Premium
Synthese von 4(5)‐acyl‐5(4)‐alkylimidazolen aus symmetrischen 1,3‐dicarbonylverbindungen
Author(s) -
Krebs ErnstPeter,
Bondi Enrico
Publication year - 1979
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.19790620216
Subject(s) - formamides , chemistry , formic acid , formamide , methanesulfonic acid , acetic anhydride , acetic acid , medicinal chemistry , organic chemistry , catalysis
Synthesis of 4(5)‐Acyl‐5(4)‐alkylimidazoles from Symmetrical 1,3‐Diones A new synthesis of 4(5)‐acyl‐5(4)‐alkylimidazoles 1 is described. The symmetrical 1,3‐diones 5a and 5b were reacted with N 2 O 4 to give the nitro compounds 7a and 7b , respectively; 5c was treated with NaNO 2 to give the nitroso compound 7c ( Scheme 2 ). Hydrogenation of 7a , 7b and 7c over Pd/C in acetic acid/acetic formic anhydride yielded the formamides 9a , 9b and 9c , whose cyclization in formamide/formic acid afforded the 4(5)‐acyl‐5(4)‐alkylimidazoles 1a, 1b and 1c , respectively. Oxazoles 11a and 11b were obtained from the corresponding formamides 9a and 9b with methanesulfonic acid/P 2 O 5 .