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K. Singhal and A. Kumar
catalytic activity of this prepared catalyst against C–C coupling reactions was indicated that the magnetically supported Pd NPs have good catalytic activity and recyclability than non-magnetic Pd nanoparticles. Furthermore, the results showed the
negligible leaching of Pd NPs after each reaction cycle. Pd@ h-Fe 2 O 3 @SiO 2 -CDNS
could be successfully recovered for several consecutive reaction cycles without any
appreciable loss in catalytic activity [69].
Thiamine (Vit-B 1 ) was immobilized on silane functionalized MNPs for catalytic
synthesis of 2,3-dihydroquinazolin-4(1H)-ones (2,3 DHQ). The prepared magnetic
catalyst provided a simple, novel, and sustainable approach for 2,3 DHQ analogues
synthesis. The above discussed studies on MNPs reveal that MNPs-based catalyst plays crucial role to develop different therapeutic agents with high production yield, less toxicity cost effectiveness, and environmentally friendly. Besides all
these discussed studies there are numerous literatures present which demonstrate the
significance of MNPs as green catalyst in drug synthesis (Table 16.3).
MNPs are considered as an excellent supportive material for immobilization of
ILs on their surface, this is because of easy separation of MNPs even under weak
magnetic field. Despite of good characteristics, ILs have some drawbacks also such as
high viscosity, high cost, difficulty in the separation of product from ionic phase, and
catalyst recovery that limit their applications in green synthesis of drug agents in ionic
phase. Therefore, grafting of ILs on MNPs surface could overcome these drawbacks
of ILs. Figure 16.7 is representing the grafting of ILs on MNPs composed of Fe
3+
ion with their corresponding surface morphology structures. Immobilization of ILs
on MNPs surface is carried out by sol-gel, polymerization, and physical adsorption
and this immobilized ILs have numerous advantages in drug synthesis compared to
pure ILs.
MNPs as supportive catalyst can prevent the leaching of grafted catalyst (i.e.
ionic liquid) and increases the possibility of product removal from ionic media. 2hydroxyethyl ammonium formate (HEAF) has been successfully grafted on Fe 3 O 4 –
SiO 2 MNPs by using epichlorohydrin (EP) and a green heterogeneous catalyst, i.e.
Fe 3 O 4 –SiO 2 @HEAF-EP was formed. Fe 3 O 4 –SiO 2 MNPs were successfully synthesized by using Stober method. Further, Fe 3 O 4 –SiO 2 @HEAF-EPgreen catalyst used
for trisubstitutedimidazole one-pot synthesis in comparatively good yield. Magnetization curve of this catalyst showed 25.90 emu g
−1 magnetic saturation value
for ionic liquid modified Fe 3 O 4 @SiO 2 . Fe 3 O 4 @SiO 2 -EP-HEAF displayed good
catalytic activity with 95% production yield in 40 s when using EtOH solvent and in
absence of this catalyst no product formation was observed. This IL grafted MNPs
was recyclable up to five reaction cycle with optimum catalytic efficiency for each
cycle [103].
One-pot green synthesis of tetrahydrobenzopyran and dihydripyranochromene
with higher yield was reported by using a modified poly-ILs with MNPs in which
Poly(2-vinylpyridinium) was synthesized as ionic liquid and further grafted on Fe 3 O 4
NPs by polymerization. MNPs grafted ILs catalyst provided good benzo pyran
yield (90%) compared to pure MNPs (17%) [104]. Pyrano[2,3-d]pyrimidinones
drug agent was synthesized by a novel, green urea-based IL catalyst immobilized
on silica-coated Fe 3 O 4 MNP. The advantages of using MNP-IL catalysts in drug
K. Singhal and A. Kumar
catalytic activity of this prepared catalyst against C–C coupling reactions was indicated that the magnetically supported Pd NPs have good catalytic activity and recyclability than non-magnetic Pd nanoparticles. Furthermore, the results showed the
negligible leaching of Pd NPs after each reaction cycle. Pd@ h-Fe 2 O 3 @SiO 2 -CDNS
could be successfully recovered for several consecutive reaction cycles without any
appreciable loss in catalytic activity [69].
Thiamine (Vit-B 1 ) was immobilized on silane functionalized MNPs for catalytic
synthesis of 2,3-dihydroquinazolin-4(1H)-ones (2,3 DHQ). The prepared magnetic
catalyst provided a simple, novel, and sustainable approach for 2,3 DHQ analogues
synthesis. The above discussed studies on MNPs reveal that MNPs-based catalyst plays crucial role to develop different therapeutic agents with high production yield, less toxicity cost effectiveness, and environmentally friendly. Besides all
these discussed studies there are numerous literatures present which demonstrate the
significance of MNPs as green catalyst in drug synthesis (Table 16.3).
MNPs are considered as an excellent supportive material for immobilization of
ILs on their surface, this is because of easy separation of MNPs even under weak
magnetic field. Despite of good characteristics, ILs have some drawbacks also such as
high viscosity, high cost, difficulty in the separation of product from ionic phase, and
catalyst recovery that limit their applications in green synthesis of drug agents in ionic
phase. Therefore, grafting of ILs on MNPs surface could overcome these drawbacks
of ILs. Figure 16.7 is representing the grafting of ILs on MNPs composed of Fe
3+
ion with their corresponding surface morphology structures. Immobilization of ILs
on MNPs surface is carried out by sol-gel, polymerization, and physical adsorption
and this immobilized ILs have numerous advantages in drug synthesis compared to
pure ILs.
MNPs as supportive catalyst can prevent the leaching of grafted catalyst (i.e.
ionic liquid) and increases the possibility of product removal from ionic media. 2hydroxyethyl ammonium formate (HEAF) has been successfully grafted on Fe 3 O 4 –
SiO 2 MNPs by using epichlorohydrin (EP) and a green heterogeneous catalyst, i.e.
Fe 3 O 4 –SiO 2 @HEAF-EP was formed. Fe 3 O 4 –SiO 2 MNPs were successfully synthesized by using Stober method. Further, Fe 3 O 4 –SiO 2 @HEAF-EPgreen catalyst used
for trisubstitutedimidazole one-pot synthesis in comparatively good yield. Magnetization curve of this catalyst showed 25.90 emu g
−1 magnetic saturation value
for ionic liquid modified Fe 3 O 4 @SiO 2 . Fe 3 O 4 @SiO 2 -EP-HEAF displayed good
catalytic activity with 95% production yield in 40 s when using EtOH solvent and in
absence of this catalyst no product formation was observed. This IL grafted MNPs
was recyclable up to five reaction cycle with optimum catalytic efficiency for each
cycle [103].
One-pot green synthesis of tetrahydrobenzopyran and dihydripyranochromene
with higher yield was reported by using a modified poly-ILs with MNPs in which
Poly(2-vinylpyridinium) was synthesized as ionic liquid and further grafted on Fe 3 O 4
NPs by polymerization. MNPs grafted ILs catalyst provided good benzo pyran
yield (90%) compared to pure MNPs (17%) [104]. Pyrano[2,3-d]pyrimidinones
drug agent was synthesized by a novel, green urea-based IL catalyst immobilized
on silica-coated Fe 3 O 4 MNP. The advantages of using MNP-IL catalysts in drug