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1.
J Org Chem ; 88(2): 805-817, 2023 01 20.
Artículo en Inglés | MEDLINE | ID: mdl-36602547

RESUMEN

Two synthetic strategies employing phosphate tether-mediated one-pot sequential protocols for the total synthesis of the polyketide nonribosomal peptide macrolide, sanctolide A, and the formal synthesis of the (2S)-epimer of sanctolide A are reported. In this work, a phosphate tether-mediated one-pot sequential ring-closing metathesis/cross metathesis/substrate-controlled "H2"/tether removal approach was developed to accomplish the total synthesis of the natural product sanctolide A.


Asunto(s)
Productos Biológicos , Macrólidos , Fosfatos
2.
Org Lett ; 24(1): 16-21, 2022 01 14.
Artículo en Inglés | MEDLINE | ID: mdl-34898227

RESUMEN

A pot-economical approach to advanced polyol subunits is reported. The key reactions involved are iterative use of a phosphate tether-mediated one-pot sequential RCM/CM/H2 with subsequent utilization of either a regio-/diasteroselective cuprate addition or a Pd-catalyzed reductive allylic transposition. This method highlights the asymmetric synthesis of 12 complex polyol subunits in 4-6 one-pot sequential operations with a total of 12-14 reactions, of which 4-5 are catalytic, with minimal workup and purification procedures.


Asunto(s)
Fosfatos
3.
ACS Med Chem Lett ; 12(2): 202-210, 2021 Feb 11.
Artículo en Inglés | MEDLINE | ID: mdl-33603966

RESUMEN

The sulfamide functional group has been extensively employed in organic synthesis to discover probes and drugs in various applications such as cancer, human immunodeficiency virus (HIV), virus, and diabetes. Herein, we describe the synthesis of 7-membered symmetric and unsymmetric sulfamide compounds and their biological evaluation through the National Cancer Institute (NCI) panel of 60 human tumor cell lines (NCI-60) and the mechanism of action study. The results of a study from the NCI-60 cell line exhibited that many synthesized cyclic sulfamide compounds inhibited breast cancer (MDA-MB-468). The mechanism of action study of a representative compound 18 showed the inhibition of proliferation and apoptosis in A549 lung cancer cells.

4.
Curr Biol ; 28(22): R1292-R1293, 2018 11 19.
Artículo en Inglés | MEDLINE | ID: mdl-30458144

RESUMEN

The origins of many large-scale 'biogenic' earthen structures are controversial, because often the species that built them have vanished. This is especially true when they form regular (over-dispersed), self-organized vegetation patterns [1]. Here, we describe a vast array of soil mounds constructed by termites (Syntermes dirus) that has persisted for up to 4000 years and covers an estimated 230,000 km2 of seasonally dry tropical forest in a relatively undisturbed and climatically stable region of Northeast Brazil. The mounds are not nests, but rather they are generated by the excavation of vast inter-connecting tunnel networks, resulting in approximately 10 km3 of soil being deposited in 200 million conical mounds that are 2.5 m tall and approximately 9 m in diameter. S. dirus termites are still present in the soil surrounding the mounds and we found that intra-specific aggression occurred at a scale much larger than an individual mound. We suggest that the complex network of tunnels built to access episodic leaf-fall has allowed for the optimization of waste soil removal, which over thousands of years has formed an over-dispersed spatial pattern of mounds.


Asunto(s)
Conducta Animal/fisiología , Isópteros/fisiología , Animales , Brasil , Ecosistema , Suelo
5.
Org Lett ; 19(10): 2552-2555, 2017 05 19.
Artículo en Inglés | MEDLINE | ID: mdl-28471175

RESUMEN

The development of P-stereogenic bicyclo[4.3.1]phosphite borane tether systems for the desymmetrization of C2-symmetric dienediols is reported. This report highlights preliminary studies including tether installation and removal as well as chemoselective functionalization of the exocyclic olefin via diimide reduction or cross-metathesis. Most notably, a divergent oxidation strategy allows for the transformation of the bicyclic phosphite borane complexes to the corresponding phosphate or thiophosphate systems, highlighting the electronic attenuation of this P-tether system.


