scholarly journals Synthesis of new, highly luminescent bis(2,2’-bithiophen-5-yl) substituted 1,3,4-oxadiazole, 1,3,4-thiadiazole and 1,2,4-triazole

2014 ◽  
Vol 10 ◽  
pp. 1596-1602 ◽  
Author(s):  
Anastasia S Kostyuchenko ◽  
Vyacheslav L.Yurpalov ◽  
Aleksandra Kurowska ◽  
Wojciech Domagala ◽  
Adam Pron ◽  
...  
Keyword(s):  
Good Yield ◽  
Ring Closure ◽  
Quantum Yields ◽  
Synthetic Approach ◽  
Structural Elements ◽  
Target Molecule ◽  
Synthetic Strategy ◽  
Donor Acceptor ◽  
Synthetic Routes ◽  
Derivatives Of

A new synthetic approach towards the preparation of functionalised, soluble, donor–acceptor (DA) alkylbithiophene derivatives of oxadiazole, thiadiazole and triazole is reported. Taking advantage of the Fiesselmann reaction, reactive bithiophene synthons having alkyl or alkoxy substituents at designated positions are prepared. Following a synthetic strategy, featuring the bottom-up approach, sequential structural elements are built, starting from a simple thiophene compound, until the target molecule is obtained, all in good yield. Supplementing the well established methods of oxadiazole and thiadiazole synthesis, efficient ring closure reaction affording a 4H-1,2,4-triazole unit is presented. All target ambipolar compounds display strong photoluminescence with measured quantum yields up to 0.59. Modification of the demonstrated synthetic routes may be exploited for the preparation of longer, specifically functionalised oligothiophenes, coupled to other heteroaromatic cores.

scholarly journals Mixed-Halide Triphenyl Methyl Radicals for Site-Selective Functionalization and Polymerization

2021 ◽  
Author(s):  
Lisa Chen ◽  
Mona Arnold ◽  
Rémi Blinder ◽  
Fedor Jelezko ◽  
Alexander Kuehne
Keyword(s):  
Cross Coupling ◽  
Open Shell ◽  
Quantum Yields ◽  
Coupling Reactions ◽  
Methyl Radicals ◽  
Cross Coupling Reactions ◽  
Donor Acceptor ◽  
Metal Catalyzed ◽  
Derivatives Of ◽  
Acceptor Molecules

<p>Derivatives of the stable, luminescent tris-2,4,6-trichlorophenylmethyl (TTM) radical exhibit unique doublet spin properties that are of interest for applications in optoelectronics, spintronics, and energy storage. However, the synthesis and variety of TTM-type donor-acceptor molecules with high quantum yields are limited by the symmetric chloride decoration and poor reactivity of chlorides in metal-catalyzed C-C cross-coupling reactions. Therefore, only few donor-acceptor molecules have been successfully coupled to the TTM radical motif. Here, we present a synthetic pathway to obtain mixed-halide derivatives of TTM, partly carrying bromo- instead of chloro-substituents, leading to improved reactivity and enabling site-specific cross-coupling reactions. These highly stable mixed-halide triphenyl methyl radicals represent a powerful tool to obtain complex, and so far inaccessible open-shell small molecules, as well as polymers.</p>

scholarly journals Efficient Synthesis of 1-Thiomansonones with Anti-MRSA Activity

Synlett ◽  
2018 ◽  
Vol 29 (07) ◽  
pp. 938-942 ◽  
Author(s):  
Dongyun Shin ◽  
Seong-Hyuk Park ◽  
Sooyoung Park ◽  
Chang-Yong Lee ◽  
Young-Ger Suh
Keyword(s):  
Cross Coupling ◽  
Ring Closure ◽  
Efficient Synthesis ◽  
Synthetic Strategy ◽  
Palladium Catalyzed ◽  
Derivatives Of ◽  
Sulfur Containing

In this study, we developed an efficient and general synthetic strategy for thiaphenalene, a sulfur-containing polyaromatic hetero­cycle, and applied for the synthesis of 1-thio derivatives of mansonone I and F, natural 1-oxaphenalenic orthoquinones. The pivotal steps for the construction of thiophenalene skeleton include formation of arylsulfide by Newman–Kwart rearrangement of thiocarbamate or palladium-­catalyzed cross-coupling, and pericyclic ring closure. Three bioisosterically modified orthoquinones were synthesized and were evaluated for anti-MRSA activity.

scholarly journals Mixed-Halide Triphenyl Methyl Radicals for Site-Selective Functionalization and Polymerization

2021 ◽  
Author(s):  
Lisa Chen ◽  
Mona Arnold ◽  
Rémi Blinder ◽  
Fedor Jelezko ◽  
Alexander Kuehne
Keyword(s):  
Cross Coupling ◽  
Open Shell ◽  
Quantum Yields ◽  
Coupling Reactions ◽  
Methyl Radicals ◽  
Cross Coupling Reactions ◽  
Donor Acceptor ◽  
Metal Catalyzed ◽  
Derivatives Of ◽  
Acceptor Molecules

