Neuartige Allylboran- und Allyldiboran(4)-Derivate / Novel Allylboran- and Allyldiboran(4) Derivatives

1990 ◽  
Vol 45 (7) ◽  
pp. 985-988 ◽  
Author(s):  
Gabriele Knörzer ◽  
Hermann Seyffer ◽  
Hans Pritzkow ◽  
Walter Siebert
Keyword(s):  
Structure Analysis ◽  
X Ray ◽  
Chloro Derivative ◽  
Chloro Derivatives ◽  
Derivatives Of

Allyldiboran(4) derivatives la—c are obtained from allylmagnesium chloride and chloro derivatives of diboran(4). la—c are air-sensitive liquids; heating of le did not yield a 2,3-dihydro-l,2-diborole derivative (B). Reaction between 1,1-bis(dichloroboryl)-3,3-dimethyl-butane (5) and H2C=C(CH2SnMe3)2 (4) leads to the heat-sensitive chloro derivative 2a, in which the chlorine is substituted by Me3SiNMe2 to give stable 1,3-bis-dimethylamino-5-methylene-2-neopentyl- 1,3-diborinane (2 b). 1,2-Bis(dichloroboryl)benzene and 4 yield the chloro derivative 3a, and its substitution with HN(i-Pr)2 leads to 1,4-bis(diisopropylamino)-2,3-benzo-6-methylene-1,4,5,7-tetrahydro-1,4-diborepine (3 b). The X-ray structure analysis reveals a folded tetrahydro-1,4-diborepine ring.

2',3'-O-Carbonyl derivatives of 6-azauridine in the synthesis of its 5-substituted and 5'-deoxy derivatives

1987 ◽  
Vol 52 (8) ◽  
pp. 2070-2082
Author(s):  
Pavel Drašar ◽  
Jiří Beránek
Keyword(s):  
Thionyl Chloride ◽  
Alkaline Hydrolysis ◽  
Triphenyl Phosphine ◽  
Carbonyl Derivatives ◽  
Tributyltin Hydride ◽  
Chloro Derivative ◽  
Ammonium Halides ◽  
Chloro Derivatives ◽  
Derivatives Of ◽  
Dichloro Derivative

Preparation of 2',3'-O-carbonyl derivatives of 5'-deoxy-6-azauridine and 6-azauridine using 1,1'-carbonyldiimidazole has been elaborated. 5'-Chloro and 5'-bromo derivatives were prepared by treatment of the 5'-O-mesyl derivative with quaternary ammonium halides, 5'-chloro derivatives also by direct halogenation with thionyl chloride in hexamethylphosphortriamide or with tetrachloromethane, triphenyl phosphine, and dimethylformamide. Derivatives of 5'-bromo-6-azauridine were reduced with tributyltin hydride to 5'-deoxy-6-azauridine compounds. 6-Azauridine 2',3'-carbonate (IVa) and its 5'-derivatives IVc and IVe on treatment with imidazole in dimethylformamide afforded 2,2'-anhydronucleosides IIIa-IIIc. The 2,2'-anhydro-5'-deoxy compound IIIc underwent alkaline hydrolysis to 5'-deoxy-1-β-D-arabino-pentofuranosyl-6-azauracil (VIa). Treatment of 2,2'-anhydro-5'-deoxy-5'-chloro derivative IIIb with hydrogen chloride led to 2',5'-dichloro derivative If.

X-ray crystal structure analysis of a bisepoxide derived from secologanin: the structure and absolute configuration

1983 ◽  
Vol 61 (2) ◽  
pp. 282-283 ◽  
Author(s):  
Stanley C. Nyburg ◽  
Pik Y. Siew ◽  
Gavin N. Saunders ◽  
John R. Purdy ◽  
Stewart McLean
Keyword(s):  
Crystal Structure ◽  
Structure Analysis ◽  
Absolute Configuration ◽  
Dimethyl Acetal ◽  
Crystal Structure Analysis ◽  
Side Chain ◽  
Bench Mark ◽  
Chemical Transformations ◽  
X Ray ◽  
Derivatives Of

The structure and absolute configuration of a bisepoxide (2) produced by oxidation of tetraacetylsecologanin dimethyl acetal (1) with m-chloroperbenzoic acid have been established by X-ray crystal structure analysis. Epoxidation of the vinyl side chain is unexceptional; epoxidation of the β-alkoxyacrylate moiety is novel. This determination represents a valuable bench mark for configurational assignments, since the bisepoxide has been correlated by chemical transformations with a number of synthetic and naturally-occurring derivatives of secologanin.

