Abstract:
In view of tht: extensive natural occurrence and biological importance of the
indole nucleus containing heterocyclic compounds a general and facile method for
the synthesis of indole derivatives through palladium catalyscd reaction using
lrimcthyl silylacetylenc followed by Friedel-Crafts acylation reactions is reported.
The heleroannulation reaction was carried out by stirring a mixture of 2-
iodoacetanilide 3 and trimethylsilylacelylene m presence of bis(.
triphenylphosphenc) palladium(II)chloride as a catalyst, Cu(l)iodidc as a cocatalyst
and a base triethylamine. The condensed product was then subjected to
Friedel-Crafts acylation reaction with acid chlorides to afford the N-aeyl-2-acyl
(Aroyl)-indolium chloride 5-8.
S/
VI (P~P~~
~. DMF, El]N, CuI,
NHCOCH] 250 C I 24 h
R
-CH)
-C,!-4 MeO-p
-Ph
-C6H4 i\1e-p
Compound
S
67
8
~COR ~;:'/"0 "'j 0-
B
(5-8) COCH]
ln vitro antimicrobial activity of N-acyl-2-aeyl (Aroyl)indolium chloride 5-8
were evaluated. The N-aeyl-2-aeyl (Aroyl)indolium chloride showed more
sensitivity against gram-positive and gram-negative bacteria as wen as human
fungal pathogens.
Varying substitution at the indole moiety and sub"equent antimicrobial screening
identified the C-2-acetyl functionality as a new structural altemativc for optimal
antimicrobial property in the indole ela~s of(;ompounds,
