Effect of a cis-4-Aminopiperidine-3-carboxylic Acid (cis-APiC) Residue on Mixed-helical Folding of Unnatural Peptides

2022 ◽  
Author(s):  
Sunglim Choi ◽  
Jihyun Shim ◽  
Philjae Kang ◽  
Soo Hyuk Choi
Keyword(s):  
Carboxylic Acid ◽  
Hydrogen Bonds ◽  
Helical Axis ◽  
Unnatural Peptides ◽  
Helical Folding

The α/β-peptide 11/9-helix and the β-peptide 12/10-helix belong to “mixed” helices, in which two types of hydrogen bonds with opposite directionality alternate along the helical axis. cis-2-Aminocyclohaxanecarboxylic acid (cis-ACHC) is...

Crystal structure of tofacitinib dihydrogen citrate (Xeljanz®), (C16H21N6O)(H2C6H5O7)

2021 ◽  
pp. 1-8
Author(s):  
James A. Kaduk ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Carboxylic Acid ◽  
Hydrogen Bonds ◽  
Powder Diffraction ◽  
Density Functional ◽  
Acid Group ◽  
Dimensional Network ◽  
Van Der Waals Contacts ◽  
Citrate Anion

The crystal structure of tofacitinib dihydrogen citrate (tofacitinib citrate) has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Tofacitinib dihydrogen citrate crystallizes in space group P212121 (#19) with a = 5.91113(1), b = 12.93131(3), c = 30.43499(7) Å, V = 2326.411(6) Å3, and Z = 4. The crystal structure consists of corrugated layers perpendicular to the c-axis. Within the layers, cation⋯anion and anion⋯anion hydrogen bonds link the fragments into a two-dimensional network parallel to the ab-plane. Between the layers, there are only van der Waals contacts. A terminal carboxylic acid group in the citrate anion forms a strong charge-assisted hydrogen bond to the ionized central carboxylate group. The other carboxylic acid acts as a donor to the carbonyl group of the cation. The citrate hydroxy group forms an intramolecular charge-assisted hydrogen bond to the ionized central carboxylate. Two protonated nitrogen atoms in the cation act as donors to the ionized central carboxylate of the anion. These hydrogen bonds form a ring with the graph set symbol R2,2(8). The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™ (PDF®).

scholarly journals 1,4a,7-Trimethyl-7-vinyl-1,2,3,4,4a,4b,5,6,7,8,10,10a-dodecahydrophenanthrene-1-carboxylic acid

2009 ◽  
Vol 65 (6) ◽  
pp. o1429-o1429
Author(s):  
Zhen-Dong Zhao ◽  
Yu-Xiang Chen ◽  
Yu-Min Wang ◽  
Liang-Wu Bi
Keyword(s):  
Hydrogen Bonding ◽  
Carboxylic Acid ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Molecular Conformation ◽  
Slash Pine ◽  
Carboxyl Groups ◽  
Isopimaric Acid ◽  
Hydrogen Bonding Interactions ◽  
Cyclohexene Ring

The title compound, also known as isopimaric acid, C20H30O2, was isolated from slash pine rosin. There are two unique molecules in the unit cell. The two cyclohexane rings have classical chair conformations. The cyclohexene ring represents a semi-chair. The molecular conformation is stabilized by weak intramolecular C—H...O hydrogen-bonding interactions. The molecules are dimerized through their carboxyl groups by O—H...O hydrogen bonds, formingR22(8) rings.

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].

