Metalation of Biginelli compounds. A general unprecedented route to C-6 functionalized 4-aryl-3,4-dihydropyrimidinones.
4-Aryl-6-methyl-3,4-dihydro-2(1H)-pyrimidinone esters (DHPMs) readily undergo metalation at the C-6 methyl (vinylogous ester) position on treatment with lithium diisopropylamide at -10 degrees C. The resulting anion intermediates can be treated with electrophilic reagents to afford functionalized DHPMs that have been chemically elaborated mainly at the C-6 position. Di- and trianion formation is also possible at both the vinylogous methyl and NH positions when reactions are performed with excess equivalents of the base.
Singh
Kamaljit
K
Department of Applied Chemical Sciences & Technology, Guru Nanak Dev University, Amritsar-143 005, India. Kamaljit19in@yahoo.co.in
Singh
Sukhdeep
S
Mahajan
Aman
A