Catalytic assay of Schiff base Co(II), Ni(II), Cu(II) and Zn(II) complexes for N-alkylation of heterocycles with 1,3-dibromopropane

Article abstract of DOI:10.1007/s12039-020-01791-4

Abstract: N-alkylation of heterocycles with 1,3-dibromopropane using Schiff base Co(II), Ni(II), Cu(II) and Zn(II) transition metal complexes as a catalyst was studied in 1:1 and 2:1 coupling ratios under mild conditions. It was observed that all the complexes worked as efficient catalyst with product yield 78–92percent for coupling ratio 1:1 and product yield 63–78percent for coupling ratio 2:1. N-alkylation of heterocycles with 1,3-dibromopropane in 1:1 coupling ratio is easier with higher yields as compared with N-alkylation in 2:1 coupling ratio. Graphic abstract: N-Alkylation of heterocycles with 1,3-dibromopropane[Figure not available: see fulltext.]

Full text of DOI:10.1007/s12039-020-01791-4

J. Chem. Sci. (2 0 2 0 ) 13 2: 92
Ó In di an Aca dem y of Sc i en c es
h t tp s: / / d o i .o r g /1 0 . 1 0 07 /s 1 20 39 - 02 0- 01 79 1- 4 Sadhan
(
0
1
2
3
4
5
6
7
8
9
(
)
,
-
v
o
l
V
)
F
T
3
]
(
0
1
2
3
4
5
7
6
8
9
)
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(
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l
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)
REGULAR ARTICLE
Catalytic assay of Schiff base Co(II), Ni(II), Cu(II) and Zn(II)
complexes for N-alkylation of heterocycles with 1,3-dibromopropane
a
a
b
S UJ IT HEGADE , YUVR AJ JADHAV , S ANJAY C HAVAN , GANP ATR AO MUL IK and
c
a,
*
GAUT AM GAI KW AD
a
De p ar tm e nt of Ch em is t r y, S hr im an t B abas a heb Des h m ukh Mah a vi dya la ya (af fi li at ed t o S hi vaj i Un i v e rs i ty ,
Ko l h a pu r ), A tpa di D is t - Sa ng li, Ma ha ras h tr a 415 301, In di a
b
De pa rt m en t of Ch em is t r y, S hi va ji Un ive r s i ty , Ko lha pu r, Mah a ras h tr a, In di a
De p ar tm e nt o f Ch em is t r y, Ba lw ant C ol l ege (af fi li at ed t o S h i vaj i Un ive rs i t y, Ko lha pu r) , Vi t a Di s t -Sa n g l i ,
M ah a r as ht ra , I nd ia
c
E- ma i l: ga ik w adg a@ r edi f fm a il .co m
MS r ecei v ed 9 J an ua r y 2 02 0 ; r ev i s ed 2 7 M ar ch 2 0 2 0; accep t ed 3 0 M ar ch 2 0 2 0
Abstract. N - al ky lat i on of he te ro c yc l es wi t h 1, 3 -d ib rom op r opa ne us i ng S chi ff bas e C o(I I ), Ni (I I) , C u( I I ) a nd
Zn (I I) tr an s it ion m et al co m p le xes as a cat al ys t was s t udi ed i n 1: 1 and 2: 1 cou pl i ng rat i os und er mi l d
c o nd i ti on s . I t w as ob s er ve d th at al l th e com pl exes wo r ked as effi c ien t cat al ys t wi t h pr oduc t yi el d 78– 92 % f or
c o up l in g r ati o 1: 1 an d pr o du ct yi el d 6 3–7 8% fo r cou pl i ng rat i o 2: 1. N- al kyl at io n of het er oc ycl es wi t h 1 ,3 -
d i b ro m op r op a ne in 1: 1 co up l in g r atio i s eas i er wi t h hi ghe r yi el ds as com par ed wi t h N- al kyl a t io n i n 2 :1
c o up l in g r ati o.
