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2 Polish Journal of Chemistry

2 1999

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The study on helix-inducing propensity of A-hydroxymethylserine based on the host-guest approach

Lisowski M., Stasiak M., Leplawy M.

Polish Journal of Chemistry

1999

vol. 73 nr 2

313-319

The solid phase synthesis of a-hydroxymethylserine peptides is affected by accumulation of deleted sequences and NŽO-acyl migrations, occurring under acidic conditions of cleavage from Wang resin. The conformational behaviour of peptides, containing alanine host-residues separated by a single or consecutive a-hydroxymethylserine (HmS) guest-residues, has been studied by CD spectroscopy in polar protic solvents. The presence of sequential motif (Ala-HmS)n, n=2,4, shifts the conformational equilibria towards ordered structures. The CD spectrum of the nonapeptide Ac-Ala-(HmS-Ala)4-OH in trifluoroethanol is indicative of a right-handed helix. Peptides with consecutive HmSn residues, n=2,3, are apparently less ordered than those containing alternating sequences Ala-HmS. Random coil conformation is adopted by the nonapeptide Ac-Ala3-(HmS)3-Ala-OH containing three neighbouring HmS residues.

Crystal Structure of Molecular Complex (R)-(+)-3-Cyclohexene-1-carboxylic Acid with Brucine

Krajewski K., Ciunik Z.

Polish Journal of Chemistry

1999

Vol. 73, nr 10

1687-1696

The 3-cyclohexene-1-carboxylic acid was prepared and resolved with brucine. Absolute configuration of (R)-(+)-3-cyclohexene-1-carboxylic acid was confirmed by X-ray diffraction methods.