The total synthesis of octalactins A and B has been achieved in 15 steps (longest linear sequence) and 10% overall yield from commercially available materials. Key steps include the Paterson-Aldol reaction for the rapid assembly of the carbonate 46, methylenation of 46 and subsequent Claisen rearrangement of the corresponding alkenyl-substituted cyclic ketene acetal to provide the core unsaturated medium-ring lactone 47, and the use of enzyme-mediated acetate deprotection in the presence of a medium-ring lactone.

7H-8,9-Dihydropyrano[2,3-c]imidazo[1,2-a]pyridines with excellent physicochemical and pharmacological properties were identified that represent interesting candidates for further development as potassium-competitive acid blockers (P-CABs). The title compounds were prepared following synthetic pathways that relied either on a Claisen rearrangement/cross-metathesis reaction or on the (asymmetric) reduction of prochiral ketones. The influence of the character of the substituents R3, R6, and Ar on the biological activity and the physicochemical properties of the target compounds was examined. In contrast to the parent system (R6 = H), compounds in which R6 represents a carboxamide residue generally show improved in vivo activity and favorable pKa/log D values. Whereas variation of R3 is useful to obtain target compounds with modified basicity and lipophilicity, strong inhibition of the H+/K+-ATPase and potent in vivo activity is observed for R3 = methyl only. Small modifications of the aryl group, e.g., replacement of hydrogen versus a fluoro atom or a methyl group, are allowed. The (9S)-enantiomers are responsible for the gastric acid secretion inhibiting action, whereas the (9R)-enantiomers are virtually inactive.

Three steps suffice for constructing the pyrroloindolino framework of the pharmacophoric moiety 2 of the highly potent anticancer agent CC‐1065. The easily accessible bis(allylamino)bromobenzene 1 was transformed by successive cyclizations mediated by [Cp2Zr(Me)Cl] and by a Pd° complex.

Die O‐Glycoside l des seco‐CI‐Derivats 2, das die seco‐Form der pharmakophoren Gruppe des cytotoxisch hochwirksamen Antibioticums CC–1065 ist, weisen nur eine sehr geringe Toxizität auf. In der tumorselektiven Krebstherapie können sie mit Konjugaten aus Glycohydrolasen und monoklonalen Antikörpern, die an tumorassoziierte Antigene binden, eingesetzt werden. Die Glycohydrolasen spalten die Prodrugs 1 unter Freisetzung der cytotoxischen Komponente 2.

No abstract