Buchwald protocol applied to the synthesis of N-heterotolan liquid crystals

Vasconcelos, Ursula Bohlke; Schrader, Abel; Vilela, Guilherme D.; Borges, Antonio C. A.; Merlo, Aloir A.

doi:10.1016/j.tet.2008.03.005

Cited by 21 publications

(11 citation statements)

References 41 publications

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“…Synthesis of 4-(1,3-benzodioxol-5-yl)-2-methyl-3-butyn-2-ol (11a). 13 To a Schlenk tube were added PdCl 2 (PPh 3 ) 2 (0.1396 g, 0.2 mmol), PPh 3 (0.1315 g, 0.5 mmol), 10a (4.019 g, 20 mmol), Et 3 N (15 mL), 2-methyl-3-butyn-2-ol (2.530 g, 30 mmol), Et 3 N (15 mL), and CuI (0.0375 g, 0.2 mmol) sequentially under an Ar atmosphere. The mixture was heated at 90 °C until the completion of the reaction as monitored by TLC (12.5 h).…”

Section: General Informationmentioning

confidence: 99%

Highly efficient and general enantioselective synthesis of naturally occurring isoquinoline alkaloids

Lin

2014

Org. Chem. Front.

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The highly efficient asymmetric synthesis of (+)-dysoxyline (three steps) and (+)-crispine A (four steps) from readily available different terminal alkynes, benzaldehyde, and 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline has been achieved, providing efficient general approaches for achieving libraries of naturally occurring chiral isoquinoline alkaloids. Fig. 1 Representative isoquinoline natural products and drugs. Scheme 1 Synthetic routes to (+)-dysoxyline. † Electronic supplementary information (ESI) available. See

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Section: General Informationmentioning

confidence: 99%

Highly efficient and general enantioselective synthesis of naturally occurring isoquinoline alkaloids

Lin

2014

Org. Chem. Front.

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“…9 Thus the alkylation of p-bromophenol with 1-bromooctane gave the corresponding alkylaryl ether (7) in 81% yield. Sonogashira reaction 11 of the alkylaryl ether with 2-methyl-3-butyn-2-ol (mebynol), followed by deprotection using KOH and isopropyl alcohol furnished the acetylene 2.…”

Section: Resultsmentioning

confidence: 99%

“…The residue was dissolved in diethyl ether (200 mL), washed with 10% sodium bicarbonate solution (2 × 100 mL), and water (100 mL), then dried over anhydrous sodium sulfate. 9 A test tube was charged with Et 3 N (100 mL), 2-methyl-3-butyn-2-ol (7 mL, 70 mmol) and 1-bromo-4-(octyloxy)benzene (7) (9 g, 32 mmol) under argon. To the solution were added CuI (216 mg), PPh 3 (123 mg) and PdCl 2 (PPh 3 ) 2 (69 mg).…”

Section: -Ethynyl-4-(octyloxy)benzene (2)mentioning

confidence: 99%

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An evaluation of the chalcogen atom effect on the mesomorphic and electronic properties in a new homologous series of chalcogeno esters

Rampon¹,

Rodembusch²,

Gonçalves³

et al. 2010

J. Braz. Chem. Soc.

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Uma série de calcogeno ésteres, 1a, 6a e 6b foi obtida em uma rota sintética conveniente. A análise de microscopia óptica de luz polarizada (POM) e calorimetria diferencial de varredura (DSC) mostrou que estes calcogeno ésteres apresentam uma ampla faixa de mesofase nemática. Além disso, espectros de absorção na região do UV-Vis em solução (ca.10 -5 mol L -1 ) também foram obtidos de maneira a se obter a diferença de energia entre os orbitais moleculares HOMO-LUMO, para posterior comparação com os resultados teóricos. Os valores calculados para o gap de HOMO-LUMO estão de acordo com os valores experimentais obtidos, onde a eletronegatividade do heteroátomo (O, S e Se) deve ser o principal fator para a localização do máximo de absorção. Um estudo teórico foi realizado utilizando cálculos de DFT/B3LYP com método híbrido de Becke aplicando uma correlação funcional de Lee-Yang-Parr (B3LYP) com a base DGDZVP a fim de avaliar algumas propriedades físico-químicas relacionadas com o mesomorfismo e as propriedades eletrônicas espectrais. Através da síntese destes compostos, a influência do átomo de calcogênio nas propriedades fotofísicas e mesomórficas pôde ser avaliada de uma forma mais precisa.A series of chalcogeno esters 1a, 6a and 6b have been synthesized in a straightforward manner. Polarized-light optical microscopy (POM) and differential scanning calorimetry (DSC) showed that these chalcogeno esters displayed a wide nematic range of mesophase. In addition, UV-Vis in solution (ca.10 -5 mol L -1 ) was applied in order to obtain the HOMO-LUMO gap for further comparison with the theoretical results. The calculated values to the HOMO-LUMO gap are in excellent agreement with the experimental results, where the electronegativity of the heteroatom (O, S and Se) seems to play a fundamental role in the absorption maxima location. A theoretical study was performed using a DFT/B3LYP calculations with Becke's three-parameter hybrid method applying the Lee-Yang-Parr functional correlation (B3LYP) with DGDZVP basis set in order to evaluate some physical chemistry data related with mesomorphic and spectral eletronic properties. By synthesizing these compounds we were able to get a more precise description about the influence of the chalcogen atom on the mesomorphic and photophysical properties. Rampon et al. 2101 Vol. 21, No. 11, 2010 The biological and medicinal properties of selenium and organoselenium compounds are increasingly appreciated, mainly due to their antioxidant, antitumor, antimicrobial and antiviral properties. 4 Besides, the synthesis of peptides containing selenocysteine is rapidly gaining interest with the discovery of an increasing number of proteins containing this aminoacid. Keywords 5Chalcogeno esters (thiol, selenol and tellurol esters) are useful synthetic intermediates that have been employed, for example, as acylating reagents, building blocks for heterocyclic compounds, precursors of acyl radicals and anions, as well asymmetric aldol reactions. However, rare are the examples where these compounds a...

