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1.
Org Biomol Chem ; 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31996878

RESUMO

This paper discloses a transition metal-free selective C-H dithiocarbamation of drug skeletons using disulfiram (DSF) in the presence of KI/K2S2O8 in DMF/H2O. Drug skeletons, including 5-aminopyrazoles, indoles, pyrroloquinoline, and Julolidine, underwent C-H dithiocarbamation smoothly to afford a variety of drug-like molecules in moderate to good yields. It was found that the in situ formed 5-aminopyrazole iodide is the key intermediate for the dithiocarbamation. Bioassay results show that some of these N-heterocyclic dithiocarbamate derivatives exhibit good antifungal activity against Colletotrichum gloeosprioides and Fusarium oxysporum, F. proliferatum, Fusarium solani, Geotrichum candidum, Penicillium digitatum, Penicillium italicum, Phyricularia grisea.

2.
Org Biomol Chem ; 17(34): 7854-7857, 2019 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-31408075

RESUMO

A copper-catalyzed DTBP oxidative dual C-H sulfurization has been developed for the direct thiocarbamation of imidazopyridines using a combination of elemental sulfur and formamides as carbamothioyl surrogates. NBS (bromo succinimide) was found to promote the thiocarbamation in good yields. This dual C-H sulfurization strategy enables access to a wide range of carbamothioyl imidazoheterocycles without the use of highly toxic phosgene.

3.
Bioorg Med Chem ; 27(19): 115048, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31439387

RESUMO

Pyrazole constitutes an important heterocyclic family covering a broad range of synthetic as well as natural products that exhibit numerous chemical, biological, agrochemical and pharmacological properties. In order to explore compounds with good fungicidal activity, a series of new pyrazole derivatives containing 5-phenyl-2-furan were designed and synthesized. In vitro and in vivo fungicidal activities were evaluated and the compound ethyl-1-(5-phenylfuran-2-carbonyl)-5-propyl-1H-pyrazole-3-carboxylate (I8) displayed significant fungicidal activity against various fungi, especially against P. infestans. The structures of the novel pyrazole derivatives were confirmed by 1H NMR, 13C NMR, MS, elemental analysis and X-ray single crystal diffraction. Further study showed that compound I8 might act on the synthesis of cell walls from morphological and ultrastructural studies by SEM and TEM. The results also revealed that compound I8 could block the nutritional transportation leading to cells senescence and death. These results suggested that the novel pyrazole derivatives proved to be promising lead compounds.

4.
Org Biomol Chem ; 17(8): 2279-2286, 2019 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-30724304

RESUMO

Dialkyl azo compounds were found to be effective alkyl radical sources for direct alkyl sulfuration with imidazopyridines using elemental sulfur under metal-free conditions. Iodine, an inexpensive and mild reagent, could promote alkyl sulfuration. A variety of quaternary cyanoalkyl radicals were successfully coupled with elemental sulfur. A subsequent C-H sulfuration of imidazopyridines afforded a diverse array of imidazopyridine derivatives bearing cyanoalkylthio groups. The cyano group could be modified and further underwent condensation with 2-aminothiazole to afford an interesting heterocyclic amide. Control experiments showed that iodine could greatly suppress the self-coupling of cyanoalkyl radicals, thus making the sulfuration proceed smoothly.

5.
Org Lett ; 21(2): 545-548, 2019 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-30596506

RESUMO

A sulfite-promoted transformation of azoles into N-difluoromethylthioureas through N-difluoromethylation and sulfuration has been developed. In this reaction, inexpensive ethyl bromodifluoroacetate and nontoxic elemental sulfur were used as the difluoromethylation and sulfuration reagents, respectively. A variety of azoles, including benzimidazoles, imidazoles, and triazoles, performed well to afford a broad range of azole thioureas in moderate to good yields.

6.
Molecules ; 23(12)2018 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-30558133

RESUMO

1,1,1,3,3,3-Hexafluoropropan-2-ol (HFIP) was found to be effective for the Bischler indole synthesis under microwave irradiation in the absence of a metal catalyst. Under the catalysis of HFIP, a wide range of α-amino arylacetones were successfully transformed into indole derivatives with moderate to good yields.


