THE SOLVOLYSIS OF THE ALPHA- AND BETA-3,4,6-TRI-O-ACETYL-D-GLUCOPYRANOSYL CHLORIDES

1955 ◽  
Vol 33 (1) ◽  
pp. 128-133 ◽  
Author(s):  
R. U. Lemieux ◽  
G. Huber
Keyword(s):  
Acetic Acid ◽  
Double Bond ◽  
Positive Charge ◽  
Main Reaction ◽  
Main Reaction Product ◽  
Double Bond Character ◽  
Ionic Reactions ◽  
Oxygen Bond ◽  
Bond Character ◽  
Anomeric Center

3,4,6-Tri-O-acetyl-β-D-glucopyranosyl chloride was found to undergo solvolysis in acetic acid to form 1,3,4,6-tetra-O-acetyl-α-D-glucopyranose as the main reaction product. The much less reactive anomeric α-chloride also appeared to undergo solvolysis with extensive inversion of the anomeric center. It is submitted that the tendencies for inversion obtained in these ionic reactions are due to the conformations imposed on the intermediate ions through distribution of the positive charge to the ring oxygen and the consequent introduction of double-bond character to the carbon-1 to ring-oxygen bond.

scholarly journals Crystal structure ofN′′-benzyl-N′′-[3-(benzyldimethylazaniumyl)propyl]-N,N,N′,N′-tetramethylguanidinium bis(tetraphenylborate)

2015 ◽  
Vol 71 (12) ◽  
pp. o1086-o1087
Author(s):  
Ioannis Tiritiris ◽  
Willi Kantlehner
Keyword(s):  
Crystal Structure ◽  
Double Bond ◽  
Positive Charge ◽  
Planar Geometry ◽  
Methyl Groups ◽  
Two Dimensional ◽  
Single Bond ◽  
Double Bond Character ◽  
Bond Lengths ◽  
Bond Character

In the crystal structure of the title salt, C24H38N42+·2C24H20B−, the C—N bond lengths in the central CN3unit of the guanidinium ion are 1.3364 (13), 1.3407 (13) and 1.3539 (13) Å, indicating partial double-bond character. The central C atom is bonded to the three N atoms in a nearly ideal trigonal–planar geometry and the positive charge is delocalized in the CN3plane. The bonds between the N atoms and the terminal methyl groups of the guanidinium moiety and the four C—N bonds to the central N atom of the (benzyldimethylazaniumyl)propyl group have single-bond character. In the crystal, C—H...π interactions between the guanidinium H atoms and the phenyl C atoms of the tetraphenylborate ions are present, leading to the formation of a two-dimensional supramolecular pattern parallel to theacplane.

scholarly journals 3-Phenyl-N,N,N′,N′-tetramethyl-1-ethyne-1-carboximidamidium bromide

2012 ◽  
Vol 68 (6) ◽  
pp. o1812-o1812 ◽  
Author(s):  
Ioannis Tiritiris ◽  
Willi Kantlehner
Keyword(s):  
Double Bond ◽  
Title Compound ◽  
Triple Bond ◽  
Positive Charge ◽  
Bond Distance ◽  
Double Bond Character ◽  
Acetylenic Bond ◽  
Compound C ◽  
Bond Character

The reaction of 3,3,3-tris(dimethylamino)-1-phenylprop-1-yne with bromine in pentane yields the title compound, C13H17N2 +·Br−. The acetylenic bond distance [1.197 (2) Å] is consistent with a C[triple-bond]C triple bond. The amidinium C=N bonds [1.325 (2) and 1.330 (2) Å] have double-bond character and the positive charge is delocalized between the two dimethylamino groups.

scholarly journals 2-Dimethylamino-1-(2-ethoxy-2-oxoethyl)-3-methyl-4,5-dihydroimidazolium tetraphenylborate

IUCrData ◽  
2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Ioannis Tiritiris ◽  
Willi Kantlehner
Keyword(s):  
Crystal Structure ◽  
Double Bond ◽  
Positive Charge ◽  
Planar Geometry ◽  
Two Dimensional ◽  
Ethoxy Group ◽  
Double Bond Character ◽  
Bond Lengths ◽  
Phenyl Rings ◽  
Bond Character

In the crystal structure of the title salt, C10H20N3O2+·C24H20B−, the C—N bond lengths in the cation are 1.327 (3), 1.339 (3) and 1.342 (3) Å, indicating partial double-bond character. The central C atom is bonded to the three N atoms, indicating only a slight deviation from a trigonal–planar geometry. The positive charge is delocalized in the CN3plane. The ethoxy group is disordered over two orientations, with an occupancy ratio of 0.60 (1):0.40 (1). C—H...π interactions are present between the guanidinium H atoms and the phenyl C atoms of the tetraphenylborate ions. The phenyl rings form aromatic pockets, in which the cations are embedded. This leads to the formation of a two-dimensional supramolecular pattern along theacplane.

