Nucleophilic Fluorination and Radiofluorination via Aziridinium Intermediates: N-Substituent Influence, Unexpected Regioselectivity, and Differences between Fluorine-19 and Fluorine-18
作者:Marie Médoc、Franck Sobrio
DOI:10.1021/acs.joc.5b01714
日期:2015.10.16
reaction was heated to 90 °C, considerable changes appeared during radiofluorination. In the latter case, the radiochemical yields increased, and degradation of the 2-fluoro-propan-1-amine isomer (b) occurred, leading to a regiospecific reaction in the radiolabeling of [18F]-fluorodeprenyl. This method involving nucleophilicradiofluorination at RT was successfully applied to the radiolabeling of [18F]-2-fluoroethylamines
[reaction: see text] N,N-Dialkyl-beta-amino alcohols derived from alpha-amino acids can be rearranged enantiospecifically by using TFAA/Et3N/NaOH to give 1,2-amino alcohols with enantiomeric excess up to 99%.
Highly enantioselective rearrangement of β-amino alcohols was realized by using a catalytic amount of H 2 SO 4 .
通过使用催化量的H 2 SO 4 实现了β-氨基醇的高度对映选择性重排。
Nucleophilic radiofluorination at room temperature via aziridinium intermediates
作者:M. Médoc、F. Sobrio
DOI:10.1039/c4ra07158a
日期:——
β-[18F]fluoroamines were radiolabeled using anchimericassistance of the amine. The ring opening of the aziridinium intermediate by different sources of nucleophilic fluoride at RT led to both fluorinated regioisomers with 18F-incorporation yields of up to 77% at RT. The radiofluorination 2-[18F]fluoroethylamines afforded single compounds from the alcohol precursor at RT.
N-alkyl 1,2-amino alcohols were rearranged stereospecifically by using TFAA/Et3N. This rearrangement has been used to synthesize N-isopropyl-3-(aryloxy)-2-hydroxypropylamines, beta-adrenergic blocking agents such as (S)-toliprolol and (S)-propanolol. (C) 2009 Elsevier Ltd. All rights reserved.