212 research outputs found
Geminal System O-N-O: XRD Studies of Structure of Cyclic N,N-dialkoxyderivatives of Amines and Ureas
N,N-Dimethoxy-N-tert-alkylamines: new synthesis methods and the crystal structure of the precursor
Under the methanolysis of N-methoxy-N-(1-pyridinium)amines salts 1aβc, nucleophilic substitution occurs at the nitrogen atom to form N,N-dimethoxyamines 2a,b; the crystal structure of precursor 1c has been studied
N,N-Dimethoxy-N-tert-alkylamines: new synthesis methods and the crystal structure of the precursor
Under the methanolysis of N-methoxy-N-(1-pyridinium)amines salts 1aβc, nucleophilic substitution occurs at the nitrogen atom to form N,N-dimethoxyamines 2a,b; the crystal structure of precursor 1c has been studied
Pyramidal amide nitrogen in N-acyloxy-N-alkoxyureas and N-acyloxy-N-alkoxycarbamates
The XRD studies of N-acyloxy-N-alkoxyamides 1, 2 have revealed a highly pyramidal configuration of amide nitrogen in the OβNβO group
On the Temperature Dependence of the Lifetime of Thermally Isolated Metastable Clusters
The temperature dependence of the lifetime of the thermally isolated
metastable N8 cubane up to its decay into N2 molecules has been calculated by
the molecular dynamics method. It has been demonstrated that this dependence
significantly deviates from the Arrhenius law. The applicability of the finite
heat bath theory to the description of thermally isolated atomic clusters has
been proved using statistical analysis of the results obtained.Comment: 14 pages, 4 figure
Synthesis and structure of new N-alkoxy-N-(1-pyridinium)urea chlorides
New N-[1-(4-amino)pyridinium]-N-methoxyurea chloride, N-[1-(2-amino)pyridinium]-N-methoxyurea chloride and their analogs were synthesized by N-alkoxy-N-chloroureas reaction with the proper pyridines in acetonitrile or ether solution by improved procedure. XRD study of N-[1-(4-amino)pyridinium]-N-methoxyurea and N-[1-(2 amino)pyridinium]-N-methoxyurea revealed the elongation of N-N+ bonds and some shortening of MeO-N bonds, qunonoid deformation of pyridine rings compare to it unsubstituted analog. The substantial pyramidality of central nitrogen atom in O-N-N+ moiety and N-C carbamoyl bonds difference were established too. The structure summary of N-alkoxy-N-(1-pyridinium)ureas salts and other derivatives of 1-(N-alkoxyamino)pyridinium salts has been done
N-Chloro-N-alkoxyureas: synthesis, structure and properties
The XRD studies of N-chloro-N-alkoxyureas 1, 2 have revealed the high pyramidality of the amide nitrogen in the OβNβCl group caused by nOβs*NβCl 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 2β4 undergo cyclization into 1-alkoxybenzimidazolin-2-ones 10β12
Geminal System O-N-O: XRD Studies of Structure of Cyclic N,N-dialkoxyderivatives of Amines and Ureas
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