A Simple Synthesis of α,β-Unsaturated γ-Aminobutyric Acid (GABA) Derivatives from Enamines
作者:Hans Henniges、Chiara Gussetti、Hans-Christian Militzer、Mark S. Baird、Armin de Meijere
DOI:10.1055/s-1994-25716
日期:——
Bromination of enamines 3b-g at - 78°C and subsequent treatment of the resulting iminium salts 4b-g with excess tert-butyl lithioacetate leads to tert-butyl 4-(N,N-dialkylamino)carboxylates 9b-g in good to very good yields. Ester cleavage of the dibenzylamino derivative 9d with trifluoroacetic acid yields the corresponding acid 10. Subsequent catalytic hydrogenation of 10 leads to the fully deprotected 4-amino-4-methylpentanoic acid (12) in high yield.
The present invention relates to spirocyclic acylguanidines and their use as inhibitors of the β-secretase enzyme (BACE1) activity, pharmaceutical compositions containing the same, and methods of using the same as therapeutic agents in the treatment of neurodegenerative disorders, disorders characterized by cognitive decline, cognitive impairment, dementia and diseases characterized by production of β-amyloid aggregates.
The first copper(I) bromide/Quinap-catalyzed synthesis of enantiomericallyenrichedpropargylamines by addition of alkynes to enamines is reported. Various functionalized terminal alkynes add smoothly to Nprotected enamines to afford the corresponding amines in good to high yields and moderate to good enantiomeric excesses. The influence of the metal salt, the ligand, and the protecting group on the
New reactions of enamines were observed with allyl bromide or methyl bromoacetate in the presence of indium powder in THF, yielding respectively homoallylamines and β-aminoesters.