Asunto(s)
Boranos/química , Estructura Molecular , Organofosfatos , Fosfitos , Estereoisomerismo
6.
Org Lett ; 19(10): 2556-2559, 2017 05 19.
Artículo en Inglés | MEDLINE | ID: mdl-28471180

RESUMEN

The development of a P-tether-mediated, iterative SN2'-cuprate alkylation protocol for the formation of 1,3-skipped polyol stereotetrads is reported. This two-directional synthetic strategy builds molecular complexity from simple, readily prepared C2-symmetric dienediols and unites the chemistry of both temporary phosphite-borane tethers and temporary phosphate tethers-through an oxidative "function switch" of the P-tether itself-to generate intermediates that were previously inaccessible via either method alone.


Asunto(s)
Polímeros/química , Alquilación , Boranos , Estructura Molecular , Oxidación-Reducción , Fosfitos
7.
Org Lett ; 19(9): 2274-2277, 2017 05 05.
Artículo en Inglés | MEDLINE | ID: mdl-28437113

RESUMEN

The development and application of high-load, recyclable magnetic Co/C hybrid ROMP-derived benzenesulfonyl chloride and analogues is reported. The regeneration and utility of these reagents in the methylation/alkylation of various carboxylic acids is demonstrated via efficient retrieval of the magnetic reagent with a neodymium magnet. Additional reactions employing the analogue sulfonic acid and in situ generated magnetic benzenesulfonyl azide are also reported.


Asunto(s)
Carbono/química , Cobalto/química , Nanopartículas de Magnetita/química , Sulfonas/síntesis química , Alquilación , Ácidos Carboxílicos/química , Indicadores y Reactivos , Tamaño de la Partícula , Propiedades de Superficie
8.
Org Lett ; 18(13): 3094-7, 2016 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-27300267

RESUMEN

The synthesis of the C9-C25 subunit of the marine natural product spirastrellolide B is reported. The key synthetic features included the union of the two key fragments 5 and 6 via a Suzuki-Miyaura coupling reaction and a late-stage, one-pot sequential deprotection/cascade Achmatowicz rearrangement-spiroketalization to install the key spirocyclic intermediate present in the C9-C25 fragment of spirastrellolide B. The synthesis of the C9-C16 fragment 6 was accomplished via a phosphate tether mediated ring-closing metathesis (RCM), a subsequent hydroboration-oxidation protocol, followed by other stereoselective transformations in a facile manner. The spirocyclic intermediate was further functionalized utilizing a Lindlar/NaBH4 reduction protocol to furnish the C9-C25 subunit 3.


Asunto(s)
Macrólidos/síntesis química , Compuestos de Espiro/síntesis química , Ciclización , Estructura Molecular , Oxidación-Reducción , Estereoisomerismo
9.
ACS Comb Sci ; 18(7): 387-93, 2016 07 11.
Artículo en Inglés | MEDLINE | ID: mdl-27300570

RESUMEN

Applications of silica-ROMP reagents in a one-pot, sequential protocol have been developed for the synthesis of a variety of diverse benzoxathiazepine 1,1-dioxides. This protocol includes sulfonylation, intramolecular SNAr, alkylation with silica-supported oligomeric benzyl (Si-OBPn) and triazole (Si-OTPn) phosphates, and intermolecular SNAr addition with a number of secondary amines in one-pot to afford a variety of unique benzoxathiazepine 1,1-dioxides sultams in good to excellent yields.


Asunto(s)
Alquilantes/química , Dióxido de Silicio/química , Tiazepinas/síntesis química , Alquilación , Aminas/síntesis química , Aminas/química , Compuestos de Bencilo/síntesis química , Indicadores y Reactivos , Óxidos , Fosfatos/química , Estereoisomerismo , Triazoles/síntesis química
10.
ACS Comb Sci ; 18(7): 394-8, 2016 07 11.
Artículo en Inglés | MEDLINE | ID: mdl-27300761

RESUMEN

The development of new ROMP-derived silica-immobilized heterocyclic phosphate reagents and their application in purification-free protocols is reported. Grafting of norbornenyl norbornenyl-functionalized (Nb-tagged) silica particles with functionalized Nb-tagged heterocyclic phosphate monomers efficiently yield high-load, hybrid silica-immobilized oligomeric heterobenzyl phosphates (Si-OHBP) and heterotriazolyl phosphates (Si-OHTP) as efficient alkylation agents. Applications of these reagents for the diversification of N-, O-, and S-nucleophilic species, for efficient heterobenzylation and hetero(triazolyl)methylation have been validated.


