Stefan Klaus

Synthesis and antimicrobial activity of N-analogous corollosporines

Corollosporine is an antimicrobial metabolite, which was isolated from the marine fungus Corollospora maritima. Owing to its basic 4-hydroxyphthalic acid anhydride structure, it has become an attractive target for a structure/activity relationship modelling of derived compounds with potential antibiotic activity. In this regard we report on the straightforward synthesis of hetero analogous corollosporines, which were easily prepared by a three-step reaction sequence, taking advantage of a novel multicomponent reaction (AAD-reaction) and a subsequent aromatization/Grignard reaction protocol. Furthermore, the obtained products were tested in several biological assays to evaluate their antimicrobial activity.

From a spin-off to the advantageous use in Diels–Alder reactions: a combined synthetic, spectroscopic and computational approach to N-(dienyl)acylamines

The acid-catalyzed condensation of aldehydes and acetamide has been shown to provide a pool of diverse equilibrating species. For the first time, the synthesis of substituted 1-N-acylamino-1,3-butadienes has been accomplished directly in moderate yields upon telomerization of two molecules of aldehyde with one molecule of carboxamide. Detailed spectroscopic and computational investigations establish the favourable formation of all-trans aminodienes under the reaction conditions. Employment thereof as diene building blocks in Diels-Alder reactions allows for the synthesis of carbocyclic molecules with high stereocontrol.

A New Efficient Synthesis of Substituted Luminols Using Multicomponent Reactions

Abstract A new general synthesis of substituted luminols (5-amino-2,3-dihydrophthalazine-1,4-diones) is presented. Diversely substituted luminol derivatives can be synthesized in three steps. The products are of interest as new materials, which exhibit chemiluminescence.