<p>Derivatives of the stable, luminescent tris-2,4,6-trichlorophenylmethyl (TTM) radical exhibit unique doublet spin properties that are of interest for applications in optoelectronics, spintronics, and energy storage. However, the synthesis and variety of TTM-type donor-acceptor molecules with high quantum yields are limited by the symmetric chloride decoration and poor reactivity of chlorides in metal-catalyzed C-C cross-coupling reactions. Therefore, only few donor-acceptor molecules have been successfully coupled to the TTM radical motif. Here, we present a synthetic pathway to obtain mixed-halide derivatives of TTM, partly carrying bromo- instead of chloro-substituents, leading to improved reactivity and enabling site-specific cross-coupling reactions. These highly stable mixed-halide triphenyl methyl radicals represent a powerful tool to obtain complex, and so far inaccessible open-shell small molecules, as well as polymers.</p>

Evaluation of Different Synthetic Routes to (2R,3R)-3-Hydroxymethyl-2-(4-hydroxy- 3-methoxyphenyl)-1,4-Benzodioxane-6-Carbaldehyde

2020 ◽  
Vol 23 (26) ◽  
pp. 2960-2968
Author(s):  
Renáta Kertiné Ferenczi ◽  
Tünde-Zita Illyés ◽  
Sándor Balázs Király ◽  
Gyula Hoffka ◽  
László Szilágyi ◽  
...  
Keyword(s):  
Absolute Configuration ◽  
Stereoselective Synthesis ◽  
Cotton Effect ◽  
Enantioselective Synthesis ◽  
Aryl Group ◽  
Target Molecule ◽  
Synthetic Routes ◽  
The Absolute

The reported enantioselective synthesis for the preparation of (+)-(2R,3R)-2-(4- hydroxy-3-methoxyphenyl)-3-hydroxymethyl-1,4-benzodioxane-6-carbaldehyde, precursor for the stereoselective synthesis of bioactive flavanolignans, could not be reproduced. Thus, the target molecule was prepared via the synthesis and separation of diastereomeric O-glucosides. TDDFT-ECD calculations and the 1,4-benzodioxane helicity rule were utilized to determine the absolute configuration. ECD calculations also confirmed that the 1Lb Cotton effect is governed by the helicity of the heteroring, while the higher-energy ECD transitions reflect mainly the orientation of the equatorial C-2 aryl group.

Synthesis of azaanthraquinones: homolytic substitution of pyridines

1982 ◽  
Vol 35 (7) ◽  
pp. 1451 ◽  
Author(s):  
DW Cameron ◽  
KR Deutscher ◽  
GI Feutrill ◽  
DE Hunt
Keyword(s):  
Ring Closure ◽  
Pyridine Derivatives ◽  
Derivatives Of ◽  
Substituted 1 ◽  
Homolytic Substitution

Synthesis of specific di- and tri-hydroxyazaanthraquinones by Friedel-Crafts procedures is limited by orientational ambiguity and by the lack of reactivity of pyridine derivatives in electrophilic acylation processes; however, suitable pyridines have been made to undergo radical benzoylation and benzylation at unsubstituted positions 2, 4 and 6. In particular, derivatives of pyridine-3-carbo-nitrile have been benzoylated at positions 2 and 4. Ring closure by intramolecular Houben-Hoesch reaction has then led to specifically substituted 1-and 2-azaanthraquinones and thence to the antibiotic bostrycoidin (1).

A Novel Synthetic Approach to Asymmetric Salen, Dihydrosalen, and Tetrahydrosalen Ligands: Structures and O2-Activating Properties of their Nickel(II) and Cobalt(II) Complexes

1994 ◽  
Vol 49 (8) ◽  
pp. 1089-1100 ◽  
Author(s):  
Arnd Böttcher ◽  
Horst Elias ◽  
Brigitte Eisenmann ◽  
Elke Hilms ◽  
Andreas Huber ◽  
...  
Keyword(s):  
Equilibrium Constants ◽  
Spectrophotometric Titration ◽  
Acetone Solution ◽  
Synthetic Approach ◽  
Coordination Core ◽  
Type Complex ◽  
Square Planar ◽  
Synthetic Procedure ◽  
Derivatives Of ◽  
Methyl Phenyl