Hydrogen Bonds in "Carboxyoximes": the Case of Bomane Derivatives

2000 ◽  
Vol 55 (8) ◽  
pp. 677-684 ◽  
Author(s):  
Maciej Kubicki ◽  
Teresa Borowiak ◽  
Wiesław Z. Antkowiak
Keyword(s):  
Carboxylic Acid ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Carboxylic Acids ◽  
Supramolecular Structures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carboxylic Groups ◽  
Acid Function

Abstract The tendency of forming mixed carboxyl-to-oxime hydrogen bonds was tested on the series of bornane derivatives: one with the acid function only (bornane-2-endo-carboxylic acid), one with the oxime function (2,2′-diethylthiobomane-3-oxime), and one with both oxime and carboxylic functions (bornane-2-oxime-3-endo-carboxylic acid). The crystal structures of these compounds were determined by means of X-ray diffraction. In bornane-2-endo-carboxylic acid and 2,2′-diethylthiobornane-3-oxime 'homogenic' hydrogen bonds were found, and these hydrogen bonds close eight-and six-membered rings, respectively. By contrast, in bornane-2-oxime-3-endo-carboxylic acid 'heterogenic' hydrogen bonds between carboxylic and oxime bonds were found. This carboxylic-oxime, or 'carboxyoxime' system is almost always present in compounds which have both oxime and carboxylic groups; therefore it can be regarded as an element of supramolecular structures (synthon). The presence of such synthons can break the tendency of carboxylic acids and oximes towards crystallizing in centrosymmetric structures.

scholarly journals Crystal structures of two 6-(2-hydroxybenzoyl)-5H-thiazolo[3,2-a]pyrimidin-5-ones

2015 ◽  
Vol 71 (7) ◽  
pp. 766-771
Author(s):  
Ligia R. Gomes ◽  
John Nicolson Low ◽  
Fernando Cagide ◽  
Fernanda Borges
Keyword(s):  
Hydrogen Bond ◽  
Carboxylic Acid ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Dihedral Angles ◽  
Stacking Interactions ◽  
Mechanism Of Formation ◽  
Π Stacking ◽  
Heterocyclic Moiety

The title compounds, 6-(2-hydroxybenzyl)-5H-thiazolo[3,2-a]pyrimidin-5-one, C13H8N2O3S, (1), and 6-(2-hydroxybenzyl)-3-methyl-5H-thiazolo[3,2-a]pyrimidin-5-one, C14H10N2O3S, (2), were synthesized when a chromone-3-carboxylic acid, activated with (benzotriazol-1-yloxy)tripyrrolidinylphosphonium hexafluoridophosphate (PyBOP), was reacted with a primary heteromamine. Instead of the expected amidation, the unusual title thiazolopyrimidine-5-one derivatives were obtained serendipitously and a mechanism of formation is proposed. Both compounds present an intramolecular O—H...O hydrogen bond, which generates anS(6) ring. The dihedral angles between the heterocyclic moiety and the 2-hydroxybenzoyl ring are 55.22 (5) and 46.83 (6)° for (1) and (2), respectively. In the crystals, the molecules are linked by weak C—H...O hydrogen bonds and π–π stacking interactions.

scholarly journals 6-(Hex-5-enyloxy)naphthalene-2-carboxylic acid

2014 ◽  
Vol 70 (6) ◽  
pp. o696-o697
Author(s):  
Md. Lutfor Rahman ◽  
H. T. Srinivasa ◽  
Mashitah Mohd. Yusoff ◽  
Huey Chong Kwong ◽  
Ching Kheng Quah
Keyword(s):  
Crystal Structure ◽  
Carboxylic Acid ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Ring System ◽  
Dihedral Angles ◽  
Carbonyl Groups ◽  
Asymmetric Unit ◽  
Compound C ◽  
Independent Molecules

The asymmetric unit of the title compound, C17H18O3, comprises three independent molecules with similar geometries. In each molecule, the carbonyl group is twisted away from the napthalene ring system, making dihedral angles of 1.0 (2), 1.05 (19)° and 1.5 (2)°. The butene group in all three molecules are disordered over two sets of sites, with a refined occupancy ratio of 0.664 (6):0.336 (6). In the crystal, molecules are oriented with respect to their carbonyl groups, forming head-to-head dimersviaO—H...O hydrogen bonds. Adjacent dimers are further interconnected by C—H...O hydrogen bonds into chains along thea-axis direction. The crystal structure is further stabilized by weak C—H...π interactions.

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