r-5-(?-Halogenbenzyl)-3,t-4-diaryl-c-4-hydroxy-oxazolidin-2-one als Ringtautomere von ?-(Arylaminocarbonyloxy)-?-halogen-dihydrochalkonen
摘要:
The reaction of chalcone halogenohydrins (1-3) with arylisocyanates does not stop at the stage of the alpha-arylaminocarbonyloxy-beta-halogeno-dihydrochalcones (7), but the cyclic urethanes 4-6 are formed. Compound 7h was synthesized independently. The structure and stereochemistry of 4-6 and 7h were determined by C-13 n.m.r. spectroscopy.
Substituenteneffekte in den13C-NMR-Spektren von diastereomeren Chalkondihalogeniden, 10. Mitt.: Erste Synthese und Konfigurationsbestimmung vonthreo-Chalkonbromhydrinen
摘要:
The first synthesis of threo chalcone bromohydrins was realized by reaction of trans chalcone epoxides with SnBr4 in molar ratios from 1:1 to 2:1. The compounds were obtained in high yields and isomeric purity. Their configuration was determined as threo by different methods based on C-13-NMR shifts of C-alpha and C-beta atoms.