0000000000379459
AUTHOR
Ferenc Fueloep
Preparation and Structure of Bicycloalkane-Condensed Aryldiaziridines Accompanied by Pyrimidines
Di-exo- and di-endo-2-aminonorbomane/enemethanamines 1-3, di-exo-oxanorbomene derivative 4 and cis-cyclohexane and trans-4-cyclohexene analogues 5, 6 were reacted with p-chlorobenzaldehyde in the presence of N-bromosuccinimide in dichloromethane. Via the reactions of 1-6, condensed diaziridines 7-12 accompanied by pyrimidine derivatives 13-16 were prepared after isolation with column chromatography. The mechanisms proposed for alternative transformations were supported by DFT calculations. The structures of the new compounds were proved by IR and NMR spectroscopy and, for 7, 9 and 12, also by means of X-ray crystallography.
Facile Regio- and Diastereoselective Syntheses of Hydroxylated2-Aminocyclohexanecarboxylic Acids
By means of total regio- and diastereoselective functionalizations of cis- and trans-2-amino-4-cyclohexenecarboxylic acid derivatives 1, 9, 12 and 16, isomers of 2-amino-4-hydroxycyclohexanecarboxylic acid 8 and 11, and 2-amino-5-hydroxycyclohexanecarboxylic acid 15 and 19 were prepared in good yields, via 1,3-oxazine or γ-lactone intermediates. The enantiomers of 8 and 15 were also prepared by the same pathway, resulting in products with ee > 99 %. The structures, stereochemistry and relative configurations of the synthesized compounds were proved by NMR, using some key vicinal couplings and characteristic NOEs. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Synthesis of bi- and tricyclic β-lactam libraries in aqueous medium
Water as a solvent is not only inexpensive and environmentally benign, but may allow good reactivity. The present work focuses on the application of a modified Ugi reaction, i.e. the Ugi four-centre three-component reaction (U-4C-3CR), in aqueous medium to construct β-lactam libraries. All the attempted reactions could be successfully performed in water. The reaction conditions under which the precipitation process was effective were investigated; no further work-up or purification was necessary. In several cases when less water-soluble β-amino acids were used, the precipitated products were isolated easily by simple filtration. In other cases, evaporation of the solvent was appropriate for…