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“…In order to synthesize the elongated (anisotropic) liquid-crystalline isoxazolines 8a-d, we again applied the DCC/ DMAP protocol to introduce the ester linkage by reaction of p-bromobenzoic acid with the alcohol 2a. To accomplish the synthesis of the homologous series 8a-d the triple bond was inserted through the Sonogashira cross-coupling reaction between the 1-alkoxy-4-ethynylbenzene 8 and the ester derived from p-bromobenzoic acid.…”

Section: Synthesismentioning

confidence: 99%

3-Arylisoxazolyl-5-carboxylic acid and 5-(Hydroxymethyl)-3-aryl-2-isoxazoline as molecular platforms for liquid-crystalline materials

Tavares¹,

Livotto²,

Gonçalves³

et al. 2009

J. Braz. Chem. Soc.

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A síntese de uma plataforma molecular para materiais líquido-cristalinos derivados do ácido 3-arilisoxazolil-5-carboxílico (1) e do 5-(hidroximetil)-3-aril-2-isoxazolina (2) é descrita. Os intermediários 1 e 2 são obtidos através da reação de cicloadição [3+2] 1,3-dipolar entre arilóxidos de nitrilas e os dipolarófilos ácido acrílico e álcool alílico, respectivamente. Os compostos cristais líquidos são sintetizados através de uma estratégia de alongamento molecular do núcleo primitivo isoxazolínico pela conexão de subunidades arilacetilênicas, as quais foram obtidas da reação de Sonogashira. Sob essas condições, séries de cristais líquidos 5a-c, 6, 7a-g e 8a-d têm sido sintetizadas com rendimentos de médios para bons. Os compostos finais apresentam propriedades líquido-cristalinas nematogênica e esmectogênica. Um cálculo DFT no nível B3LYP/6-31G(d,p) é também apresentado e alguns parâmetros estruturais obtidos são analisados. The synthesis of the molecular platform for liquid-crystalline materials based on 3-arylisoxazolyl-5-carboxylic acid (1) and 5-(hydroxymethyl)-3-aryl-2-isoxazoline (2) is described. The key intermediates 1 and 2 are obtained by [3+2] 1,3-dipolar cycloaddition reaction between an arylnitrile oxide and an acrylic acid and allylic alcohol as the dipolarophile. The liquid crystals (LC) compounds are synthesized through a "molecular elongation strategy" from the initial isoxazolinic core by connecting the arylacetylene moiety obtained from the Sonogashira reaction. Under these conditions, the series of liquid crystals 5a-c, 6, 7a-g and 8a-d have been successfully synthesized in fair to good yields. The final compounds display nematic and smectic liquid-crystalline properties. The structural properties of the series of the liquid crystals has been studied using DFT methods at level B3LYP/6-31G(d,p). The equilibrium geometries in the gas phase are presented and analyzed.

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Buchwald protocol applied to the synthesis of N-heterotolan liquid crystals

Cited by 21 publications

References 41 publications

Highly efficient and general enantioselective synthesis of naturally occurring isoquinoline alkaloids

Highly efficient and general enantioselective synthesis of naturally occurring isoquinoline alkaloids

An evaluation of the chalcogen atom effect on the mesomorphic and electronic properties in a new homologous series of chalcogeno esters

3-Arylisoxazolyl-5-carboxylic acid and 5-(Hydroxymethyl)-3-aryl-2-isoxazoline as molecular platforms for liquid-crystalline materials

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