Keywords. S chi f f ba s e; tr an s it ion m et al com p le xes ; N- al kyl a t io n of het er oc ycl es ; 1, 3-d ib r om op rop an e .
1
. Introduction
C s C O in DMP U a nd ph ase - tr a nsf e r c a ta lytic
2 3
7
c ondi tio ns.
A va r ie ty of m et hods ha ve be e n de m onst ra te d f or
8
th e N- a lkyl at ion of di ff e r en t he te r oc yc le s . S ome of
Th e im p ro v e m e n t of en vi r on men t al l y be ni g n or ga ni c
re a c ti o n s is a ri si ng ar ea o f i nt er es t . Th e r ed uc tio n
i m p a c t o f c h e mi c a l r eac t io ns on t he en vi r on ment c oul d
b e a c co m p li s h ed b y t he mi ni mi z at io n o f u nemp loye d
p ro d u c e d in th e p ro ces s, t he em pl oy me nt of th e sup -
p l e m e n ta ry e ffi c ien t r eag en t s an d ca t al ys ts an d by th e
th e m or e ge ne r al m et hods in cl ude th e use of s odium
9
1 0
hyd r ide in DMF ( 25– 80 °C ), THF ( 20 °C to r t) , a s
2, 4
1 1
we ll a s c al ci um hyd r ide ( Ca H 0– 50 °C ), c ondi-
ti ons whi ch ha ve be e n f oun d sui ta bl e f or de r i va tive s
wit h e le ct r on- wit hdra wing sub sti tue nts on the a r o-
1
a p p li c a tio n o f mi cr owa ve . N-al k yl at i on o f is at in
1
2
re d u c e s th e li a b i li t y of t he i sa ti n nu cl e us to war ds
b a s e s , wh i le ma i n t ai ni ng i ts t yp ic al r eac t iv i ty . Thu s,
N-s u b s tit u te d is a ti n s h ave be en f re qu ent l y use d a s
i n t e rm e d iat e s a n d sy nt h et ic p rec ur so r s f or t he pr e pa -
m at ic nu cl eu s. Ano the r ge ne r al pr ot oc ol in vol ve s the
1
use of K C O or C s C O ( 1.2 e qui v) in DMF ( r t to
3
2
3
2
3
1
4
8
0 °C ) in th e pr e se nc e of KI ( 0.2 e qui v) . T he s us-
c ep tib ili ty of 5- ni tr ois at in to un der go nu cl e ophili c
c le av ag e of th e a mi de bon d un der ba si c c ondi-
ti ons, f or N- al kyl at ion e mp loyi ng a m ild ba s e
c om bina t ion of C uCO /C s C O ( 1:2 ) in a nhydr ous
2
, 3
ra t i o n o f a wi d e v ar i et y of he t er oc yc li c co mp ou nds .
1
5 , 1 6
N- A lk y la t e d in d o le an d p yr ro le pr o du ced by re gi ose -
l e ct iv e s y n th e s is be l on g t o an ex t re mel y at tr ac t ive
d o ma i n in h e te r o cy cl i c ch em is tr y as a r esu l t of th ei r
u n u s u a l b io a c ti v it ie s. On e p oss i bl e way o f a cc om -
p l i s h in g th e N-a l ky la t io n i s b y u si ng a st o ic hi ome tr i c
a m ou n t o f a s tr o ng ba se . Th e es t abl i sh ed me tho ds of
a cco m p li s h in g th is i nc lu de t he u se of al k al i sod ium
3
2
3
1
7
D
M
F
(
5
0
–
7
0
°
C
)
.
