RESUMO
In this paper, we report the synthesis of spirocyclopropane-containing 4H-pyrazolo[1,5-a]indoles 6a-e via alkylative dearomatization and intramolecular N-imination of indole-O-(methylsulfonyl)oxime 11. Starting materials tryptophol (7) and 2-bromocyclopetanone (8) were reacted in the presence of HBF4·OEt2, providing 1,2,3,5,6,11-hexahydrocyclopenta[2,3]oxepino[4,5-b]indole (9) in a 63% yield. Compound 9 was reacted with hydroxylamine hydrochloride to afford oxime 10 (65% yield), which was subsequently bis-methanesulfonated to form 11 in a 85% yield. Heating 11 with various alcohols in the presence of N,N-diisopropylethylamine (DIPEA) triggered the alkylative dearomatization and intramolecular N-imination, forming the spirocyclopropane and 4H-pyrazolo[1,5-a]indole structures in the targets 6a-e with 67-84% yields.
RESUMO
This paper presents the design and synthesis of 4-(3-hydroxyanilino)-6-(1H-1,2,3-triazol-4-yl)quinazolines of scaffold 9 as selective B-Raf/B-RafV600E and potent EGFR/VEGFR2 kinase inhibitors. Total 14 compounds of scaffold 9 having different side chains at the triazolyl group with/without fluoro substituents at the anilino group were synthesized and investigated. Among them, 9m with a 2-carbamoylethyl side chain and C-4'/C-6' difluoro substituents was the most potent, which selectively inhibited B-Raf (IC50: 57 nM) and B-RafV600E (IC50: 51 nM) over C-Raf (IC50: 1.0 µM). Compound 9m also actively inhibited EGFR (IC50: 73 nM) and VEGFR2 (IC50: 7.0 nM) but not EGFRT790M and PDGFR-ß (IC50: >10 µM). Despite having good potency for B-Raf and B-RafV600E in the enzymatic assays, 9m was less active to inhibit melanoma A375 cells which proliferate due to constitutively activated B-Raf600E. The inferior activity of 9m for A375 was similar to that of sorafenib (6), suggesting that 9m might bind to the inactive conformations of B-Raf and B-RafV600E. Docking simulations could thus be performed to reveal the binding poses of 9m in B-Raf, B-RafV600E, and VEGFR2 kinases.
Assuntos
Receptores ErbB/antagonistas & inibidores , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Quinazolinas/farmacologia , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Quinases raf/antagonistas & inibidores , Linhagem Celular Tumoral , Receptores ErbB/genética , Receptores ErbB/metabolismo , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Simulação de Acoplamento Molecular , Quinazolinas/química , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/genética , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismoRESUMO
In this paper, we present a copper(I)-catalyzed nitrile-addition/N-arylation ring-closure cascade for the synthesis of 5,11-dihydro-6H-indolo[3,2-c]quinolin-6-ones from 2-(2-bromophenyl)-N-(2-cyanophenyl)acetamides. Using CuBr and t-BuONa in dimethylformamide (DMF) as the optimal reaction conditions, the cascade reaction gave the target products, in high yields, with a good substrate scope. Application of the cascade reaction was demonstrated on the concise total syntheses of alkaloid isocryptolepine. Further optimization of the products from the cascade reaction led to 3-chloro-5,12-bis[2-(dimethylamino)ethyl]-5,12-dihydro-6H-[1,3]dioxolo[4',5':5,6]indolo[3,2-c]quinolin-6-one (2k), which exhibited the characteristic DNA topoisomerase-I inhibitory mechanism of action with potent in vitro anticancer activity. Compound 2k actively inhibited ARC-111- and SN-38-resistant HCT-116 cells and showed in vivo activity in mice bearing human HCT-116 and SJCRH30 xenografts. The interaction of 2k with the Top-DNA cleavable complex was revealed by docking simulations to guide the future optimization of 5,11-dihydro-6H-indolo[3,2-c]quinolin-6-ones as topoisomerase-I inhibitors.
Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Cobre/química , Nitrilas/química , Quinolonas/síntese química , Quinolonas/farmacologia , Inibidores da Topoisomerase I/síntese química , Inibidores da Topoisomerase I/farmacologia , Animais , Catálise , DNA Topoisomerases Tipo I/química , Desenho de Fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Masculino , Camundongos , Camundongos Nus , Modelos Moleculares , Simulação de Acoplamento Molecular , Quinolonas/farmacocinética , Ratos , Ratos Sprague-Dawley , Relação Estrutura-Atividade , Inibidores da Topoisomerase I/farmacocinética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Highly expressed in cancer 1 (Hec1) plays an essential role in mitosis and is correlated with cancer formation, progression, and survival. Phosphorylation of Hec1 by Nek2 kinase is essential for its mitotic function, thus any disruption of Hec1/Nek2 protein-protein interaction has potential for cancer therapy. We have developed T-1101 tosylate (9j tosylate, 9j formerly known as TAI-95), optimized from 4-aryl-N-pyridinylcarbonyl-2-aminothiazole of scaffold 9 by introducing various C-4' substituents to enhance potency and water solubility, as a first-in-class oral clinical candidate for Hec1 inhibition with potential for cancer therapy. T-1101 has good oral absorption, along with potent in vitro antiproliferative activity (IC50: 14.8-21.5 nM). It can achieve high concentrations in Huh-7 and MDA-MB-231 tumor tissues, and showed promise in antitumor activity in mice bearing human tumor xenografts of liver cancer (Huh-7), as well as of breast cancer (BT474, MDA-MB-231, and MCF7) with oral administration. Oral co-administration of T-1101 halved the dose of sorafenib (25 mg/kg to 12.5 mg/kg) required to exhibit comparable in vivo activity towards Huh-7 xenografts. Cellular events resulting from Hec1/Nek2 inhibition with T-1101 treatment include Nek2 degradation, chromosomal misalignment, and apoptotic cell death. A combination of T-1101 with either of doxorubicin, paclitaxel, and topotecan in select cancer cells also resulted in synergistic effects. Inactivity of T-1101 on non-cancerous cells, a panel of kinases, and hERG demonstrates cancer specificity, target specificity, and cardiac safety, respectively. Subsequent salt screening showed that T-1101 tosylate has good oral AUC (62.5 µM·h), bioavailability (F = 77.4%), and thermal stability. T-1101 tosylate is currently in phase I clinical trials as an orally administered drug for cancer therapy.
Assuntos
Antineoplásicos/farmacologia , Proteínas do Citoesqueleto/antagonistas & inibidores , Descoberta de Drogas , Quinases Relacionadas a NIMA/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Proteínas do Citoesqueleto/metabolismo , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Células K562 , Neoplasias Hepáticas Experimentais/tratamento farmacológico , Neoplasias Hepáticas Experimentais/metabolismo , Neoplasias Hepáticas Experimentais/patologia , Camundongos , Camundongos SCID , Simulação de Acoplamento Molecular , Estrutura Molecular , Quinases Relacionadas a NIMA/metabolismo , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/química , Relação Estrutura-Atividade , Distribuição TecidualRESUMO
PURPOSE: Highly expressed in cancer protein 1 (Hec1) is an oncogene and a promising molecular target for novel anticancer drugs. The purpose of this study was to evaluate the potential of a Hec1 inhibitor, TAI-95, as a treatment for primary liver cancer. METHODS: In vitro and in vivo methods were used to test the activity of TAI-95. Gene expression analysis was used to evaluate clinical correlation of the target. RESULTS: In vitro growth inhibition results showed that TAI-95 has excellent potency on a wide range of primary liver cancer cell lines (hepatoblastoma or hepatocellular carcinoma) (GI(50) 30-70 nM), which was superior to sorafenib and other cytotoxic agents. TAI-95 was relatively inactive in non-cancerous cell lines (GI(50) > 10 µM). TAI-95 disrupts the interaction between Hec1 and Nek2 and leads to degradation of Nek2, chromosomal misalignment, and apoptotic cell death. TAI-95 showed synergistic activity in selected cancer cell lines with doxorubicin, paclitaxel, and topotecan, but not with sorafenib. TAI-95 shows excellent potency in a Huh-7 xenograft mouse model when administered orally. Gene expression analysis of clinical samples demonstrated increased expression of Hec1/NDC80 and associated genes (Nek2, SMC1A, and SMC2) in 27 % of patients, highlighting the potential for using this therapeutic approach to target patients with high Hec1 expression. CONCLUSION: Inhibition of Hec1 using small molecule approach may represent a promising novel approach for the treatment of primary liver cancers.
