Graphical Abstract
Scheme 1: Scaled industrial processes for the synthesis of simple pyridines.
Scheme 2: Synthesis of nicotinic acid from 2-methyl-5-ethylpyridine (1.11).
Scheme 3: Synthesis of 3-picoline and nicotinic acid.
Scheme 4: Synthesis of 3-picoline from 2-methylglutarodinitrile 1.19.
Scheme 5: Picoline-based synthesis of clarinex (no yields reported).
Scheme 6: Mode of action of proton-pump inhibitors and structures of the API’s.
Scheme 7: Hantzsch-like route towards the pyridine rings in common proton pump inhibitors.
Figure 1: Structures of rosiglitazone (1.40) and pioglitazone (1.41).
Scheme 8: Synthesis of rosiglitazone.
Scheme 9: Syntheses of 2-pyridones.
Scheme 10: Synthesis and mechanism of 2-pyrone from malic acid.
Scheme 11: Polymer-assisted synthesis of rosiglitazone.
Scheme 12: Synthesis of pioglitazone.
Scheme 13: Meerwein arylation reaction towards pioglitazone.
Scheme 14: Route towards pioglitazone utilising tyrosine.
Scheme 15: Route towards pioglitazone via Darzens ester formation.
Scheme 16: Syntheses of the thiazolidinedione moiety.
Scheme 17: Synthesis of etoricoxib utilising Negishi and Stille cross-coupling reactions.
Scheme 18: Synthesis of etoricoxib via vinamidinium condensation.
Figure 2: Structures of nalidixic acid, levofloxacin and moxifloxacin.
Scheme 19: Synthesis of moxifloxacin.
Scheme 20: Synthesis of (S,S)-2,8-diazabicyclo[4.3.0]nonane 1.105.
Scheme 21: Synthesis of levofloxacin.
Scheme 22: Alternative approach to the levofloxacin core 1.125.
Figure 3: Structures of nifedipine, amlodipine and clevidipine.
Scheme 23: Mg3N2-mediated synthesis of nifedipine.
Scheme 24: Synthesis of rac-amlodipine as besylate salt.
Scheme 25: Aza Diels–Alder approach towards amlodipine.
Scheme 26: Routes towards clevidipine.
Figure 4: Examples of piperidine containing drugs.
Figure 5: Discovery of tiagabine based on early leads.
Scheme 27: Synthetic sequences to tiagabine.
Figure 6: Structures of solifenacin (2.57) and muscarine (2.58).
Scheme 28: Enantioselective synthesis of solifenacin.
Figure 7: Structures of DPP-4 inhibitors of the gliptin-type.
Scheme 29: Formation of inactive diketopiperazines from cis-rotameric precursors.
Figure 8: Co-crystal structure of carmegliptin bound in the human DPP-4 active site (PDB 3kwf).
Scheme 30: Improved route to carmegliptin.
Figure 9: Structures of lamivudine and zidovudine.
Scheme 31: Typical routes accessing uracil, thymine and cytosine.
Scheme 32: Coupling between pyrimidones and riboses via the Vorbrüggen nucleosidation.
Scheme 33: Synthesis of lamivudine.
Scheme 34: Synthesis of raltegravir.
Scheme 35: Mechanistic studies on the formation of 3.22.
Figure 10: Structures of selected pyrimidine containing drugs.
Scheme 36: General preparation of pyrimidines and dihydropyrimidones.
Scheme 37: Synthesis of imatinib.
Scheme 38: Flow synthesis of imatinib.
Scheme 39: Syntheses of erlotinib.
Scheme 40: Synthesis of erlotinib proceeding via Dimroth rearrangement.
Scheme 41: Synthesis of lapatinib.
Scheme 42: Synthesis of rosuvastatin.
Scheme 43: Alternative preparation of the key aldehyde towards rosuvastatin.
Figure 11: Structure comparison between nicotinic acetylcholine receptor agonists.
Scheme 44: Syntheses of varenicline and its key building block 4.5.
Scheme 45: Synthetic access to eszopiclone and brimonidine via quinoxaline intermediates.
Figure 12: Bortezomib bound in an active site of the yeast 20S proteasome ([114], pdb 2F16).
Scheme 46: Asymmetric synthesis of bortezomib.
Figure 13: Structures of some prominent piperazine containing drugs.
Figure 14: Structural comparison between the core of aplaviroc (4.35) and a type-1 β-turn (4.36).
Scheme 47: Examplary synthesis of an aplaviroc analogue via the Ugi-MCR.
Scheme 48: Syntheses of azelastine (5.1).
Figure 15: Structures of captopril, enalapril and cilazapril.
Scheme 49: Synthesis of cilazapril.
Figure 16: Structures of lamotrigine, ceftriaxone and azapropazone.
Scheme 50: Synthesis of lamotrigine.
Scheme 51: Alternative synthesis of lamotrigine (no yields reported).
Figure 17: Structural comparison between imiquimod and the related adenosine nucleoside.
Scheme 52: Conventional synthesis of imiquimod (no yields reported).
Scheme 53: Synthesis of imiquimod.
