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5 results on '"Günther Snatzke"'

1. Synthesis and Absolute Configuration of Enantiomerically Pure Vitamin K3 2,3-Epoxide

Author

Günther Snatzke, Bea Marsman, Hans Wijnberg, Bernard Feringa, Henk Pluim, Ben Greydanus, Stratingh Institute of Chemistry, and Synthetic Organic Chemistry

Subjects
chemistry.chemical_compound, Menadione, Chemistry, Organic Chemistry, Absolute configuration, Vitamin K3, Organic chemistry, Epoxide, Cotton effect
Abstract

The 2,3-epoxide of vitamin K3 (menadione, 1) has been prepared in enantiomerically pure form, and the absolute configuration has been deduced from the CD spectrum. The compound with the negative Cotton effect between 340 and 400 nm has the 2R,3S configuration.

Published
1980

2. Foreword

Author

Günther Snatzke and Vitomir Šunjić

Abstract

SPECIAL SUBJECT ISSUE ON CHIROPTICAL METHODS Part A

Published
1989

3. Foreword

Author

Günther Snatzke and Vitomir Šunjić

Published
1989

4. Long-acting contraceptive agents: Levonorgestrel esters of unsaturated acids

Author

Tong Lan Ngiam, J.A.Noguez A., B. Milenkov, Ernesto Suárez, A.Acosta H., J. Vlahov, José A. Salazar, O. Jimeno, R. Vlahov, A.S.C. Wan, Velichko Tarpanov, Günther Snatzke, Cosme G. Francisco, S.L. Leung, Genoveva García, Rosendo Hernández, M.L. Go, V. Stoilova, M. Boshkova-Ljapova, Raimundo Freire, and World Health Organization

Subjects
Magnetic Resonance Spectroscopy, Research methodology, Clinical Biochemistry, Levonorgestrel, Biochemistry, Structure-Activity Relationship, Endocrinology, medicine, Organic chemistry, Molecular Biology, Pharmacology, Chemistry, Organic Chemistry, Norgestrel, Reproductive Control Agents, Esters, Stereoisomerism, Contraceptives, Oral, Combined, Long acting, Spectrophotometry, Delayed-Action Preparations, Fatty Acids, Unsaturated, Indicators and Reagents, medicine.drug, Contraceptives, Oral
Abstract

10 pages, 1 scheme.-- Available online 10 January 2003., Esters of levonorgestrel (13β-ethyl-17β-ethynyl-17β-hydroxygon-4-en-3-one) with a variety of unsaturated carboxylic acids have been synthesized for evaluation as potential long-acting, injectable contraceptive agents., The authors thank the World Health Organization for financial support of this work.

Published
1983

5. Chiroptical properties and enantioselectivity in hydrogenation with rhodium(I) complexes of chiral bis-diphenylphosphines derived from D-glucose and D-galactose

Author

Ivan Habuš, Günther Snatzke, and Vitomir Šunjić

Subjects
Circular dichroism, Denticity, Chemistry, Stereochemistry, Organic Chemistry, chemistry.chemical_element, Biochemistry, Rhodium, Inorganic Chemistry, chemistry.chemical_compound, D-Glucose, Yield (chemistry), Galactose, Materials Chemistry, Physical and Theoretical Chemistry, Z-α -acetylaminocinnamic acid, α -acetylaminoacrylic acid, bidentate ligands (3, 6)
Abstract

(2 R ,3 S )-2-Diphenylphosphinomethyl-3-diphenylphosphinotetrahydropyran ( 3 ) has been prepared in 64% yield from the dimesylate 5 , derived from d -galactose. The surprisingly different reactivities of dimesylates 2 and 5 towards diphenylphosphide anion are considered and the conformational properties of 1–6 discussed in terms of their CD spectra. The rhodium(I) complexes 9 and 10 exhibit low to relatively high enantioselectivities in hydrogenation of Z -α-acetylaminocinnamic acid and α-acetylaminoacrylic acid. The chiroptical and conformational properties of the bidentate ligands ( 3 , 6 ), and their rhodium(I) complexes ( 9 , 10 ) are correlated with the observed enantioselectivities.

Published
1989

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