The preparation of some heteroaromatic and aromatic aldehydes

Katritzky, Alan R.; He, Hongwu; Long, Qiuhe; Cui, Xilin; Level, Julian; Wilcox, Allan L.

doi:10.3998/ark.5550190.0001.307

Cited by 10 publications

(4 citation statements)

References 6 publications

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“…The second part consists of the thiophene−cyclopentene conjugates, carrying different substitutions at the thiophene moiety. We synthesized three different thiophene bromides 6a − c , depicted in Scheme , following published procedures − and converted them in a one-pot reaction, first to the respective boronic esters using n -BuLi and tributylborate, followed by direct conjugation via Suzuki coupling with 1,2-dibromocyclopentene (1.5 equiv) in the presence of 5 mol % palladium, sodium carbonate, and water. Under these conditions, the reactions afforded a series of monosubstituted cyclopentenes ( 7a − c ) in 40−44% yield with only 5−10% of symmetric diarylethenes formed as byproducts that were separated by column chromatography.…”

Section: Resultsmentioning

confidence: 99%

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Reversibly Photoswitchable Nucleosides: Synthesis and Photochromic Properties of Diarylethene-Functionalized 7-Deazaadenosine Derivatives

2010

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Photochromic nucleosides were designed that combine the structural features and molecular recognition properties of nucleic acids with the light-sensitivity of diarylethenes. Target compounds 1a-c consist of a 7-deazaadenosine unit that is linked to a thiophene as the second aryl functionality via a 1,2-cyclopentenyl linker. These nucleoside analogues undergo a reversible electrocyclic rearrangement, generating strongly colored closed-ring isomers upon irradiation with UV-light, while exposure to light in the visible range triggers the cycloreversion to the colorless opened-ring form. UV-vis spectroscopy, HPLC, and (1)H NMR measurements revealed recognition of complementary thymidine and up to 97% conversion to the thermally stable closed-ring isomers after illumination with UV-light. The required wavelength for ring closure was found to vary depending on the substituents attached to the thiophene moiety. In a first design step, we used this important feature of diarylethenes to shift the switching wavelength from initially 300 nm (1a) to 405 nm (1cH(+)). In a second step, we generated a pair of orthogonal switches, differing enough in their respective switching wavelengths to be controlled independently in the same sample. Finally, a molecular switch was developed that showed both photochromism and acidichromism, thereby illustrating the possibility to gate the spectral properties to multiple stimuli. These new photochromic nucleosides represent useful building blocks for the generation of light-sensitive nucleic acids either by inducing conformational changes upon isomerization or by exploring the different spectral properties of the closed and opened isomers, for example, for use as reversible fluorescence quenchers.

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Section: Resultsmentioning

confidence: 99%

“…Compounds 2 and 6a − c were prepared as reported previously. − The synthesis and characterization of compounds 3 − 5 as well as 7a − c , 8a − c , 9a − c , and the final switches 1a − c are described in the Supporting Information.…”

Section: Methodsmentioning

confidence: 99%

Reversibly Photoswitchable Nucleosides: Synthesis and Photochromic Properties of Diarylethene-Functionalized 7-Deazaadenosine Derivatives

2010

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“…R - and S -1-Phenylethanol picolinic acid ester ( 1 ) and R - and S -1-phenylethanol pyridine-2-phosphonic acid ester ( 13 ) were prepared by literature procedures . (4 R ,5 R )-2,2-Dimethyl-1,3-dioxolane-4,5-dimethanamine ( 2 ) and (4 R ,5 R )-bis(aminodiphenylmethyl)-2,2-dimethyl-1,3-dioxolane ( 3 ) were prepared and purified by a literature procedure. , The aldehyde precursors N -isopropyl-imidazole, N - tert -butyl-imidazole, N -benzylimidazole, 4,5-diphenylimidazole, and N -methyl-4,5-diphenylimidazole were prepared by reported procedures. , The heterocyclic aldehydes 5 – 9 were prepared by a modification of the procedure reported by Katritsky (see Supporting Information).…”

Section: Methodsmentioning

confidence: 99%

“…30,42 The aldehyde precursors Nisopropyl-imidazole, N-tert-butyl-imidazole, N-benzylimidazole, 4,5diphenylimidazole, and N-methyl-4,5-diphenylimidazole were prepared by reported procedures. 43,44 The heterocyclic aldehydes 5−9 were prepared by a modification of the procedure reported by Katritsky 45 (see Supporting Information).…”

Section: ■ Experimental Proceduresmentioning

confidence: 99%

Selection of Chiral Zinc Catalysts for the Kinetic Resolution of Esters via Dynamic Templating

Kannappan

Nicholas

2013

ACS Comb. Sci.