Assuntos
Antineoplásicos/farmacologia , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Neoplasias Hepáticas/tratamento farmacológico , Proteínas Nucleares/antagonistas & inibidores , Animais , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Proteínas do Citoesqueleto , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Camundongos , Camundongos SCID , Terapia de Alvo Molecular/métodos , Quinases Relacionadas a NIMA , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
A series of 4-aryl-N-arylcarbonyl-2-aminothiazoles of scaffold 4 was designed and synthesized as Hec1/Nek2 inhibitors. Structural optimization of 4 led to compound 32 bearing C-4' 4-methoxyphenoxy and 4-(o-fluoropyridyl)carbonyl groups that showed low nanomolar in vitro antiproliferative activity (IC50: 16.3-42.7 nM), high intravenous AUC (64.9 µM·h, 2.0 mg/kg) in SD rats, and significant in vivo antitumor activity (T/C = 32%, 20 mg/kg, IV) in mice bearing human MDA-MB-231 xenografts. Cell responses resulting from Hec1/Nek2 inhibition were observed in cells treated with 32, including a reduced level of Hec1 coimmunoprecipitated with Nek2, degradation of Nek2, mitotic abnormalities, and apoptosis. Compound 32 showed selectivity toward cancer cells over normal phenotype cells and was inactive in a [(3)H]astemizole competitive binding assay for hERG liability screening. Therefore, 32 is as a good lead toward the discovery of a preclinical candidate targeting Hec1/Nek2 interaction.
Assuntos
Antineoplásicos/farmacologia , Proteínas Nucleares/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Tiazóis/farmacologia , Animais , Linhagem Celular Tumoral , Proteínas do Citoesqueleto , Descoberta de Drogas , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Quinases Relacionadas a NIMA , Ratos , Ratos Sprague-Dawley , Tiazóis/farmacocinética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Current cytotoxic chemotherapy produces clinical benefit in patients with breast cancer but the survival impact is modest. To explore novel cytotoxic agents for the treatment of advanced disease, we have characterized a new and pharmacokinetically improved Hec1-targeted compound, TAI-95. Nine of 11 breast cancer cell lines tested were sensitive to nanomolar levels of TAI-95 (GI(50) = 14.29-73.65 nmol/L), and more importantly, TAI-95 was active on a number of cell lines that were resistant (GI(50) > 10 µmol/L) to other established cytotoxic agents. TAI-95 demonstrates strong inhibition of in vivo tumor growth of breast cancer model when administered orally, without inducing weight loss or other obvious toxicity. Mechanistically, TAI-95 acts by disrupting the interaction between Hec1 and Nek2, leading to apoptotic cell death in breast cancer cells. Furthermore, TAI-95 is active on multidrug-resistant (MDR) cell lines and led to downregulation of the expression of P-glycoprotein (Pgp), an MDR gene. In addition, TAI-95 increased the potency of cytotoxic Pgp substrates, including doxorubicin and topotecan. Certain clinical subtypes of breast cancer more likely to respond to Hec1-targeted therapy were identified and these subtypes are the ones associated with poor prognosis. This study highlights the potential of the novel anticancer compound TAI-95 in difficult-to-treat breast cancers.