I n th e pr e se nt wor k, we r ep or t N- a lkyl a tion of
he te r oc yc le s wit h 1,3 -d ibr om opr opa ne usi ng S c hif f
ba se C o( II ) , Ni( I I ) , C u( II ) a nd Zn( I I ) tr a nsi tio n me ta l
c om ple xe s un der m ild c ondi tio ns. I t wa s obs er v e d tha t
4
5
6
h y d ro x id e in DM F, NaH or KH i n DM F, H MP A,
*
F
o
r
c
o
r
r
e
s
p
o
n
d
e
n
c
e
Electronic supplementary material: The online version of this article (https://doi.org/10.1007/s12039-020-01791-4) contains
supplementary material, which is available to authorized users.

9
2
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J. Chem. Sci. (2 020) 1 32: 92
a l l th e c o mp le xe s wo rk ed as ef fic ie nt c at al yst . be nz im ida z ole , in dole a nd is at in wit h 1,3 -d ib r omo-
N- al k y la ti o n o f h et e ro cy cl es wi th 1, 3- di br o mopr op an e pr op ane in 1: 1 c oupl ing r at io ( Sc he m e 2, Ta ble 2) .
i n 1: 1 c o u p li n g rat i o i s ea si er wi th hi g he r y ie lds a s Usi ng be st pe r f or me r f r om e ac h se r ie s c om ple x es C - 1,
c o mp ar ed wi th N- al ky la t io n i n 2 :1 co up l in g r at io.
C -6 a nd C -1 1 ga ve be tt er yi el ds. C omp le x C -1 s hows
1 –76% yi el d ( Ta ble 2 e ntr i es 1, 4, 7, 10) c ompl ex
4
C -6 sho ws 73 –88% yi el d ( Ta ble 2 e ntr i es 2, 5, 8, 11)
a nd c om ple x C -1 1 sho ws 78 –92% yi el d ( Ta bl e 2
e ntr i es 3, 6, 9, 12) . Esp ec ia ll y c om ple x C -1 0 ga ve
be tt er yi el d 92% ( Ta ble 2 e ntr y 9) . The r ea c ti on tim e
r eq uir e d f or th is r ea c ti on is 30 h. I t r eq uir e s le s s
r ea c ti on ti me a s c om pa re d to ot he r r ea c ti ons. S i mila r ly
th es e th re e se le c te d c om ple xe s C -1 , C -7 a nd C - 10
we r e sc r ee ne d f or N- a lkyl at ion of he te r oc yc le s s uc h a s
im id az ol e, be nz im ida zol e, in dole a nd is at in w ith 1,3-
di br om opr opa ne in 2: 1 c oupl ing r at io ( Sc h e me - 3,
Ta ble 3 ) . C omp le x C -1 sho ws 43– 56% yi el d ( Ta ble 3
e ntr i es 1,4 ,7,10 ) c om ple x C -7 sho ws 57 –69% yie ld
2
. Result and Discussion
Th e c a ta ly t ic s tu d y of Sc hi f f ba se t ra ns it i on m et al
c o mp le x e s C- 1 to C- 12 i s st u di ed f or N- al ky lat ion of
i n d ol e wi th 1 , 3- d ibr o mopr op ane . W e ha ve sy nt he si ze d
t h r e e s e rie s o f S c h if f ba se t ra ns it i on me ta l co mpl ex es
C -1 to C- 4 , C- 5 to C- 8, C- 9 t o C- 12 . Th es e co mpl ex es
a re s c re e n e d fo r N- al ky la t io n o f i nd ol e wi th 1,3 -d i-
b ro mo p r o pa n e u n de r mi l d co nd i ti on s. I t i s ob ser ve d
t h a t a ll th e S c h if f ba se t ra ns it i on me ta l co mpl ex es
wo rk e d a s e ffi c ie n t ca t al ys t f or N- al ky la t io n o f in dole
wi t h 1 ,3 -d ib ro mo pr op an e wi th 4 1–9 2 % yi el d
(
6
Ta ble 3 e ntr i es 2,5 ,8,11 ), a nd c om ple x C -1 0 s hows
3 –78% yi el d ( Ta ble 3 e ntr i es 3,6 ,9,12 ). Esp e c ia lly
(S c h e me 1 , T ab l e 1 ) . Co mpl e x C- 1 f ro m fir s t se r ie s
g a v e b e tt e r y ie l d 7 6% ( Tab l e 1 en t ry 2 ), co mp le x C -6
fr o m s e c o n d s e rie s g ave be t te r yi e ld 88 % ( Ta ble 1
e n t r y 8 ) a n d c o m pl ex C- 11 f ro m t hi r d se ri es ga ve
b e t t e r y ie l d 9 2 % (Ta bl e 1 en t ry 11 ) . W e ha ve sc r ee ne d
c om ple x C -1 0 ga ve be tt er pr od uct yi el d 78% ha ving
le ss r ea c ti on ti me 30. 5 h ( Ta ble 3 e ntr i es 9) .
