Convenient Synthesis of More Complex 2-Substituted 4(3H)-Quinazolinones via Lithiation of 2-Alkyl-4(3H)-quinazolinones

[img]PDF - Authorized users only
Language: English
101Kb
Title:Convenient Synthesis of More Complex 2-Substituted 4(3H)-Quinazolinones via Lithiation of 2-Alkyl-4(3H)-quinazolinones
Creators:
Smith, Keith
El-Hiti, Gamal A.
Abdel-Megeed, Mohamed F.
Abdo, Mohamed A.
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 64, 3, pp. 515-526
Uncontrolled Keywords:Nucleophilic additions, Quinazolinones, Metallation, Carbanions, Ketones, Double lithiation

Abstract

2-Methylquinazolin-4(3<i>H</i>)-one has been doubly lithiated, at nitrogen and in the 2-methyl group, with n-butylithium. The lithium reagent thus obtained reacts with a variety of electrophiles (iodomethane, D<sub>2</sub>O, phenyl isocyanate, benzaldehyde, benzophenone, cyclopentanone, 2-butanone, carvone) to give the corresponding 2-substituted derivatives in very good yields. Reaction of the dilithio reagent with acetonitrile gives an α,β-unsaturated imine by tautomerization of the initial addition product. Double lithiation of 2-ethyl- and 2-propyl-4(3<i>H</i>)-quinazolinones can be achieved using lithium diisopropylamide and the lithiated reagents thus obtained react with similar electrophiles to give the corresponding products in very good yields. In the reaction of the dianion of the 2-ethyl-4(3<i>H</i>)-quinazolinone with iodine, an oxidatively dimerised product was obtained. Lithiation of 2-unsubstituted 4(3<i>H</i>)-quinazolinone does not take place on C-2 under similar conditions. <p>

Title:Convenient Synthesis of More Complex 2-Substituted 4(3H)-Quinazolinones via Lithiation of 2-Alkyl-4(3H)-quinazolinones
Creators:
Smith, Keith
El-Hiti, Gamal A.
Abdel-Megeed, Mohamed F.
Abdo, Mohamed A.
Uncontrolled Keywords:Nucleophilic additions, Quinazolinones, Metallation, Carbanions, Ketones, Double lithiation
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:64
Number:3
Page Range:pp. 515-526
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc19990515UNSPECIFIED
ID Code:1493
Item Type:Article
Deposited On:06 Feb 2009 17:10
Last Modified:06 Feb 2009 16:10

Citation

Smith, Keith; El-Hiti, Gamal A.; Abdel-Megeed, Mohamed F.; Abdo, Mohamed A. (1999) Convenient Synthesis of More Complex 2-Substituted 4(3H)-Quinazolinones via Lithiation of 2-Alkyl-4(3H)-quinazolinones. Collection of Czechoslovak Chemical Communications, 64 (3). pp. 515-526. ISSN 0010-0765

Repository Staff Only: item control page