Stephacidin A and its congeners are a collection of secondary metabolites that possess intriguing structural motifs. They stem from unusual biosynthetic sequences that lead to the incorporation of a prenyl or reverse-prenyl group into a bicyclo[2.2.2]diazaoctane framework, a chromene unit or the vestige thereof. To complement biosynthetic studies, which normally play a significant role in unveiling the biosynthetic pathways of natural products, here we demonstrate that chemical synthesis can provide important insights into biosynthesis. We identify a short total synthesis of congeners in the reverse-prenylated indole alkaloid family related to stephacidin A by taking advantage of a direct indole C6 halogenation of the related ketopremalbrancheamide. This novel strategic approach has now made possible the syntheses of several natural products, including malbrancheamides B and C, notoamides F, I and R, aspergamide B, and waikialoid A, which is a heterodimer of avrainvillamide and aspergamide B. Our approach to the preparation of these prenylated and reverse-prenylated indole alkaloids is bioinspired, and may also inform the as-yet undetermined biosynthesis of several congeners.
Musculoskeletal injuries are among the most common chief complaints in the geriatric population. Shoulder pain with associated deformity should be evaluated for possible joint dislocations, fractures, and musculotendinous tears. A comprehensive evaluation beginning with history and physical examination is important. Typical imaging utilized for the diagnosis of shoulder injuries includes plain radiography, ultrasound, and magnetic resonance imaging (MRI). We present a case of a 75-year-old male with massive rotator cuff tears and subsequent shoulder deformity. Management with non-surgical or surgical approaches should begin as soon as possible to delay the development of rotator cuff arthropathy.
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