Asunto(s)
Alquilantes/química , Compuestos de Bencilo/síntesis química , Compuestos Heterocíclicos/síntesis química , Dióxido de Silicio/química , Triazoles/química , Boranos/química , Indicadores y Reactivos , Niobio/química , Polimerizacion , Reproducibilidad de los Resultados
11.
Chemistry ; 22(20): 6755-6758, 2016 05 10.
Artículo en Inglés | MEDLINE | ID: mdl-27059428

RESUMEN

A series of one-pot, sequential protocols was developed for the synthesis of novel macrocycles bearing α,ß-unsaturated chemotypes. The method highlights a phosphate tether-mediated approach to establish asymmetry, and consecutive one-pot, sequential processes to access the macrocycles with minimal purification procedures. This library amenable strategy provided diverse macrocycles containing α,ß-unsaturated carbon-, sulfur-, or phosphorus-based warheads.


Asunto(s)
Compuestos Macrocíclicos/síntesis química , Lactamas Macrocíclicas/síntesis química , Naftalenosulfonatos/síntesis química , Estereoisomerismo
12.
Curr Med Chem ; 23(16): 1609-24, 2016 May 27.
Artículo en Inglés | MEDLINE | ID: mdl-27063260

RESUMEN

Onychomycosis (fungal nail infections) is very common worldwide but is fortunately not often lethal. Several powerful drugs have been introduced into clinical practice in recent years, but these infections remain difficult to cure primarily due to the difficulty of penetration of drug to the site of the infection in therapeutic concentrations. The nature of the disease, the causative fungi, and the characteristics of the drugs employed to treat this condition are discussed in this review.


Asunto(s)
Antifúngicos/farmacología , Onicomicosis/tratamiento farmacológico , Animales , Antifúngicos/uso terapéutico , Humanos , Uñas/microbiología
13.
J Org Chem ; 81(3): 899-911, 2016 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-26794367

RESUMEN

A phosphate tether-mediated ring-closing metathesis (RCM) study to the synthesis of Z-configured, P-stereogenic bicyclo[7.3.1]- and bicyclo[8.3.1]phosphates is reported. Investigations suggest that C3-substitution, olefin substitution, and proximity of the forming olefin to the bridgehead carbon of the bicyclic affect the efficiency and stereochemical outcome of the RCM event. This study demonstrates the utility of phosphate tether-mediated desymmetrization of C2-symmetric, 1,3-anti-diol-containing dienes in the generation of macrocyclic phosphates with potential synthetic and biological utility.


Asunto(s)
Compuestos Bicíclicos Heterocíclicos con Puentes/química , Compuestos Bicíclicos Heterocíclicos con Puentes/síntesis química , Compuestos Macrocíclicos/química , Compuestos Macrocíclicos/síntesis química , Fosfatos/química , Catálisis , Estereoisomerismo
14.
Org Lett ; 18(3): 516-9, 2016 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-26760683

RESUMEN

A pot-economical total synthesis of antifungal Sch-725674, 1, is reported. The approach takes advantage of a number of one-pot, sequential transformations, including a phosphate tether-mediated one-pot, sequential RCM/CM/chemoselective hydrogenation protocol, a one-pot tosylation/acrylation sequence, and a one-pot, sequential Finkelstein reaction/Boord olefination/acetonide deprotection procedure to streamline the synthesis route by reducing isolation and purification procedures, thus saving time. Overall, an asymmetric route has been developed that is efficiently accomplished in seven pots from phosphate (S,S)-triene and with minimal purification.


Asunto(s)
Antifúngicos/síntesis química , Macrólidos/síntesis química , Antifúngicos/química , Antifúngicos/farmacología , Catálisis , Hidrogenación , Macrólidos/química , Macrólidos/farmacología , Estructura Molecular , Organofosfatos , Estereoisomerismo
15.
Tetrahedron ; 71(35): 5734-5740, 2015 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-26430283

RESUMEN

A phosphate tether-mediated ring-closing metathesis study towards the synthesis of P-stereogenic bicyclo[6.3.1]-, bicyclo[7.3.1]-, and bicyclo[8.3.1]phosphates is reported. This study demonstrates expanded utility of phosphate tether-mediated desymmetrization of C2-symmetric, 1,3-anti-diol dienes in generating complex medium to large, P-stereogenic bicyclo[n.3.1]phosphates..

