RESUMEN
Non-enzymatic dynamic kinetic resolution (DKR) of secondary alcohols by enantioselective acylation using an isothiourea-derived HyperBTM catalyst and racemization of slowly reacting alcohol by Bäckvall's ruthenium complex is reported. The DKR approach features high enantioselectivities (up to 99:1), employs easy-to-handle crystalline 4-nitrophenyl isobutyrate as the acylating reagent, and proceeds at room temperature and under an ambient atmosphere. The stereoinduction model featuring cation-π system interactions between the acylated HyperBTM catalyst and π electrons of an alcohol aryl subunit has been elaborated by DFT calculations.
Asunto(s)
Rutenio , Alcoholes , Catálisis , Cinética , EstereoisomerismoRESUMEN
BACKGROUND: Insects of the order Lepidoptera are among the most destructive global pests, causing billions of dollars in damage annually. A new class of N-arylpyrazole-4-methylpiperidines with potent activity on lepidopteran species has been discovered. RESULTS: In a high-throughput insecticide screen compound 1 was identified to possess modest activity on the lepidopteran insect Plutella xylostella. Optimization of 1 to compound 42 resulted in a compound with excellent activity on Spodoptera exigua, Spodoptera frugiperda, and Helicoverpa zea with median lethal concentrations values of 2.8, 1.4, and 12.5 ppm respectively. Although the mode of action remains unknown, these compounds do not appear to work by many of the known biochemical mechanisms of insect control. CONCLUSION: N-Arylpyrazole-4-methylpiperidines represent a new class of insecticides with excellent activity on a broad spectrum of lepidopteran pests. Studies to date indicate the potential for a novel mode of action; however, the target site is unknown at present. © 2023 Society of Chemical Industry.
Asunto(s)
Insecticidas , Mariposas Nocturnas , Animales , Insecticidas/farmacología , Pirazoles/farmacología , Insectos , Control de Insectos/métodos , Spodoptera , LarvaRESUMEN
A general strategy for the directed and stereocontrolled assembly of carbon-carbon linked heterodimeric hexahydropyrroloindoles is described. The stepwise union of complex amines in the form of mixed diazenes followed by photoexpulsion of dinitrogen in a solvent cage provides completely guided assembly at challenging C(sp(3))-C(sp(3)) and C(sp(3))-C(sp(2)) connections.
Asunto(s)
Dimerización , Imidas/química , Indoles , Solventes , EstereoisomerismoRESUMEN
The direct condensation of cyanic acid derivatives with N-vinyl/aryl amides affords the corresponding C4-heteroatom substituted pyrimidines. The use of cyanic bromide and thiocyanatomethane in this chemistry provides versatile azaheterocycles poised for further derivatization. The synthesis of a variety of previously inaccessible C2- and C4-pyrimidine derivatives using this methodology is described.
Asunto(s)
Pirimidinas/síntesis química , Espectroscopía de Resonancia Magnética , Pirimidinas/química , Espectrometría de Masa por Ionización de Electrospray , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
BACKGROUND: In Egypt, breast cancer is estimated to be the most common cancer among females. It is also a leading cause of cancer-related mortality. Use of circulating cell-free DNA (ccf-DNA) as non-invasive biomarkers is a promising tool for diagnosis and follow-up of breast cancer (BC) patients. OBJECTIVE: To assess the role of circulating cell free DNA (nuclear and mitochondrial) in diagnosing BC. MATERIALS AND METHODS: Multiplex real time PCR was used to detect the level of ccf nuclear and mitochondrial DNA in the peripheral blood of 50 breast cancer patients together with 30 patients with benign lesions and 20 healthy controls. Laboratory investigations, histopathological staging and receptor studies were carried out for the cancer group. Receiver operating characteristic curves were used to evaluate the performance of ccf-nDNA and mtDNA. RESULTS: The levels of both nDNA and mtDNA in the cancer group were significantly higher in comparison to the benign and the healthy control group. There was a statistically significant association between nDNA and mtDNA levels and well established prognostic parameters; namely, histological grade, tumour stage, lymph node status andhormonal receptor status. CONCLUSIONS: Our data suggests that nuclear and mitochondrial ccf-DNA may be used as non-invasive biomarkers in BC.
Asunto(s)
Adenocarcinoma/diagnóstico , Neoplasias de la Mama/diagnóstico , Carcinoma Ductal de Mama/diagnóstico , Carcinoma Lobular/diagnóstico , Núcleo Celular/genética , ADN Mitocondrial/genética , ADN de Neoplasias/genética , Células Neoplásicas Circulantes/patología , Adenocarcinoma/sangre , Adenocarcinoma/genética , Adulto , Anciano , Biomarcadores de Tumor/sangre , Biomarcadores de Tumor/genética , Neoplasias de la Mama/sangre , Neoplasias de la Mama/genética , Carcinoma Ductal de Mama/sangre , Carcinoma Ductal de Mama/genética , Carcinoma Lobular/sangre , Carcinoma Lobular/genética , Estudios de Casos y Controles , Egipto , Femenino , Estudios de Seguimiento , Humanos , Técnicas para Inmunoenzimas , Persona de Mediana Edad , Clasificación del Tumor , Invasividad Neoplásica , Estadificación de Neoplasias , Pronóstico , Curva ROC , Reacción en Cadena en Tiempo Real de la PolimerasaRESUMEN
The reagent N-isopropylidene-N'-2-nitrobenzenesulfonyl hydrazine (IPNBSH) is used in the reduction of alcohols via the loss of dinitrogen from transiently formed monoalkyl diazene intermediates accessed by sequential Mitsunobu displacement, hydrolysis, and fragmentation under mild reaction conditions.