Assuntos
Indóis/química , Micro-Ondas , Catálise , Ciclização , Estrutura Molecular
7.
Chemistry ; 24(14): 3434-3438, 2018 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-29345002

RESUMO

A single and simple ortho-sulfonyl benzonitrile template was developed to achieve remote C-H olefination of six different classes of N-heterocycles. We demonstrate that, by varying precatalysts and conditions, the same template can be applied to the remote C-H activation of six structurally distinct heterocyclic scaffolds, and the site-selectivity can be predicted based on distance and geometry. Furthermore, this new development shows that template-directed remote C-H activation is possible through macrocyclopalladation processes with smaller ring sizes.

8.
Chem Commun (Camb) ; 53(55): 7784-7787, 2017 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-28650506

RESUMO

Dual C-H thiolation reactions using elemental sulphur remain a challenge. This communication discloses an oxidative radical dual sp2/sp3 C-H thiolation strategy for the coupling of imidazopyridines with ethers or alkanes using elemental sulphur.

9.
Chem Commun (Camb) ; 53(45): 6073-6076, 2017 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-28480912

RESUMO

The Langlois reagent was found to be effective for the isothiocyanation of primary amines in the presence of copper iodide and diethyl phosphonate.

10.
Chem Commun (Camb) ; 51(19): 4097-100, 2015 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-25666080

RESUMO

A new palladium-catalyzed oxidative carbamoylation reaction of isoquinoline N-oxides with formylamides for the synthesis of isoquinoline-1-carboxamides is established. The method represents the first example of the carbamoylation of isoquinoline N-oxides with formylamides to furnish arylamides using the dual C-H oxidation strategy.

11.
Org Biomol Chem ; 13(10): 3122-7, 2015 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-25632941

RESUMO

A new ring expansion of 2-aminobenzothiazoles with alkynyl carboxylic acids was developed, which allows for one-pot synthesis of 1,4-benzothiazines in moderate to excellent yields. The cascade reaction was achieved through decarboxylative coupling, nucleophilic ring-opening reaction and intramolecular hydroamination process.


Assuntos
Ácidos Carboxílicos/química , Cobre/química , Tiazinas/síntese química , Tiazóis/química , Catálise , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Solventes/química , Temperatura Ambiente
12.
Chem Commun (Camb) ; 50(94): 14775-7, 2014 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-25317723

RESUMO

A novel and convenient protocol for the formation of amides via palladium-catalyzed N-dealkylative carbonylation of alkyl tertiary amines has been developed. In the presence of PdCl2(PhCN)2, CuO, PhCN and CO, a range of substituents on both aryl iodides and alkyl tertiary amines were compatible with the reaction to afford a series of N,N-disubstituted amides in moderate to excellent yields.


Assuntos
Amidas/química , Aminas/química , Cetonas/química , Nitrogênio/química , Paládio/química , Alquilação , Catálise
13.
J Am Chem Soc ; 136(30): 10807-13, 2014 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-25007097

RESUMO

meta-C-H olefination, arylation, and acetoxylation of indolines have been developed using nitrile-containing templates. The combination of a monoprotected amino acid ligand and the nitrile template attached at the indolinyl nitrogen via a sulfonamide linkage is crucial for the meta-selective C-H functionalization of electron-rich indolines that are otherwise highly reactive toward electrophilic palladation at the para-positions. A wide range of synthetically important and advanced indoline analogues are selectively functionalized at the meta-positions.

14.
Nature ; 507(7491): 215-20, 2014 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-24622200

RESUMO

Achieving site selectivity in carbon-hydrogen (C-H) functionalization reactions is a long-standing challenge in organic chemistry. The small differences in intrinsic reactivity of C-H bonds in any given organic molecule can lead to the activation of undesired C-H bonds by a non-selective catalyst. One solution to this problem is to distinguish C-H bonds on the basis of their location in the molecule relative to a specific functional group. In this context, the activation of C-H bonds five or six bonds away from a functional group by cyclometallation has been extensively studied. However, the directed activation of C-H bonds that are distal to (more than six bonds away) functional groups has remained challenging, especially when the target C-H bond is geometrically inaccessible to directed metallation owing to the ring strain encountered in cyclometallation. Here we report a recyclable template that directs the olefination and acetoxylation of distal meta-C-H bonds--as far as 11 bonds away--of anilines and benzylic amines. This template is able to direct the meta-selective C-H functionalization of bicyclic heterocycles via a highly strained, tricyclic-cyclophane-like palladated intermediate. X-ray and nuclear magnetic resonance studies reveal that the conformational biases induced by a single fluorine substitution in the template can be enhanced by using a ligand to switch from ortho- to meta-selectivity.


