[Fesipmim]Cl as highly efficient and reusable catalyst for solventless synthesis of dihydropyridine derivatives through Hantzsch reaction

Article abstract of DOI:10.1007/s12039-020-01770-9

Abstract: In the present investigation, magnetic ferrite nanoparticles (ferrite NPs) were synthesized and coated with silica (ferrite?SiO₂NPs) by using the sol-gel method. After that, silica propylmethylimidazolium chloride ionic liquid [Sipmim]Cl was prepared and linked with the above-prepared ferrite?SiO₂NPs to synthesize ferrite silica propylmethylimidazolium chloride [Fesipmim]Cl catalyst. The formation of [Fesipmim]Cl catalyst was confirmed by Fourier-transform infrared (FT-IR) spectroscopy analysis. X-ray diffraction (XRD) analysis confirmed the structure of ferrite NPs and ferrite?SiO₂ NPs. Transmission electron microscopy (TEM) evidenced the successful formation of ferrite NPs and ferrite?SiO₂ NPs. Scanning electron microscopy (SEM) results revealed the change in morphology of ferrite NPs, ferrite?SiO₂NPs and [Fesipmim]Cl. The magnetic properties of [Fesipmim]Cl catalyst were measured by vibrating sample magnetometer (VSM). The efficiency of the [Fesipmim]Cl catalyst was checked by using it for the synthesis of different derivatives of dihydropyridine through Hantzsch reaction via a three-component coupling reaction of substituted benzaldehydes, ethyl/ methyl acetoacetate and ammonium acetate. The formation and structures of all the synthesized compounds were confirmed by FT-IR, ¹HNMR, ¹³C NMR spectral analyses. The reusability of the catalyst [Fesipmim]Cl was checked up to seven cycles and found to have excellent activity up to five cycles. Graphic abstract: [Figure not available: see fulltext.].

Full text of DOI:10.1007/s12039-020-01770-9

J. Chem. Sci. ( 2 0 2 0 ) 1 3 2 : 6 7
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REGULAR ARTICLE
[Fesipmim]Cl as highly efficient and reusable catalyst for solventless
synthesis of dihydropyridine derivatives through Hantzsch reaction
a ,
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A K A N S H A A G R W A L
a
a n d V I RE N D RA K A S A N A
D e p a r t m e n t o f C h e m i s t r y , K IE T G r o u p o f I n s ti t u t i o n s , D e l h i - N C R, M e e r u t R o a d ( N H - 5 8 ) ,
G h a zi a b a d 2 0 1 2 0 6 , I n d i a
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D e p a rt m e n t o f C h e m i s t r y , G . B . P a n t U n iv e r s i t y o f A g r i c u l t u r e a n d T e c h n o l o g y , P a n t n a g a r , I n d i a
E - m a i l : a k a n s h a . a g r w a l 9 0 @ g m a i l . c o m
M S r e c e i v e d 1 5 N o ve m b e r 2 01 9 ; r e v i s e d 4 J a n u a r y 2 0 2 0; a c c e p t e d 6 J a n u a r y 2 0 2 0
Abstract. I n t h e p r e s e n t i n v e s t i g a t i o n , m a g n e t i c f e r r i t e n a n o p a r t i c l e s ( f e r r it e N P s ) w e r e s y n t h e s i ze d a nd
c o at e d w i t h s i l i c a ( fe r ri t e @S i O N Ps ) b y u s i n g t h e s o l - g e l m e t h o d . A f t e r t h a t , s i li c a p r o p y l m e t h y l im i d az ol i u m
2
c h lo r i d e i o n i c l i q u i d [ Si p m i m ] C l w a s p r e p a r e d a n d l in k e d w i t h t h e a b o v e - p r e p a r e d f e r r i t e @ S i O N P s t o
2
s y n th e s i z e f e r r i t e s i l i c a p r o p y l m e t h y l im i d a z o l i u m c h l o r id e [ F e s i p m i m ] C l c a t a l y s t . T h e f o r m a t i o n o f [ F e s i p -
m i m] C l c a t a l y s t w a s c o n fi r m e d b y F o u r ie r - t r a n s f o r m i n f r a r e d ( F T - I R ) s p e c tr o s c o p y a n a ly si s . X - r ay
d i f f r a c t i o n ( XR D) a n a l y s i s c o n fi r me d t h e s t r u c t u r e o f f e r r i t e N P s a n d f e r r i t e @ S i O N P s . T r a n s m i s s i o n
2
e le ct r o n m i c ro s c o p y ( T E M ) e v i d e n c e d t h e s u c c e s s f u l f o r m a t i o n o f f e r r i t e N P s a n d f e r r i t e @ S i O N P s .
2
S c a n n i n g e l e c t ro n m i c ro s c o p y ( SE M ) r e s u l ts r e v e a l e d t h e c h a n g e i n m o r p h o l o g y o f f e r r i t e N P s , f er -
r i t e @S i O N Ps a n d [ Fe s i p m i m ]C l . T h e m a g n e ti c p r o p e r t i e s o f [ F e s i p m i m ] C l c a t a l y s t w e r e m e a s u r e d b y
2
v i b r a t i n g s a m p l e m a g n e t o m e t e r ( V S M ) . T h e e f fi c ie n c y o f t h e [ F e s i p m i m ] C l c a t a l y s t w a s c h e c k e d b y u s i n g i t
f o r t h e s y n t h e s i s o f d i f f e r e n t d e ri v a t i v e s o f d i h y d r o p y r i d i n e t h r o u g h H a n tz s c h r e a c t io n via a t h r e e - c o m p on en t
c o up l i n g r e a c t i o n o f s u b s t i t u t e d b e n z a l d e h y d e s , e t h y l / m e t h y l a c e t o a c e t a t e a n d a m m o n i u m a c e t a t e. T he
1
1 3
f o r m a t i o n a n d s t r u c t u re s o f a l l t h e s y n t h e s i z e d c o m p o u n d s w e r e c o n fi r m e d b y F T - I R, H N M R , C N M R
s p ec t r a l a n a l y s e s . T h e r e u s a b i l i t y o f t h e c a t a l y s t [ F e s i p m i m ] C l w a s c h e c k e d u p t o s e v e n c y c l e s a n d f o un d t o
h a ve e x c e l l e n t a c t i v i t y u p t o fi v e c y c l e s .
Keywords. 1 , 4 - D i h y d r o p y r i d i n e ; H a n tz s c h r e a c t io n ; f e r r i t e n a n o p a r t i c l e s ( N P s) ; [ S i p m i m ]C l ,
[ F es i p m i m ] C l .