F ina ll y
it
is
c onc lu ded
th at
Ni( L) ( PP h ) C l ] sho ws c om pa ra ti ve ly hi ghe r yie lds .
com ple x
[
I t is be c au se of hi gh th er m al st ab ili ty wit h C r yst al
3
2
2
d i f fe re n t
h e te r oc yc les
su ch
as
i mi da z ole ,
Table 1. S cr ee ni ng of co m pl ex es f or N- al kyl at i on of i ndol e wi t h 1, 3-d i br om opr opa ne.
Complex
N H+ Br
Br
DMF K CO
2
3
N
Br
RT
(Scheme 1)
Co m p l ex
–
En t r y
Ti m e (h )
Yi el d %
1
2
3
4
5
6
7
8
9
48
36
3 6
3 6
3 6
3 3
3 3
33
3 3
3 0
30
3 0
3 0
0
C- 1
C- 2
C- 3
C- 4
C- 5
C- 6
C- 7
C- 8
C- 9
C- 1 0
C- 1 1
C- 1 2
[ Co( L) C l ]
2
[ N i( L ) C l ]
2
[ Cu( L) C l ]
2
[ Zn (L) C l ]
2
[ Co( L) (P he n)C l 2 ]
[ N i( L )( P hen)C l 2 ]
[ Cu( L) (P he n)C l 2 ]
[ Zn (L)( P he n) Cl 2 ]
[ Co( L) (P P h ) C l ]
76
6 2
4 1
5 6
7 3
7 7
88
8 0
7 8
92
7 9
8 3
2
2
2
2
1 0
1 1
1 2
1 3
3
2
2
[ N i( L )( P Ph ) C l ]
2
[ Cu( L) (P P h ) C l ]
3
[ Zn (L)( P Ph ) C l ]
3
3
2
2
2
2
2
Reaction conditions: Co up lin g of he t eroc ycl es (1 m m ol ) wi t h 1, 3-d ib r om op ropa ne (1 m m ol ),
B as e K CO , S ol ven t D M F R. T.: r oo m t em per at ure .
2
3

J. Chem. Sci. (2 0 2 0 ) 13 2: 92
P age 3 of 7 92
Table 2. N- a lk y l a tio n of he te r ocy cl es w ith 1, 3- dib r om op ro pane cou pl ing rat i o 1: 1.
Complex
Nu-H
+
Br
Br
Nu
Br
K CO R. T.