Assuntos
Aminas/química , Carbono/química , Hidrogênio/química , Alcenos/química , Compostos de Anilina/química , Benzilaminas/química , Desenho de Drogas , Quinolinas/química
15.
J Org Chem ; 79(2): 686-91, 2014 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-24369039

RESUMO

A novel Lewis acid catalyzed annulation reaction has been established for the synthesis of benzocyclohepta[b]indoles. This method represents a new annulation strategy to a seven-membered carbocyclic ring system from two 3-(1H-isochromen-1-yl)-1H-indole molecules using Cu(OTf)2 catalyst; moreover, the products, benzocyclohepta[b]indoles, can be used as the rapid mercuric ion colorimetric detection reagents.


Assuntos
Cromanos/química , Cicloeptanos/química , Indóis/química , Ácidos de Lewis/química , Mesilatos/química , Catálise , Estrutura Molecular
16.
J Org Chem ; 78(22): 11163-71, 2013 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-24144079

RESUMO

A new and selective C-N bond oxidative cleavage method to 3-acylated indoles by Pd-catalyzed oxidative cross coupling of indoles with α-amino carbonyl compounds has been developed; moreover, one-pot synthesis of 3-acylated indoles from 2-ethynylanilines and α-amino carbonyl compounds has also been established. Importantly, the products 3-acylated indoles can be used to construct polyheterocyclic compound, which can be employed as efficient probes for Hg(2+) and Fe(3+).


Assuntos
Aminas/química , Indóis/química , Indóis/síntese química , Cetonas/síntese química , Compostos Organometálicos/química , Paládio/química , Acilação , Catálise , Cetonas/química , Estrutura Molecular , Oxirredução
17.
J Org Chem ; 77(6): 2850-6, 2012 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-22352410

RESUMO

A palladium- and copper-catalyzed tandem N-H/C-H bond functionalization reaction of ortho-(2-chlorovinyl)bromobenzenes with indoles and pyrroles has been developed. A variety of CF(3)-containing indolo- and pyrrolo[2,1-a]isoquinolines were prepared in moderate to good yields via the cyclization of 1-bromo-2-(2-chloro-3,3,3-trifluoroprop-1-enyl)benzenes with indoles and pyrroles.


Assuntos
Bromobenzenos/química , Cobre/química , Indóis/química , Indóis/síntese química , Isoquinolinas/química , Isoquinolinas/síntese química , Paládio/química , Pirróis/química , Pirróis/síntese química , Catálise , Estrutura Molecular
18.
Chem Commun (Camb) ; 47(48): 12867-9, 2011 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-22037478

RESUMO

The first example of molecular sieve-promoted TBHP-mediated direct oxidative thiolation of an sp(3) C-H bond adjacent to a nitrogen atom with disulfides under metal-free conditions, which allows for preparation of numerous S,N-containing compounds, is presented. Moreover, diverse benzothiazoles and a fipronil analog can be synthesized through this strategy.

20.
J Org Chem ; 76(18): 7546-50, 2011 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-21812478

RESUMO

A copper-catalyzed thiolation annulation reaction of 2-bromo alkynylbenzenes with sodium sulfide has been developed. In the presence of CuI and TMEDA, a variety of 2-substituted benzo[b]thiophenes were readily prepared in moderate to good yields by the reaction of 2-bromo alkynylbenzenes and Na(2)S·9H(2)O.


Assuntos
Benzeno/química , Compostos Organometálicos/química , Sulfetos/química , Tiofenos/síntese química , Catálise , Cromatografia em Camada Delgada , Cromatografia Gasosa-Espectrometria de Massas , Espectroscopia de Ressonância Magnética , Espectrofotometria Infravermelho
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