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Biomedical subjects

Martin W Bredenkamp

Publications and source records attributed to Martin W Bredenkamp.

7 recordsLinked to original sources
PubMed2005

Polymorphism in bipodal O,O'-dimethyl N,N'-(m-phenylenedicarbonyl)bis(thiocarbamate).

The title compound, C12H12N2O4S2, crystallizes in white and yellow polymeric forms as a result of interesting anti-anti and syn-anti conformational isomerism of the thiocarbonyl and carbonyl moieties relative to one another. This work is the first reported X-ray crystallographic structure determination of isomers of this class of bipodal ligand. The white form, anti-anti, (I), crystallizes with the benzene ring lying about a twofold rotation axis, resulting in both of the thiocarbonyl and carbonyl moieties being anti relative to each other. The yellow modification crystallizes as syn-anti, (II), with one thiocarbonyl moiety syn and the other anti relative to the respective carbonyl groups. The individual molecules of both (I) and (II) are extensively linked through intermolecular hydrogen bonds. Intermolecular hydrogen bonding in (II) includes a network of bifurcated N-H...O and N-H...S hydrogen bonds, while molecules of (I) include bifurcated C-H...O hydrogen bonds.

Journal Article↗
PubMed2004

Resolution of (S,S)-4-(2,2,4-trimethylchroman-4-yl)phenyl camphanate and its 4-chromanyl epimer by crystallization.

Dianin's compound (4-p-hydroxyphenyl-2,2,4-trimethylchroman) has been resolved by crystallization of the (S)-(-)-camphanic esters (S,S)- and (R,S)-4-(2,2,4-trimethylchroman-4-yl)phenyl 4,7,7-trimethyl-3-oxo-2-oxabicyclo[2.2.1]heptane-1-carboxylate, both C28H32O5, from 2-methoxyethanol, yielding the pure S,S diastereomer. The relative stereochemistry of both diastereomers has been determined by X-ray crystallography, from which the absolute stereochemistry could be deduced from the known configuration of the camphanate moiety. The crystallographic conformations have been analysed, including the 1:1 disorder of the R,S diastereomer.

Journal Article↗
PubMed2004

The first bipodal thiocarbamic acid ester, O,O'-diethyl N,N'-(p-phenylenedicarbonyl)bis(thiocarbamate).

The title compound, C(14)H(16)N(2)O(4)S(2), is the first reported X-ray crystallographic structure determination of a bipodal O-alkyl N-benzoylthiocarbamate. This compound crystallizes in a cis-S,O orientation (Z,Z' configuration), with the two S/O moieties anti relative to one another, as indicated by the twofold rotation axis located at the center of the benzene ring.

Journal Article↗