scholarly journals Halogen effects on the solid-state packing of phenylalanine derivatives and the resultant gelation properties

2017 ◽  
Vol 203 ◽  
pp. 423-439 ◽  
Author(s):  
Susana M. Ramalhete ◽  
Jamie S. Foster ◽  
Hayley R. Green ◽  
Karol P. Nartowski ◽  
Margaux Heinrich ◽  
...  
Keyword(s):  
Amino Acid ◽  
Solid State ◽  
Human Health ◽  
Crystal Structures ◽  
Aromatic Ring ◽  
Building Block ◽  
Artificial Sweeteners ◽  
Aromatic Group ◽  
Important Amino Acid

Phenylalanine is an important amino acid both biologically, essential to human health, and industrially, as a building block of artificial sweeteners. Our interest in this particular amino acid and its derivatives lies with its ability to form gels in a number of solvents. We present here the studies of the influence of halogen addition to the aromatic ring on the gelation properties and we analyse the crystal structures of a number of these materials to elucidate the trends in their behaviour based on the halogen addition to the aromatic group and the interactions that result.

scholarly journals Synthesis of 2-aminosuberic acid derivatives as components of some histone deacetylase inhibiting cyclic tetrapeptides

2017 ◽  
Vol 13 ◽  
pp. 2153-2156 ◽  
Author(s):  
Shital Kumar Chattopadhyay ◽  
Suman Sil ◽  
Jyoti Prasad Mukherjee
Keyword(s):  
Amino Acid ◽  
Histone Deacetylase ◽  
Building Block ◽  
Suberic Acid ◽  
Metathesis Reaction ◽  
Cross Metathesis ◽  
Important Amino Acid ◽  
New Synthesis ◽  
Cyclic Tetrapeptides ◽  
Derivatives Of

A new synthesis of the important amino acid 2-aminosuberic acid from aspartic acid is reported. The methodology involves the alternate preparation of (S)-2-aminohept-6-enoate ester as a building block and its diversification through a cross-metathesis reaction to prepare the title compounds. The utility of the protocol is demonstrated through the preparation of three suberic acid derivatives of relevance to the design and the synthesis of peptides of biological relevance.

scholarly journals Solid-state conformations of linear depsipeptide amides with an alternating sequence of α,α-disubstituted α-amino acid and α-hydroxy acid

2019 ◽  
Vol 76 (1) ◽  
pp. 1-9
Author(s):  
Anthony Linden ◽  
J. E. Florian Magirius ◽  
Heinz Heimgartner
Keyword(s):  
Amino Acid ◽  
Solid State ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Hydroxy Acid ◽  
Mandelic Acid ◽  
Type I ◽  
Two Dimensional ◽  
Phenyllactic Acid ◽  
Torsion Angles

Depsipeptides and cyclodepsipeptides are analogues of the corresponding peptides in which one or more amide groups are replaced by ester functions. Reports of crystal structures of linear depsipeptides are rare. The crystal structures and conformational analyses of four depsipeptides with an alternating sequence of an α,α-disubstituted α-amino acid and an α-hydroxy acid are reported. The molecules in the linear hexadepsipeptide amide in (S)-Pms-Acp-(S)-Pms-Acp-(S)-Pms-Acp-NMe2 acetonitrile solvate, C47H58N4O9·C2H3N, (3b), as well as in the related linear tetradepsipeptide amide (S)-Pms-Aib-(S)-Pms-Aib-NMe2, C28H37N3O6, (5a), the diastereoisomeric mixture (S,R)-Pms-Acp-(R,S)-Pms-Acp-NMe2/(R,S)-Pms-Acp-(R,S)-Pms-Acp-NMe2 (1:1), C32H41N3O6, (5b), and (R,S)-Mns-Acp-(S,R)-Mns-Acp-NMe2, C30H37N3O6, (5c) (Pms is phenyllactic acid, Acp is 1-aminocyclopentanecarboxylic acid and Mns is mandelic acid), generally adopt a β-turn conformation in the solid state, which is stabilized by intramolecular N—H...O hydrogen bonds. Whereas β-turns of type I (or I′) are formed in the cases of (3b), (5a) and (5b), which contain phenyllactic acid, the torsion angles for (5c), which incorporates mandelic acid, indicate a β-turn in between type I and type III. Intermolecular N—H...O and O—H...O hydrogen bonds link the molecules of (3a) and (5b) into extended chains, and those of (5a) and (5c) into two-dimensional networks.

