Lithiation and side-chain substitution of 3-alkyl-1H-quinoxalin-2-ones

Smith, Keith, El-Hiti, Gamal A. and Mahgoub, Safaa A. 2003. Lithiation and side-chain substitution of 3-alkyl-1H-quinoxalin-2-ones. Synthesis (Stuttgart) (15) , pp. 2345-2348. 10.1055/s-2003-41064

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Abstract

3-Methyl-1H-quinoxalin-2-one has been doubly lithi­ated with n-butylithium at -78 °C in THF. The dilithio reagent thus obtained reacts with various electrophiles (iodomethane, iodoethane, D2O, benzaldehyde, benzophenone, cyclohexanone) to give modified 3-substituted 1H-quinoxalin-2-ones in good yields. In the reaction of the dilithio reagent with phenyl isothiocyanate the product was a tautomer of the simple substitution product. Reaction of the dilithio reagent with iodine gives an oxidatively dimerised product instead of the 3-iodomethyl derivative. Lithiations of 3-ethyl- and 3-propyl-1H-quinoxalin-2-ones, followed by reactions with representative electrophiles (benzaldehyde, benzophenone, cyclohexanone), behaved in a similar manner to give the corresponding modified 3-substituted derivatives in good yields.

Item Type:	Article
Status:	Published
Schools:	Chemistry
Subjects:	Q Science > QD Chemistry
Uncontrolled Keywords:	double lithiation ; 1H-quinoxalin-2-ones ; electrophiles ; tautomerisation ; oxidative dimerisation
Publisher:	Georg Thieme Verlag
ISSN:	0039-7881
Date of First Compliant Deposit:	30 March 2016
Last Modified:	04 May 2023 23:46
URI:	https://orca.cardiff.ac.uk/id/eprint/12706

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