4
1. Introduction
p r e p a r at i o n o f h e t e r o g e n e o u s c at a l y s t s . T o m a k e t h e
c at al y t i c s y s t e m h e t e r o g e n e o u s , t h e c at a l y s t c a n b e
b o n d e d w i t h m ag n e t i c N P s w h i ch a l l o w t h e c at a l y s t t o
r em a i n i m m i s c i b l e i n t h e r e ac t i o n m i x t u r e, a nd a f t e r
c o m p l e t i o n o f r e ac t i o n m ak es i t s s e p a r at i o n e a si er f o r
f u r t h er u s e , t h u s r e d u c i n g t h e w a s t e a n d m ak i n g t h e
c at al y t i c s y s t e m g r e en er . T o p r o t ec t t h e m a g n e t i c
p r o p er t i es o f m ag n e t i c N P s , t h ei r c o r e c an b e c o a t e d
w i t h s o m e i n er t , i n o r g a n i c , n o n - ma g n e t i c m at er i a l l i k e
s i l i c a w h i ch c an b e e as i l y b o n d e d w i t h m o s t o f t h e
c at al y t i c s p e c i e s . A n u mb e r o f h e t e r o g e n e o u s c a t a l y t i c
C at a l y s t s a c c el e r a t e t he r a t e o f c h e m ic a l r e ac t i o n s ,
i n c r ea se y i el d a n d r e d u c e a c t iv a t io n e n e r g y b u t t h e
s e r i o u s p r o b l em w i th c a t a l yt ic r e a c t io ns i s t h e s e p a -
r a t i o n o f c a t a l ys t f ro m t h e r e a c t io n m i x tu re s o t h at i t
c an b e r e u s e d . T o o v e r c o m e t hi s p ro b l e m , a h e t e r o -
1
g e n e o u s c a t a l ys t c a n b e u s e d i n o rg a n ic s y n t h es i s . I n
t h e p r e s e n t t i me , h e t e r og e n e o us c a t a l ys ts a r e b e i n g
p r e p a r e d b y u s i n g v a ri o u s s u bs t a n c e s i n a s i mp l e
2
w h o l e r a t i o . H e t e r og e n e o u s c a t a l y s ts c a n b e e ffi -
c i en t l y p r e p a r e d b y m o d i fy i n g t he s u pp o r t b y u s i n g t h e
5
s y s t e ms s u c h a s i o n i c l i q u i d s u p p o r t e d o n s i l i c a , n a n o
3
n a n o s y st e m a n d j o i n in g i t w i th c a t a l ys ts . M a g n e t i c
6
n i ck el -c o b al t f e rr i t e , H M M S , n a n o Z S M - 5 , a n d
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c u c u r b i t ( 6 ) u r i l - O SO H w i t h g o o d r ec o v e r y a n d
e ffi c i e n t a ct i v i t y h a v e b e e n r ep o r t e d . I o n i c l i q u i d s
n a n o p a r t i cl es ( N P s ) a r e a n i m p o rt a nt c l a s s o f n a n o -
m a t e r i a l s w h i ch a r e t he b e s t s o l ut i on t o s u pp o r t t h e
3
* F o r c o r re s p o n d e n c e
Electronic supplementary material: The online version of this article (https://doi.org/10.1007/s12039-020-01770-9) contains
supplementary material, which is available to authorized users.

6 7 P a g e 2 o f 1 1
J. Chem. Sci. ( 2 0 2 0 ) 1 3 2 : 6 7
t r a n s m i s s io n e l e c t r o n m i c r o s c o p e . S E M w a s r e c o r de d o n
J E O L ( J S M - 6 6 1 0 L V ) u s i n g a p r im a r y b e a m v o l t a ge o f
5 k V . X R D s p e c t r a o f p o w d e r e d s a m p l e s w e r e r e c o r de d a t
r o o m t e m p e r a t u r e o v e r R ig a k u - G e ig e r fl e x X - R a y d if f ra c -
t o m e t e r u s i n g C u - K a r a d ia t i o n ( k = 0 . 1 5 4 n m ) i n t he r an ge
o f 1 0 8– 7 0 8 a t 3 0 k V a n d 1 5 m A w i t h s t e p s i z e 0 . 0 5 a nd s t e p
t im e o f 1 9 . 2 s e c . V S M w a s p e r f o r m e d o n i n s t r u m e n t P A R
M o d e l 1 5 5 .
h a v e a m aj o r a p pl i c a ti o n i n s y n t h e t ic o r g a n i c c h e m-
1 0
i s t r y . I o n i c l i q u i d s c a n b e u s e d a s i m m o b i l iz ed c at -
1 1
a l ys t s w h i c h g a i n e f fi c ie n t a c t iv i ty a n d s e l e ct i v i t y .
1 2
M o r e o v e r , t h e y c a n a l s o b e u s e d a s s o l v e n t s w h i ch
p r o m ot e a n d p r o v i d e a m e d i um t o v a r io us c h e mi ca l ,
b i o c h em i c a l , e n z y m a ti c a n d i n d us tr ia l r e a c t io n s .
1 3 – 1 5
M u l t i c o m po ne n t r e a c t io ns ( MC R s )
a r e g a i n i n g
i m p o r t a nc e i n m o d e r n o r g a n i c c h e m is t ry f o r t h e s y n -
t h e s i s o f m ul t i f u n c ti o n a l b i o lo g ic a l l y a c t iv e m o l e c u l e s
f r o m r e a d i l y a v a i l a b le s t a rt i n g m a te ri a l s w i th o u t i s o -
l a ti o n o f i n t e r m e di a t e s . H a n t z s c h r e a c t io n a f f o r d s 1 ,
4 - d i h yd ro py r i d i n e s ( D H P s ) i n a s i n g l e s t e p . D H P
n u c l e u s i s a n e s s e n ti a l c o m p o n e n t o f b i o lo g i c a l l y
i m p o r t a nt m ol e c u l e s p o s s e s s i n g i m p o r ta n t p h a r ma c o -
l o g i c a l p r o p e r t ie s . D H P d r u gs s u c h a s n i f e d i p i n e,
n i c a r di p i n , f e l od i p in e , e t c . , a r e u s e d f or t he t re a t m e n t
o f h y p e r t e n s i on a s a n e f f e c ti ve c a l c i u m c h a n n e l
2 . 2 Synthesis of ferrite nano particles (Fe3O4
NPs)
F e r r it e m a g n e t i c N P s w e r e p r e p a r e d b y m o d i f y i ng t he
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r i n g , 2 5 m L ( 3 0 % ) N H s o l u t i o n w a s a d d e d t o t h e s o lu t i on .
3
T h e r e a c t io n w a s c o n t i n u e d f o r 2 4 h a t r o o m t e m p er a tu r e.
T h e p r e p a r e d b l a c k f e r r i t e N P s w e r e t h e n w a s h e d s e v er a l
t im e s w i t h d i s t i l le d w a t e r a n d d r ie d a t 8 0 °C u n d e r v a cu u m .
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b l o c k er . D H P s e x hi b it a n t it u m o r , a n t i- i n fl am m a -
1 9
1 8
t o r y a n d a n a l g e s i c a c t iv it i e s . M o r e t ha n t w e l v e
m e di c i n a l l y i m p o rt a nt c o m p o u nd s h a vi n g D H P
n u c l e u s a r e m an u f a c tu r e d a n d u s e d a l l o v e r t h e
2 0 –2 2
w o r l d .
t h e s i s o f D H P s h a ve b e e n d e ve l o p e d i n c l u d i n g
A l a r g e n u m b e r o f m e th o d s f o r t h e s y n -
2 . 3 Coating of silica on ferrite NPs
(Fe3O4@SiO2NPs)
2 3 –2 9
m ic r o w a v e - a s s i st e d r ea c ti on , u lt r a s o u n d i r r a d i a -
3 0
t i o n , s o l a r t h e r m a l e n e r g y , i o n i c l iq u id s a n d w a t e r -
3 1
T h e s i li c a - c o a t e d m a g n e t i c n a n o p a r t i c l e s ( f e r r it e @ S iO
2 -
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N P s ) w e r e p r e p a r e d u s i n g a s o l - g e l m e t h o d . I n t h e w h ol e
3 2 – 3 7
3 8 ,3 9
e t ha n o l g r e e n s o l ve n t s ,
4 0
v i s i b l e l i g h t . V a r io us c a t a l y t i c s y s t e m s h a v e b e e n
d e v e l o p e d t o i m p r o v e H a n t z s c h r e a c t io n b y u s i n g n a n o
s o l id s u p p o rt
a n d
p r o c e s s , f e r r i t e N P s w e r e d i s c r e te i n a c o m b in a t i on o f
e t h a n o l , d i s t il l e d w a t e r a n d c o n c e n t r a t e d a m m o n i a w a t er .