DMF
2
3
a: Imidazole
1a: 1-(3-bromopropyl)-1
H
-imidazole
-benzimidazole
-indole
b: Benzimidazole
c: Indole
1b: 1-(3-bromopropyl)-1
H
1c: 1-(3-bromopropyl)-1
H
d: Isatin
1d: 1-(3-bromopropyl)-1 -isatin
H
Coupling Ratio 1:1
(
Scheme-2)
Complex
[Co(L) Cl
[Cu(L)(Phen)Cl
[Ni(L)(PPh Cl
[Co(L) Cl
[Cu(L)(Phen)Cl
[Ni(L)(PPh Cl
[Co(L) Cl
[Cu(L)(Phen)Cl
[Ni(L)(PPh Cl
[Co(L) Cl
[Cu(L)(Phen)Cl
[Ni(L)(PPh Cl
Time
h)
Yield
(%)
Entry
Heterocycles
Product
1a
(
1
2
3
2
2
]
36
33
30
36
33
30
36
33
30
36
76
73
78
62
77
79
41
88
92
56
N
2
]
N
H
3
)
2
2
]
4
5
6
7
8
9
2
2
]
N
2
]
1b
1c
1d
N
H
3
)
2
2
]
2
2
]
2
]
N
H
3
)
2
2
]
10
11
12
2
2
]
O
O
2
]
33
30
80
N
H
3
)
2
2
]
83
2 3
Reaction conditions: Co up lin g of he te ro c yc le s ( 1 mm o l ) wi t h 1, 3-d ib r om op ro pane (1 m m ol ) (1 :1 ), B as e K C O , So l v en t
DM F R .T. : R o o m t em p er atu r e .

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J. Chem. Sci. (2 020) 1 32: 92
Table 3. N- a lk y l a tio n of he te r ocy cl es w ith 1, 3- dib r om op ro pane cou pl ing rat i o 2: 1.
Complex
Nu-H
+
Br
Br
Nu
Nu
K CO R. T.
DMF
2
3
a: Imidazole
2
2
a: 1,1'-(propane-1,3-diyl)di(1
H
-imidazole)
b: Benzimidazole
c: Indole
b: 1,1'-(propane-1,3-diyl)di(1
H
-benzimidazole)
Coupling Ratio 2:1
2c: 1,1'-(propane-1,3-diyl)di(1
H
-indole)
d: Isatin
2
d: 1,1'-(propane-1,3-diyl)di(1 -isatin)
H
(
Scheme 3)
Complex
Co(L) Cl
[Cu(L)(Phen)Cl
Time
Yield
(%)
Entry
Heterocycles
N
Product
2a
(h)
1
2
3
4
5
6
7
8
9
36.5
33.5
30.5
36.5
33.5
30.5
36.5
33.5
30.5
36.5
43
57
63
48
62
74
53
69
75
56
[
2
2
]
N
H
2
]
[
Ni(L)(PPh
3
)
2
Cl ]
2
[
Co(L)
Cu(L)(Phen)Cl
Ni(L)(PPh Cl
2
Cl
2
]
N
2b
2c
2d
[
2
]
N
H
[
3
)
2
2
]
[
Co(L)
Cu(L)(Phen)Cl
Ni(L)(PPh Cl
2
Cl
2
]
[
2
]
N
H
[
3
)
2
2
]
1
0
1
2
[
Co(L)
Cu(L)(Phen)Cl
Ni(L)(PPh Cl
2
Cl
2
]
O
1
1
O
33.5
30.5
68
[
2
]
N
H
78
[
3
)
2
2
]
2 3
Reaction conditions: Co u pl in g of he te r ocy cl es ( 2 m m ol ) wi t h 1, 3-d ib r om op ro pane (1 m m ol ), (2 : 1) , B as e K C O , So l v en t
DM F R .T. : R o o m t em p er atu r e .
˚
s y s te m - mo n o c lin i c, Ce ll pa ra me te rs : a = 9 .597 A , b ge om e tr ic al pr op er ti es of [ Ni ( L) ( PP h ) C l ] i s me a -
3
2
2
˚
˚
=
u n i t c e ll v o lu m e V = 1 946 .3 2 A 3 ( XRD) ( Fi gur e 1 ) st at e ( EP R) . He nc e c om ple x C -1 0 ga ve be tt er pr oduc t
1 9 .4 5 5 A, c = 1 1 .28 7 A ; a = c= 9 0°, b= 1 12. 5 2° a nd sur e d wit h X ba nd EP R spe c tr um a t 100 K in the s olid-
˚
2
a
n
d
h
i
g
h
c
a
t
a
l
y
t
i
c
S
u
r
f
a
c
e
a
r
e
a
(
a
B
E
T
=
3
.
