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Transformation of Amino Acids into Nonracemic 1‐(Heteroaryl)ethanamines by the Enamino Ketone Methodology
Author(s) -
Pirc Samo,
Bevk David,
Golobič Amalija,
Stanovnik Branko,
Svete Jurij
Publication year - 2006
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200690010
Subject(s) - chemistry , ketone , hydrazine (antidepressant) , catalysis , transformation (genetics) , hydrazone , threonine , medicinal chemistry , organic chemistry , stereochemistry , serine , biochemistry , gene , enzyme
N ‐Protected L ‐phenylalanines 1a,b were transformed, via the corresponding Weinreb amides 2 and ethynyl ketones 3 , into chiral enamino ketones 4 ( Scheme 1 ). Similarly, L ‐threonine 6 was transformed in four steps into the enamino ketone 10 . Cyclocondensations of 4 and 10 with pyrazolamines 11 , benzenecarboximidamide ( 12 ), and hydrazine derivatives 18 afforded N ‐protected 1‐heteroaryl‐2‐phenylethanamines 15a – e, 16, 17 , and 21a – k and 1‐heteroaryl‐1‐aminopropan‐2‐ols 23a,b in good yields ( Schemes 2 and 3 ). Finally, deprotection by catalytic hydrogenation furnished free amines 22a – g and 24a,b ( Scheme 3 ).