Angular Regioselectivity in the Reactions of 2-Thioxopyrimidin-4-ones and Hydrazonoyl Chlorides: Synthesis of Novel Stereoisomeric Octahydro[1,2,4]triazolo[4,3-a]quinazolin-5-ones

Awad I. Said; Márta Palkó; Matti Haukka; Ferenc Fülöp

doi:10.3390/molecules25235673

Angular Regioselectivity in the Reactions of 2-Thioxopyrimidin-4-ones and Hydrazonoyl Chlorides: Synthesis of Novel Stereoisomeric Octahydro[1,2,4]triazolo[4,3-a]quinazolin-5-ones

Molecules ◽

10.3390/molecules25235673 ◽

2020 ◽

Vol 25 (23) ◽

pp. 5673

Author(s):

Awad I. Said ◽

Márta Palkó ◽

Matti Haukka ◽

Ferenc Fülöp

Keyword(s):

Regioselective Synthesis ◽

Synthesis Process ◽

Two Dimensional ◽

Electronic Control ◽

Nmr Studies ◽

X Ray ◽

Hydrazonoyl Chlorides ◽

Cis And Trans

The regioselective synthesis of cis and trans stereoisomers of variously functionalized octahydro[1,2,4]triazolo[4,3-a]quinazolin-5-ones was performed. The 2-thioxopyrimidin-4-ones used in the synthesis reacted with hydrazonoyl chlorides in a regioselective manner to produce the angular regioisomers [1,2,4]triazolo[4,3-a]quinazolin-5-ones rather than the linear isomers [1,2,4]triazolo[4,3-a]quinazolin-5-ones. The synthesis process took place with electronic control. The angular regiochemistry of the products was confirmed by X-ray experiments and two-dimensional NMR studies.

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Absolute stereochemistry of disidein and of two new related halogenated sesterterpenoids. Two-dimensional nmr studies and x-ray crystal structure

Tetrahedron ◽

10.1016/s0040-4020(01)86919-2 ◽

1987 ◽

Vol 43 (20) ◽

pp. 4777-4784 ◽

Cited By ~ 8

Author(s):

G. Cimino ◽

S. De Rosa ◽

S. De Stefano ◽

R. Puliti ◽

G. Strazzullo ◽

...

Keyword(s):

Crystal Structure ◽

Two Dimensional ◽

Nmr Studies ◽

X Ray ◽

Absolute Stereochemistry

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Gold complexes of ditelluridoimidodiphosphinate ligands — Reversible oxidation of Au(I) to Au(III) via insertion of gold into a phosphorus–tellurium bond

Canadian Journal of Chemistry ◽

10.1139/v08-074 ◽

2009 ◽

Vol 87 (1) ◽

pp. 39-46 ◽

Cited By ~ 10

Author(s):

Dana J Eisler ◽

Stuart D Robertson ◽

Tristram Chivers

Keyword(s):

Solid State ◽

Solid State Nmr ◽

Trans Isomers ◽

Nmr Studies ◽

Gold Complexes ◽

X Ray ◽

Cis And Trans Isomers ◽

Cis And Trans ◽

Insertion Process

The reaction of (THT)AuCl with (TMEDA)Na[N(TePR2)2] (R = Ph, i-Pr, t-Bu) produces a series of gold (III) complexes of the type [{R2PNP(Te)R2}Au(µ-Te)]2 (4a, R = i-Pr; 4b, R = Ph; 4c, R = t-Bu) rather than the expected homoleptic Au(I) complexes of the ditelluridoimidodiphosphinate ligands. A combination of solution- and solid-state NMR studies shows that both cis and trans isomers of 4a–4c are formed in these reactions. X-ray structural determinations of the trans isomers of 4a–4c reveal a centrosymmetric arrangement with a central four-membered Au2Te2 ring formed by the formal insertion of gold into a P–Te bond; this insertion process was shown to be reversible upon addition of PPh3 to 4a to give the monomeric gold(I) complex Ph3PAu[N{TeP(i-Pr)2}2]. The X-ray structure of cis-4b is also described.Key words: gold, tellurium, redox, X-ray structures, imidodiphosphinate.

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ChemInform Abstract: Heteronuclear Transition Metal-Alkyne Clusters. Part 1. Reactions of Tris(alkyne)monocarbonyltungsten Complexes with Octacarbonyldicobalt. Synthesis, X-Ray Crystal Structure, and Two-Dimensional NMR Studies of (WCo2(μ-C2Et2)(μ-C4Et4)(

ChemInform ◽

10.1002/chin.198947274 ◽

1989 ◽

Vol 20 (47) ◽

Author(s):

I. D. SCOTT ◽

D. O. SMITH ◽

M. J. WENT ◽

L. J. FARRUGIA

Keyword(s):

Crystal Structure ◽

Transition Metal ◽

Two Dimensional ◽

Nmr Studies ◽

X Ray

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Stereodynamics of sterically crowded metal-phosphine complexes: trans-[(tert-Bu)2P(iso-Pr)]2MCl2 [M = platinum(II) and palladium(II)]: one-dimensional dynamic and two-dimensional chemical exchange NMR studies, x-ray crystallographic studies, molecular conformation trapping, and molecular mechanics calculations

The Journal of Physical Chemistry ◽

10.1021/j100201a018 ◽

1992 ◽

Vol 96 (22) ◽

pp. 8765-8777 ◽

Cited By ~ 9

Author(s):

Christine M. DiMeglio ◽

Kazi J. Ahmed ◽

Linda A. Luck ◽

Eugen E. Weltin ◽

Arnold L. Rheingold ◽

...