16.
J Org Chem ; 80(20): 9942-50, 2015 Oct 16.
Artículo en Inglés | MEDLINE | ID: mdl-26430955

RESUMEN

The syntheses of silica-supported oligomeric benzyl phosphates (Si-OBP(n)) and triazole phosphates (Si-OTP(n)) using ring-opening metathesis polymerization (ROMP) for use as efficient alkylating reagents is reported. Ease of synthesis and grafting onto the surface of norbornenyl-tagged (Nb-tagged) silica particles has been demonstrated for benzyl phosphate and triazole phosphate monomers. It is shown that these silica polymer hybrid reagents, Si-OBP(n) and Si-OTP(n), can be used to carry out alkylation reactions with an array of different nucleophiles to afford the corresponding benzylated and (triazolyl)methylated products in good yield and high purity.


Asunto(s)
Compuestos de Bencilo/química , Fosfatos/química , Dióxido de Silicio/química , Triazoles/química , Alquilación , Conformación Molecular , Tamaño de la Partícula , Fosfatos/síntesis química , Propiedades de Superficie
17.
J Org Chem ; 80(20): 9926-41, 2015 Oct 16.
Artículo en Inglés | MEDLINE | ID: mdl-26446396

RESUMEN

The generation of common and stereochemically rich medium-sized benzo-fused sultams via complementary pairing of heretofore-unknown (o-fluoroaryl)sulfonyl aziridine building blocks with an array of amino alcohols/amines in a modular one-pot, sequential protocol using an aziridine ring opening and intramolecular nucleophilic aromatic substitution is reported. The strategy employs a variety of amino alcohols/amines and proceeds with 6 + 4/6 + 5 and 6 + 1 cycloetherification pathways in a highly chemo- and regioselective fashion to obtain skeletally and structurally diverse, polycyclic, 10- to 11- and 7-membered benzo-fused sultams for broad-scale screening.


Asunto(s)
Aziridinas/química , Naftalenosulfonatos/síntesis química , Cristalografía por Rayos X , Modelos Moleculares , Estructura Molecular , Naftalenosulfonatos/química
18.
Tetrahedron Lett ; 56(23): 3330-3333, 2015 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-26388654

RESUMEN

A concise synthetic pathway to the originally assigned structure of lyngbouilloside macrolactone (3) is reported. The core macrocycle 3 was synthesized via a phosphate tether-mediated, one-pot, sequential RCM/CM/chemoselective hydrogenation reaction, Roskamp homologation, and a high yielding Boeckman acylketene cyclization.

19.
Top Curr Chem ; 361: 253-71, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25518970

RESUMEN

Recent advances in phosphate tether-mediated natural product synthesis are reviewed. Synthetic approaches toward dolabelide C, (-)-salicylihalimide A, (-)-tetrahydrolipstatin, and (+)-strictifolione are included. In addition, current efforts in method development are briefly reviewed, including a detailed study on the effect of stereochemical complexity on the phosphate-mediated, diastereoselective ring-closing metathesis reaction and recent advances in multi-reaction, one-pot sequential processes mediated by the phosphate tether. Overall, this review seeks to highlight the utility of phosphate triesters to serve as multifunctional tethers with protecting group and latent leaving group characteristics and the ability to orchestrate multiple, orthogonal reaction pathways to allow for the facile synthesis of complex, bioactive small molecules and their analogs.


Asunto(s)
Productos Biológicos/química , Compuestos Bicíclicos Heterocíclicos con Puentes/síntesis química , Lactonas/síntesis química , Macrólidos/síntesis química , Fosfatos/química , Pironas/síntesis química , Catálisis , Estructura Molecular , Orlistat , Estereoisomerismo
20.
Beilstein J Org Chem ; 10: 2332-2337, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25298800

RESUMEN

An efficient and divergent synthesis of polyol subunits utilizing a phosphate tether-mediated, one-pot, sequential RCM/CM/reduction process is reported. A modular, 3-component coupling strategy has been developed, in which, simple "order of addition" of a pair of olefinic-alcohol components to a pseudo-C 2-symmetric phosphoryl chloride, coupled with the RCM/CM/reduction protocol, yields five polyol fragments. Each of the product polyols bears a central 1,3-anti-diol subunit with differential olefinic geometries at the periphery.

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