Pigmentary demarcation lines are abrupt transition lines between the areas of deeper pigmentation and the areas of lighter, normal pigmentation. Type B pigmentary demarcation lines involve the posterior medial portion of the lower extremities and are more commonly associated with pregnancy. We present a case of pigmentary demarcation lines of pregnancy with erythematous changes, involving both the anterior and posterior aspects of the lower extremities.
View Article and Find Full Text PDFThe spirastrellolides are a novel family of structurally unprecedented marine macrolides which show promising anticancer properties due to their potent inhibition of protein phosphatase 2A. In the preceding paper, a modular strategy for the synthesis of spirastellolide A methyl ester which allowed for the initial stereochemical uncertainties was outlined, together with the synthesis of a series of suitably functionalised fragments. In this paper, the realisation of this synthesis is described.
View Article and Find Full Text PDFDue to a combination of their promising anticancer properties, limited supply from the marine sponge source and their unprecedented molecular architecture, spirastrellolides represent attractive and challenging synthetic targets. A modular strategy for the synthesis of spirastrellolide A methyl ester, which allowed for the initial stereochemical uncertainties in the assigned structure was adopted, based on the envisaged sequential coupling of a series of suitably functionalised fragments; in this first paper, full details of the synthesis of these fragments are described. The pivotal C26-C40 DEF bis-spiroacetal was assembled by a double Sharpless asymmetric dihydroxylation/acetalisation cascade process on a linear diene intermediate, configuring the C31 and C35 acetal centres under suitably mild acidic conditions.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
March 2012
Marine macrolides: an improved second-generation total synthesis of the anticancer macrolide spirastrellolide A methyl ester has been achieved. The synthesis features a uniformly high level of stereocontrol combined with more expedient fragment assembly, and demonstrates a critical dependence of the crucial macrolactonization step on the substitution pattern of the C22-C24 linker region.
View Article and Find Full Text PDFChromium is a transition metal and has been shown to elicit contact dermatitis. Although leather products have been known to be the most significant source of chromium exposure these days, the majority of reports have been related to exposure from shoe products. We herein report a professional golfer who became allergic to golf gloves made of chromium-tanned leather.
View Article and Find Full Text PDFThe optimisation of a synthetic strategy towards the ABC segment of the cytotoxic macrolide spirastrellolide A is reported, together with its application to the synthesis of two diastereomeric C(1)-C(22) fragments for stereochemical correlation purposes with a putative spirastrellolide degradation product.
View Article and Find Full Text PDFAn efficient synthesis of the C(26)-C(40) tricyclic [5,6,6]-bis-spiroacetal segment of the marine macrolide spirastrellolide A has been developed, exploiting a novel double Sharpless asymmetric dihydroxylation/spiroacetalisation sequence.
View Article and Find Full Text PDFBetaine, coumarin, hesperidin and kaempferol are the components derived from Lycium chinense, Angelicae decursiva, Poncirus trifoliata and Polygonatum odoratum, respectively. These plants have been used for the treatment of respiratory diseases in oriental medicine and their respective components were reported to have various biological effects. In this study, we investigated whether these natural products affect mucin release from cultured hamster tracheal surface epithelial cells and compared the possible activities of these agents with the inhibitory action on mucin release by poly-L-lysine and the stimulatory action by adenosine triphosphate.
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