Assuntos
Antineoplásicos/administração & dosagem , Neoplasias da Mama/tratamento farmacológico , Terapia de Alvo Molecular , Niacinamida/análogos & derivados , Proteínas Nucleares/genética , Tiazóis/administração & dosagem , Animais , Apoptose/genética , Neoplasias da Mama/patologia , Proteínas do Citoesqueleto , Doxorrubicina/administração & dosagem , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Compostos Heterocíclicos de 4 ou mais Anéis , Humanos , Técnicas In Vitro , Células MCF-7 , Camundongos , Niacinamida/administração & dosagem , Proteínas Nucleares/antagonistas & inibidores , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
BACKGROUND: Hec1 (NDC80) is an integral part of the kinetochore and is overexpressed in a variety of human cancers, making it an attractive molecular target for the design of novel anticancer therapeutics. A highly potent first-in-class compound targeting Hec1, TAI-1, was identified and is characterized in this study to determine its potential as an anticancer agent for clinical utility. METHODS: The in vitro potency, cancer cell specificity, synergy activity, and markers for response of TAI-1 were evaluated with cell lines. Mechanism of action was confirmed with western blotting and immunofluorescent staining. The in vivo potency of TAI-1 was evaluated in three xenograft models in mice. Preliminary toxicity was evaluated in mice. Specificity to the target was tested with a kinase panel. Cardiac safety was evaluated with hERG assay. Clinical correlation was performed with human gene database. RESULTS: TAI-1 showed strong potency across a broad spectrum of tumor cells. TAI-1 disrupted Hec1-Nek2 protein interaction, led to Nek2 degradation, induced significant chromosomal misalignment in metaphase, and induced apoptotic cell death. TAI-1 was effective orally in in vivo animal models of triple negative breast cancer, colon cancer and liver cancer. Preliminary toxicity shows no effect on the body weights, organ weights, and blood indices at efficacious doses. TAI-1 shows high specificity to cancer cells and to target and had no effect on the cardiac channel hERG. TAI-1 is synergistic with doxorubicin, topotecan and paclitaxel in leukemia, breast and liver cancer cells. Sensitivity to TAI-1 was associated with the status of RB and P53 gene. Knockdown of RB and P53 in cancer cells increased sensitivity to TAI-1. Hec1-overexpressing molecular subtypes of human lung cancer were identified. CONCLUSIONS: The excellent potency, safety and synergistic profiles of this potent first-in-class Hec1-targeted small molecule TAI-1 show its potential for clinically utility in anti-cancer treatment regimens.
Assuntos
Antineoplásicos/administração & dosagem , Niacinamida/análogos & derivados , Proteínas Nucleares/antagonistas & inibidores , Tiazóis/administração & dosagem , Adenocarcinoma/metabolismo , Administração Intravenosa , Administração Oral , Animais , Antineoplásicos/toxicidade , Apoptose , Carcinoma de Células Escamosas/metabolismo , Linhagem Celular Tumoral , Proteínas do Citoesqueleto , Sinergismo Farmacológico , Feminino , Técnicas de Silenciamento de Genes , Neoplasias Pulmonares/metabolismo , Masculino , Camundongos , Camundongos Nus , Quinases Relacionadas a NIMA , Niacinamida/administração & dosagem , Niacinamida/toxicidade , Proteínas Nucleares/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteólise , Proteína do Retinoblastoma/genética , Proteína do Retinoblastoma/metabolismo , Tiazóis/toxicidade , Carga Tumoral , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Through the syntheses of its C-1 desvinyl, C-7 methylene, C-7 exocyclic ethylidene, and various C-3 phenylmethyl analogues, the structure-activity relationship of antimitotic ottelione A (4) against tubulin and various cancer cells was established. The results indicated that compound 4 was a colchicine-competitive inhibitor and that the C-1 vinyl group is unnecessary for its potency, whereas the C-7 exocyclic double bond is essential, possibly because of its irreversible interaction with tubulin. Further optimization of the substituents on the phenylmethyl group at the C-3 position generated compound 10g with a 3'-fluoro-4'-methoxyphenylmethyl substituent, which was 6-38-fold more active against MCF-7, NCI-H460, and COLO205 cancer cells relative to 4. Results from in vitro tubulin polymerization assay confirmed the potency of compounds 4, 10g, and 11a.
