Structure Elucidation of 2-Amino-5-phenyl-2-oxazolin-4-one (Pemoline) and X-Ray Structure of its Hydrolysis Product 5-Phenyl-oxazolidine-2,4- dione

2005 ◽  
Vol 60 (8) ◽  
pp. 853-857 ◽  
Author(s):  
Piotr Kuś ◽  
Peter G. Jones ◽  
Rafał Celiński
Keyword(s):  
Acetic Acid ◽  
Hydrogen Bonds ◽  
Acid Hydrolysis ◽  
Single Crystals ◽  
Structure Elucidation ◽  
Hydrolysis Product ◽  
Spectroscopic Properties ◽  
Aqueous Acetic Acid ◽  
X Ray ◽  
Independent Molecules

In this study we compare spectroscopic properties of pemoline (2-amino-5-phenyl-2-oxazolin- 4-one) and its acid hydrolysis product 5-phenyl-oxazolidine-2,4-dione. Crystallization of pemoline from aqueous acetic acid gave single crystals of compound 2, the structure of which was determined by X-ray studies. All four crystallographically independent molecules form dimers linked by N-H···O = C hydrogen bonds.

Systhesis, Characterization and Spectroscopic Properties of (2E,6E)-2,6-Bis(2,3,4-tri-methoxy-benzylidene)cyclohexanone

2011 ◽  
Vol 396-398 ◽  
pp. 2338-2341
Author(s):  
Xing Chuan Wei ◽  
Zhi Li Liu ◽  
Kun Zhang ◽  
Zhi Yun Du ◽  
Xi Zheng
Keyword(s):  
Crystal Structure ◽  
Acetic Acid ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Spectroscopic Properties ◽  
Spectral Studies ◽  
Double Bonds ◽  
X Ray ◽  
Π Interactions ◽  
X Ray Crystallography

In this paper, (2E,6E)-2,6-Bis(2,3,4-tri-methoxy -benzylidene)cyclohexanone (omitted as tmbcho) (1) was obtained by the reaction of acetic acid, tetrahydrofuran, cyclohexanone and 2,3,4-tri-methoxy-benzaldehyde. Three non-classic hydrogen bonds were observed in the compound. X-ray crystallography shows that the crystal structure is stabilized by intermolecular C-H•••π interactions and it contains plenty of conjugated double bonds. The title compound was characterized by UV-vis and fluorescent spectral studies.

Crystal Structures of Seven Terephthaldiamide Derivatives

2002 ◽  
Vol 57 (8) ◽  
pp. 914-921 ◽  
Author(s):  
P. G. Jones ◽  
J. Ossowski ◽  
P. Kus
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Layer Structure ◽  
Inversion Symmetry ◽  
Asymmetric Unit ◽  
X Ray ◽  
Layer Structures ◽  
Structure Determinations ◽  
Independent Molecules

N,N′-Dibutyl-terephthaldiamide (1), N,N′-dihexyl-terephthaldiamide (2), N,N′-di(tert-butyl)- terephthaldiamide (3), N,N,N′,N′-tetrabutyl-terephthaldiamide (4), 1,1′-terephthaloylbis- pyrrolidine (5), 1,1′-terephthaloyl-bis-piperidine (6), and 4,4′-terephthaloyl-bis-morpholine (7) have been synthesised and physicochemically characterised. The X-ray structure determinations reveal imposed inversion symmetry for compounds 1-6; compound 3 has two independent molecules with inversion symmetry in the asymmetric unit. Compounds 1-3 form classical hydrogen bonds of the type N-H···O=C, leading to a ribbon-like arrangement of molecules (1 and 2) or a layer structure (3). Compound 3 also displays a very short C-H···O interaction, a type of hydrogen bond that is also observed in compounds 4-7, which lack classical donors; thereby compounds 4-6 form layer structures and 7 a complex threedimensional network.

3-[(Diphenylphosphinothioyl)oxy]-N-methylpropan-1-aminium diphenylphosphanylthioate

2014 ◽  
Vol 70 (3) ◽  
pp. 320-322
Author(s):  
Merve Karaman ◽  
Sevil İrişli ◽  
Orhan Büyükgüngör
Keyword(s):  
Hydrogen Bond ◽  
Melting Point ◽  
Hydrogen Bonds ◽  
Single Crystals ◽  
Spectroscopic Methods ◽  
High Melting ◽  
Asymmetric Unit ◽  
Slow Evaporation ◽  
High Melting Point ◽  
X Ray

