Abstract
ABSTRACT
Double lithiation of 2-alkyl-3H-quinazoline-4-thiones at nitrogen and at the α-hydrogen of the 2-alkyl group (Me, Et, Pr) has been achieved with N-butyllithium at -78 °C in anhydrous THF under nitrogen. Reactions of the dilithium reagents obtained with various electrophiles (iodomethane, iodoethane, 1-bromobutane, D
2
O, benzaldehyde, 4-anisaldehyde, butan-2-one, cyclohexanone, benzophenone, phenyl isothiocyanate, tetraisopropylthiuram disulfide) gave the corresponding modified 2-substituted 3H-quinazoline-4-thiones 4-22 in excellent yields.