A f te r s l o w a d d it i o n o f 1 . 2 m L T E O S , t h e s o l u t i o n w a s
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c o n s ta n t l y s t ir r e d f o r 1 2 h . T h e p r e p a r e d f e r r i t e @ S i O N P s
2
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w e r e w a s h e d a n d r e - d i s p e r s e d i n d e i o n iz e d w a t e r f o r f ur t he r
u s e ( S c h e m e 1 ) .
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Y e a s t , o r g a n o c a t a l y s t s a n d m e ta l t ri fl a t e s . A l l
t h e s e m et h o d s a r e a s s o c i a t e d w i th o n e o r m o r e d r a w -
b a c k s l i k e l o n g r e a c t io n t im e , h a r s h r e a c t io n c o n d i -
t i o n s , t o xi c c a t a l ys ts a n d t e d io us w o r k up . W e h e r ei n
r e p o r t , f o r t h e fi r s t t im e , t h e u s e o f [ F e s i pm i m ] C l a s a n
e f fi c i e n t , r e u s a b l e a n d g r e e n c a t a l ys t f or t he s y n t h e s i s
o f 1 , 4 - D H P d e r i va ti v e s .
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1 - M e t h y l im i d a z o l e ( 4 .8 m L , 0 . 0 6 m o l ) a n d ( 3 - c h l o r op r o p yl )
t r i e t h o x y s i la n e ( 1 4 .5 m L , 0 . 0 7 m o l ) w e r e r e fl u x e d a t 8 0 °C
f o r 2 4 h ( S c h e m e 2 ) . T h e u n r e a c t e d v o l a t il e m a t e ri a l w a s
d i s t il l e d o f f u n d e r r e d u c e d p r e s s u r e . T h e c r u d e p r o d uc t w a s
w a s h e d w i t h d i e t h y l e t h e r ( 5 95 m L ) . T h e r e m a in i n g d i et h yl
e t h e r w a s r e m o v e d u n d e r v a c u u m a t r o o m t e m p e r a tu r e, t o
g i v e a y e l l o w i s h v i s c o u s l iq u i d .
2. Materials and methods
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m e d i a , I n d i a a n d w e re u s e d w i t h o u t f u r t h e r p u r i fi c a t io n . I R
s p e c t r a w e r e r e c or d e d o n B r u c k e r F T - IR s p e c t r o p h o t o m e t e r
1
u s in g K B r p e ll e t s. H N M R s p e c t r a w e r e r e c o r d e d o n
B r u c k e r A V A N C E I I 4 0 0 M H z a n d B r u c k e r A VA N C E I I
5 0 0 M H z i n s t r u m e n t s u s i n g C D C l M e l t i n g p o i n t s w e r e
3 .
r e c o r d ed u s i ng D e c i b e l d i g i t a l m e l t i n g p o i n t a p p a r a tu s . T h e
p u ri t y o f p r o d u c ts a n d r e a c t i o n p r o g r e s s w a s c h e c k e d b y
T L C o n s i li c a g el p l a t e s u s i n g h e x a n e : e t h y l a c e t a t e s o l v e n t
s y st em a n d v i s u a li z e d u s i n g i o d i n e v a p o rs a n d U V l ig h t .
T E M m ea s u r e me n t s w e r e p e rf o rm e d o n a J S M - 1 0 1 1
Scheme 1. C o a t in g o f s i li c a o n f e r r i t e n a n o p a r t i c le s .

J. Chem. Sci. ( 2 0 2 0 ) 1 3 2 : 6 7
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u l tr a s o n i ca t io n. 1 - M e t h y l -3 -( 3 - t r i m e t h o x y s i l y l p ro p y l ) - 1 H -
i mi d azo l - 3 - iu m c hl o r i d e ( 1 g m , 2 . 7 m m o l ) w as a d d e d
d ro p w i s e a t r o o m t e m p e r a t u r e a n d s t i rr e d f o r 1 6 h a t 8 0 °C
( S c h e m e 3 ) . T h e r e s u l t a n t p r o d u c t s w e r e c o l l e c t e d a n d
w a s he d w i t h e th a n o l a n d d e i o n i z e d w a t e r i n s e q u e n c e , a n d
t h e n d r i e d u n d er v a c u u m a t 6 0 °C f o r 2 h f o r f u r t h e r u s e .
2 . 6 Synthesis of dihydropyridine derivatives using
[Fesipmim]Cl catalyst
S u b s t i t u t ed b en za l d e h y d e ( 1 m m o l e ) , e t h y l / m e t h y l a c e -
t o a c et a te ( 2 m m o l e ) a n d a m m o n i u m a c e t a t e ( 1 . 2 m m o l e )
w e r e t ak e n i n a r o u n d b o t t o m fl a s k , [ Fe s i p mi m ] C l ( 1 0 0 m g )
w a s a d de d a nd h ea t e d o n a w a t e r b a t h a t 8 0 °C ( Sc h e m e 4 ) .
P r o g r e s s o f t h e r e a c t i o n w a s c h e c k e d o v e r s i l i c a g e l T L C
p l a t e s u s i n g h e xa n e a n d e t h y l a c e t a t e ( 8 0 : 2 0 ) s o l v e n t s y s t e m .
A f t e r c o mp l et i o n o f t h e r e a c t i o n , t h e c a t a l y s t w a s s e p a r a t e d
f ro m t h e r e ac t i o n m i x t u r e u s i n g a n e x t e rn a l m a g n e t . T h e
c a t al y s t w a s w a s h e d w i t h e t h a n o l 4 - 5 t i m e s a n d u s e d f o r t h e
n e x t c y cl e . T h e p r o c e s s w a s r e p e a t e d f o r fi v e t i m e s . T h e
s o li d c r u d e p r o d u c t w a s c o l l e c t e d a n d d i s s o l v e d i n h o t E t O H .
T h e fi l t r a t e w a s c o n c e n t ra t e d a n d t h e s o l i d c r u d e p r o d u c t
w a s p u r i fi e d b y r e cr y s t a l l i z a t i o n i n a q u e o u s E t O H .
Scheme 3. S y n t h e s i s o f f e r r i t e s i li c a p r o p y l m e t h y l i m i -
d a z o li u m c h l o r i d e ( [ F e s i p m i m] C l ) c a t a l y s t .
b y F T - IR t e c h n i q u e ( Fi g u r e 1 ) . F T I R a n a l y s i s w as
c ar r i e d o u t t o d i ff e r en t i a t e t h e c h e mi ca l s t ru c t u r e o f
f e rr i t e a n d m o d i fie d f e rr i t e N P s . I n f e rr i t e N P s , t w o
c h a r ac t e r i s t i c p e a k s w e r e a t 5 6 0 a n d 3 4 7 2 c m -1 d u e t o
F e- O a n d F e- O H ( Fi g u r e 1a ) , w h i l e i n s i l i c a - c o a t e d
N P s t h e p e a k s w e re o b s er v e d a t 5 6 8 , 9 6 3 a n d
1 0 8 9 c m -1 d u e t o F e- O , S i - O a n d S i - O - Si g r o u p
r e s p e ct i v e l y , a n d a t 7 9 8 c m -1 t h e p e a k i s d u e t o S i - O-
S i b e n d i n g a n d a t 3 4 2 2 c m -1 d u e t o F e- O H a n d S i - OH
s t re t ch i n g ( Fi g u r e 1b ) . I n t h e s p e c t r a o f [ Fe s i p m i m ] C l
c at a l y s t t w o n e w b a n d s w e r e s e e n a t 1 5 3 6 c m -1 a n d
2 8 5 1 c m-1 w h i ch w e r e d u e t o t h e b e n d i n g v i b r a t i o n o f
3. Results and Discussion
3 . 1 FT-IR analysis of [Fesipmim]Cl
T h e f u n c t i on al g ro u p s o f t h e s y nt h e s i z e d [ Fe s i p - - N H a n d – C H s t re t ch i n g v i b r at i o n ( Fi g u r e 1 c ).
