RESUMO
A protocol has been developed in which annulation reactions of various dihalides with keto esters can be carried out to provide entry to eight- and nine-membered carbocycles. In this process wherein one alkenyl- or aryl bromide and a tethered alkyl chloride comprise the organic dihalide, a selective metal-halogen exchange reaction between the sp(2)-hybridized bromide and an organolithium initiates the process. Transmetalation to an organoytterbium reagent generates a species that undergoes selective carbonyl addition to the ketone of the keto ester, creating a lactone intermediate. Subjection of the resulting chloroalkyl lactone to intramolecular reductive coupling with samarium(II) iodide completes the desired annulation.
Assuntos
Hidrocarbonetos Halogenados/química , Cetonas/síntese química , Ciclização , Ésteres/química , Indicadores e Reagentes , Cetonas/química , Lactonas/síntese química , Lactonas/química , Compostos Organometálicos/síntese química , Compostos Organometálicos/química , Samário , ItérbioRESUMO
A 69-year-old woman was examined because of progressive dysphagie. A barium esophagogram showed no obstruction but a swallowing in trachea suggested a neuromuscular disorder. ENT examination showed no specific signs of infection. The clinical diagnosis of tetanus was confirmed by electromyography. This case demonstrates an uncommon cause of dysphagia where the classical signs of tetanus in the early stages of this disease were absent and dysphagia was the initial and sole presenting symptom.
Assuntos
Transtornos de Deglutição/etiologia , Tétano/complicações , Idoso , Transtornos de Deglutição/diagnóstico , Eletromiografia , Feminino , Humanos , Tétano/diagnósticoRESUMO
A total of 36 patients with chronic unilateral circumscribed medial and dorsolateral frontal lobe lesions were investigated with a range of neuropsychological tests. Lateralized deficits in tasks depending on language functions were found with dorsolateral but not with medial lesions. The specific role of Broca's area could not be confirmed. Lesions of the supplementary motor area led to mild deficits in tests of "concept formation". Frontomedial lesions situated more deeply in the interhemispheric fissure resulted in memory deficits. The results are discussed on the basis of recent neurophysiological theories of brain function.