The title salt, C16H21NOPS+·C12H10OPS, was synthesized from the reaction between 3-(methylamino)propan-1-ol and PPh2(S)Cl in the presence of Et3N. Its structure has been identified using spectroscopic methods and X-ray analysis. Single crystals were obtained from ethanol by slow evaporation. In the asymmetric unit, a cation–anion pair is formed through an intermolecular N—H...O [N...O = 2.6974 (18) Å] hydrogen bond. The molecules are packed through N—H...O and N—H...S hydrogen bonds in the crystal and these hydrogen bonds are responsible for the high melting point. The P atoms of the anion and cation both have distorted tetrahedral environments.

scholarly journals Success or Failure of Chiral Crystallization of Similar Heterocyclic Compounds

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5691
Author(s):  
Cyprian M. Chunkang ◽  
Iris E. Ikome ◽  
Emmanuel N. Nfor ◽  
Yuta Mitani ◽  
Natsuki Katsuumi ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Single Crystal ◽  
Single Crystals ◽  
Heterocyclic Compounds ◽  
Van Der Waals ◽  
Van Der Waals Forces ◽  
The Other ◽  
X Ray ◽  
Other Hand

Single crystals of two achiral and planar heterocyclic compounds, C9H8H3O(CA1) and C8H5NO2 (CA4), recrystallized from ethanol, were characterized by single crystal X-ray analysis, respectively, and chiral crystallization was observed only for CA1 as P212121 (# 19), whereas it was not observed for CA4 P21/c (# 14). In CA1, as a monohydrate, the hydrogen bonds were pronounced around the water of crystallization (O4), and the planar cyclic sites were arranged in parallel to slightly tilted positions. On the other hand, an anhydride CA4 formed a dimer by hydrogen bonds between adjacent molecules in the crystal, which were aggregated by van der Waals forces and placed in parallel planar cyclic sites.

Synthesis and Crystal Structure of (dmaaH)2(dmaH)2[P12Sn12N12(NH)2] · 4 dmaa, dmaa = N,N-Dimethylacetamide, dma = Dimethylamine, an Anhydrous Example of the P12N14Cage

2001 ◽  
Vol 56 (10) ◽  
pp. 1020-1024
Author(s):  
Stephan Roth ◽  
Wolfgang Schnick
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Single Crystals ◽  
Structure Determination ◽  
Title Compound ◽  
Saturated Solution ◽  
Synthesis And Crystal Structure ◽  
X Ray

Abstract The title compound (dmaaH)2(dmaH)2[P12S12N12(NH)2] · 4 dmaa (1) was obtained by crys­tallization from a saturated solution of anhydrous P12S12N8(NH)6 in N,N-dimethylacetamide (dmaa) as large single crystals. According to the X-ray structure determination (P21/n, a = 1421.8(1), b = 1556.5(2), c = 1645.8(1) pm, ß = 112.207(6)°, Z = 2, 6388 observed reflections, R1 = 0.046, wR2 = 0.111) the anionic cage is built up from twelve P3N3 rings in boat confor­ mation. N,N-dimethylammonium ions (dmaH+) are directly connected to the cage, and pairs of N,N-dimethylacetamidonium ions (dmaaH+) and N,N-dimethylacetamide molecules (dmaa) are interconnected by hydrogen-bonds.

scholarly journals New superprotonic crystals with dynamically disordered hydrogen bonds: cation replacements as the alternative to temperature increase

2017 ◽  
Vol 73 (6) ◽  
pp. 1105-1113 ◽  
Author(s):  
Elena V. Selezneva ◽  
Irina P. Makarova ◽  
Inna A. Malyshkina ◽  
Nadezhda D. Gavrilova ◽  
Vadim V. Grebenev ◽  
...  
Keyword(s):  
High Temperature ◽  
Dielectric Properties ◽  
Hydrogen Bonds ◽  
Single Crystals ◽  
Diffraction Data ◽  
Room Temperature ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Superprotonic Phase

Investigations of new single crystals grown in the K3H(SO4)2–(NH4)3H(SO4)2–H2O system from solutions with different K:NH4 concentration ratios have been carried out. Based on the X-ray diffraction data, the atomic structure of the crystals was determined at room temperature taking H atoms into account. It has been determined that [K0.43(NH4)0.57]3H(SO4)2 crystals are trigonal at ambient conditions such as the superprotonic phase of (NH4)3H(SO4)2 at high temperature. A distribution of the K and N atoms in the crystal was modelled on the basis of the refined occupancies of K/N positions. Studies of dielectric properties over the temperature range 223–353 K revealed high values of conductivity of the crystals comparable with the conductivity of known superprotonic compounds at high temperatures, and an anomaly corresponding to a transition to the phase with low conductivity upon cooling.

