Direct Alkylation of Amines with Primary and Secondary Alcohols through Biocatalytic Hydrogen Borrowing
The reductive aminase from Aspergillus oryzae (AspRedAm) was combined with a single alcohol dehydrogenase (either metagenomic ADH-150, an ADH from Sphingobium yanoikuyae (SyADH), or a variant of the ADH from Thermoanaerobacter ethanolicus (TeSADH W110A)) in a redox-neutral cascade for the biocatalytic alkylation of amines using primary and secondary alcohols. Aliphatic and aromatic secondary amines were obtained in up to 99 % conversion, as well as chiral amines directly from the racemic alcohol precursors in up to >97 % ee, releasing water as the only byproduct.
Montgomery, Sarah L.,Mangas-Sanchez, Juan,Thompson, Matthew P.,Aleku, Godwin A.,Dominguez, Beatriz,Turner, Nicholas J.
supporting information
p. 10491 - 10494
(2017/08/22)
Synthesis of (R)-(-)- and (S)-(+)-4-fluorodeprenyl and (R)-(-)- and (S)-(+)-[N-11C-methyl]-4-fluorodeprenyl and positron emission tomography studies in baboon brain
(R)-(-)- and (S)-(+)-α-methyl-β-4-(fluorophenyl)-N-methyl-N-propynylethylamine ((R)-(-)- and (S)-(+)-4-fluorodeprenyl) were synthesized via the reaction of 4-fluorobenzaldehyde with nitroethane followed by reduction with lithium aluminum hydride to produce racemic 4-fluoroamphetamine, which was resolved by recrystallization with L- or D-N-acetylleucine to yield (R)-(-)-4-fluoroamphetamine or (S)-(+)-4-fluoroamphetamine in >96% enantiomeric excesses and in yields of 42 and 39%, respectively. Alkylation with propargyl bromide gave (R)-(-)- or (S)-(+)-4-fluoronordeprenyl which was reductively methylated (Borch conditions) to produce (R)-(-)- or (S)-(+)-4-fluorodeprenyl. Alkylation of (R)-(-)- or (S)-(+)-4-fluoronordeprenyl with carbon-11 labeled methyl iodide gave (R)-(-)- or (S)-(+)-[N-11C-methyl]-4-fluorodeprenyl in a radiochemical yield of 30-40%. Comparative PET studies of the two labeled enantiomers in baboons showed a significantly lower retention of radioactivity in the striatum for the (S)-(+) enantiomer relative to the (R)-(-) enantiomer.
Plenevaux,Dewey,Fowler,Guillaume,Wolf
p. 2015 - 2019
(2007/10/02)
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