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Chapter – 5 Synthesis and Characterization…..
Anschutz 1 reported the synthesis of 4-anilinocoumarin during his
pioneering work by heating 4-hydroxycoumarin with aniline.
Checchi and Vettori 2 prepared 4-aminocoumarin-3-sulphonamide and
its derivatives. Sulphonation of 4-hydroxycoumarin in absence of any solvent,
with an excess of chlorosulphonic acid yielded 3-sulphonic acid, which was
converted to its potassium salt and on further chlorination with phosphorous
oxychloride, afforded 4-chlorocoumarin sulphochloride. The treatment of
either ammonia or primary aliphatic and aromatic amines led to the formation
of 4-aminocoumarin-3-sulphonamide and its derivatives.
Zagorevskii 3 reported that the action of liquor ammonia on 4chlorocoumarin
in the presence of copper powder exclusively afforded the 4aminocoumarin.
In another method, 4-chlorocoumarin when treated with
concentrated ammonium hydroxide in dioxane for 40 hours at room
temperature afforded 4-aminocoumarin in 25% yield and ohydroxyphenylpropionamide
(52% yield) 4, 5 due to opening of the lactone ring.
However, only the desired 4-aminocoumarins were obtained in some cases. 6-
9
(Fig. 5.2)
O O
NH 2
Mustafa et. al. 10 reported the synthesis for the preparation of 4anilinocoumarin
in low yield by refluxing 4-hydroxycoumarin with aniline in
ethanol.
Wolfbeis 11 reported the synthesis of 4-arylaminocoumarin from 4hydroxycoumarin
by direct condensation with anilines.
Department of Chemistry, Saurashtra University, Rajkot – 360 005 278
OH
O
NH 2
4-aminocoumarin o-hydroxyphenylpropionamide
Fig. 5.2