m i m ] C l c a t a l y s t a n d i ts p r e c u rs o r s w e r e c h a r a c t e r i z e d
3 . 2 TEM analysis of Ferrite and Silica-coated
ferrite NPs
T h e i n t e rn al m o r p h o l o g y a n d s i ze o f f er r i t e N Ps ( -
F i g u r e 2a ) a n d s i l i c a - co at ed f e rr i t e N P s ( Fi g u r e 2b )
w e r e c h a r ac t e r i z ed b y T E M a n a l y s i s . T h e m o r p h o -
l o g i c a l a n d s i ze c h a n g e s w e r e o b s er v e d i n S i l i c a
c o a t e d f er r i t e M N Ps . I n T E M a n a l y s i s s i ze o f F e r ri t e
N P s w e r e 7 - 1 1 n m w h i ch i n cr e a s ed i n s i l i c a - c o a t e d
f er r i t e N P s .
3
.
3
S
E
M
a
n
a
l
y
s
i
s
o
f
[
F
e
s
i
p
m
i
m
]
C
l
c
a
t
a
l
y
s
t
T h e s u r f a ce m o r p h o l o g y o f F e O M N Ps , s i l i c a - c o a t e d
3
4
n a n o p ar t i cl e s a n d [ Fe s i p m i m ]C l c at a l y s t w e r e c h a r -
a ct e ri ze d b y u s i n g S E M t e c h n i q u e ( Fi g u r e 3 ) . T h e
r es u l t s c l e a rl y s h o w ed t h at t h er e w a s a c h a n g e i n
m o r p h o l o g y .
Scheme 2. S y n t h e s i s o f s i l i c a p r o p y l m e t h y l i m id a z o l i -
u mc h l o r i d e[ ( S ip m i m ) C l ] i o n i c l i q u i d .

6
7
P
a
g
e
4
o
f
1
1
J. Chem. Sci. ( 2 0 2 0 ) 1 3 2 : 6 7
Scheme 4. S y n t h e s i s o f d i h y d r o p y r i d i n e d e r iv a ti v e s c a t a l y z e d b y ( [ F e s ip m im ] C l ) .
3 . 4 VSM analysis of [Fesipmim]Cl catalyst
T h e m ag n e t i c p r o p e r t i es o f [ Fe s i p m i m ]C l c a t a l y s t ,
s i l i c a - co at ed f e rr i t e N P s a n d f er r i t e N P s w e r e m e a -
s u r e d b y V S M ( Fi g u r e 4 ) . T h e s a t u ra t i o n m ag n e t i z a-
t i o n o f f er r i t e N P s ( Fi g u r e 4a ) w a s f o u n d t o b e 4 4 . 4
e mu g-1 . T h e r e w a s a d e c re a s e i n t h e m ag n e t i z a t i o n o f
s i l i c a - co at ed f er r i t e N P s ( Fi g u r e 4 b ) t o 2 2 e m u g -1 .
T h i s d e c re a s e w a s b e c au s e o f t h e c o a t i n g o f s i l i c a o n
f e rr i t e N P s . T h e r e w a s a g a i n a d e c re a s e i n t h e m a g -
n e t i za t i o n o f I L s u p p o r t e d o n s i l i c a - co at ed f e rr i t e N Ps
( Fi g u r e 4c ) c at a l y s t t o 1 3 e mu g -1 . D u e t o t h is m a g -
n e t i c b e h a v i o r o f t h e [ Fe s i p m i m ]C l c at al y s t , i t i s e a si l y
s e p a r ab l e f r o m t h e r e ac t i o n m i x t u r e b y u s i n g a n
e x t e r n a l m ag n e t i c fi el d .
Figure 1. F T I R o f F e O N Ps ( b ) F e O @ Si O N P s
2
( c ) ( [ F e si p m i m ] C l) c a t a l y s t .
3 . 5 XRD analysis of ferrite NPs
and [Fesipmim]Cl catalyst
3
4
3
4
T h e X R D p a t t er n o f F e O c l e a rl y c o n f o r m s t o t h e
3
4
f o r ma t i o n o f a c u b i c s p i n e l s t ru ct u r e w i t h t h e d i f f r a c -
t i o n p e a k s ( 2 h) a t 3 0 . 2 4°, 3 5 . 5 1°, 4 3 . 0 5 °, 5 2 . 8 8°,
Figure 2. T E M i m a g e s o f ( a ) F e r r it e N P s ( b ) S i li c a - c o a t e d F e r r it e N P s .

J. Chem. Sci. ( 2 0 2 0 ) 1 3 2 : 6 7
P
a
g
e
5
o
f
1
1
6
7
Figure 3. S E M i m a g e s o f ( a ) F e r r i t e N P s ( b ) S i li c a - c o a t e d F e r r i te N P s ( c ) ( [ F e s i p m i m] C l ) c a t a l y s t .
Figure 4. V S M o f ( a ) F e r ri t e N Ps ( b ) S i l i c a - c o a t e d F e r r it e
N P s ( c ) ( [ F e si p m i m ]C l ) c a t a l y s t .
5 7 . 1 9° a n d 6 2 . 1 1 °, w h ic h c o rr e s p o n d t o ( 2 2 0 ) ,
( 3 1 1 ) , ( 4 0 0 ) , ( 4 2 2 ), ( 5 1 1 ), a n d ( 4 4 0 ) p h as e s ,
r e s p e c t i v el y ( F i g u re 5a ) . A b r o a d p e a k i n t h e s p e c t r u m
o f [ F e s i p m i m ] C l a t 2h = 2 3 . 2 5 ° i s d u e t o t he c o a t i n g o f
Figure 5. ( a ) X R D p a t t e r n o f F e r r it e N P s ( b ) X R D p a tt e r n
s i l i c a w h i c h i s a m or ph o u s i n n a t u r e ( F i gu re 5b ) . T h e
o f ( [ F e s i p m i m] C l ) c a t a l y s t .
X R D p a t t e r n i s i n g o o d a g re e m e n t w i th t h e r ep o r t e d
5 2
d
a
t
a
(
J
C
P
D
S
c
a
r
d
n
o
.
8
5
-
1
4
3
6
)
.
[F esip mim] Cl a s ca ta ly st u nd er so lv en tle ss c ond it ion
w er e c ar rie d o ut , fir st , to o pt imiz e t he t emp er at ur e. T he
3 . 6 Plausible mechanism
re acti on mix tur e w as st irr ed at r oo m t emp er at ur e. T he
re acti on di d n ot t ak e p la ce ev en up to 1 2 h . T he n, the
B as e d o n t h e r e s u lt s a n d t he p re v i o u s w o r k s r e p o r t ed ,
t h e p l a u s i b le m e c h a n is m o f t h e H a n t z s c h r e ac t i o n
re acti on w as t rie d at te mpe ra tu re s 40 °C , 50 °C , 6 0 °C ,
c at a l y z e d b y [ F e s i pm i m ] C l i s p ro p o s e d ( S c h e me 5) .
T h e c a t a l ys t i n c r e a s e s t he e l e c t ro ph i l ic c h a r a c te r o f t h e
te mpe ra tu re , th e y ie ld inc re ase d st ea di ly an d ti me o f
7
0
°
C
,
8
0
°
C
,
9
0
°
C
a
n
d
1
0
0
°
C
.