Synthesis of 6-Methoxy-2-methyl-2-[(1'-methyl-2',5'-dioxocyclopentyl)methyl]-3,4-dihydro-naphthalen-1(2H)-one: Its Novel Base-Catalyzed Rearrangement to a Hydrophenanthrene Keto Acid

1994 ◽  
Vol 47 (4) ◽  
pp. 623 ◽  
Author(s):  
DJ Collins ◽  
GD Fallon ◽  
CE Skene
Keyword(s):  
Acetic Acid ◽  
Ethylene Glycol ◽  
Acid Hydrolysis ◽  
Keto Acid ◽  
X Ray ◽  
X Ray Crystallography ◽  
Aldol Cyclization ◽  
Diastereomeric Mixture ◽  
Rearrangement Reaction ◽  
Reactions With Nucleophiles

Reaction of 2-dimethylaminomethyl-6-methoxy-3,4-dihydronaphthalen-1(2H)-one (7) with 2-methylcyclopentane-1,3-dione gave 64% of 6-methoxy-2-[(1′-methyl-2′,5′-dioxocyclopentyl)-methyl]-3,4-dihydronaphthalen-1(2H)-one(6a), which with 1 equiv. of ethylene glycol in refluxing benzene in the presence of 4-toluenesulfonic acid yielded a diastereomeric mixture of the 2′,2̶-ethylenedioxy derivatives (13a,b); the major diastereomer (13a) was shown to have 1′SR,2RS stereochemistry by X-ray crystallography. With an excess of ethylene glycol and prolonged reflux the triketone (6a) underwent aldol cyclization/acetalization to give 9,9,12,12-bis(ethylenedioxy)-3-methoxy-8-methyl-5,6,8,9,10,11-hexahydro-8,11-methano-7H-cyclohepta[a]naphthalene (19). With pyridinium 4-toluenesulfonate as catalyst, aldol cyclization was avoided, and the tri-ketone (6a) afforded 2-[(2′,2′,5′,5′-bis(ethylenedioxy)-1′-methylcyclopentyl)methyl]-6-methoxy-3,4-dihydronaphthalen-1(2H)-one (15). The triketone (6a) and its monoacetal (13a,b) were susceptible to reverse Michael cleavage in reactions with nucleophiles under either acidic or basic conditions. Methylation of the keto diacetal (15), followed by acid hydrolysis, gave 6-methoxy-2-methyl-2-[(1′-methyl-2′,5′-dioxocyclopentyl)methyl]-3,4-dihydronaphthalen-1(2H)-one (6b); 2-[(2′,2′-ethylenedioxy-1′-methyl-5′-oxocyclopentyl)methyl]-6-methoxy-2-methyl-3,4-dihydronaphtha - len-1(2H)-one (32), resulting from incomplete hydrolysis, was shown to have 1′RS,2RS stereochemistry by X-ray crystallography. The triketone (6b) underwent a novel base-catalysed rearrangement reaction to give 7-methoxy-2ξ,10a-dimethyl-3-oxo-1,2,3,9,10,10a-hexahydrophenanthrene-4-acetic acid (33) which readily afforded the corresponding enol lactone (35).

3,5-Dimethoxybenzohydrazide

2006 ◽  
Vol 62 (5) ◽  
pp. o1976-o1977 ◽  
Author(s):  
Hui-Yan Liu ◽  
Feng Gao ◽  
Zai-Sheng Lu ◽  
De-Zhong Niu
Keyword(s):  
Hydrogen Bonds ◽  
Title Compound ◽  
Asymmetric Unit ◽  
X Ray ◽  
Compound C ◽  
Independent Molecules

The title compound, C9H12N2O3, was synthesized by the reaction of ethyl 3,5-dimethoxybenzoate with hydrazine. X-ray analysis reveals that the asymmetric unit contains two independent molecules. N—H...O and C—H...O hydrogen bonds link the molecules into layers. Molecules in adjacent layers are linked via N—H...O hydrogen bonds.

SYNTHESIS OF CELLULOSE FROM ETHANOL-SOLUBLE PRECURSORS IN GREEN PLANTS

1961 ◽  
Vol 39 (12) ◽  
pp. 1921-1926 ◽  
Author(s):  
J. Ross Colvin
Keyword(s):  
Electron Microscopy ◽  
Acetic Acid ◽  
Acid Hydrolysis ◽  
Acetobacter Xylinum ◽  
Neutral Sugar ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bacterial Enzyme ◽  
General Similarity ◽  
Ethanol Extracts

The formation of microfibrillar material from filtered 80% (v/v) ethanol extracts of etiolated Avena coleoptiles and Pisum seedlings was demonstrated by electron microscopy. The microfibrils were resistant to alkali, molar acetic acid, and extraction by lipid solvents. After acid hydrolysis, only glucose was detected as a component neutral sugar. The X-ray diffraction powder diagram of these microfibrils was identical with that of a standard alkali-digested bacterial cellulose. On this evidence, the microfibrils are assumed to be cellulose produced from a soluble precursor together with an extracellular bacterial enzyme. The general similarity between these results and those previously obtained with extracts of Acetobacter xylinum is discussed.

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