RESUMO
Patients with lupus nephritis show an impaired oxidative status and increased levels of interleukin (IL)-1ß and IL-18, which are closely linked to inflammation and correlated with disease activity. Although epigallocatechin-3-gallate (EGCG), the major bioactive polyphenol present in green tea with antioxidant and free radical scavenging activities, has been reported to have anti-inflammatory effects by inhibiting nuclear factor-kappa B (NF-κB)-mediated inflammatory responses in vivo, its effectiveness for the treatment of lupus nephritis is still unknown. In the present study, 12-week-old New Zealand black/white (NZB/W) F1 lupus-prone mice were treated daily with EGCG by gavage until sacrificed at 34 weeks old for clinical, pathological, and mechanistic evaluation. We found that the administration (1) prevented proteinuria, renal function impairment, and severe renal lesions; (2) increased renal nuclear factor E2-related factor 2 (Nrf2) and glutathione peroxidase activity; (3) reduced renal oxidative stress, NF-κB activation, and NLRP3 mRNA/protein expression and protein levels of mature caspase-1, IL-1ß, and IL-18; and (4) enhanced splenic regulatory T (Treg) cell activity. Our data clearly demonstrate that EGCG has prophylactic effects on lupus nephritis in these mice that are highly associated with its effects of enhancing the Nrf2 antioxidant signaling pathway, decreasing renal NLRP3 inflammasome activation, and increasing systemic Treg cell activity.
Assuntos
Antioxidantes/administração & dosagem , Catequina/análogos & derivados , Inflamassomos/efeitos dos fármacos , Rim/efeitos dos fármacos , Nefrite Lúpica/tratamento farmacológico , Animais , Antioxidantes/efeitos adversos , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Catequina/administração & dosagem , Catequina/efeitos adversos , Progressão da Doença , Regulação da Expressão Gênica/efeitos dos fármacos , Inflamassomos/metabolismo , Interleucina-18/genética , Interleucina-18/metabolismo , Interleucina-1beta/genética , Interleucina-1beta/metabolismo , Rim/metabolismo , Rim/patologia , Nefrite Lúpica/imunologia , Nefrite Lúpica/patologia , Nefrite Lúpica/fisiopatologia , Camundongos , Camundongos Endogâmicos NZB , Fator 2 Relacionado a NF-E2/genética , Fator 2 Relacionado a NF-E2/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR , Estresse OxidativoRESUMO
A series of 3-O-acylated (-)-epigallocatechins were synthesized and their inhibition of steroid 5α-reductase was studied. They were prepared from the reaction of EGCG with tert-butyldimethylsilyl chloride followed by reductive cleavage of the ester bond. The resultant (-)-epigallocatechins penta-O-tert-butyldimethylsilyl ether was esterified with different fatty acids then desilylated to provide the corresponding products. The activity of 3-O-acylated (-)-epigallocatechins increased with the increasing carbon numbers of the fatty acid moiety, reaching maximum for 16 carbon atoms (compound 4h) with an IC50 of 0.53 µM, which was â¼12-fold more potent than EGCG (IC50=6.29 µM). Introduction of monounsaturated fatty acid provided the most potent compound 6 (IC50=0.48 µM), which showed moderate anti-tumor activity in vivo.