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Dynamic combinatorial libraries of chiral tetradentate bis-imine zinc(II) complexes have been prepared and screened for (1) their discrimination of enantiomeric picolinate esters and pyridyl phosphonate transition state analogs (TSAs) and (2) their catalytic activity and selectivity for enantioselective methanolysis of racemic picolinate esters. The zinc complexes are in equilibrium with their imine ligands as well as with the aldehyde and amine building blocks that form them, enabling the composition of the library to adapt in response to the introduction of coordinating substrates or TSAs. Binary (L)Zn(OTf)(solv)(+) complexes are generated either individually or in libraries from chiral tartrate-derived diamines (2,3) and a set of N-heterocyclic aldehydes (4-12) and the distribution of complexes established by ESI-MS analysis. Binding studies of the (diimine)Zn(OTf)(2) complex libraries with enantiomeric R- and S-2-pyridyl phosphonate TSA 13 show chiral discrimination via formation of diastereomeric LZn(R/S-13)(+) complexes with low to moderate enatioselectivity ratios, k(R)/k(S) (α), ranging from 0.5 to 5.0; corresponding templating of selected binary complexes with the enantiomeric substrates, PyrCO(2)CH(OH)Ph (1), show negligible chiral recognition. The rate constants for methanolysis of the R- and S-esters, PyrCO(2)CH(OH)Ph (1) catalyzed by several L*Zn(OTf)(2) complexes range in value several fold depending on L and with enantioselectivity ratios, k(R)/k(S) (α), ranging from 0.76 to 2.8.

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Synthesis of Sulfonylhydrazone‐ and Acylhydrazone‐Substituted 8‐Ethoxy‐3‐nitro‐2H‐chromenes as Potent Antiproliferative and Apoptosis Inducing Agents

Zhang

Liu

et al. 2014

Archiv der Pharmazie

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3-Nitro-2H-chromenes have recently been identified as a novel class of potent antitumor agents. In view of the favorable effects shown by sulfonylhydrazones and acylhydrazones, we designed and synthesized a series of sulfonylhydrazone- and acylhydrazone-substituted 8-ethoxy-3-nitro-2H-chromene derivatives, and evaluated their cell growth inhibition activities against A549, KG-1, A2780, and K562 cells. All the tested compounds exhibited more potent antiproliferative activity than BENC-511 against KG-1 cells. These compounds displayed IC50 values in the nanomolar range against A2780 cells. Compound 7d showed prominent cytotoxicity against K562 cells with an IC50 of 0.11 µM, which was comparable to that of BENC-511. Compound 7d arrested K562 cells at the G1 phase at high concentrations and induced apoptosis in K562 cells. Furthermore, 7d increased the levels of cleaved caspase-3, decreased the expression of bcl-2 and induced the cleavage of poly(ADP-ribose) polymerase in K562 cells. Thus, this study provides the development of a series of novel compounds as effective antitumor agents with apoptotic death ability.

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The preparation of some heteroaromatic and aromatic aldehydes

Cited by 10 publications

References 6 publications

Reversibly Photoswitchable Nucleosides: Synthesis and Photochromic Properties of Diarylethene-Functionalized 7-Deazaadenosine Derivatives

Reversibly Photoswitchable Nucleosides: Synthesis and Photochromic Properties of Diarylethene-Functionalized 7-Deazaadenosine Derivatives

Selection of Chiral Zinc Catalysts for the Kinetic Resolution of Esters via Dynamic Templating

Synthesis of Sulfonylhydrazone‐ and Acylhydrazone‐Substituted 8‐Ethoxy‐3‐nitro‐2H‐chromenes as Potent Antiproliferative and Apoptosis Inducing Agents

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