6377-82-8Relevant academic research and scientific papers
13C CP MAS NMR, FTIR, X-ray diffraction and PM3 studies of some N-(ω-carboxyalkyl)morpholine hydrohalides
Dega-Szafran,Ga?szczyk,Maciejewska,Szafran,Tykarska,Wawer
, p. 261 - 273 (2007/10/03)
N-(ω-carboxyalkyl)morpholine hydrochlorides, OC4H8N(CH2)nCOOH·HCI, n = 1-5, were obtained and analyzed by 13C cross polarization (CP) magic angle spinning (MAS) NMR, FTIR and PM3 calculations. The structure of N-(3-carboxy-propyl)morpholine hydrochloride (n = 3) has been solved by X-ray diffraction method at 100 K and refined to the R = 0.031. The crystals are monoclinic, space group P21/c, a = 14.307(3), b = 9.879(2), c = 7.166(1) A?, β = 93.20(3)°, V = 1011.3(3) A?3, Z = 4. In this compound the nitrogen atom is protonated and two molecules form a centrosymmetric dimer, connected by two N+-H···Cl- (3.095(1) A?) and two O-H···Cl- (3.003(1) A?) hydrogen bonds. 13C CP MAS NMR spectra, contrary to the solution, showed non-equivalence of the ring carbon atoms. The PM3 calculations predict a molecular dimer without proton transfer for an HCl complex, while for an HBr complex an ion pairs with proton transfer, and reproduces correctly the conformation of both dimers but overestimates H-bond distances. Shielding constants calculated from the PM3 geometry of ion pairs gave a linear correlation with the 13C chemical shifts in solids.
EFFECT OF THE NATURE OF THE LEAVING GROUP IN REACTIONS OF 2-X-N-ETHYLPYRIDINIUM SALTS WITH AMINES IN ACETONITRILE
Titskii, G. D.,Mitchenko, E. S.
, p. 1949 - 1954 (2007/10/02)
The rate-determining stage in the nucleophilic substitution reactions of 2-X-N-ethylpyridinium salts with piperidine in acetonitrile changes, depending on the nature of the leaving group X.In the case where X = Hlg the controlling stage is the formation of the C-N bond.When X = 4-NO2C6H4O3, 3,4-(NO2)2C6H3O, and 2,6-(NO2)2C6H3O, nucleophilic substitution at the carbon atom is controlled by cleavage of the C-X bond.Nucleophilic substitution at a carbon atom of the benzene ring predominates in the reaction of 2-(2,4-dinitrophenoxy)-N-ethylpyridinium salt with piperidine.
KINETICS AND MECHANISM OF REACTION OF AMINES WITH β-BROMOPROPIOPHENONE
Popov, A. F.,Piskunova, Z.,Matvienko, V. N.
, p. 1299 - 1302 (2007/10/02)
The reaction of β-bromopropiophenone with different amines in acetonitrile at 25 deg C was studied.It was found that in the case of primary and secondary amines, the end products of the reaction are β-aminopropiophenones, which form via the intermediate phenyl vinyl ketone.In the case of tertiary amines, the reaction ends at the stage of the formation of phenyl vinyl ketone.The reactivity of the amines in the formation of phenyl vinyl ketone is preferentially determined by their basicity.
