Dirk Böttger

A structurally and biogenetically interesting moenomycin antibiotic

Isolation and structure elucidation of a new moenomycin antibiotic (A12, 1a) is reported that differs from moenomycin A by lack of the branching methyl group and by the configuration at C-4 of unit F. The smallest antibiotically active degradation product of 1a is the trisaccharide derivative 3a. This observation is in contrast to structure activity relations in the moenomycin A series where it was found that disaccharide 4b is fully active. An explanation is offered for this difference.

Structures of some moenomycin antibiotics-inhibitors of peptidoglycan biosynthesis

Abstract Isolation, structural assignment, and antibiotic efficiency of the new moenomycin antibiotics C3 (1b) and C4 (1c) is decribed. The previously published structure of pholipomycin (1d) is modified.

The first moenomycin antibiotic without the methyl-branched uronic acid constituent.- Unexpected structure activity relations

Abstract Isolation and structure elucidation of a new moenomycin antibiotic (C1, 1e) that lacks the branching methyl group in the 4-position of unit F are reported. The smallest antibiotically active degradation product of 1e is the trisaccharide derivative 3. This observation is in contrast to structure activity relations in the moenomycin A series where it was found that disaccharide 4a is fully active.

Exploratory investigations into the biosynthesis of the antibiotic moenomycin A

Abstract Feeding experiments shed light on the biosynthetic origin of the chromopphore unit, the N-acetyl groups, the 4-C-methyl group of the moenuronamide unit, and the lipid part of moenomycin A.

The first enzymatic degradation products of the antibiotic moenomycin A.

Abstract Moenomycin A was degraded by enzymatic cleavage of the bond between the moenuronic acid moiety and the phosphate group. The phosphoric acid monoester 4a could be dephosphorylated further to yield 3a . Compound 3a was used to confirm the previous configurational assignment at C-2 of the glycerate part of moenomycin A and to prepare ent - 4a . 4a and ent - 4a are antibiotically inactive.

A synthesis of moenocinol from isoprenoid precursors

Abstract The C 25 compound moenocinol ( 1 ) is synthesized starting from 7 , geranyl chloride, and Moiseenkovs C 5 unit.

14β-hydroxy steroids - VI. Synthesis of digitoxigenin

A short and efficient synthesis of digitoxigenin (10) is reported using a new method for the introduction of the 14β-OH group.

1,9-Dideoxyforskolin : Enolate formation - oxidation

Abstract According to trapping experiments the 1,9-dideoxyforskolin derivatives 10 and 12 react with KH in THF exclusively to form the corresponding 9(ll)-enolates. Reaction of enol ethers 14 and 16 with m-chloroperbenzoic acid leads to the 12α-silyioxy ketones 20 and 21, respectively.

Model studies directed toward forskolin: 1,9-dideoxyforskolin from a bicyclic precursor

Abstract From the bicyclic labdane derivative 4 the silyl ether of 1,9-dideoxy-forskolin 22 was obtained by a) HCl addition (4→16), b) cyclization uith N-phenylselenophthalimide-SnCI 4 , and c) reductive elimination.