9
3
6
9
M
yi el d in bot h c oupl ing r at io 1.1 ( 92%) a s w el l a s
to t a l p o re v ol ume ( P/ Po =0. 99 0) = 0.0 2006 c oupl ing r at io 2: 1 ( 75%) a s c om pa re d to ot her c om-
s
-1
g
c m g a n d M e a n po r e di a met er = 2 0.3 81 nm ( BE T) pl ex es. I ntr od uc tio n of on e a lky l gr ou p is m uc h e a si er
3
-1
(F i gu re 2). T h e co rr el a ti on b et wee n el e ct ro ni c a nd c om pa re d wit h dou ble a lky la tio n.

J. Chem. Sci. (2 0 2 0 ) 13 2: 92
P age 5 of 7 92
to th e r ea c ti on m ixt ur e. The r ea c ti on wa s st ir r e d a t
r oom te m pe ra t ur e. The in or ga nic sa lt wa s r em o ve d by
fi ltr a ti on a nd r ins ed twi ce wit h di ch lor om e tha n e. The
sol uti on wa s po ur ed in to wa te r a nd e xtr a c te d w ith
di ch lor om e tha ne ( 2 x 25 m l) . The c om bine d or ga nic
la ye r s we r e wa she d wit h br in e, dr ie d ov er a nh ydr ous
sod ium sul pha te , fi lte r e d, a nd c onc e ntr a te d in va c uo
r es ult ing in th e f or ma t ion of th e pr od uct in 92 % yie ld
wit h c oupl ing r at io 1: 1 a nd pr od uct yi el d 78 % w ith
c oupl ing r at io 2: 1. N- a lkyl at ion of he te r oc yc le s w ith
1,3 -d ibr om opr op ane ha vi ng 1: 1 c oupl ing pr o por tion
(
(
Sc he m e- 2 ) is e as ie r th an 2: 1 c oupl ing pr o por tion
Sc he m e- 3 ).
Figure 1. X- ra y
[
po w d er
di f fr a ct og ra m
com pl ex
1-(3-bromopropyl)-1H-indole (1c)
Yie ld 92% [ C H NB r]
Cu (L ) (p h e n )C l 2 ].
1
1 1 2
1
H NMR ( CDC l , 300 MHz ) d 7.7 0–6. 56( Ar- H) , d
3
Adsorption / desorption isotherm
1 3
2
1
1
.8 0 ( 2H, t) , d 2.8 5 ( 2H, m ), d 2.9 0 ( 2H, t) . C N MR :
63 .2, 136 .3, 128 .7, 12 5.3, 12 4.5, 12 3.1, 12 0.2, 110.4 ,
04 .4, 38 .8, 32. 7 ppm .
1
8
2
6
0
MS ( ES ): m/z= 238 [ M] ?.
1, 1-(propane-1, 3-diyl) di(1H-indole) (2c)
Yie ld 75% [ C H N ]
1
1
9 1 8 2
1
H NMR ( CDC l , 300 MHz ) d 7.6 6–6.8 5 ( Ar - H) , d
3
2
.6 2 ( 2H, t) , d 2.7 8 ( 2H, m ), d 2.8 3 ( 2H, t) .
1 3
C NMR : 186 .3, 17 6.8, 169 .4, 16 6.5, 163 .4 , 159.7 ,
56 .2, 136 .8, 131 .1, 12 3.3, 12 2.5, 12 1.1, 12 0.5, 109.4 ,
1
0
0.5
1
107 .9, 10 0.9, 99. 5, 40 .4, 36 .8 pp m.
p/p0
MS ( ES ): m/z= 273 [ M] ?.
ADS
DES
Figure 2. B ET cu rv e of co m pl e x [ N i( L) (P P h ) C l ].