Scheme 54: Synthesis of imiquimod via tetrazole formation (not all yields reported).
Figure 18: Structures of various anti HIV-medications.
Scheme 55: Synthesis of abacavir.
Figure 19: Structures of diazepam compared to modern replacements.
Scheme 56: Synthesis of ocinaplon.
Scheme 57: Access to zaleplon and indiplon.
Scheme 58: Different routes towards the required N-methylpyrazole 6.65 of sildenafil.
Scheme 59: Polymer-supported reagents in the synthesis of key aminopyrazole 6.72.
Scheme 60: Early synthetic route to sildenafil.
Scheme 61: Convergent preparations of sildenafil.
Figure 20: Comparison of the structures of sildenafil, tadalafil and vardenafil.
Scheme 62: Short route to imidazotriazinones.
Scheme 63: Alternative route towards vardenafils core imidazotriazinone (6.95).
Scheme 64: Bayer’s approach to the vardenafil core.
Scheme 65: Large scale synthesis of vardenafil.
Scheme 66: Mode of action of temozolomide (6.105) as methylating agent.
Scheme 67: Different routes to temozolomide.
Scheme 68: Safer route towards temozolomide.
Figure 21: Some unreported heterocyclic scaffolds in top market drugs.
Graphical Abstract
Figure 1: Chemical structures of 1 and POZ-DBPHZ.
Scheme 1: Synthesis of compound 1.
Figure 2: Steady-state UV–vis absorption (Abs) and photoluminescence (PL) spectra of dilute solutions (c ≈ 10...
Figure 3: Time-resolved PL decay profiles (intensity vs delay time) and spectra of 1 in a), b) Zeonex® and c,...
Figure 4: The characteristics of the OLED devices: a) electroluminescence spectra; b) current density-bias ch...
Figure 5: Schematics of the TADF mechanisms along with NTOs for the relevant electronic states for a) D–A com...
Graphical Abstract
Figure 1: Routes to isoxazoles.
Figure 2: Possible products of the reaction between nitrile oxides and 1,3-diketones. Path D (C-trapping) pro...
Figure 3: Reactions between various arylhydroximoyl chlorides and 1,3-diketones. The reactions were performed...
Figure 4: Reactions between various phenyl hydroximoyl chlorides and β-ketoesters or β-ketoamides. The reacti...
Figure 5: Reactions between 4-fluorophenyl hydroximoyl chloride (1a) and diethyl malonate (2j) or dibenzyl ma...
Figure 6: Reactions between phenyl hydroximoyl chlorides 1a,c and 4,4,4-trifluoro-1-phenyl- (2l) and 4,4,4-tr...
Figure 7: 1H NMR spectra of 1-phenyl-1,3-butanedione (2a) in methanol-d4 (top) and in CDCl3 (bottom).
Figure 8: A plausible mechanism for the formation of the 3,4,5-trisubstituted isoxazoles 3 in the presence of...
Figure 9: Structures of β-lactamase-resistant antibiotics oxacillin, cloxacillin, dicloxacillin, and flucloxa...
Graphical Abstract
Scheme 1: The four-component reactions containing dimedone (a) and cyclopentane-1,3-dione (b).
Figure 1: Molecular structure of spiro[dihydropyridine-oxindole] 1b.
Figure 2: The two kinds of spiro compounds from reactions of isatins with arylamines and cyclic 1,3-diketones....
Figure 3: Molecular structure of spiro[dihydropyridine-oxindole] 2f.
Scheme 2: Condensation reactions of isatins with cyclopentane-1,3-dione.
Figure 4: Molecular structure of compound 3d.
Scheme 3: Proposed reaction mechanism for the three-component reaction.
Graphical Abstract
Figure 1: Representative bioactive dispirooxindoles.
Scheme 1: Reductive cyclization for the synthesis of dispirocyclopentanebisoxindole derivatives.
Scheme 2: Substrate scope of product 3 (part 1). Reaction conditions: substrates: 1 (1 mmol) and 2 (0.5 mmol)...
Scheme 3: Substrate scope of product 3 (part 2). Reaction conditions: substrates: 1 (1 mmol) and 2 (0.5 mmol)...
Figure 2: ORTEP diagram of product 3g (CCDC NO. 2072521).
Figure 3: NOESY Spectra of compound 3e.
Scheme 4: Plausible mechanism of the reaction.
Figure 4: HRMS spectrum of the crude reaction mixture after 1 hour of the reaction.
Scheme 5: Control experiment.
Graphical Abstract
Figure 1: Pharmaceutical structures targeted in early flow syntheses.
Scheme 1: Flow synthesis of 6-hydroxybuspirone (9). Inserted photograph reprinted with permission from [45]. Copy...
Figure 2: Configuration of a baffled reactor tube (left) and its schematic working principle (right).
Scheme 2: McQuade’s flow synthesis of ibuprofen (16).
Scheme 3: Jamison’s flow synthesis of ibuprofen sodium salt (17).
Scheme 4: Flow synthesis of imatinib (23).
Scheme 5: Flow synthesis of the potent 5HT1B antagonist 28.