Assuntos
3-Oxo-5-alfa-Esteroide 4-Desidrogenase/metabolismo , Inibidores de 5-alfa Redutase/farmacologia , Antineoplásicos/farmacologia , Catequina/análogos & derivados , Inibidores de 5-alfa Redutase/síntese química , Inibidores de 5-alfa Redutase/química , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Catequina/síntese química , Catequina/química , Catequina/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Masculino , Camundongos , Camundongos SCID , Modelos Moleculares , Estrutura Molecular , Estereoisomerismo , Relação Estrutura-Atividade , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
A series of N,N-disubstituted-N'-[1-aryl-1H-pyrazol-5-yl]-methnimidamides was synthesized by a newly developed microwave reaction and their antiproliferative activities were evaluated. Microwave irradiation of 5-amino-1,3-disubstituted pyrazoles with various amide solvents in the presence of POCl(3) provided the corresponding 2a-2k, 3a-3c, and 4a-4f in good to excellent yields. The obtained methnimidamides were tested against NCI-H661, NPC-TW01, and Jurkat cancer cell lines and the results indicated that compounds 2d and 2e were the most potent with IC(50) values in low micromolar range.
Assuntos
Proliferação de Células/efeitos dos fármacos , Pirazóis/síntese química , Pirazóis/farmacologia , Linhagem Celular Tumoral , HumanosRESUMO
A series of pyrrole-indolin-2-ones were synthesized, and their inhibition profile for Aurora kinases was studied. The potent compound 33 with phenylsulfonamido at the C-5 position and a carboxyethyl group at the C-3' position selectively inhibited Aurora A over Aurora B with IC50 values of 12 and 156 nM, respectively. Replacement of the carboxyl group with an amino group led to compound 47, which retained the activity for Aurora B and lost activity for Aurora A (IC50=2.19 microM). Computation modeling was used to address the different inhibition profiles of 33 and 47. Compounds 47 and 36 (the ethyl ester analogue of 33) inhibited the proliferation of HCT-116 and HT-29 cells and suppressed levels of the phosphorylated substrates of Aurora A and Aurora B in the Western blots.
Assuntos
Antineoplásicos/síntese química , Indóis/síntese química , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Pirróis/síntese química , Antineoplásicos/química , Antineoplásicos/farmacologia , Aurora Quinase B , Aurora Quinases , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Células HCT116 , Células HT29 , Células HeLa , Histonas/metabolismo , Humanos , Indóis/química , Indóis/farmacologia , Modelos Moleculares , Fosforilação , Ligação Proteica , Pirróis/química , Pirróis/farmacologia , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
A mechanistic study on the nucleophilic substitution of a strictly geometric 21-bromo-3alpha-hydroxyl-3beta-methoxymethyl-5alpha-pregnan-20-one was described. Reaction of the alpha-bromoketone with excess lithium imidazole followed by the addition of extra bases including n-butyllithium, methyllithium, lithium piperidine, and lithium pyrrolidine provided unexpected alpha-nucleophilic carbonyl adducts that derived from strong base. Data from HPLC and proton NMR suggested an epoxide as the intermediate. Two possible reaction pathways were proposed for the nucleophilic substitution reaction. One pathway is the normal SN2 substitution reaction, directly provided the imidazoly product without the formation of the unexpected alpha-substituted products. The other pathway went through an epoxide intermediate, in which imidazole anion or the strong bases added would attack from the less hindered site of the epoxide to give the substitution product.
Assuntos
Pregnanos/química , Imidazóis/química , Cetonas/química , Compostos de Lítio/química , Estrutura MolecularRESUMO
The synthesis of biologically active 3alpha-hydroxyl-21-(1'-imidazolyl)-3beta-methoxymethyl-5alpha-pregnan-20-one was accomplished in six steps. The key steps were the improvement of stereoselectivity for acetyl isomers in C-17 and the introduction of imidazole into the core structure by use of lithium imidazole. This latter key step provided the desired product in 82% yield without the formation of 1,3-disubstituted imidazolium salt as impurity, which is generally observed in traditional method.
Assuntos
Pregnanolona/análogos & derivados , Pregnanolona/química , Pregnanolona/síntese química , Hidrogenação , Imidazóis/química , Oxirredução , TemperaturaRESUMO
[reaction: see text]. Symmetric azoxy arenes were successfully prepared in one step from 2 equiv of the corresponding nitroarenes by use of sodium bis(trimethylsilyl)amide as the deoxygenating agents in THF at 150 degrees C in a sealed tube.