W
i
t
h
a
n
i
n
c
r
e
a
s
e
i
n
c ar b o n o f a l d e h y d e g r o up . T h e p r o du c t f o r m at i o n
c o m p l e t e s b y c y c l i s a t io n f o l l o w e d b y d e h y d ra t i o n .
re acti on d ec re as ed. A fte r 80 °C th e yi el d di d n ot
in crea se a nd time d id n ot d ec re as e. S o, t he 8 0 °C
te mpe ra tu re w as tak en as o pt imum.
T o es ta bl ish th e ne ce ss ar y r ol e o f ca ta ly st, w e t rie d th e
3 . 7 Reaction optimization
re pre se nta ti ve r ea ct io n in th e a bs en ce o f ca ta ly st at 8 0 °C
u nd er so lv en tle ss co ndi tio n, an d i n so lv ents w at er a nd
A r e p r e s e n t a t i v e r e a c t i o n t a k i n g e t h y l a c e t o a c e t a t e ,
e th yl alc oho l. No re acti on w as o bs er ve d e ven af te r 1 2 h
b en za ld eh yde a nd a mmo nium a ce ta te a s r ea ct an ts u sin g

6 7 P a g e 6 o f 1 1
J. Chem. Sci. ( 2 0 2 0 ) 1 3 2 : 6 7
Scheme 5. P l a u s i b l e M e c h a n i s m o f t h e H a n t z s c h R e a c t i o n c a t a l y z e d b y ( [ F e s ip m i m ] C l) .
Table 1. O p t i m a l c o n d i t i o n s f o r t h e s y n t h e s i s o f 4 k c a t a l y z e d b y [ F e s i p m i m ] C l a t 8 0 °C .
E n t r y
C a t a l y s t
S o l v e n t
T i m e ( h o u r )
Y i e l d ( % )
1
2
3
4
5
6
7
8
9
–
–
–
–
W a te r
E t h a n o l
–
–
–
–
–
–
1 2
1 2
1 2
4
–
–
–
4 0
2 0
–
–
9 5
9 5
1 - M e t h y l i m i d a z o l e
( 3 - c h l o r o p ro p y l ) t r i e t h o x y s i la n e
F e r ri t e N Ps
F e r ri t e @ S i O N Ps
2
[ (S i p m i m ) C l ] i o n i c l i q u i d
( [F e s i p m i m ] C l ) c a t a l y s t
5
1 2
1 2
0 . 3 3
0 . 3 3

J. Chem. Sci. ( 2 0 2 0 ) 1 3 2 : 6 7
P a g e 7 o f 1 1 6 7
Table 2. S y n t h es i s o f 1 , 4 - d i h y d r o p y r i d i n e s c a t a l y z e d b y [ F e s i p m i m ] C l.
C
o
d
e
- R
- R
Y i e l d ( % )
M . P . (°C )
T i m e ( m i n )
1
2
4 a
4 b
4 c
4 d
4 e
4 f
4 g
4 h
4 i
4 j
4 k
4 l
4 m
4 n
4 o
4 p
4 q
4 r
- C H
2
- C H
2
- C H
2
- C H
2
- C H
2
- C H
2
- C H
2
- C H
2
4 - f u r y l
4 - C H
3 , 4 ( OC H )
3 - O H
4 - O H
4 - C l
9 0
8 5
9 0
9 5
9 0
9 0
9 0
8 5
7 0
8 0
9 5
9 0
9 0
9 0
9 5
8 5
9 0
9 5
8 5
9 0
9 0
8 5
1 5 5 – 1 5 7
1 1 7 – 1 1 9
1 4 2 – 1 4 4
1 7 0 – 1 7 2
2 1 0 – 2 1 5
1 4 5 – 1 4 8
1 5 0 – 1 5 2
1 3 8 – 1 4 0
1 2 5 – 1 2 8
1 6 2 – 1 6 4
1 5 0 – 1 5 2
1 7 0 – 1 7 2
1 5 4 – 1 6 0
1 2 0 – 1 2 5
1 2 5 – 1 3 0
1 3 8 – 1 4 0
1 5 4 – 1 5 6
2 1 0 – 2 1 2
1 6 5 – 1 7 0
1 5 5 – 1 5 7
1 1 7 – 1 2 2
1 8 0 – 1 8 5
2 0
8 0
1 2 0
8 0
8 0
5 0
4 0
1 0 0
8 0
4 0
2 0
2 0
5 0
3 0
8 0
3 0
4 0
4 0
1 2 0
8 0
8 0
2 0
5
5
5
5
5
5
5
5
5
5
5
3
3 2
4 - O C H
3 - O C H
3
3
- C H
2
- C H
2
- C H
2
4 - N O
3 - N O
2
2
- H
- H
- C H
- C H
3
3 - N O
4 - N O
3
2
- C H
- C H
3
2
3 - O C H
4 - O C H
4 - C l
3
3
- C H
- C H
3
3
3
- C H
- C H
4 - O H
3 - O H
3 , 4 ( OC H )
3 2
4 - C H
3
4 - f u r y l
3
4 s
4 t
4 u
4 v
3
- C H
- C H
- C H
3
3
3
st ir rin g. To pr ov e th e c at aly ti c a cti on of [ Fe si pmi m] Cl o f 1 -Me th ylimi da zo le t he y ie ld w as 4 0% a nd i t t oo k 4 h t o
c ata ly st vis-a`-vis it s in iti al r ea ct an ts i. e. , 1- Meth ylimi - c omp le te t he r ea ct io n. I n t he p re se nce o f (3 -ch lo ro -
d az ol e, (3 -c hl or op ro pyl ) t rie th oxy si la ne , [ Si pmi m]C l p ro py l) t ri eth oxy si la ne , it t oo k 5 h t o c omp le te t he re ac -
io nic l iq ui d, fer ri te NP s a nd fe rr it e@S iO 2NP s, w e c ar - ti on af fo rd in g on ly 20 % y ie ld . [S ip mim]C l io nic l iq uid
ri ed o ut a r ea ct io n i n t he pr es en ce o f in div id ua l in it ia l c ata ly ze d th e re ac tio n an d af fo rd ed 7 0% y ie ld a nd it to ok
re acta nts. In th e pr es en ce o f f err it e N Ps a nd f er - 4 h t o co mpl ete th e re ac ti on w hi le at 80 °C t h e r e a c t i o n
r i te @Si O N Ps re ac tio n d id n ot t ak e pl ac e. I n th e pr es en ce c o m p l e t e d w i t h i n 0 . 3 3 h a f f o r d i n g 9 5 % y i e l d . [ F e s i p -
2
m i m ] Cl c a ta ly st g av e t h e s am e r e s u l ts . I t m a y b e c o n -
c lu de d t ha t [ Si pmi m] Cl i on ic liq uid al so w or ks as an
e ffi ci en t c at al ys t. Th e ad van ta ge o f s up por tin g it on
Table 3. O p t i m i z a t i o n o f t h e a m o u n t o f [ Fe s i p m i m ] C l
c a t a l y s t f o r t h e f o r m a t i o n o f 4 k .
n an op ar ti cl es pr ov id es i t r eu sa bili ty (T abl e 1) .
