RESUMO
The enantioselective synthesis of a fully functionalized cycloheptane core of the naturally occurring triterpenoid volvalerenol A, exhibiting pseudo-C2 symmetry, was achieved. Enantioselective enzymatic desymmetrization (EED), asymmetric methallylation, and reductive ring opening of an cyclopropane overbred intermediate were the key reactions to access the cycloheptanone core. Further synthetic manipulations, via a unique "MPV" (Meerwein-Ponndorf-Verley) type reductive ring-opening of an epoxide and other synthetic transformations, afforded two fully functionalized cycloheptane frameworks of the target molecule.
RESUMO
Retroperitoneal spindle cell neoplasms are diagnostically challenging. Malignant peripheral nerve sheath tumours (MPNSTs) can sometimes present as sporadic primary retroperitoneal tumours. MPNSTs are usually high-grade and highly aggressive tumours and are associated with a poor prognosis. Low-grade MPNSTs are very rarely described. This current case report describes a case of sporadic primary low-grade MPNST presenting as retroperitoneal spindle cell neoplasm. The diagnosis, imaging and immunohistopathological findings, as well as its successful surgical management, are presented.
Assuntos
Neoplasias de Bainha Neural , Neoplasias Retroperitoneais , Humanos , Diagnóstico Diferencial , Gradação de Tumores , Neoplasias de Bainha Neural/patologia , Neoplasias de Bainha Neural/diagnóstico , Neoplasias de Bainha Neural/cirurgia , Neoplasias Retroperitoneais/patologia , Neoplasias Retroperitoneais/diagnóstico , Neoplasias Retroperitoneais/cirurgia , Neoplasias Retroperitoneais/diagnóstico por imagem , Sarcoma/diagnóstico , Sarcoma/patologia , Sarcoma/cirurgia , Sarcoma/diagnóstico por imagem , Tomografia Computadorizada por Raios XRESUMO
An efficient sequential double-annulation strategy has been developed to afford a series of unsymmetrical acridines with high yield and regioselectivity for the first time. This simple protocol enables the sequential assembly of two aromatic rings from simple starting materials. The reaction proceeds via modified Friedländer annulation and subsequent base-mediated benzannulation with acrylates as Michael acceptors. A range of substrate scope and functional group tolerance is observed. Late-stage synthetic modification is also explored to access novel unsymmetrical acridines in good yield.