Synthesis and structure of 1,1,3,3,-tetramethyl-2-phenyl-2-(2′,6′-diphenyl-4′-pyrylio)-guanidinium diperchlorate

1994 ◽  
Vol 72 (2) ◽  
pp. 352-356 ◽  
Author(s):  
Wlodzimierz Galezowski ◽  
Pradip K. Bakshi ◽  
Kenneth T. Leffek ◽  
T. Stanley Cameron
Keyword(s):  
Double Bond ◽  
Carbon Atom ◽  
Perchloric Acid ◽  
Positive Charge ◽  
Monoclinic Space Group ◽  
Double Bond Character ◽  
Central Carbon ◽  
Guanidinium Cation ◽  
Bond Character ◽  
Positively Charged

The reaction of 2-N-phenyl-1,1,3,3-tetramethylguanidine with 2,6-diphenylpyran-4-one in the presence of phosphorus oxy-chloride, followed by treatment with perchloric acid, yields 1,1,3,3-tetramethyl-2-phenyl-2-(2′,6′-diphenyl-4′-pyrylio)guanidinium diperchlorate. Crystals of this material are monoclinic, space group P21/n, a = 14.535(3), b = 13.685(3), c = 23.579(7) Å, β = 140.38(2)°, R = 0.0633 based on 1691 observed reflections. The substitution of the positively charged pyrylio group on one of the three nitrogen atoms of the guanidinium cation disrupts the symmetry of the distribution of the positive charge on the nitrogen atoms. The two C—N bonds of the central carbon atom of the guanidinium ion to the two methylated nitrogen atoms show more double-bond character than that to the nitrogen carrying the pyrylio group.

scholarly journals N,N,N′,N′,N′′-Pentamethyl-N′′-[3-(trimethylazaniumyl)propyl]guanidinium bis(tetraphenylborate)

2013 ◽  
Vol 69 (2) ◽  
pp. o292-o292 ◽  
Author(s):  
Ioannis Tiritiris
Keyword(s):  
Crystal Structure ◽  
Double Bond ◽  
Positive Charge ◽  
Planar Geometry ◽  
Methyl Groups ◽  
Single Bond ◽  
Double Bond Character ◽  
Bond Lengths ◽  
Phenyl Rings ◽  
Bond Character

In the crystal structure of the title salt, C12H30N42+·2C24H20B−, the C—N bond lengths in the central CN3unit of the guanidinium ion are 1.3388 (17), 1.3390 (16) and 1.3540 (17) Å, indicating partial double-bond character in each. The central C atom is bonded to the three N atoms in a nearly ideal trigonal-planar geometry and the positive charge is delocalized in the CN3plane. The bonds between the N atoms and the terminalC-methyl groups of the guanidinium moiety, all have values close to a typical single bond [1.4630 (16)–1.4697 (17) Å]. C—H...π interactions are present between the guanidinium H atoms and the phenyl C atoms of one tetraphenylborate ion. The phenyl rings form a kind of aromatic pocket, in which the guanidinium ion is embedded.

scholarly journals Crystal structure ofN′′-(2-ethoxy-2-oxoethyl)-N,N,N′,N′-tetramethyl-N′′-[3-(1,3,3-trimethylureido)propyl]guanidinium tetraphenylborate

2015 ◽  
Vol 71 (12) ◽  
pp. o1026-o1027 ◽  
Author(s):  
Ioannis Tiritiris ◽  
Willi Kantlehner
Keyword(s):  
Crystal Structure ◽  
Double Bond ◽  
Positive Charge ◽  
Planar Geometry ◽  
Two Dimensional ◽  
Aromatic Rings ◽  
Double Bond Character ◽  
Bond Lengths ◽  
Phenyl Rings ◽  
Bond Character

In the title salt, C16H34N5O3+·C24H20B−, the C—N bond lengths in the cation are 1.3368 (16), 1.3375 (18) and 1.3594 (17) Å, indicating partial double-bond character. The central C atom is bonded to the three N atoms in a nearly ideal trigonal–planar geometry and the positive charge is delocalized in the CN3plane. In the crystal, weak C—H...O contacts are observed between neighbouring guanidinium ions and between guanidinium ions and tetraphenylborate anions. In addition, C—H...π interactions involving guanidinium H atoms and aromatic rings of the anion are present. The phenyl rings form aromatic pockets, in which the cations are embedded. This leads to the formation of a two-dimensional supramolecular pattern along theabplane.