E n tr y
C at a ly st ( m g )
T i m e ( h o u r )
Y i e l d ( % )
1
2
3
4
5
6
2 0
4 0
6 0
8 0
1 0 0
1 2 0
7
5
4
3
0 . 3 3
0 . 3 3
5 0
6 5
7 5
8 5
9 5
9 5
3 . 8 Substrate scope
T o i nv es ti ga te th e s ub st ra te sc op e o f t he re ac ti on , v ar -
io us b en za ld ehy de d er iv ati ve s we re tr ie d. T he p ro du ct s
w er e ob ta in ed in e xc el le nt y ie ld. T he re ac tio n t oo k 20
to 12 0 mi n t o c omp le te . T he re ac tio n wa s f ou nd

6 7 P a g e 8 o f 1 1
J. Chem. Sci. ( 2 0 2 0 ) 1 3 2 : 6 7
Catalyst (mg)
Time (hour)
Yield (%)
100
a mo u n t s o f c at a l y s t ( T a b l e 3, F i g u re 6 ) . T h e r e su l t s
i n d i c a t e t h at w i t h a n i n cr e a s e i n t h e a mo u n t o f c a t a l y s t
f r o m 2 0 m g t o 1 0 0 m g , t h er e i s a n i n cr e a s e i n t h e y i e l d
f r o m 5 0 -9 5 % w i t h a d e c r ea s e i n t i me . N o s i g n i fi c a n t
i m p r o v em e n t i n t h e y i el d o f t h e p r o d u c t w a s o b s e r v e d
w i t h f u r t h e r i n cr e a s e i n t h e c at a l y s t a mo u n t f r om 1 0 0
m g t o 1 2 0 m g . H e n c e, 1 0 0 m g o f [ Fe s i p m i m ] C l c a t -
a l y s t w a s f o u n d t o b e t h e o p t i m u m a mo u n t f o r t h e
r e p r es e n t at i v e r e ac t i o n .
120
120
100
80
60
40
20
0
95
95
85
80
75
65
60
50
40
20
7
5
4
3
0.33
5
0.33
1
2
3
4
6
Reaction
3
.
1
0
R
e
c
y
c
l
i
n
g
s
t
u
d
y
o
f
t
h
e
c
a
t
a
l
y
s
t
Figure 6. O p t i m i z a t i o n o f c a t a l y s t a m o u n t o n r e a c ti o n
a g a i n s t c o m p o u n d 4 k .
T o s h o w t h e r eu s a b i l i t y o f [ Fe s i p m i m ]C l c at al y st , t h e
c at a l y s t w a s r ec o v er e d f r o m t h e r e ac t i o n m i x t u r e ,
w a s h e d w i t h a l c o h o l , d r i e d a t 1 0 0 – 1 1 0 °C f o r 3 h a n d
r e u s e d u p t o s e v e n c y c l e s . T h e r e w a s n o t a s i g n i fi c a n t
d e c r ea s e i n y i el d u p t o fi v e c y c l e s . I n t h e s i x t h c y c l e ,
t h e y i el d d e c r ea s e d t o 6 8 % a n d i n t h e s e v e n t h c y c l e ,
t h e y i el d d e c r ea s e d t o 5 5 % ( Fi g u r e 7 ) . T h e r e su l t s
c l e a rl y i n d i c a t e t h at t h e a ct i v i t y o f t h e c at al y s t r e m ai n s
i n t a ct u p t o fi v e c y c l e s , a n d i n s u b s e q u e n t c y c l e s , t h e
c at a l y s t d e g r a d e s a n d c o n s e q u en t l y l o s e s i t s a ct i v i t y . I t
c an b e c o n c l u d e d t h at c at a l y s t m ay b e u s e d e ffi c i e n t l y
u p t o fi v e c y c l e s . 7
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Figure 7. R e c yc l i n g s t u d y o f ( [F e s i p m i m ]C l ) c a t a l y s t
a g a i n s t c o m p o u n d 4 k .
3 . 1 1 Comparison of the efficiency
of [Fesipmim]Cl catalyst with other reported
catalysts
fe asib le f or el ec tr on -w it hd ra win g as w el l a s el ec tro n-
d on at in g g ro ups on t he b en ze ne ri ng o f b enz al de hy de
d er iv ati ve s, a nd e th yl as w ell as met hy l es ter s of a ce -
to ace tat e e st er , c le ar ly pr ov in g w ide su bstr at e s co pe o f
th e re ac ti on c at al yz ed b y [F esip mim] Cl ( Ta bl e 2) .
T o i l l u s t r a t e t h e s u p e r i o r i t y o f [ F e s i p m i m ] C l c a t a l y s t ,
w e c o m p a r e d o u r r e s u l t s w i t h t h e c a t a l y s t s r e p o r t e d i n
t h e l i t e r a t u r e ( T a b l e 4 ) . A p e r u s a l o f t h e t a b l e r e v e a l s
t h a t t i m e t a k e n f o r t h e r e a c t i o n c a r r i e d o u t u s i n g
c a t a l y s t [ F e s i p m i m ] C l i s l e a s t ( 2 0 m i n ) i n c o m p a r i s o n
t o t h e m e t h o d s r e p o r t e d i n t h e l i t e r a t u r e . M o r e o v e r ,
t h e c a t a l y s t w o r k s w e l l u n d e r s o l v e n t l e s s c o n d i t i o n s
a n d i s r e u s a b l e i n d i c a t i n g t h e s u p e r i o r i t y o f o u r
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u n d e r o p t i mu m c o nd i ti o n s o f t e m p e r a t u re f o r d i ff e r en t
Table 4. C o m pa r i s o n o f t h e e f fi c i e n c y o f [ Fe s i p m i m ] C l c a t a l y s t w i t h o t h e r r e p o r t e d c a t a l y s t s .
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T M S C L / N a I
S i l i ca g e l / N a H S O
3 , 4 , 5 - T ri fl u o r o B e n z e n e b o r o n i c A c i d
[ ( F e si p m i m )C l ]
E t O H / Re flu x
C H C N
C H C N
3
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S o l v e n t l e s s
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J. Chem. Sci. ( 2 0 2 0 ) 1 3 2 : 6 7
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6
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5 . N e j a d s h a fi e e V a n d N a e im i H 2 0 1 8 M o l e c u l ar I on i c
L i q u i d S u p p o r t e d o n M e s o p o r o u s S i li c a N a n o p a rt i c l es -
I m p r i n te d I r o n M e t a l : A R e c y c la b le H e t e r og e ne o us
C a t a ly s t f o r O n e - P o t , T h r e e - C o m p o n e n t S y n t h e s i s o f a
L i b r a r y o f B e n z o d ia z e p i n e s Curr. Org. Synth. 16 1 36
6 . K o r u pol u R B , M ar i p i S , M a d a su S B , M a j j i R K , G a n t a R
K a n d C h il l a P N 2 0 17 N a no n ic k el - c ob a lt f e rr i t e c a t a l y ze d
on e po t syn thes is of 1 4-Ary l- 14H-d iben zo[a , j]xa nthen es
a nd 1 2- A r y l- 8, 9 , 1 0, 1 2- t e t r a hyd ro b enz o[ a] x ant h ene - 11-
o n e d er i v at i v es Orient. J. Chem. 33 1 2 2
4. Conclusions
A m a g n et i c n a n o p a r ti c l e s u pp o r t e d i on ic l iq u i d c at -
a l yt i c s y s t e m [ F e s i pm i m ] C l h a s b e e n s u c c e s s fu l l y
p r e p a r e d . T h e f o r m a t i o n o f t h e c a t a l ys t w a s c o n fi r me d
b y F T- I R , T EM , S E M , X R D a n d V S M a n a l y s i s . T h e
e f fi c i e n c y o f t h e [ F e s i p m im ] C l c a t a l y s t w a s v a l i d a t e d
b y i t s s u c c e ss fu l a p pl i c a b i l it y f o r t h e s y n t h e s i s o f
d i f f e r e n t d e r i v a t i v e s o f d i h y d ro p y r id i n e d e r i v a t i v e s
t h r o u g h H a n t zs c h r e a c t io n via a t h r e e -c o m p o n e n t
c o u p l i n g r e a c t i o n o f d if fe re n t b e nz a l d e h y d es , e t h y l /
m e t h y l a c et o a ce t a t e a n d a m m on iu m a c e t a t e. T h e
r e u s a b i l i t y o f t h e c a t a l y s t [ F e s i p m im ] C l w a s f o u n d
i n t a c t u p t o fi v e c y c l e s . I n c o n c lu s io n, [ F e s i p mi m] C l
h a s b e e n d e v e l o p e d a s a g re e n , r e u s a b l e a n d h i g h l y
e f fi c i e n t c a t a l y s t f o r t h e t h r e e -c o m p o n e n t s y nt h e s i s o f
d i h y d r o p y r i d i n e d e r i v a ti v e s a f f or di n g e x c e l le n t y i el d s .
