Binding structure of elastase inhibitor scyptolin A

Natural bioactive compounds are of general interest to pharmaceutical research because they may be used as leads in drug development campaigns. Among them, scyptolin A and B from Scytonema hofmanni PCC 7110 are known to inhibit porcine pancreatic elastase, which in turn resembles the attractive drug target neutrophil elastase. The crystal structure of scyptolin A as bound to pancreatic elastase was solved at 2.8 A resolution. The inhibitor occupies the most prominent subsites S1 through S4 of the elastase and prevents a hydrolytic attack by covering the active center with its rigid ring structure. The observed binding structure may help to design potent elastase inhibitors.     

Preparation of,and alkylation of enolate anions with,dimethyl 3-bromo-2 ethoxypropenylphosphonate. An efficient,convergent synthesis of 2-cyclo-penten-1-ones

The alkylation of enolate anions with dimethyl 3-bromo-2-ethoxypropenylphosphonate, followed by acid hydrolysis of the resultant products, affords diketo phosphonate compounds which can be cyclized efficiently to give the corresponding 2-cyclopenten-1-ones. This overall five-membered ring annelation process can be carried out without affecting acid-labile functional groups (e.g. ketal) in the enolate substrate.     

Spaltungen mittels Diazonium verbindungen und Chinonimidchlorid, 12. Mitt.: Über die Strukturzuordnung bei Azokupplungsprodukten des Resorcins

Zusammenfassung Es wird die Struktur der beiden möglichen isomeren Bis-(p-nitrobenzolazo)-resorcinverbindungen1 und4 mittels gezielter Azokupplung geeigneter Modellsubstanzen und durch NMR-spektroskopische Messungen festgelegt.

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The structures of the two possible isomeric bis(p-nitrophenylazo)-resorcinol derivatives1 and4 have been determined by diazo coupling of suitable model compounds and by n.m.r. spectroscopic studies.