Keyword(s):

Molecular Mechanics ◽

Molecular Conformation ◽

Chemical Exchange ◽

Two Dimensional ◽

Nmr Studies ◽

Molecular Mechanics Calculations ◽

One Dimensional ◽

X Ray ◽

Phosphine Complexes

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Microwave-Assisted Regioselective Synthesis of Variously Functionalized [1,2,4]triazolo[3,4-b]quinazolin-5(1H)-ones

Current Organic Chemistry ◽

10.2174/1385272824666200814134911 ◽

2020 ◽

Vol 24 (16) ◽

pp. 1892-1896 ◽

Cited By ~ 1

Author(s):

Awad I. Said ◽

Matti Haukka ◽

Ferenc Fülöp

Keyword(s):

Regioselective Synthesis ◽

X Ray ◽

Hydrazonoyl Chlorides ◽

Microwave Assisted

[1,2,4]Triazolo[3,4-b]quinazolin-5(1H)-ones with varied functionalization patterns were synthesized in a regioselective manner by reacting 2-thioxo-2,3- dihydroquinazolin-4(1H)-one (2) with variously functionalized hydrazonoyl chlorides (3ah). Linear regioselectivity of the formed products was confirmed by X-ray measurements. Under microwave conditions, the reactions were completed in a few minutes without a change in the regioselectivity.

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Darstellung und Strukturelle Charakterisierung von cis-und trans- Dicyclohexyl-3,3′,4,4′-tetracarbonsäure-tetramethylestern / Preparation and Structural Characterization of cis- and trans-Tetramethyl Dicyclohexyl-3,3′,4,4′-tetracarboxylates

Zeitschrift für Naturforschung B ◽

10.1515/znb-2001-0211 ◽

2001 ◽

Vol 56 (2) ◽

pp. 189-201

Author(s):

Akinori Shiotani

Keyword(s):

Catalytic Hydrogenation ◽

Two Dimensional ◽

X Ray Diffraction ◽

Trans Isomers ◽

X Ray ◽

Nmr Data ◽

Methoxycarbonyl Group ◽

Cis And Trans ◽

C Nmr

Abstract In the catalytic hydrogenation of tetramethyl biphenyl-3,3′,4,4′-tetracarboxylate, tetramethyl dicyclohexyl-3,3′,4,4′-tetracarboxylates were obtained, from which we have isolated cis isomers as crystals. The base-catalyzed isomerization afforded the trans isomers. The structure of the products isolated was determined by single-crystal x-ray diffraction, which clearly reveals the axial and equatorial positions of the methoxycarbonyl group. The structures in solution are supported by 1H and 13C NMR data, and also by two-dimensional COSY techniques.

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Solid-state structure and solution conformation of the nootropic agent N[2-(N,N-Diisopropylamino)ethyl]-2-oxo-1-pyrrolidinacetamide sulphate. X-ray and homonuclear two-dimensional 1H NMR studies

Journal of Molecular Structure ◽

10.1016/0022-2860(87)87039-4 ◽

1987 ◽

Vol 157 (4) ◽

pp. 311-320 ◽

Cited By ~ 10

Author(s):

Giuliano Bandoli ◽

Marino Nicolini ◽

Giuseppe C. Pappalardo ◽

Antonio Grassi ◽

Bruno Perly

Keyword(s):

Solid State ◽

1H Nmr ◽

Two Dimensional ◽

State Structure ◽

Solution Conformation ◽

Nmr Studies ◽

Solid State Structure ◽

X Ray ◽

Nootropic Agent

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Regioselective Synthesis of a Stereodefined Heterocyclic Push-Pull Alkene. 1H NMR Studies and Two-Dimensional TLC Illustrating Z/E Isomerization

Journal of Chemical Education ◽

10.1021/ed081p1026 ◽

2004 ◽

Vol 81 (7) ◽

pp. 1026 ◽

Cited By ~ 7

Author(s):

Zdravko Dzambaski ◽

Rade Markovic ◽

Marija Baranac ◽

Vesna Jovanovic

Keyword(s):

1H Nmr ◽

Regioselective Synthesis ◽

Two Dimensional ◽

Nmr Studies

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Tubulin structure at intermediate resolution

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100140634 ◽

1995 ◽

Vol 53 ◽

pp. 852-853

Author(s):

K. H. Downing ◽

S. G. Wolf ◽

E. Nogales

Keyword(s):

High Resolution ◽

Structural Data ◽

Therapeutic Drug ◽

Zinc Ions ◽

Two Dimensional ◽

X Ray Diffraction ◽

X Ray ◽

Negative Stain ◽

Functional Mechanisms ◽

Tubulin Structure

Microtubules are involved in a host of critical cell activities, many of which involve transport of organelles through the cell. Different sets of microtubules appear to form during the cell cycle for different functions. Knowledge of the structure of tubulin will be necessary in order to understand the various functional mechanisms of microtubule assemble, disassembly, and interaction with other molecules, but tubulin has so far resisted crystallization for x-ray diffraction studies. Fortuitously, in the presence of zinc ions, tubulin also forms two-dimensional, crystalline sheets that are ideally suited for study by electron microscopy. We have refined procedures for forming the sheets and preparing them for EM, and have been able to obtain high-resolution structural data that sheds light on the formation and stabilization of microtubules, and even the interaction with a therapeutic drug.Tubulin sheets had been extensively studied in negative stain, demonstrating that the same protofilament structure was formed in the sheets and microtubules. For high resolution studies, we have found that the sheets embedded in either glucose or tannin diffract to around 3 Å.

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