3. Conclusions
MCRs have been used for more than a century; yet it is still unclear who made the first discovery and first publication of an MCR, however, the Strecker multicomponent reaction [
84] (S-3CR) was described in 1850, followed by the Hantzsch [
85] dihydropyridine (DHP) synthesis reported in 1882. To date, MCRs are considered an advantageous approach because of their ability to rapidly generate molecular diversity and structural complexity of interest for different applications [
86,
87].
The involvement of MCRs in the synthesis of bioactive scaffolds in medicinal chemistry and drug discovery paved the way for the discovery and preparation of drugs such as lidocaine (xylocaine) [
88], mandipropamid [
89],nifedipine (procardia) [
90], ezetimibe (zetia) [
91], and prostaglandin B1 [
92].
MCRs approach is considered an alternative route that adheres to green chemistry standards practiced in laboratories. MCRs offer a great chance for green chemical production methods to realise safe environments and pleasant practices in laboratories. The use of green solvents, working at mild temperatures, utilising biocatalysts, and engaging in catalyst-free reactions are some of the most well-known suggested practices and circumstances for a green chemical process.
The development of polymer science and innovative materials has been greatly accelerated by multicomponent polymerisation (MCP). These polymeric materials have distinctive mechanical, chemical, optical, thermal, fluorescence sensing, and optoelectronic features that improve their various practical chemical applications. In addition MCRs are used in solid-phase synthesis (SPS) and peptide synthesis for the development of bioactive heterocyclic compounds with distinct structural diversity.
On the other hand, multicomponent asymmetric reactions produce useful desired products, such as enantiopure natural scaffolds and bioactive compounds with benefits such as atom economy and recyclable catalysts. Whereas C-H functionalisation in MCRs can be done in different approaches, however, the formation of a C-H bond is relatively challenging in useful organic compounds. The synthesis and formation of this bonds is more efficient and atom-economical during the preparation and modification of scaffolds in organic chemistry. MCRs remains a better alternative route for organic synthesis todate as demonstrated in this review and in the future.
Figure 1.
Linear stepwise synthesis vs multicomponent reactions.
Figure 1.
Linear stepwise synthesis vs multicomponent reactions.
Scheme 1.
Synthesis of bioactive tetrahydropyrimidines (THPMs) derivatives.
Scheme 1.
Synthesis of bioactive tetrahydropyrimidines (THPMs) derivatives.
Scheme 2.
Synthesis of 3,3-bis(indolyl)methanes (BIMs).
Scheme 2.
Synthesis of 3,3-bis(indolyl)methanes (BIMs).
Scheme 3.
Synthesis of therapeutic dihydropyrano[2,3-c]pyrazoles.
Scheme 3.
Synthesis of therapeutic dihydropyrano[2,3-c]pyrazoles.
Scheme 4.
Synthesis of arylphosphinoyl-functionalised dihydroisoquinoline derivatives.
Scheme 4.
Synthesis of arylphosphinoyl-functionalised dihydroisoquinoline derivatives.
Scheme 5.
Synthesis of biologically active S-benzyl dithiocarbamates.
Scheme 5.
Synthesis of biologically active S-benzyl dithiocarbamates.
Scheme 6.
Synthesis imidazo[1,2-a]pyridine-based inhibitors.
Scheme 6.
Synthesis imidazo[1,2-a]pyridine-based inhibitors.
Scheme 7.
Synthesis of pyrano[3,2- e]pyrazolo[1,5- a ]pyrimidines.
Scheme 7.
Synthesis of pyrano[3,2- e]pyrazolo[1,5- a ]pyrimidines.
Scheme 8.
Synthesis biologically active 2-amino-4H-pyrans.
Scheme 8.
Synthesis biologically active 2-amino-4H-pyrans.
Scheme 9.
Synthesis of anticancer propargylamines.
Scheme 9.
Synthesis of anticancer propargylamines.
Scheme 10.
The synthesis of a-acyloxycarboxamides.
Scheme 10.
The synthesis of a-acyloxycarboxamides.
Scheme 11.
The synthesis of pyrimidine-fused pyrazolo[3,4-b]pyridine derivatives and hexahydroquinazoline-fused pyrazole [3,4-b] pyridine derivatives.
Scheme 11.
The synthesis of pyrimidine-fused pyrazolo[3,4-b]pyridine derivatives and hexahydroquinazoline-fused pyrazole [3,4-b] pyridine derivatives.
Scheme 12.
The synthesis of biologically active 6-amino-1-(2,4-dinitrophenyl)-4-phenyl- 1,4-dihydropyrano [2,3-c]pyrazole-5-carbonitrile derivatives.
Scheme 12.
The synthesis of biologically active 6-amino-1-(2,4-dinitrophenyl)-4-phenyl- 1,4-dihydropyrano [2,3-c]pyrazole-5-carbonitrile derivatives.
