1Ojarikre Enoo, 1Mgboh
Vivian Onyinyechi 2Wokpara Iheanyichukwu, 3Ikenazor
Herbert, 4Awemu G.A.
1Department of Industrial Chemistry, Madonna
University, Elele, Rivers State, Nigeria
2Department of Biochemistry, Madonna
University, Elele Campus, Rivers State, Nigeria
3Department
of Medical Laboratory Science, Madonna University, Elele , Rivers State,
Nigeria.
4Department
of Pharmaceutical Chemistry, Madonna University, Elele, Rivers State, Nigeria
Email: ojasmotivation@yahoo.com
ABSTRACT
New
anilino derivatives of angular azaphenoxazine were obtained via
Buchwald-Hartwig cross-couplingreaction.
This was achieved by first synthesizing the intermediate
6-chlorobenzo[a]-11-azaphenoxazin-5-one by anhydrous base catalyzed
condensation reaction between 2-amino-3-pyridinol and
2,3-dichloro-1,4-naphthoquinone. The palladium catalyzed Buchwald-Hartwig cross
coupling of this electron rich 6-chlorobenzo[a]-11-azaphenoxazin-5-one with
aniline and paranitrophenol, employing Pd(OAc)2, 1,4-bis(2-hydroxy-3,5-di-tert-butylbenzyl)piperazine
ligand and Na2CO3 in a 1:1 mixture of
1,4-dioxacyclohexane (1,4-dioxane) and N,N-dimethylformamide as solvent at 90o
C, afforded the highly coloured anilino derivatives
6-phenylaminobenzo[a]-11-azaphenoxazin-5-one and
6-(4-hydroxy-phenylamino)-benzo[a]-11-azaphenoxazin-5-one in 50% and 75%
yield respectively. Structural assignments were established by spectroscopic
(UV,IR, 1H and 13C NMR).
Keywords: Anilino, angular, anhydrous, azaphenoxazine, Buchwald-Hartwig, cross-coupling