Abstract:
In view of the 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 catalyzed reaction using Terminal alkyne
followed by base catalyzed reactions is reported. In this purpose different 2-iodo
acetanilide compounds were synthesized from m~substituted aryl amines by iodination
reaction (Seheme- I).
~
OC"' ~'"
I + I -'
R, R,
X, X,
4 ~ 3~'l,7,8,9
, CH'COOH,j11",0,lJl
1lO.(,~4-5h
~
ICOCH,
, , X,
x, "
ti, 10,li
~- l.~, R=.(:~,.""'I
J X,=X,=!.R,='(:Il,
4, X,=H,R,=-CH,
5.6 X,=lX,=llR,=.('H,
7 X,=H,X,-I,Rl~'(:1
S X,=I,X,=llR,='(:1
9 X,.ll,X,-llR,--C1
10, x,=',X,=H,R,=<:1
II X,-H,X,.II,R,~-CI
Nil, .-l- Cu(OAc)"CH,COOH,I,
!LA Iwoe 9_IOhr " , "
Scheme-}
The hctcroannulation reaction was carried out by stirring a mixture of 2-iodo substituted
acetanilide and different terminal alkynes in presence of bis(ltiphenylphosphine)
palladium (11) chloride as a catalyst, Cu(l) iodide a~ a eo-catalyst and a base
lrielhylamine. The condensed product was then subjected to base catalyzed reaction with
sodium ethoxide in ethanol to afford the substituted indole (Schemc-2).
R,C=CH. ;n:::" x 1 (Ph,P)'pd<.C'Iu,i, X;D;;\'~ I I x, ",-4 ''(Y' '."", +1
n~HCOCH Et,N.DMr, R N HCOCH, ", '0 'H" 4,6.,10 60-80C,6--30hr 12,J3 15,16,t7,t8 lNaOP.t1EtOll
X R1 R, Comp, No, 80_8SoC 12hr
H -CHj -Ph 12
Ii -Cli] -C(CHu2Cl'b13 x~'~
! -CH] -Ph 15,20 "" I
I -CHJ -C(CH2);,CHJ 16 ,~ '
I -CHl -C(CH
'
)lCH, 17 20,21 I -CI -Ph 18,21
Scbeme-2
All the synthesized compounds were chllI'llcterized by lL,ingllOalytical data. obtained from
M.P, UV, IR, lHNMR and BC NMR.