Scheme 13.
The synthesis biologically active α-sulfonamidophosphonate derivatives.
Scheme 13.
The synthesis biologically active α-sulfonamidophosphonate derivatives.
Scheme 14.
3CR for the synthesis of biologically active 1,2,3-triazole.
Scheme 14.
3CR for the synthesis of biologically active 1,2,3-triazole.
Scheme 15.
3CR for the synthesis of pyrano[2,3-d]-pyrimidinone derivatives.
Scheme 15.
3CR for the synthesis of pyrano[2,3-d]-pyrimidinone derivatives.
Figure 2.
Conditions and benefits of green chemistry practices.
Figure 2.
Conditions and benefits of green chemistry practices.
Scheme 16.
Green chemical synthesis of (E)-quinoxalinone oximes.
Scheme 16.
Green chemical synthesis of (E)-quinoxalinone oximes.
Scheme 17.
Electrochemical multicomponent reaction for the synthesis of 4-selanylpyrazoles.
Scheme 17.
Electrochemical multicomponent reaction for the synthesis of 4-selanylpyrazoles.
Scheme 18.
The 4CR for synthesis of S-alkyl phosphorothioate.
Scheme 18.
The 4CR for synthesis of S-alkyl phosphorothioate.
Scheme 19.
The 3CR for synthesis of S-alkyl phosphorothioate.
Scheme 19.
The 3CR for synthesis of S-alkyl phosphorothioate.
Scheme 20.
Synthesis of functionalised N-amino-3-cyano-2-pyridone.
Scheme 20.
Synthesis of functionalised N-amino-3-cyano-2-pyridone.
Scheme 21.
3CR for the synthesis of dihydro-[
1,
2,
4]triazolo[1,5-
a]pyrimidines.
Scheme 21.
3CR for the synthesis of dihydro-[
1,
2,
4]triazolo[1,5-
a]pyrimidines.
Scheme 22.
Synthesis of highly functionalised 2-(diarylphosphoryl)-1,2-dihydropyridine derivatives.
Scheme 22.
Synthesis of highly functionalised 2-(diarylphosphoryl)-1,2-dihydropyridine derivatives.
Scheme 23.
Synthesis of pyrrolidine-2-one using β-cyclodextrin.
Scheme 23.
Synthesis of pyrrolidine-2-one using β-cyclodextrin.
Scheme 24.
4CR for the synthesis of 1,2,4-triazole-tagged 1,4-dihydropyridine derivatives.
Scheme 24.
4CR for the synthesis of 1,2,4-triazole-tagged 1,4-dihydropyridine derivatives.
Scheme 25.
Synthesis of tetrahydro-pyrrolobenzodiazepine derivatives.
Scheme 25.
Synthesis of tetrahydro-pyrrolobenzodiazepine derivatives.
Scheme 26.
Synthesis of 3-Cyanopyridines.
Scheme 26.
Synthesis of 3-Cyanopyridines.
Scheme 27.
Amidine-containing polymers.
Scheme 27.
Amidine-containing polymers.
Scheme 28.
Poly(N-sulfonylimine)s functional polymers.
Scheme 28.
Poly(N-sulfonylimine)s functional polymers.
Scheme 29.
a-b. Polymerisation of sulfur, diamines, and diisocyanides to form polythioureas.
Scheme 29.
a-b. Polymerisation of sulfur, diamines, and diisocyanides to form polythioureas.
Scheme 30.
a-c. Polymers with aggregation-induced emission (AIE).
Scheme 30.
a-c. Polymers with aggregation-induced emission (AIE).
Scheme 31.
3CR of diisocyanide, diamine and selenium to form polymers.
Scheme 31.
3CR of diisocyanide, diamine and selenium to form polymers.
Scheme 32.
Polymerisation of sulfur, alkynes and diamines to afford polythioamides.
Scheme 32.
Polymerisation of sulfur, alkynes and diamines to afford polythioamides.
Scheme 33.
Synthesis of poly(sulfonamide urethane).
Scheme 33.
Synthesis of poly(sulfonamide urethane).
Scheme 34.
The substituted α-aryl glycines from 3CR.
Scheme 34.
The substituted α-aryl glycines from 3CR.
Scheme 35.
Synthesis of 2-amino-4H-benzo[b]pyrans from one-pot multicomponent reaction in solid-phase reactions.
Scheme 35.
Synthesis of 2-amino-4H-benzo[b]pyrans from one-pot multicomponent reaction in solid-phase reactions.
Scheme 36.
Solid phase MCR for the synthesis of depsipeptides.
Scheme 36.
Solid phase MCR for the synthesis of depsipeptides.
Scheme 37.
Solid-phase synthesis of tetrazole-peptidomimetics by on-resin Ugi-azide-4CR.
Scheme 37.