T h e k e y a d v a n t a g e s o f t he p re s e n t e n v i r on m en t a l l y
b e n i g n p r o c e s s a r e r e u s a b il i ty o f c a t a l ys t, s o l v en t l e s s
c o n d i t i o n , e a s y w or k- up a n d e x c e ll e nt y ie ld s .
7 . S a f a e i- G h o m i J , E n a y a t - M e h r i N a n d E s h t e g h a l F 2 01 8
4 - ( 4 0- D i a m in o - d i- p h e n y l ) - s u l f o n e s u p p o r t e d o n h ol l o w
m a g n e t i c m e s o p o r o u s F e 3 O 4 @ Si O 2 N P s : A s a r eu s a bl e
a n d e f fi c i e n t c a t a l y s t f o r t h e s y n t h e si s o f e t h y l 2 - am i no -
5
,
1
0
-
d
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1
0
-
d
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y
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4
H
b e n z o [ g ]c hr o -
m e n e - 3 - c a r b o x y l a t e s J. Saudi Chem. Soc. 22 4 8 5
8 . K u ma r i A , K a u r B , S r i v a s t a v a R a n d S a n g w a n R S 2 01 5
I s o la t i o n a n d i m m o b i l iz a ti o n o f a l k a l i n e p r o t ea s e o n
m e s o p o r o u s s i li c a a n d m e s o p o r o u s Z S M - 5 z eo l it e
m a t e r i a l s f o r i m p r o v e d c a t a l y t i c p r o p e r ti e s Biochem.
Biophys. Rep. 2 1 0 8
9 . S a g h a n e z h a d S J , N a z a r i Y a n d D a v o d F 2 01 6
C u c u r b i t [ 6 ] u r i l - O S O 3 H : A n o v e l a c i d i c n a n oc a t al y s t
f o r t h e o n e - p o t p r e p a r a t i o n o f 1 4 - a r y l - 14 H -
d i b e n z o [ a , j ] x a n t h e n e s a n d 1 , 8 - d i o x o - o c t a h y d r o- xa n -
t h e n e s RSC Adv. 6 2 5 5 2 5
Supplementary Information (SI)
1 0 . F e r l i n N , C o u r t y M , V a n N h ie n A N , G a t a r d S , P o u r M ,
Q u il t y B , G h a v r e M , H a i b A , K u mm e r e r K , G a t he r g oo g
N a n d B o u q u i l l o n S 2 0 1 3 T e t r a b u ty l a m m o n iu m p ro l i -
n a t e - b a s e d i o n i c l iq u i d s : A c o m b in e d a s y m m e t r ic
c a t a l y s i s , a n t i m ic r o b ia l t o x i c i t y a n d b i o d e gr a d at i o n
a s s e s s m e n t RSC Adv. 3 2 6 2 4 1
1 1 . L i ts c h a u e r M a n d N e o u z e M A 2 0 0 8 N a n o p ar t i cl e s
c o n n e c t e d t h r o u g h a n i o n i c l iq u i d - l i k e n e t w or k J.
Mater. Chem. 18 6 4 0
E x p e r i m e n ta l a n d s p e c t r o s c o p i c d a t a a r e a v a i l a b l e a t w w w .
i a s. a c . i n / ch e m s ci .
Acknowledgements
T h e a ut h o r s w i s h t o t h a n k G o v i n d B a l l a b h P a n t U n i v e r s i t y
o f A g r i c u l t u r e & T e c h n o l o g y , P a n t n a g a r f o r p r o v id i n g
n e c e s s ar y r e s e a r c h f a c i l i t i e s a n d K IE T G ro u p o f I n s t it u t i o n s
f or t i me t o t i me h e l p a n d s u p p o r t f o r c o m p l e t in g t h e
r e s e ar c h w o r k . A u t h o r s a l s o t h a n k A IR F- J N U D e l h i a n d I I T
R o p ar f o r p r o v i d i n g N M R s p e c t r a a n d I SF A L , M o g a f o r
P r o v id i n g I R s p ec t r a a n d I IT R o o r k e e f o r T E M , S E M , X R D
a n d V S M a n al y s i s.
1 2 . H e r a v i M M , Z a k e r i M , K a r i mi N , S a e e d i M , O s k o oi e H
A a n d T a v a k o l i - H o s ie n i N 2 0 1 0 A c i d i c i o n i c l i qu i d
[ ( CH ) 4 SO H M I M ] [ H S O ] : A g r e e n m e d i a f or t he
2
3
4
s i m p l e a n d s t r a i g h t f o r w a r d s y n t h e s i s o f 2 , 4 , 5 - t r i s u b s t i -
t u t e d i m id a z o l e s Synth. Commun. 40 1 9 9 8
1 3 . B o n n e D , C o q u e r e l Y , C o n s t a n t ie u x T a n d R o d ri g ue z J
2 0 1 0 1 , 3 - D i c a r b o n y l c o m p o u n d s i n s t e r e o s e le c ti v e
d o m i n o a n d m u l t ic o m p o n e n t r e a c t io n s Tetrahedron
Asymm. 21 1 0 8 5
1 4 . C h o u d h u r y L H a n d P a r v in T 2 0 1 1 R e c e n t a d v an c es i n
t h e c h e m i s tr y o f i m i n e - b a s e d m u l t ic o m p o n e n t r ea ct i o ns
( M CR s ) Tetrahedron 67 8 2 1 3
Compliance with ethical standards
Conflict of interest T h e re i s n o c o n fl i c t o f i n t e re st f r o m t h e
a u t h o r s.