A synthetic procedure is described for the preparation of the tetradentate N2O2 ligands H2[H4]L1=6-(2-hydroxyphenyl)-2,5-diaza-3,3-dimethyl-1-(2-hydroxy-3-t-butyl-5-methyl- phenyl)heptane, H2[H2]L1 = 6-(2-hydroxyphenyl)-2,5-diaza-3,3-dimethyl-1-(2-hydroxy-3-t-butyl-5-methylphenyl)-1-heptene, and H2L1 = 6-(2-hydroxyphenyl)-2,5-diaza-3,3-dimethyl-1-(2- hydroxy-3-t-butyl-5-methylphenyl)-1,5-heptadiene, which are asymmetric derivatives of the ligands tetrahydrosalen, dihydrosalen, and salen. Complexes Ni[H4]L1, Ni[H2]L1, NiL1, CoL1, Ni[H4]L2 (([H4]L2)2- = anion of H2[H4]L2 = N,N'-bis(2-hydroxy-3-t-butyl-5-methylbenzyl)- trans-(S,S)-1,2-diaminocyclohexane), and NiL2 were prepared, characterized (VIS and IR ab­sorption, magnetic moment) and subjected to spectrophotometric titration with pyridine, to determine the equilibrium constants for adduct formation. Single crystal X-ray structure analy­ses were carried out for Ni[H2]L1 (monoclinic, P21/n; a = 8.926(4), b = 29.324(7), c = 8.411(4) Å; β = 95.3(1)°; Z = 4), CoL1 (monoclinic, C2/c; a = 25.389(2), b = 18.139(2), c = 10.179(1) Å; β = 112.227(6); Z = 8), and Ni[H4]L2·acetone (tetragonal, P41212; a = 13.928(3), c = 33.698(5) Å; Z = 8). In all of the three complexes, the N2O2-metal coordination core is square-planar. The skeleton of the tetradentate ligand is more or less twisted. The planar cobalt(II) complex CoL1 is a low spin d7 system with μexp = 2.02 BM at 298 K, whereas the planar complexes NiL1, Ni[H2]L1 and Ni[H4]L2 are diamagnetic (μexp = 0.28-0.64 BM). The blue solvate Ni[H4]L1- 3EtOH · H2O is paramagnetic (μexp = 3.04 BM), which points to octahedral coordination. In aerated acetone solution, the tetrahydrosalen-type complex Ni[H4]L1 activates dioxygen and one C-N bond is oxidatively dehydrogenated. The VIS spectrum of the dihydrosalen-type complex formed is virtually identical with that of the aldimine complex Ni[H2]L1. In the pres­ence of dioxygen, Co[H4]L1 and Co[H2]L1 are readily oxidized to CoL1 in acetone solution.

Synthesis and chemiluminescence of new derivatives of isoluminol

1987 ◽  
Vol 65 (6) ◽  
pp. 1392-1396 ◽  
Author(s):  
Alain Bélanger ◽  
Paul Brassard ◽  
Sylvie Laquerre ◽  
Yves Mérand
Keyword(s):  
Maleic Acid ◽  
Quantum Yields ◽  
Methyl Group ◽  
Derivatives Of

In an attempt to improve the sensitivity of luminescent immunoassays, we have prepared some new isoluminol, 7-(N,N-dialkylamino)-5-methyl-2,3-dihydrophthalazine-1,4-diones by means of a novel procedure involving the cycloaddition of dienamines to maleic acid derivatives. These compounds are characterized by the presence of a methyl group at C-5 and give quantum yields three to five times greater than those of the most efficient isoluminols in use at present.

scholarly journals Synthesis, Oral Bioavailability and in vivo Activity of Acetal Derivatives of the Selective Antiherpesvirus Agent 9-(3-hydroxypropoxy) Guanine (BRL 44385)

1994 ◽  
Vol 5 (3) ◽  
pp. 147-154
Author(s):  
M. R. Harnden ◽  
R. J. Ashton ◽  
M. R. Boyd ◽  
L. J. Jennings ◽  
D. Sutton ◽  
...  
Keyword(s):  
Oral Administration ◽  
Oral Bioavailability ◽  
Oral Delivery ◽  
Ring Closure ◽  
Guanine Derivatives ◽  
Derivatives Of ◽  
Lesion Severity ◽  
Hsv 1

Acyclic acetal derivatives of the selective antiherpesvirus agent 9-(3-hydroxypropoxy) guanine (BRL44385) and of its 2-aminopurine congener (BRL46720) have been prepared and evaluated in mice for oral delivery of BRL 44385. Guanine derivatives (6 a-c) were prepared via Mitsunobu condensation of an alcohol with a 9-hydroxy-6-methoxypurine (Harnden and Wyatt, 1990). Synthesis of derivatives of 2-aminopurine (10 a-d) was achieved by hydrogenolysis of 9-alkoxy-6-chloropurines, which were obtained either by reaction of an alkoxyamine with 4,6-dichloro-2,5-diformamidopyrimidine and subsequent ring closure or by Mitsunobu condensation of an alcohol with a 6-chloro-9-hydroxypurine. Following oral administration, 2-amino-9-[3-(iso-propoxymethyl)propoxy]-purine (10b, BRL 55792) was very well absorbed and provided high and prolonged concentrations of BRL44385 in the blood. In a cutaneous HSV-1 infection in the ear pinna of mice, orally dosed BRL 55792 was at least 3-fold more potent than both BRL44385 and Acyclovir in reduction of lesion severity.

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