Scheme 6: Flow synthesis of a selective δ-opioid receptor agonist 33.
Scheme 7: Flow synthesis of a casein kinase I inhibitor library (38).
Scheme 8: Flow synthesis of fluoxetine (46).
Scheme 9: Flow synthesis of artemisinin (55).
Scheme 10: Telescoped flow synthesis of artemisinin (55) and derivatives (62–64).
Scheme 11: Flow approach towards AZD6906 (65).
Scheme 12: Pilot scale flow synthesis of key intermediate 73.
Scheme 13: Semi-flow synthesis of vildagliptine (77).
Scheme 14: Pilot scale asymmetric flow hydrogenation towards 83. Inserted photograph reprinted with permission...
Figure 3: Schematic representation of the ‘tube-in-tube’ reactor.
Scheme 15: Flow synthesis of fanetizole (87) via tube-in-tube system.
Scheme 16: Flow synthesis of diphenhydramine.HCl (92).
Scheme 17: Flow synthesis of rufinamide (95).
Scheme 18: Large scale flow synthesis of rufinamide precursor 102.
Scheme 19: First stage in the flow synthesis of meclinertant (103).
Scheme 20: Completion of the flow synthesis of meclinertant (103).
Scheme 21: Flow synthesis of olanzapine (121) utilising inductive heating techniques.
Scheme 22: Flow synthesis of amitriptyline·HCl (127).
Scheme 23: Flow synthesis of E/Z-tamoxifen (132) using peristaltic pumping modules.
Figure 4: Container sized portable mini factory (photograph credit: INVITE GmbH, Leverkusen Germany).
Scheme 24: Flow synthesis of imidazo[1,2-a]pyridines 136 linked to frontal affinity chromatography (FAC).
Figure 5: Structures of zolpidem (142) and alpidem (143).
Scheme 25: Synthesis and screening loops in the discovery of new Abl kinase inhibitors.
Figure 6: Schotten–Baumann approach towards LY573636.Na (147).
Scheme 26: Pilot scale flow synthesis of LY2886721 (146).
Scheme 27: Continuous flow manufacture of alikiren hemifumarate 152.
Graphical Abstract
Figure 1: The carbenes IPr, IMes, IXy and their imidazolium salt precursors
Scheme 1: Synthetic routes to and diazadiene precursors for imidazolium salts.
Scheme 2: The imidazolium salt synthesis as a 1, 5-dipolar electrocyclization.
Scheme 3: Potential side-reactions in the imidazolium salt synthesis.
Graphical Abstract
Figure 1: 2-Modified 4,6-bis(3,6-di-tert-butyl-9H-carbazol-9-yl)-5-methylpyrimidines.
Scheme 1: Synthesis of 4,6-bis(3,6-di-tert-butyl-9H-carbazol-9-yl)-5-methyl-2-substituted pyrimidines 1–6. Re...
Figure 2: HOMO and LUMO spatial distributions of carbazole–pyrimidine TADF compounds.
Figure 3: Absorption (grey lines), fluorescence (black lines) and 10K phosphorescence (red lines) spectra of ...
Figure 4: Fluorescence decay transients of 1 wt % PMMA films of carbazole–pyrimidine TADF compounds in oxygen...
Graphical Abstract
Figure 1: Schematic representation of a computer-aided drug discovery (CADD) pipeline. CADD methods are broad...
Figure 2: FDA approved drugs Saquinavir and Amprenavir for the treatment of HIV infections. (a) The structure...
Figure 3: (a) The crystal structure showing the binding of Dorzolamide (orange) to carbonic anhydrase II (pur...
Figure 4: The best ligand binding site identified by SiteHound in HIV-1 protease. The ligand binding pocket i...
Figure 5: Binding mode prediction. The known inhibitor Dorzolamide is docked into Carbonic anhydrase II cryst...
Figure 6: The molecular structure of Raltegravir. Raltegravir is an FDA approved drug used in the treatment o...
Figure 7: An example alchemical thermodynamic cycle for a protein–ligand binding free energy calculation. The...
Figure 8: Schematic diagram showing the steps involved in QSAR. Known drug molecule activity and descriptor d...
Figure 9: A few drugs discovered with the help of ligand-based drug discovery tools. (a) Zolmitriptan: used a...
Graphical Abstract
Figure 1: The structures of chloroquine, hydroxychloroquine, and amodiaquine.
Scheme 1: Synthesis of 3-azolylpyrazoles 3a–c.
Scheme 2: Assumed mechanism for the formation of 1H-pyrazoles 3a–c.
Scheme 3: Synthesis of 3-aminopyrazoles 5b–k and 5-aminopyrazoles 5a and 5l–o.
Scheme 4: Orientation of nucleophilic attack of 7-chloro-4-hydrazinylquinoline on nitrobutadienes 4.
Scheme 5: Synthesis of oxazolidine 6 and pyrazole 7.
Scheme 6: A plausible mechanism for the formation of pyrazole 7.
Scheme 7: Synthesis of pyrazoles 9 and sulfoxide 10d.
Scheme 8: Synthesis of pyrazole 11.