Formal transfers of hydride from carbon–hydrogen bonds. Attempted generation of H2 by intramolecular protonolyses of the activated carbon–hydrogen bonds of dihydrobenzimidazoles

1996 ◽  
Vol 74 (5) ◽  
pp. 689-696 ◽  
Author(s):  
Philippe Brunet ◽  
James D. Wuest
Keyword(s):  
Activated Carbon ◽  
Carboxylic Acid ◽  
Hydrogen Bonds ◽  
Key Words ◽  
Hydride Generation ◽  
Carboxylic Acid Groups ◽  
Lone Pairs ◽  
Close Proximity ◽  
Acidic Sites ◽  
Carbon Hydrogen Bonds

Protonolyses of carbon–hydrogen bonds can occur under suitable conditions to produce carbocations and H2. In an effort to accelerate these fundamental reactions, we have attempted to make them intramolecular by devising compounds in which carbon–hydrogen bonds designed to be particularly good formal donors of hydride are held in close proximity to acidic sites. Dihydrobenzimidazoles 4 and 11 are compounds of this type, since the carbon–hydrogen bonds at C2 are activated as formal donors of hydride by adjacent lone pairs in a dihydroaromatic ring, and acidic anilinium and carboxylic acid groups are held nearby. Unfortunately, this proximity does not lead to the formation of H2 by protonolysis; instead, other reactions intervene when compounds 4 and 11 are subjected to pyrolysis. Key words: intramolecular protonolysis of carbon–hydrogen bonds, formal donors of hydride, generation of H2, dihydrobenzimidazoles.

scholarly journals A new solvate of epalerstat, a drug for diabetic neuropathy

2017 ◽  
Vol 73 (8) ◽  
pp. 1264-1267 ◽  
Author(s):  
Okky Dwichandra Putra ◽  
Daiki Umeda ◽  
Kaori Fukuzawa ◽  
Mihoko Gunji ◽  
Etsuo Yonemochi
Keyword(s):  
Hydrogen Bond ◽  
Acetic Acid ◽  
Carboxylic Acid ◽  
Hydrogen Bonds ◽  
Diabetic Neuropathy ◽  
Dihedral Angle ◽  
Phenyl Ring ◽  
Acid Moiety ◽  
Acta Cryst ◽  
Carboxylic Acid Groups

Epalerstat {systematic name: (5Z)-5-[(2E)-2-methyl-3-phenylprop-2-en-1-ylidene]-4-oxo-2-sulfanylidene-1,3-thiazolidine-3-acetic acid} crystallized as an acetone monosolvate, C15H13NO3S2·C3H6O. In the epalerstat molecule, the methylpropylenediene moiety is inclined to the phenyl ring and the five-membered rhodamine ring by 21.4 (4) and 4.7 (4)°, respectively. In addition, the acetic acid moiety is found to be almost normal to the rhodamine ring, making a dihedral angle of 85.1 (2)°. In the crystal, a pair of O—H...O hydrogen bonds between the carboxylic acid groups of epalerstat molecules form inversion dimers with an R 2 2(8) loop. The dimers are linked by pairs of C—H...O hydrogen bonds, enclosing R 2 2(20) loops, forming chains propagating along the [101] direction. In addition, the acetone molecules are linked to the chain by a C—H...O hydrogen bond. Epalerstat acetone monosolvate was found to be isotypic with epalerstat tertrahydrofuran solvate [Umeda et al. (2017). Acta Cryst. E73, 941–944].

scholarly journals 4-Methylanilinium 3-carboxy-2-hydroxypropanoate

IUCrData ◽  
2016 ◽  
Vol 1 (9) ◽  
Author(s):  
S. Kalaiyarasi ◽  
S. Reena Devi ◽  
R. Akilan ◽  
R. Mohan Kumar ◽  
G. Chakkaravarthi
Keyword(s):  
Hydrogen Bond ◽  
Carboxylic Acid ◽  
Hydrogen Bonds ◽  
Two Dimensional ◽  
Asymmetric Unit ◽  
Carboxylic Acid Groups ◽  
Dimensional Network ◽  
Anions And Cations ◽  
Graph Set ◽  
Molecular Salt

The title molecular salt, C7H10N+·C4H5O5−, contains a 4-methylanilinium cation and a 3-carboxy-2-hydroxypropanoate (hydrogen 2-hydroxysuccinate) anion in the asymmetric unit. The cation is protonated at the amine N atom and the anion is deprotonated at one of the hydroxy O atoms of the carboxylic acid groups. An O—H...O hydrogen bond in the anion generates anS(5) graph-set motif. An N—H...O hydrogen bond links the anion and cation in the asymmetric unit. In the crystal, N—H...O and O—H...O hydrogen bonds link adjacent anions and cations, forming a two-dimensional network parallel to theacplane and enclosingR23(12),R23(14) andR32(10) ring motifs.

scholarly journals Crystal structure of [3-(1H-benzimidazol-2-yl)propanoato-κN3][3-(1H-benzimidazol-2-yl)propanoic acid-κN3]copper(I)

2015 ◽  
Vol 71 (1) ◽  
pp. m5-m6 ◽  
Author(s):  
Zhimin Liu ◽  
Shengrun Zheng ◽  
Sisi Feng
Keyword(s):  
Crystal Structure ◽  
Carboxylic Acid ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Propanoic Acid ◽  
Two Dimensional ◽  
Axis Direction ◽  
Carboxylic Acid Groups

In the title compound, [Cu(C10H9N2O2)(C10H10N2O2)], the CuIion is situated at a crystallographic centre of inversion and is coordinated in a linear environment by two benzimidazole N atoms from two symmetry-related 2-propanoic-1H-benzimidazole ligands. The ligands are disordered in a sense that statistically one of the carboxylic acid groups in each molecule is deprotonated. In the crystal, O—H...O hydrogen bonds link the molecules into chains along thea-axis direction. These chains are additionally linked into infinite two-dimensional networks in theabplane by N—H...O hydrogen bonds.