Preparation of Carboranyl and Dodecaborate Derivatives of Coumarin

2007 ◽  
Vol 72 (12) ◽  
pp. 1740-1754 ◽  
Author(s):  
Eugen Justus ◽  
Dana T. Izteleuova ◽  
Alexander V. Kasantsev ◽  
Mendel M. Axartov ◽  
Enno Lork ◽  
...  
Keyword(s):  
Structure Analysis ◽  
The Other ◽  
Magnesium Salt ◽  
Ester Bond ◽  
Coumarin Derivatives ◽  
X Ray ◽  
Derivatives Of ◽  
Coumarin Ring

A series of derivatives of coumarin (2H-chromen-2-one) and 6,7-benzocoumarin (3H-benzo-[f]chromen-3-one) carrying the o-carborane, m-carborane, and dodecaborate clusters, has been obtained. X-ray structure analysis has been carried out for three of the products. The addition of o-carborane occurs in the 4-position of the coumarin ring, in a stereoselective way, independent of whether the cluster was reacted as the lithium or magnesium salt. m-Carborane gives two products, one being the result of 1,2-addition to an exocyclic ester bond and 1,4-addition to the coumarin system, the other resulting from 1,4-addition. The negatively charged dodecaborate derivatives obtained, link the cluster via oxygen or sulfur and an appropriate linker to a 7-hydroxy-substituted coumarin. For the coumarin derivatives, an o-carboranecarbonyl derivative could also be obtained.

A PASE Approach to the Synthesis of Benzimidazopurines as Polycondensed Purine Derivatives

Synthesis ◽  
2020 ◽  
Vol 52 (23) ◽  
pp. 3622-3631
Author(s):  
Victor V. Fedotov ◽  
Evgeny N. Ulomsky ◽  
Konstantin V. Savateev ◽  
Evgeny M. Mukhin ◽  
Denis A. Gazizov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Structure Analysis ◽  
Medicinal Chemistry ◽  
Crystal Structure Analysis ◽  
Purine Derivatives ◽  
Acidic Media ◽  
X Ray ◽  
New Class ◽  
Highly Efficient ◽  
Derivatives Of

A highly efficient PASE approach to a new class of polycyclic purine derivatives has been proposed. The strategy includes a consecutive reduction, auto-aromatization, and heterocyclization of the initial nitrobenzimidazopyrimidines obtained by a three-component condensation. It was shown that reduction of nitrobenzimidazopyrimidines by metals in acidic media was more efficient than heterogeneous hydro­genation. Novel derivatives of benz[4,5]imidazo[1,2-a]purines were obtained­ in good yields and the proposed structure was confirmed by X-ray crystal structure analysis. The obtained convergent benzimidazopurines combine two relevant medicinal chemistry scaffolds – benz­imidazole and purine.

Structure and reactivity of the arenecarbonyl cation iodotricarbonylhexamethylbenzenetungsten(II)

1969 ◽  
Vol 22 (4) ◽  
pp. 709 ◽  
Author(s):  
MR Snow ◽  
P Pauling ◽  
MHB Stiddard
Keyword(s):  
Structure Analysis ◽  
Triphenyl Phosphine ◽  
X Ray ◽  
Derivatives Of

Substituted carbonyls of the type (arene)M(CO)3 (M = Mo, W) react with iodine to yield compounds containing the cation [(arene)M(CO)3I]+. X-ray structure analysis shows the [(hexamethylbenzene)W(CO)3I]+ species to possess approximate Cs symmetry. It is unstable in solution and reaction with bipyridyl and triphenyl-phosphine offers a new route to derivatives of the type W(bipyridyl)2(CO)3I2 and W(PPh3)2(CO)3I2.

Synthesis and reactions of 2-and 4-substituted furo[3,2-c]pyridines

2006 ◽  
Vol 60 (3) ◽  
Author(s):  
M. Búdová ◽  
K. Fojtíková ◽  
J. Miklovič ◽  
V. Mrázová ◽  
B. Horváth ◽  
...  
Keyword(s):  
Nucleophilic Substitution ◽  
Hydrazine Hydrate ◽  
Chlorine Atom ◽  
Phosphorus Oxychloride ◽  
Sodium Ethoxide ◽  
Secondary Amines ◽  
Chloro Derivative ◽  
Chloro Derivatives ◽  
Derivatives Of

AbstractSubstituted furopropenoic acids were prepared from appropriate aldehyde under the Doebner’s conditions. Obtained acids were converted to the corresponding azides, which were cyclized by heating in Dowtherm to furopyridones. These compounds were aromatized with phosphorus oxychloride to chloro derivatives of furo[3,2-c]pyridine (Va, Vb). Chloro derivative Vb was reduced with hydrazine hydrate to 2-(4-aminophenyl)furo[3,2-c]pyridine in ethanol and Pd/C as a catalyst. Chloro derivative Va was converted to 4-amino-2-(3-pyridyl)furo[3,2-c]pyridine under the same conditions. The chlorine atom in other chloro derivatives (VIIa, VIIb) was replaced by nucleophilic substitution with alkoxides (sodium ethoxide, propoxide, and isopropoxide) and the corresponding alkoxy derivatives were formed. By reaction of VII with cyclic secondary amines (morpholine, piperidine, and pyrrolidine) 4-substituted furopyridines were prepared.

