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K. Singhal and A. Kumar
delocalization of negative charges on oxygen’s in acetate ([OAc]) or dimethylphosphate ([(MeO) 2 PO 2 ]) anions in ILs were found to excellent solvation tendency with
drug molecules when compared with ILs having tetrafluoroborate ([BF 4 ]), hexafluorophosphate ([PF 6 ]), and bis(trifluoromethylsulfonyl)imide ([NTf 2 ]) anions. Some
of the commonly known chemical reactions where ionic liquid can be used as solvent
and catalyst are Diels–Alder reaction, Friedel–Crafts reaction, Esterification reaction,
displacement reaction with cyanide, Beckmann rearrangement, reduction of aldehydes and ketone, etc. [75, 94–96]. In numerous one-pot multicomponent synthesis
reactions, the utilization of ILs as solvent as well as catalysts have been examined and studied. ZrOCl 2 ·8H 2 O under microwave irradiation, ceric (IV) ammonium
nitrate (CAN), L-proline, cobalt (II) chloride hexahydrate, K-10 under microwave
irradiation methods are used for the synthesis of Benzimidazoles scaffolds for experimental drug design, these reported methods were time consuming and carried out
under vigorous reaction conditions that provided unsatisfactory yields of the products causing environmental pollution but in the presence of a catalytic amount
of IL 3,3-(butane-1,4-diyl)bis(1,2-dimethyl-1H-imidazole-3-ium)Br, the yield of
benzimidazoles is relatively increased [29].
In most of the drug synthesis the CuI/amino acid (AA) systems are widely used
for C–N, C–O bond cross coupling where AA works as effective ligands to insert
the nitrogen atom in starting material. To make these synthesis reactions ‘green’, the
incorporation of AA (as cationic component) in ILs is carried out at large level and
this incorporation in ILs change its functionality into N, O-ligand which is now more
suitable for nitrogen and/or oxygen insertion in raw materials or drug molecules via
1,3-dipolar cycloaddition asymmetric allylic alkylation Diels–Alder reaction and so
on.
From last few years, ILs are most used green solvent and catalyst in numerous
drug delivery systems and in synthesis of medicines because of their interesting
properties as discussed above which make our mind to synthesis DMs analogues via
green approach having minimum drawbacks (Table 16.2).
The extraction of ILs is quite difficult from reaction media so, a supporting catalyst
must be required that carry ILs compounds on its surface and get easily separated
from the media. Moreover, to enhance the physiochemical properties of ILs, the
grafting of ILs on the surface of supporting catalyst has become necessary. It should
also keep under consideration that the supporting materials must be easily separated
from reaction media otherwise they could enter human body through drug consumption and cause various harmful impacts on the body. Therefore, in next section we
will cover the MNP and MBC as supporting catalysts for ILs as they have good
potential for grafting of ILs on their surface and because these supporting materials
are magnetic in nature so it is easy to separate them from drug synthesis reaction
media via magnetic separation method. To the best our knowledge, there are very
few literatures on MBC in which they act as supporting catalyst or catalyst for drug
synthesis.
K. Singhal and A. Kumar
delocalization of negative charges on oxygen’s in acetate ([OAc]) or dimethylphosphate ([(MeO) 2 PO 2 ]) anions in ILs were found to excellent solvation tendency with
drug molecules when compared with ILs having tetrafluoroborate ([BF 4 ]), hexafluorophosphate ([PF 6 ]), and bis(trifluoromethylsulfonyl)imide ([NTf 2 ]) anions. Some
of the commonly known chemical reactions where ionic liquid can be used as solvent
and catalyst are Diels–Alder reaction, Friedel–Crafts reaction, Esterification reaction,
displacement reaction with cyanide, Beckmann rearrangement, reduction of aldehydes and ketone, etc. [75, 94–96]. In numerous one-pot multicomponent synthesis
reactions, the utilization of ILs as solvent as well as catalysts have been examined and studied. ZrOCl 2 ·8H 2 O under microwave irradiation, ceric (IV) ammonium
nitrate (CAN), L-proline, cobalt (II) chloride hexahydrate, K-10 under microwave
irradiation methods are used for the synthesis of Benzimidazoles scaffolds for experimental drug design, these reported methods were time consuming and carried out
under vigorous reaction conditions that provided unsatisfactory yields of the products causing environmental pollution but in the presence of a catalytic amount
of IL 3,3-(butane-1,4-diyl)bis(1,2-dimethyl-1H-imidazole-3-ium)Br, the yield of
benzimidazoles is relatively increased [29].
In most of the drug synthesis the CuI/amino acid (AA) systems are widely used
for C–N, C–O bond cross coupling where AA works as effective ligands to insert
the nitrogen atom in starting material. To make these synthesis reactions ‘green’, the
incorporation of AA (as cationic component) in ILs is carried out at large level and
this incorporation in ILs change its functionality into N, O-ligand which is now more
suitable for nitrogen and/or oxygen insertion in raw materials or drug molecules via
1,3-dipolar cycloaddition asymmetric allylic alkylation Diels–Alder reaction and so
on.
From last few years, ILs are most used green solvent and catalyst in numerous
drug delivery systems and in synthesis of medicines because of their interesting
properties as discussed above which make our mind to synthesis DMs analogues via
green approach having minimum drawbacks (Table 16.2).
The extraction of ILs is quite difficult from reaction media so, a supporting catalyst
must be required that carry ILs compounds on its surface and get easily separated
from the media. Moreover, to enhance the physiochemical properties of ILs, the
grafting of ILs on the surface of supporting catalyst has become necessary. It should
also keep under consideration that the supporting materials must be easily separated
from reaction media otherwise they could enter human body through drug consumption and cause various harmful impacts on the body. Therefore, in next section we
will cover the MNP and MBC as supporting catalysts for ILs as they have good
potential for grafting of ILs on their surface and because these supporting materials
are magnetic in nature so it is easy to separate them from drug synthesis reaction
media via magnetic separation method. To the best our knowledge, there are very
few literatures on MBC in which they act as supporting catalyst or catalyst for drug
synthesis.