scholarly journals 1-Benzyl-2-dimethylamino-3-methyl-3,4,5,6-tetrahydropyrimidin-1-ium bromide

2012 ◽  
Vol 68 (8) ◽  
pp. o2308-o2308 ◽  
Author(s):  
Ioannis Tiritiris ◽  
Willi Kantlehner
Keyword(s):  
Double Bond ◽  
Bond Length ◽  
Dihedral Angle ◽  
Positive Charge ◽  
Chair Conformation ◽  
Planar Geometry ◽  
Double Bond Character ◽  
Bond Lengths ◽  
Molecular Salt ◽  
Bond Character

In the title molecular salt, C14H22N3+·Br−, the ring incorporating the guanidinium grouping exhibits a half-chair conformation and the dihedral angle between the N—C—N and C—C—C planes is 55.0 (3)°. The C—N bond lengths in the central CN3unit are 1.333 (4), 1.338 (3) and 1.341 (4) Å, indicating partial double-bond character. The central C atom is bonded to the three N atoms in a nearly ideal trigonal–planar geometry and the positive charge is delocalized in the CN3plane. The distances between the N atom and the terminal methyl C atoms [1.453 (4)–1.461 (4) Å] are all close to a typical single C—N bond length.

scholarly journals Crystal structure of 2-dimethylamino-1-ethoxycarbonyl-3-methyl-3,4,5,6-tetrahydropyrimidin-1-ium tetraphenylborate

2015 ◽  
Vol 71 (11) ◽  
pp. o894-o895
Author(s):  
Ioannis Tiritiris ◽  
Willi Kantlehner
Keyword(s):  
Crystal Structure ◽  
Double Bond ◽  
Positive Charge ◽  
Dihedral Angles ◽  
Planar Geometry ◽  
Asymmetric Unit ◽  
Double Bond Character ◽  
Bond Lengths ◽  
Phenyl Rings ◽  
Bond Character

The asymmetric unit of the title salt, C10H20N3O2+·C24H20B−, contains two cations and two tetraphenylborate ions. The C—N bond lengths in the central CN3unit of the guanidinium ions range between 1.323 (2) and 1.381 (2) Å, indicating partial double-bond character. The central C atoms are bonded to the three N atoms in a nearly ideal trigonal–planar geometry and the positive charge is delocalized in the CN3plane. The cationic six-membered rings are nonplanar, the dihedral angles between the N/C/N and C/C/C planes ranging from 45.8 (1) to 53.6 (1)°. In the crystal, C—H...π interactions are present between the guanidinium H atoms and the phenyl rings of the tetraphenylborate ions. The phenyl rings form aromatic pockets, in which the guanidinium ions are embedded.

CO-ORDINATION COMPLEXES OF TITANIUM (IV) HALIDES: 1. PREPARATION AND INFRARED SPECTRA OF THE COMPLEXES OF TITANIUM (IV) HALIDES WITH N,N-DIMETHYL AND N,N-DIPHENYL FORMAMIDE

1960 ◽  
Vol 38 (8) ◽  
pp. 1331-1338 ◽  
Author(s):  
Jacques Archambault ◽  
Roland Rivest
Keyword(s):  
Double Bond ◽  
Carbonyl Group ◽  
Infrared Spectra ◽  
Dimethyl Formamide ◽  
Double Bond Character ◽  
Positive Shift ◽  
Negative Shift ◽  
Oxygen Bond ◽  
Bond Character

Co-ordination complexes of titanium (IV) halides with N,N-dimethyl formamide and N,N-diphenyl formamide have been prepared and their infrared spectra have been measured. In all these complexes, there is a metal-to-oxygen bond as evidenced in the infrared spectra by a negative shift of the carbonyl stretching frequency and a positive shift of the CN stretching frequency. The relative values of these shifts and the ease of decomposition observed for these complexes indicate that their stability decreases with decreasing the electronegativity of the halide bonded to titanium (IV).In the complexes of N,N-diphenyl formamide, the effect of the conjugated phenyl groups has been observed. In these complexes the decrease of double-bond character of the carbonyl group and the increase of double-bond character of the CN group, resulting from the metal-to-oxygen co-ordination bond, are quite larger than in the complexes of N,N-dimethyl formamide.

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