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.

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.

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.

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.

Beiträge zur Chemie des Bors, 168 [1] Synthese und Struktur von Azadiboriridinen / Contributions to the Chemistry of Boron, 168 [1] Synthesis and Structure of Azadiboriridines

1986 ◽  
Vol 41 (1) ◽  
pp. 32-37 ◽  
Author(s):  
Franz Dirschl ◽  
Elisabeth Hanecker ◽  
Heinrich Nöth ◽  
Wilfried Rattay ◽  
Walter Wagner
Keyword(s):  
Low Temperature ◽  
Structure Analysis ◽  
Ring System ◽  
The Other ◽  
Ring Plane ◽  
X Ray ◽  
Restricted Rotation

Two representatives of the three membered B2N-ring system have been obtained by dehalogenation of diborylamines Me3CN[BHalNR2]2. In solution there is no restricted rotation at the exocyclic BN bond, even at low temperature. In contrast, the X-ray structure analysis of the bis-tetramethylpiperidino derivative 10a reveals alternation of short and long BN bonds; one of the tetramethylpiperidino groups stands nearly coplanar with the B2N-ring system, the other, however, is almost perpendicular to the ring plane. The ring contains a short BB bond (1.612 Å).

scholarly journals Antioxidant activity of some coumarins / Antioxidačná activita niektorých kumarínov

2015 ◽  
Vol 62 (s9) ◽  
pp. 41-45 ◽  
Author(s):  
F. Šeršeň ◽  
M. Lácová
Keyword(s):  
Antioxidant Activity ◽  
Acetic Acid ◽  
Superoxide Anion ◽  
The Other ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Coumarin Derivatives ◽  
Antioxidant Effectiveness ◽  
Derivatives Of ◽  
Superoxide Anion Radicals

AbstractNineteen derivatives of coumarin were tested on the scavenging of 2,2-diphenyl-1-picrylhydrazyl, hydroxyl and superoxide anion radicals. It was found that antioxidant activity exhibits only such coumarins that contain hydroxyl groups. The derivatives without hydroxyl group showed very low antioxidant effectiveness or they were ineffective. On the other hand, the greatest antioxidant effectiveness was exhibited by coumarin derivatives that contained hydroxyl groups in 6 or 8 position, whereas the effectiveness of derivatives with one hydroxyl group in 4, 5 or 7 position was very low. Based on scavenging of the above-mentioned radicals, it was found that the most effective scavengers were 7,8-dihydroxy-4-methylcoumarin (i.e. compound that contains two hydroxyl groups in 7 and 8 positions), (7,8-dihydroxy-2-oxo-2H-chromen-4-yl)acetic acid (this compound contains in addition to two hydroxyl groups in 7 and 8 positions also one hydroxyl group in the acidic residue), esculetin (6,7-dihydroxycoumarin) and 6,7-dihydroxy-4-methylcoumarin.

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.

Derivatives of the triaminoguanidinium ion, 6. Aminal-forming reactions with aldehydes and ketones

2020 ◽  
Vol 75 (3) ◽  
pp. 317-326
Author(s):  
Jan Szabo ◽  
Gerhard Maas
Keyword(s):  
Crystal Structure ◽  
The Other ◽  
Guanidinium Chloride ◽  
X Ray ◽  
Other Hand ◽  
Aldehydes And Ketones ◽  
Structure Determinations ◽  
Derivatives Of

AbstractCyclic aminals (N,N-acetals) could be prepared by the reaction of N,N′,N″-triaminoguanidinium sulfate, N,N′,N″-tris(benzylamino)guanidinium chloride or N,N′,N″-tris(benzylamino)guanidine with formaldehyde or acetone. In all cases, 1,2,4,5-tetrazinane derivatives were obtained, which were structurally confirmed by X-ray crystal structure determinations. In two cases, 1:1 cocrystals of two different tetrazinane products were isolated. On the other hand, the reaction of N,N′,N″-tris(benzylamino)guanidinium chloride with benzaldehyde yielded a 3-(2-benzylidenehydrazin-1-yl)-1H-1,2,4-triazole.

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.

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