Rifamycin antibiotics-new compounds and synthetic methods. Part 3: Study of the reaction of 3-formylrifamycin SV with primary amines and ketones

作者：Bujnowski Krzysztof^*; Synoradzki Ludwik; Zevaco Thomas; Dinjus Eckhard

来源：Tetrahedron, 2012, 68(29): 5925-5934.

DOI：10.1016/j.tet.2012.04.071

• Antibiotics
• Ansa compounds
• Aldol condensation of imines
• NMR spectroscopy
• alpha,beta-Unsaturated imines/isomerisation

In the third stage of our study concerning the search for new antibacterial rifamycin antibiotics, the reactions of 3-formylrifamycin SV (1) with a range of primary alkylamines and ketones of general structure R-1-CH2-CO-R-2 (R-1=H or alkyl and R-2=alkyl or aryl) has been investigated. A new synthetic method for the preparation of a new group of rifamycin derivatives with an alpha,beta-unsaturated imine substituent at C-3 has been developed. %26lt;br%26gt;These compounds showed a tendency to reversibly isomerise in organic solvents and, in the presence of water, to rapidly hydrolyse. The structures of four isolated microcrystalline compounds 2, 3, 4, 5 and a reaction%26apos;s mechanism have been proposed on the basis of mass spectrometry results as well as (1D) and (20) H-1 and C-13 NMR analysis. The new synthetic route reported herein is a promising pathway to new reactive rifamycins displaying broader capabilities than the plain 3-formylrifamycin SV.

• 出版日期2012-7-22