Hydrogen-bonding patterns in 2-amino-4,6-dimethoxypyrimidine–phthalic acid (1/1)

2007 ◽  
Vol 63 (11) ◽  
pp. o4212-o4212 ◽  
Author(s):  
Kaliyaperumal Thanigaimani ◽  
Packianathan Thomas Muthiah ◽  
Daniel E. Lynch
Keyword(s):  
Hydrogen Bonding ◽  
Carboxylic Acid ◽  
Hydrogen Bonds ◽  
Phthalic Acid ◽  
Helical Chain ◽  
Acid Form ◽  
Carboxylic Acid Groups ◽  
Π Stacking ◽  
Centroid Distance ◽  
Ring Motif

In the title cocrystal, C6H9N3O2·C8H6O4, both carboxylic acid groups of phthalic acid form an R 2 2(8) ring motif (through N—H...O and O—H...N hydrogen bonds) on either side of the 2-amino-4,6-dimethoxypyrimidine molecule, generating a helical chain along the b axis. This chain is interpenetrated by a centrosymmetrically related chain to which it is linked by π–π stacking [perpendicular separation 3.332 Å, centroid–centroid distance 3.6424 (7) Å].

ChemInform Abstract: REACTION OF CHLORAL WITH COMPOUNDS CONTAINING ACTIVATED CARBON-HYDROGEN BONDS

1979 ◽  
Vol 10 (26) ◽  
Author(s):  
K. A. PETROV ◽  
N. A. TIKHONOVA ◽  
Z. YA. LAPSHINA ◽  
N. A. TIL'KUNOVA ◽  
N. N. BARANOV
Keyword(s):  
Activated Carbon ◽  
Hydrogen Bonds ◽  
Carbon Hydrogen Bonds

scholarly journals Crystal structure of 4-{[(naphthalen-2-yl)sulfonylamino]methyl}cyclohexanecarboxylic acid

2015 ◽  
Vol 71 (3) ◽  
pp. o145-o145 ◽  
Author(s):  
Muhammad Danish ◽  
Muhammad Nawaz Tahir ◽  
Asif Hussain ◽  
Muhammad Ashfaq ◽  
Muhammad Nadeem Sadiq
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Carboxylic Acid ◽  
Hydrogen Bonds ◽  
Tranexamic Acid ◽  
Title Compound ◽  
Π Interactions ◽  
Carboxylic Acid Groups ◽  
Compound C ◽  
Thick Layers

The title compound, C18H21NO4S, is a new sulfonamide derivative of tranexamic acid. In the crystal, molecules form inversion dimersviaO—H...O hydrogen bonds involving the carboxylic acid groups. Hydrogen bonding between the sulfonamide N—H group and the carboxylic acid O atom assembles the dimers into thick layers parallel to (100). The naphthalene groups of adjacent layers are arranged in a herring-bone motif. There are C—H...π interactions between the naphthalene rings of neighbouring layers.

scholarly journals Crystal structure of [1,1′:3′,1′′-terphenyl]-2′,3,3′′-tricarboxylic acid

2015 ◽  
Vol 71 (9) ◽  
pp. o667-o668
Author(s):  
Daniel A. Decato ◽  
Orion B. Berryman
Keyword(s):  
Carboxylic Acid ◽  
Hydrogen Bonds ◽  
Acid Group ◽  
Polar Space ◽  
Dihedral Angles ◽  
Hydrogen Bond Donor ◽  
Carboxylic Acid Groups ◽  
Compound C ◽  
Donor And Acceptor ◽  
Benzene Rings

The asymmetric unit of the title compound, C21H14O6, comprises two symmetrically independent molecules that form a locally centrosymmetric hydrogen-bonded dimer, with the planes of the corresponding carboxylic acid groups rotated by 15.8 (1) and 17.5 (1)° relative to those of the adjacent benzene rings. The crystal as a whole, however, exhibits a noncentrosymmetric packing, described by the polar space groupPca21. The dimers form layers along theabplane, being interconnected by hydrogen bonds involving the remaining carboxylic acid groups. The plane of the central carboxylic acid group forms dihedral angles of 62.5 (1) and 63.0 (1)° with those of the adjacent benzene rings and functions as a hydrogen-bond donor and acceptor. As a donor, it interconnects adjacent layers, while as an acceptor it stabilizes the packing within the layers. The `distal' carboxylic acid groups are nearly coplanar with the planes of the adjacent benzene rings, forming dihedral angles of 1.8 (1) and 7.1 (1)°. These groups also form intra- and inter-layer hydrogen bonds, but with `reversed' functionality, as compared with the central carboxylic acid groups.

Sign in / Sign up

Export Citation Format

Share Document