Color and Conformation of Some Derivatives of Benzil in the Solid-State: Crystal-Structures of 2,2′-Dimethoxy- 4,4′-Dimethoxy- , 4-4′Diethoxy- and 4,4'-Dibenzyloxy-benzil

1989 ◽  
Vol 42 (10) ◽  
pp. 1631 ◽  
Author(s):  
JR Cannon ◽  
VA Patrick ◽  
AH White
Keyword(s):  
Solid State ◽  
Single Crystal ◽  
Least Squares ◽  
Crystal Structures ◽  
Aromatic Ring ◽  
Full Matrix ◽  
X Ray ◽  
Derivatives Of ◽  
Least Squares Techniques

The crystal structures of the colourless 2,2'-dimethoxybenzil (2) and 4,4'-diethoxybenzil (6), the yellow 4,4'-dimethoxybenzi (5), and the yellow polymorph of 4,4'-dibenzyloxybenzil (7) have been determined by single-crystal X-ray studies from diffractometer data at 295 K, and refined by full matrix least-squares techniques to residuals of 0.048 (1281 'observed' reflections), 0.041 (610), 0.052 (662) and 0.043 (2140) respectively. Crystals of 2,2′-dimethoxybenzil (2) are monoclinic, P21/c, a 7.861(4), b 7.991(2), c 21.557(9)�, β90.37(4)�, Z 4. Crystals of 4,4'-dimethoxybenzil (6) are monoclinic C2/c, a 21.912(9), b 4.055(2), c 15.197(5) �,β 102 13(3)� Z 4. Crystals of 4,4′-diethoxybenzil (6) are monoclinic C21/c, a 14.544(7), b 4.781(2), c 22.128(7), β 99.06(3)�, Z 4. Crystals of the yellow modification of 4,4'-dibenzyloxybenzil (7) are monoclinic P21/c, a 19.126(4), b 6.91 1(2), c 16.673(7) � β 99.52(3)�, Z 4. It has been found that there is a correlation between the colour of the crystal and the conformation adopted by the molecule in the solid state with the colourless derivatives of benzil having the aromatic ring planes orthogonal.

1-(7-Chloro-1,4-dihydroquinolin-4-ylidene)thiosemicarbazide and its hydrochloride: evidence for the existence of a stable imine tautomer in the solid state of 4-aminoquinoline free bases, an anomalous case in nitrogen heterocycles

2015 ◽  
Vol 71 (7) ◽  
pp. 564-569 ◽  
Author(s):  
Rafael C. Machado ◽  
Richard M. Grazul ◽  
Renata Diniz
Keyword(s):  
Double Bond ◽  
Solid State ◽  
Crystal Structures ◽  
Aromatic Ring ◽  
Tautomeric Form ◽  
Bond Angle ◽  
Nitrogen Heterocycles ◽  
Hydrochloride Salt ◽  
Substituted Quinolines ◽  
Bond Character

In the solid state, crystals of both 1-(7-chloro-1,4-dihydroquinolin-4-ylidene)thiosemicarbazide–methanol–water (2/1/1), 2C10H9ClN4S·CH3OH·H2O, (I), and its hydrochloride salt {systematic name: [(7-chloro-1,4-dihydroquinolin-4-ylidene)azaniumyl]thiourea chloride}, C10H10ClN4S+·Cl−, (II), assume the imine tautomeric form, contrary to other 4-amino-7-chloroquinolines. Of particular interest are the N—C bond lengths, which have appreciable double-bond character, and the C—N—C aromatic ring bond angle. Both of these parameters have been studied extensively in 4-amino-substituted quinolines. The crystal structures of (I) and (II) in this study provide interesting examples of the amino–imino tautomerism which exists in this class of compound and is, to the best of our knowledge, hitherto unreported.