Preparation and Characterisation of Iodo-functionalised Azobenzene Derivatives of the Type I–p-C6H4–N=N–p-C6H4–X

2008 ◽  
Vol 63 (12) ◽  
pp. 1395-1401 ◽  
Author(s):  
Ulrich Siemeling ◽  
Clemens Bruhn ◽  
Mario Meier ◽  
Christian Schirrmacher
Keyword(s):  
Single Crystal ◽  
Structure Analysis ◽  
General Type ◽  
Starting Material ◽  
Type I ◽  
X Ray Diffraction ◽  
Ferrocene Derivative ◽  
X Ray ◽  
Derivatives Of ◽  
Azobenzene Derivatives

A broad range of azobenzene derivates of the general type I-p-C6H4-N=N-p-C6H4-X (1) have been prepared. In the case of X = Ph (b), C≡C-Fc (e, Fc = ferrocenyl), OMe (g), Oi-Pr (i), and NMe2 (m), these compounds have been characterised by single-crystal X-ray structure analysis. In addition, the closely related 4-dimethylamino-1-(4-iodophenylazo)naphthalene 2 and 8-(4-iodophenylazo) quinoline 3 have also been prepared. Furthermore, the ferrocene derivative Fc-C≡C-p-C6H4- NH2 (4), which served as a starting material for the synthesis of I-p-C6H4-N=N-p-C6H4-p-C6H4- C≡C-Fc (1e), was prepared and structurally characterised by X-ray diffraction.

An X-ray and conformational study of the α-chloro derivatives of 5,7-dihydro-1,11-dimethyl-6H-dibenzo[a,c]cyclohepten-6-one

1994 ◽  
Vol 72 (6) ◽  
pp. 1481-1488
Author(s):  
Robert R. Fraser ◽  
Corinne Bensimon ◽  
Neil C. Faibish ◽  
Fanzuo Kong
Keyword(s):  
Molecular Mechanics ◽  
Benzene Ring ◽  
Membered Ring ◽  
Single Atom ◽  
Conformational Study ◽  
Molecular Mechanics Calculations ◽  
X Ray ◽  
Chloro Derivatives ◽  
Torsional Angles ◽  
Derivatives Of

The crystal structures for four α-chloro derivatives 2–5 of the titled ketone 1 have been determined, confirming their earlier assignments of stereochemistry. Variations in the conformations of 2–5 suggested some flexibility in the central seven-membered ring. Molecular mechanics calculations of the changes in energy as a function of the internal torsional angles at the carbonyl of these chloro derivatives indicated the ring flexibility to be comparable to that of cyclohexanone. In the three compounds containing an axial chlorine the distance between the chlorine atom and two of the carbon atoms of the more remote benzene ring was 3.2 ± 0.1 Å, suggesting the value for the thickness of a benzene ring may be significantly smaller than the accepted value when it is interacting with a single atom.

Zur Struktur und Komplexchemie von Phosphinoderivaten des 5-Methoxy-2(5H)-furanons / Structure and Coordination Chemistry of Phosphino Derivatives of 5-Methoxy-2(5H)-furanon

1980 ◽  
Vol 35 (9) ◽  
pp. 1075-1082 ◽  
Author(s):  
D. Fenske ◽  
H. Prokscha ◽  
P. Stock ◽  
H. J. Becher
Keyword(s):  
Crystal Structure ◽  
Coordination Chemistry ◽  
Structure Analysis ◽  
Model Compound ◽  
Crystal Structure Analysis ◽  
X Ray ◽  
Derivatives Of ◽  
Cl Atoms ◽  
Cl Atom ◽  
Similar Complex

With R2PSi(CH3)3 (R = C6H5, i-C3H7, t-C4H9) one Cl atom of 3,4-dichlor-5-methoxy-2(5 H)-furanon (1) is substituted by the R2P group. An x-ray crystal structure analysis of the phosphino derivative with R = C6H5 (2) it has shown that of the two Cl atoms in 1 only the β-position (to C= O) is substituted. The coordination chemistry of 2 and its bis- (diphenylphosphino) derivative (3) is studied by preparation of the compounds 2 · Mo(CO)5 and 3 · Mo(CO)4. With PdCl2 · 2 C6H5CN (2) gives a dinuclear complex [2 · PdCl2]2, with bridging Cl atoms. The structure is established by a comparison with the similar complex of PdCl2 and 2-chloro-diphenylphosphino-maleic acid dimethylestor, which was synthe­sized as a model compound and studied by x-ray crystal structure analysis.

Sign in / Sign up

Export Citation Format

Share Document