1 5 . B ig g s - H o u c k J E , Y o u n a i A a n d S h a w J T 2 0 1 0 R e c en t
a d v a n c e s i n m u l t ic o m p o n e n t r e a c t io n s f o r d i v e r s i t y-
o r ie n te d s y n t h e s i s Curr. Opin. Chem. Biol. 14 3 7 1
1 6 . T r i g g le D J 2 0 0 7 C a l c iu m c h a n n e l a n t a g o n is t s : C l i n i ca l
u s e s - P a s t , p r e s e n t a n d f u t u r e Biochem. Pharmacol. 74 1
1 7 . G e k e l e r R 1 9 9 5 C h e m o s e n s i t iz e r s i n t u m o r t he r a py :
n e w c o m p o u n d s p r o m is e b e t t e r e f fi c a c y Drugs Future
20 4 9 9
1 8 . S h i n d e S 2 0 0 2 S y n t h e s i s a n d a n t i - i n fl a m m a t o r y a ct i vi t y
o f 1 , 4 - d ih y d r o p y r id i n e s Acta Pharm. 52 2 8 1
1 9 . G u ll a p a l l i S a n d R a m a r a o P 2 0 0 2 L - t y p e C a 2 ? c ha nn e l
m o d u la ti o n b y d i h y d r o p y r i d i n e s p o t e n ti a t e s j- op i oi d
r e c e p t o r a g o n i st i n d u c e d a c u te a n a l g e s i a a n d i nh i b i t s
d e v e lo p m e n t o f t o l e r a n c e i n r a t s Neuropharmacology
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s t it u t e d - 1 ,4 - d i h y d r o p y r i d i n e d e r iv a ti v e s v i a H an t zs ch
r e a c ti o n Tetrahedron Lett. 46 5 7 7 1
2 8 . V a n d en E y n d e J a n d M a y e n c e A 2 0 0 3 S y n t h e s i s a n d
a r o ma t iz a ti o n o f H a n t z s c h 1 , 4 - d i h y d r o p y r i d i n e s u n d e r
m i cr o wa v e i r r a d i a t i o n . A n o v e r v i e w Molecules 8 3 8 1
2 9 . Y a da v J S, S u bba Re dd y , B V a n d Re d d y P T 2 00 1
U n pr e c e d e nt e d sy n t he s i s o f h a n t z s c h 1, 4 - d i h yd r o pyr i di n e s
u nd e r b i gi ne l l i r e a c t i o n c o nd i t i o n s Synth. Commun. 31 4 2 5
4 5 . K o S a n d Y a o C F 2 0 0 6 C e r i c A m m o n i u m N i t r at e
( C A N ) c a t a l y z e s t h e o n e - p o t s y n t h e s i s o f p o l yh y d ro -
q u i n o li n e v i a t h e H a n tz s c h r e a c t io n Tetrahedron 62
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d r o p y r i d i n es i n a n i o n i c l i q u i d Monatsh. Chem. 137 7 7
3 1 . M ek h e i m er R A , H a m e e d A A a n d S a d e k K U 2 0 0 8
b u t y l a m m o n i u m h y d r o g e n s u l f a t e c a t a l y z e d e co -
f r ie n d l y a n d e f fi c i e n t s y n t h e si s o f g l y c o s y l 1 , 4 -d i hy -
d r o p y r id i n e s Tetrahedron Lett. 45 9 0 1 1
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s o l ar t h er m a l e n e r g y Green Chem. 10 5 9 2 7 3 2 9
3 2 . L e g ea y J C , V a n d e n E y n d e J J a n d B a z u re a u J P 2 0 0 5 4 8 . K u ma r A a n d M a u r y a R A 2 0 0 7 S y n t h e s i s o f p ol y hy -
I o n i c l i q u id p h a s e t e c h n o l o g y s u p p o rt e d t h e t h r e e
c o mp o ne n t s y n t h e si s o f H a n t z s c h 1 , 4 - d i h y d r o p y r i d i n e s
a n d B ig i n el l i 3 , 4 -d i h y d r o p y r i m i d i n -2 ( 1 H ) -o n e s u n d e r 4 9 . W a n g L M , S h e n g J , Z h a n g L , H a n J W , F a n Z Y , T ia n
d r o q u i n o l i n e d e r iv a t i v e s t h r o u g h u n s y m m e t r i c H a n t zs ch
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m i cr o wa v e d i el e c t r i c h e a t i n g Tetrahedron 61 1 2 3 8 6
3 3 . Y a d av J S , R ed d y B V S , B a s a k A K a n d N a r s a i a h A V
2 0 0 3 T h r ee - c o m p o n e n t c o u p l i n g r e a c t i o n s i n i o n i c
H a n d C h a n T Q 2 0 0 5 F a c i l e Y b ( O T f ) p r o m o t e d o ne -
3
p o t s y n t h e s i s o f p o l y h y d r o q u i n o l i n e d e r iv a t i v e s t hr o ug h
H a n tz s c h r e a c t io n Tetrahedron 61 1 5 3 9
l i q u id s : A n i m p ro v e d p r o t o c o l f o r t h e s y n t h e s i s o f 1 , 4 - 5 0 . A z g o m i N a n d M o k h t a r y M 2 0 1 5 N a n o - F e O @ S iO
2
3
4
d i h y d r o p y r i d i n e s Green Chem. 5 6 0
3 4 . J i n T S , Z h a n g J S , X i a o J C , W a n g A Q a n d L i T S
2 0 0 4 C l ea n S y n t h e s i s o f 1 , 8 - Di o x o - o c t a h y d r o x a n t h e n e
s u p p o r t e d i o n i c l iq u i d a s a n e f fi c ie n t c a t a l y s t f or t he
s y n t h e s i s o f 1 , 3 - t h i a z o li d i n - 4 - o n e s u n d e r s o l v e nt - fr e e
c o n d i ti o n s J. Mol. Catal. A Chem. 398 5 8
D e r i v at iv es C at a l y z e d b y p - D o d e c y l b e n e z e n e s u l f o n i c 5 1 . D e n g M , Z h a o H , Z h a n g S , T i a n C , Z h a n g D , D u P , L iu
A c i d i n A q u e o u s M e d i a Synlett. 2004 0 8 6 6
3 5 . Z o n o u z , A M a n d S a h r a n a v a r d N 2 0 1 0 S y n t h e s i s o f 1 , 4 -
D i h y d r o p y r i d i n e D e r i v a t i v e s U n d e r A q u e o u s M e d i a E-
Journal Chem. 7 3 7 2
C , C a o H a n d L i H 1 9 7 0 H i g h c a t a l y t ic a c t i vi t y o f
i m m o b i li z e d l a c c a s e o n c o r e – s h e ll m a g n e t i c n a n op a r t i-
c l e s b y d o p a m i n e s e l f - p o l y m e r i z a t io n J. Mol. Catal.
B Enzym. 112 1 5
3 6 . T a m ad d o n F , R a z m i Z a n d J a f a r i A A 2 0 1 0 S y n t h e s i s o f 5 2 . W a n g Y , Z h u Q a n d T a o L 2 0 1 1 F a b r ic a t i o n a n d g ro w t h
3 , 4 - di h y d r o p y r i m i d i n -2 (1 H ) -o n e s a n d 1 , 4 - d i h y d r o p y -
r i d i n e s u s i n g a m m o n i u m c a rb o n a t e i n w a t e r Tetrahe-
dron Lett. 51 1 1 8 7
m e c h a n i s m o f h i e r a r c h i c a l p o r o u s F e 3 O 4 h o l l o w s u b -
m i c r o s p h e r e s a n d t h e i r m a g n e t i c p r o p e r t i e s CrystEng-
Comm 13 4 6 5 2
3 7 . E v d o k i m o v N M , M a g e d o v I V , K i r e e v A S a n d 5 3 . S a b i t h a G , R e d d y G S K K , R e d d y C S a n d Y a da v J S
K o r n i e n k o 2 0 0 6 O n e - St e p , T h re e - C o m p o n e n t 2 0 0 3 A n o v e l T M S I - m e d i a t e d s y n t h e si s o f H an t zs ch
A

J. Chem. Sci. ( 2 0 2 0 ) 1 3 2 : 6 7
P a g e 1 1 o f 1 1 6 7
1 , 4 - d ih y d r o p y r i d i n e s a t a m b i e n t t e m p e r a t u r e Tetrahe-
dron Lett. 44 4 1 2 9
t r i fl u o r o b e n z e n e b o r o n i c a c i d a s a c a t a l y s t i n i o n i c
l i q u i d : S y n t h e s i s o f n o v e l 4 - ( 3 - c a r b o x y l - 1 H - p y r a z o l -
5 4 . S r i d h a r R a n d P e r u m a l P T 2 0 0 5 A n e w p r o t o c o l t o
s y n t h e s i z e 1 , 4 - d i h y d r o p y r i d i n e s b y u s i n g 3 , 4 , 5 -
4 - y l ) - 1 , 4 - d i h y d r o p y r i d i n e s
2 4 6 5
Tetrahedron
61