3
2
2
4. Probable mechanism of N-alkylation of indole
with 1,3-dibromopropane
3
. Experimental Section
. 1 Synthesis of Schiff base and their transition
metal complexes
The po ssib le m ec ha ni sm f or th e N- a lkyl at ion of indo le
wit h 1,3 -d ibr om opr op ane is il lus tr at ed . I nit ia lly 1,3-
di br om opr opa ne is ox ida tiv el y a dde d to Nic ke l ( I I )
c om ple x i.e . c om poun d ( I ) to gi ve c om poun d ( I I ) . The
se c onda r y he te r oc yc le in dole c oor di na te to N ic ke l
c en te r to f or m c om poun d ( I II ) a nd c om poun d ( I II ) a ga in
a ct iva te in pr e se nc e of ba se wit h r em ov al of hydr og en
br om ide . F ina ll y c hlo ri ne io ns f r om out e r s phe r e
tr a nsf e r re d to in ne r sph er e wit h f or ma t ion of N -A lky-
la te d pr od uct ( N- (3 -b ro mopr o pyl) in dole ) a nd ge ne r a te
th e c or r esp ondi ng c om ple x c at al yst ( Fi gur e 3 ) .
3
Th e S c h iff b a s e 2 - Phe ny l , 3- b enz yl a mi no , 1, 2- di hy-
d ro q u in a z o l i -4 (3 H )- on e ( PBADQ) i s sy nt h es i ze d by
m o di fi e d re p o rte d me th od . Sc hi f f ba se and th ei r
t ra ns i ti o n me t a l Co (I I) , Ni (I I ), Cu (I I) an d Zn( I I )
c o mp le x e s C- 1 to C- 12 wer e sy nt h es iz ed by m odifi e d
18
19 – 21
re p o rte d me t h o d .
3 . 2 General procedure for N-alkylation
of heterocycles with 1,3-dibromopropane
5. Conclusion
Th e g e n e ra l p ro c e du re f or t he N- al ky la t io n o f he te r o-
2
2
The c at al yti c r ole of c om ple xe s 1– 12 we r e te s te d f or
N- a lkyl at ion of di ff e r en t he te r oc yc le s wit h 1,3 - dibr o-
m opr opa ne . I t wa s obs er ve d th at a ll th e c ompl ex es
wor ke d a s th e e ffi c ie nt c at al yst s. Esp e c ia lly
c y c le s wa s a s fo ll o ws. Het e ro cy cl e ( 1 mm ol) wa s
d i s so l v e d in 5 ml an hy dr ou s DM F. Th en c om ple x
(
0 . 0 5 mm o l) a n d K CO was ad de d t o t he so l uti on a t
2 3
ro o m te m p e ra tu re . Sh or t ly af t er war ds ( 20 m in) ,
, 3 - d ib ro mo p r o p a ne ( 1 mmo l ) was ad de d i n po rt ion s
[
Ni( L) ( PP h ) C l ] c om ple x is m or e sui ta bl e f or the s e
3 2 2
1

9
2
Pa g e 6 o f 7
J. Chem. Sci. (2 020) 1 32: 92
Br-(CH ) -Br
2
3
N
Cl
O
N
PPh
3
L
Ni
Cl
Br
PPh
3
I
(
CH ) -Br
2 3
(
CH ) -Br
2 3
O
N
PPh
3
O
N
PPh
3
L
Ni
L
Ni
Br
PPh
3
N
PPh
3
Cl2
Cl2
II
III
Base
H
Br
N
H
Figure 3. Pr o b ab le m ec ha ni s m f or N -a lk yl at ion of i ndol e wi t h 1, 3-d ib r om op ro pane cat al yzed by Ni (I I) P P h co mp l e x .
3
re a c ti o n s . T h e mi l d ca t al yt ic r eac t io n co nd i ti on s, e as y References
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