Solid-phase synthesis of tetrazole-peptidomimetics by on-resin Ugi-azide-4CR.
Scheme 38.
Solid-phase synthesis of 3-substituted soindolinone derivatives.
Scheme 38.
Solid-phase synthesis of 3-substituted soindolinone derivatives.
Scheme 39.
Enantioselective multicomponent reaction.
Scheme 39.
Enantioselective multicomponent reaction.
Scheme 40.
Enantioselective multicomponent reaction.
Scheme 40.
Enantioselective multicomponent reaction.
Scheme 41.
High enantioselective method for the synthesis of tetrahydroindolizines.
Scheme 41.
High enantioselective method for the synthesis of tetrahydroindolizines.
Scheme 42.
The synthesis of optically active tetracyclic indolines.
Scheme 42.
The synthesis of optically active tetracyclic indolines.
Scheme 44.
The asymmetric catalytic synthesis of spiropyrazolones.
Scheme 44.
The asymmetric catalytic synthesis of spiropyrazolones.
Scheme 45.
The asymmetric synthesis of hydrothiazole derivatives.
Scheme 45.
The asymmetric synthesis of hydrothiazole derivatives.
Scheme 46.
The asymmetric synthesis of hydrothiazole derivatives.
Scheme 46.
The asymmetric synthesis of hydrothiazole derivatives.
Scheme 46.
The single-step synthesis of symmetric and (novel) asymmetric bisphosphoramidate and bisphosphoramidothioate derivatives.
Scheme 46.
The single-step synthesis of symmetric and (novel) asymmetric bisphosphoramidate and bisphosphoramidothioate derivatives.
Scheme 47.
The 3CR C-H functionalisation towards synthesis of pyrimido[4,5-d]-pyrimidines.
Scheme 47.
The 3CR C-H functionalisation towards synthesis of pyrimido[4,5-d]-pyrimidines.
Scheme 48.
The 3CR C-H functionalisation using ruthenium as a catalyst.
Scheme 48.
The 3CR C-H functionalisation using ruthenium as a catalyst.
Scheme 49.
The diastereoselective and enantioselective C-H functionalisation reaction.
Scheme 49.
The diastereoselective and enantioselective C-H functionalisation reaction.
Scheme 50.
Multicomponent phosphorothiolation.
Scheme 50.
Multicomponent phosphorothiolation.
Scheme 51.
Exploring the multicomponent phosphorothiolation.
Scheme 51.
Exploring the multicomponent phosphorothiolation.
Scheme 52.
Metal-free C-H functionalisation multicomponent reaction.
Scheme 52.
Metal-free C-H functionalisation multicomponent reaction.
Scheme 53.
The C-H functionalisation of phenol derivatives,.
Scheme 53.
The C-H functionalisation of phenol derivatives,.
Scheme 54.
The C-H functionalisation multicomponent reaction of a radical source.
Scheme 54.
The C-H functionalisation multicomponent reaction of a radical source.
Scheme 55.
The C-H functionalisation multicomponent reaction of tetrahydroisoquinolines.
Scheme 55.
The C-H functionalisation multicomponent reaction of tetrahydroisoquinolines.
Scheme 56.
Synthesis of cyclopentenones using C-H functionalisation multicomponent reaction.
Scheme 56.
Synthesis of cyclopentenones using C-H functionalisation multicomponent reaction.
Scheme 57.
Multicomponent synthesis of chromeno [2,3-d] pyrimidin-8-amine.
Scheme 57.
Multicomponent synthesis of chromeno [2,3-d] pyrimidin-8-amine.
Scheme 58.
Synthesis of indazole.
Scheme 58.
Synthesis of indazole.
Scheme 59.
Multicomponent reaction for the synthesis of isoxazolidin-5-ones.
Scheme 59.
Multicomponent reaction for the synthesis of isoxazolidin-5-ones.
Scheme 60.
Hantzsch multicomponent reaction of l-histidine, 4-cyanobenzaldehyde and barbituric acid.
Scheme 60.
Hantzsch multicomponent reaction of l-histidine, 4-cyanobenzaldehyde and barbituric acid.
Scheme 61.
The Ugi-four component reaction for the synthesis of quinolines.
Scheme 61.
The Ugi-four component reaction for the synthesis of quinolines.
Scheme 62.
Ugi-4 component reaction for the synthesis of peptoids and peptides.
Scheme 62.
Ugi-4 component reaction for the synthesis of peptoids and peptides.
Scheme 63.
Multicomponent synthesis of diazoketones.
Scheme 63.
Multicomponent synthesis of diazoketones.
Scheme 64.
Ugi-4 multicomponent for synthesis of peptides.
Scheme 64.
Ugi-4 multicomponent for synthesis of peptides.
Scheme 65.
Synthesis of pseudo-peptides.
Scheme 65.
Synthesis of pseudo-peptides.