsky, R. G.
N-Alkoxy-N-(1-pyridinium)urea salts 3, 4 have been prepared, the conversions of N-acetoxy-N-methoxyurea 7 into N,N-dimethoxyurea 8 and of N-n-propyloxy-N-(1-pyridinium)-N',N'-dimethylurea chloride 6 into N,N dimethoxy-N',N'-dimethylurea 11 were carried out. A high pyramidality of the amide nitrogen in O–N–X groups [X = N+C5H5, OMe, OC(O)C6H4Cl-p] has been revealed by XRD studies of ureas 3b, 8 and N-p chlorobenzoyloxy-N-n-butyloxyurea 9.
N-Chloro-N-alkoxyureas: synthesis, structure and properties
(Elsevier Inc., 2006) Shtamburg, V. G.; Shishkin, O. V.; Zubatyuk, R. I.; Kravchenko, S. V.; Tsygankov, A. V.; Mazepa, A. V.; Klots, E. A.; Kostyanovsky, R. G.
The XRD studies of N-chloro-N-alkoxyureas 1, 2 have revealed the high pyramidality of the amide nitrogen in the O–N–Cl group caused by nO–s*N–Cl anomeric effect, the other sequence of this effect is anionic lability of the chlorine atom; nucleophilic substitution at the nitrogen depends on the N'-substitutent nature: chlorine atoms in ureas 1 and 5 are replaced by outer nucleophile whereas, under the same conditions, ureas 2–4 undergo cyclization into 1-alkoxybenzimidazolin-2-ones 10–12.
Pyramidal amide nitrogen in N-acyloxy-N-alkoxyureas and N-acyloxy-N-alkoxycarbamates
(Elsevier Inc., 2006) Shishkin, O. V.; Zubatyuk, R. I.; Shtamburg, V. G.; Tsygankov, A. V.; Klots, E. A.; Mazepa, A. V.; Kostyanovsky, R. G.
The XRD studies of N-acyloxy-N-alkoxyamides 1, 2 have revealed a highly pyramidal configuration of amide nitrogen in the O–N–O group.
N,N-Dimethoxy-N-tert-alkylamines: new synthesis methods and the crystal structure of the precursor
(Elsevier Inc., 2006) Shtamburg, V. G.; Tsygankov, A. V.; Klots, E. A.; Fedyanin, I. V.; Lyssenko, K. A.; Kostyanovsky, R. G.
Under the methanolysis of N-methoxy-N-(1-pyridinium)amines salts 1a–c, nucleophilic substitution occurs at the nitrogen atom to form N,N-dimethoxyamines 2a,b; the crystal structure of precursor 1c has been studied.
Chiral ureas with two electronegative substituents at 1-N: An unusual case of coexisting pyramidal and almost planar 1-N atoms in the same crystal
(Wiley‐Liss, Inc., 2009) Shishkin, O. V.; Shtamburg, V. G.; Zubatyuk, R. I.; Olefir, D. A.; Tsygankov, A. V.; Prosyanik, A. V.; Mazepa, A. V.; Kostyanovsky, R. G.
XRD studies of structure of N‐acetoxy‐N‐methoxyurea and N,N‐bis(methoxycarbonyl)‐N‐methoxyimide have revealed that in N‐methoxy‐N‐X‐ureas (X = OAc, Cl, OMe, N+C5H5) the additional shortening of N–OMe bond took place, which arising from an nO(Me)‐σ*N–X anomeric orbital interaction. XRD studies of N‐chloro‐N‐ethoxyurea crystal have revealed the presence of two kinds of anomeric nitrogen configuration in the O–N–Cl group in the form of a pyramidal configuration and a planar configuration for same 1‐N nitrogen atom. XRD studies of N‐4‐chlorobenzoyloxy‐N‐ethoxyurea have revealed that the degree of pyramidality of the 1‐N nitrogen in N‐aroyloxy‐N‐alkoxyureas is tuned by orientation of benzoyl group with respect to the N–O bond, which in turn depends of size of N‐alkoxy group.