scholarly journals Investigation of solid-state photochemical nitro–nitrito linkage isomerization: crystal structures of trans-bis(ethylenediamine)(isothiocyanato)nitritocobalt(III) salts: thiocyanate, chloride monohydrate, and perchlorate–thiocyanate(0.75/0.25)

2018 ◽  
Vol 74 (10) ◽  
pp. 1526-1531 ◽  
Author(s):  
Shigeru Ohba ◽  
Masanobu Tsuchimoto ◽  
Saeko Kurachi
Keyword(s):  
Solid State ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Building Block ◽  
Main Building ◽  
Linkage Isomerization ◽  
The Common ◽  
Chloride Monohydrate

The reaction cavities of the nitro groups in the crystals of the title compounds, trans-[Co(NO2)(NCS)(C2H8N2)2]·X, X = SCN− (I), Cl−·H2O (II), and (ClO4 −)0.75(SCN−)0.25 (III), have been investigated, revealing that the geometry of the intermolecular N—H...O hydrogen bonds in (I) is unsuitable for nitro–nitrito photo-isomerization. The common main building block of these crystal structures is a centrosymmetric pair of complex cations connected by pairwise N—H...O(nitro) hydrogen bonds forming an R 2 2(4) ring, which is a narrow diamond shape in (I) but is approximately square in (II) and (III). The structure of (I) was reported earlier [Börtin (1976). Acta Chem. Scand. A, 30, 503–506] but is described here with an improved disorder model for the thiocyanate anions and to higher precision.

scholarly journals Functionalised Terpyridines and Their Metal Complexes—Solid-State Interactions

Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 199-227
Author(s):  
Young Hoon Lee ◽  
Jee Young Kim ◽  
Sotaro Kusumoto ◽  
Hitomi Ohmagari ◽  
Miki Hasegawa ◽  
...  
Keyword(s):  
Solid State ◽  
Metal Complexes ◽  
Crystal Structures ◽  
Weak Interactions ◽  
Dispersion Interactions ◽  
Derivatives Of

Analysis of the weak interactions within the crystal structures of 33 complexes of various 4′-aromatic derivatives of 2,2′:6′,2″-terpyridine (tpy) shows that interactions that exceed dispersion are dominated, as expected, by cation⋯anion contacts but are associated with both ligand–ligand and ligand–solvent contacts, sometimes multicentred, in generally complicated arrays, probably largely determined by dispersion interactions between stacked aromatic units. With V(V) as the coordinating cation, there is evidence that the polarisation of the ligand results in an interaction exceeding dispersion at a carbon bound to nitrogen with oxygen or fluorine, an interaction unseen in the structures of M(II) (M = Fe, Co, Ni, Cu, Zn, Ru and Cd) complexes, except when 1,2,3-trimethoxyphenyl substituents are present in the 4′-tpy.

Quantitative helix handedness bias through a single H vs. CH3 stereochemical differentiation

2021 ◽  
Author(s):  
Daniel Bindl ◽  
Elisabeth Heinemann ◽  
Pradeep Kumar Mandal ◽  
Ivan Huc
Keyword(s):  
Amino Acid ◽  
Building Block

A novel chiral aromatic δ-amino acid building block was shown to fully induce handedness in quinoline oligoamide foldamers with the possibility to further increase the bias by combining multiple of...

Advantages of naphthalene as building block for organic solid state laser dyes: Smaller energy gaps and enhanced stability

2021 ◽  
Author(s):  
Yuya Oyama ◽  
Masashi Mamada ◽  
Akihiro Kondo ◽  
Chihaya Adachi
Keyword(s):  
Solid State ◽  
Spontaneous Emission ◽  
Building Block ◽  
Solid State Laser ◽  
Laser Dyes ◽  
Energy Gaps ◽  
Organic Solid ◽  
Organic Laser ◽  
Yellow Region ◽  
Enhanced Stability

Organic laser dyes exhibiting very low amplified spontaneous emission (ASE) thresholds in green and yellow region were developed based on a stilbene structure which is often used for the blue...

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