Sabine Giesa

Studies on the interaction of the antibiotic moenomycin A with the enzyme penicillin-binding protein 1b

The interaction of a moenomycin derivative with the enzyme penicillin binding protein 1b (PBP 1b) has been studied by means of STD NMR. The results obtained initiated the synthesis of a number of moenomycin derivatives modified in unit A including a moenomycin-ampicillin conjugate and determination of their antibiotic activities. A protocol is described that allows studying the interaction of moenomycin analogues with PBP 1b by fluorescence correlation spectroscopy.

Moenomycin analogues with modified lipid side chains from indium-mediated Barbier-type reactions

Abstract From moenomycin A both the chromophore part and the lipid side chain were degraded by ozonolysis to give an analogue with a glycolaldehyde unit in 2-position of the glyceric acid moiety. The aldehyde was converted to a number of homoallylic alcohols by indium-mediated Barbier-type reactions with allylic and benzylic halides. With exception of the phytyl bromide-derived reaction product all compounds were antibiotically inactive.

Moenomycin analogues with long-chain amine lipid parts from reductive aminations

Abstract From a moenomycin A glycolic aldehyde degradation product lacking the chromophore unit and most of the lipid part, a number of amines were prepared by reductive amination. Their interaction with artificial membranes as well as their transglycosylase inhibiting and antibiotic properties were studied.

Synthesis of a building block for phosphonate analogues of moenomycin A12 from d-tartaric acid

Abstract An approach for the synthesis of moenomycin A12 C-glycoside partial structures is reported based on allyltin chemistry.

Synthesis of fluorescent derivatives of the antibiotic moenomycin A.

Moenomycin has been highly selectively converted into amino derivative 3b. The primary amino group of this compound can be used to attach various fluorescent labels to moenomycin, through conversion of isothiocyanates into thioureas and squaric acid diesters into diamides. The application of some of the derivatives is outlined. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

Synthesis of a complex disaccharide precursor of phosphonate analogues of the antibiotic moenomycin A12

Abstract An approach for the synthesis of moenomycin A12 C-glycoside partial structures is reported.

A Method for the Introduction of Reporter Groups into Moenomycin A, Based on Thiouronium Salt Chemistry

p-Alkoxy-substituted cinnamylthiouronium salts 7, 13, 21a, and 21b reacted selectively with the 2-acylamino-1,3-cyclopentanedione unit A of moenomycin A (1) to give the corresponding 2-alkylated products 14a, 14b, 22a, and 22b. These products, depending on the pH of the solution, were either stable under the reaction conditions or they underwent retro-Claisen-type reactions. The method can be used for the attachment of reporter groups to moenomycin A for the synthesis of, for example, 25. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

A cross metathesis-based synthesis of analogues of the 2-O-alkyl glycerate part of the moenomycins

Abstract Conditions are reported which allow to convert optically active methyl glycerate to the 2- O -allyl derivative without racemization. Cross metathesis reactions then lead to analogues of the 2- O -alkyl glycerate part of the moenomycin antibiotics.