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Search for "indole formation" in Full Text gives 7 result(s) in Beilstein Journal of Organic Chemistry.
Consecutive four-component synthesis of trisubstituted 3-iodoindoles by an alkynylation–cyclization–iodination–alkylation sequence
- Nadia Ledermann,
- Alae-Eddine Moubsit and
- Thomas J. J. Müller
Beilstein J. Org. Chem. 2023, 19, 1379–1385, doi:10.3762/bjoc.19.99
- generated by a consecutive four-component reaction starting from ortho-haloanilines, terminal alkynes, N-iodosuccinimide, and alkyl halides in yields of 11–69%. Initiated by a copper-free alkynylation, followed by a base-catalyzed cyclizive indole formation, electrophilic iodination, and finally
Graphical Abstract
Scheme 1: Consecutive alkynylation–cyclization–alkylation three-component synthesis and conception of a conse...
Scheme 2: Consecutive alkynylation–cyclization–iodination–alkylation four-component synthesis of trisubstitut...
Scheme 3: Consecutive double alkynylation–cyclization–iodination–alkylation pseudo-five-component synthesis o...
Scheme 4: Suzuki coupling of 3-iodoindole 5a with arylboronic acids 7 to give 1,2,3-trisubstituted indoles 8.
Figure 1: A: Absorption and emission spectra of 1-methyl-2-phenyl-3-(p-tolyl)-1H-indole (8b), recorded in dic...
Tuneable access to indole, indolone, and cinnoline derivatives from a common 1,4-diketone Michael acceptor
- Dalel El-Marrouki,
- Sabrina Touchet,
- Abderrahmen Abdelli,
- Hédi M’Rabet,
- Mohamed Lotfi Efrit and
- Philippe C. Gros
Beilstein J. Org. Chem. 2020, 16, 1722–1731, doi:10.3762/bjoc.16.144
- directing the reaction exclusively towards indole formation by reacting the diketone with appropriate substrates, combining a primary amine with a tertiary amine or a pyridine separated by several spacer arms (Scheme 6). Under these conditions, the functional indoles 6h–l were obtained exclusively in 45–55
Graphical Abstract
Figure 1: Examples of bioactive nitrogen-containing heterocycles (indole [9], indolone [10], and cinnoline [11] derivati...
Scheme 1: General strategy to access indole, indolone, and cinnoline derivatives from 1,4-diketones.
Scheme 2: Synthesis of the 1,4-diketones 5a–k via the Nef reaction or the Wittig reaction. i) HCHO (aq), DMAP...
Scheme 3: Mechanism of the formation of indole and indolone derivatives.
Scheme 4: Synthesis of the indoles 6a–f and the corresponding side product indolones 7a–f.
Scheme 5: Reaction of 5b with a diamine.
Scheme 6: Synthesis of the indoles 6h–l.
Scheme 7: Synthesis of the indolone derivatives 7b, 7d, and 7g–k.
Scheme 8: Synthesis of the cinnoline derivatives 8a–k.
Scheme 9: Proposed mechanism for the preparation of the compounds 6, 7, and 8.
Synthesis of indolo[1,2-c]quinazolines from 2-alkynylaniline derivatives through Pd-catalyzed indole formation/cyclization with N,N-dimethylformamide dimethyl acetal
- Antonio Arcadi,
- Sandro Cacchi,
- Giancarlo Fabrizi,
- Francesca Ghirga,
- Antonella Goggiamani,
- Antonia Iazzetti and
- Fabio Marinelli
Beilstein J. Org. Chem. 2018, 14, 2411–2417, doi:10.3762/bjoc.14.218
Graphical Abstract
Scheme 1: Synthesis of 6-trifluoromethyl-12-aryl(vinyl)indolo[1,2-c]quinazolines 4.
Scheme 2: Present and previously reported reactions starting from 5. DMFDMA: dimethylformamide dimethyl aceta...
Scheme 3: Two-step synthesis of 12-arylindolo[1,2-c]quinazoline 10a.
Scheme 4: Synthesis of indoles 14.
Scheme 5: Sequential preparation of 13a from 15a.
Synthesis of benzannelated sultams by intramolecular Pd-catalyzed arylation of tertiary sulfonamides
- Valentin A. Rassadin,
- Mirko Scholz,
- Anastasiia A. Klochkova,
- Armin de Meijere and
- Victor V. Sokolov
Beilstein J. Org. Chem. 2017, 13, 1932–1939, doi:10.3762/bjoc.13.187
- formation of a 2,3-diarylindole was observed under the same conditions. Keywords: arylation; fused-ring systems; indole formation; palladium catalysis; sultams; Introduction The sulfonamide functional group stands out as one of the most important pharmacophores. At the same time, cyclic sulfonamides
Graphical Abstract
Scheme 1: A previous and a new approach to arene-annelated sultams.
Scheme 2: Pd-catalyzed cyclization of (2-iodophenyl)sulfonamides 3 and 5.
Scheme 3: Preparation of 4-methoxybenzyl-protected methyl 2-(N-o-iodoarylsulfamoyl)acetates 8. Reagents and c...
Scheme 4: Synthesis of arene-annelated sultams 10 by Pd-catalyzed intramolecular arylation of a C–H acidic me...
Figure 1: Structure of methyl 5-chloro-1-(4-methoxybenzyl)-1,3-dihydrobenzo[c]isothiazole-3-carboxylate-2,2-d...
Scheme 5: Palladium-catalyzed transformation of N-(2-iodophenyl)-N-(4-methoxybenzyl-benzylsulfonamide 12. Ar ...
Scheme 6: Palladium-catalyzed intramolecular arylation to yield a benzannelated six-membered sultam 21. Ar = ...
Scheme 7: An attempted and a successful removal of the PMB group from the sultam 10a.
Figure 2: Structure of methyl 1-(4-methoxybenzyl)-3-(nitrooxy)-1,3-dihydrobenzo[c]isothiazole-3-carboxylate-2...
Accessing simply-substituted 4-hydroxytetrahydroisoquinolines via Pomeranz–Fritsch–Bobbitt reaction with non-activated and moderately-activated systems
- Marco Mottinelli,
- Mathew P. Leese and
- Barry V. L. Potter
Beilstein J. Org. Chem. 2017, 13, 1871–1878, doi:10.3762/bjoc.13.182
- , compounds bearing a different number of methoxy groups were selected in order to understand the electronic constrains that might render indole formation competitive. Upon treatment with 70% HClO4, acetals 9a and 9o yielded the respective THIQs 10a and 10o. However, the highly-activated acetal 9p exclusively
- cyclized into the indole 16p. It is thus possible to infer that indole formation is highly disfavored and only the presence of a great number of activating groups can make this outcome competitive. We then decided to expand our analysis to include competition between 6- and 7-membered ring formation
Graphical Abstract
Figure 1: Non-steroidal templates from estradiol.
Scheme 1: Pomeranz–Fritsch and Pomeranz–Fritsch–Bobbitt reactions. Conditions: (a) conc. H2SO4; (b) benzene, ...
Scheme 2: Designed synthesis of THIQ. Conditions: (a) NaBH(OAc)3, CHCl3, rt; (b) 6 M HCl or 70% HClO4 (see Table 1),...
Scheme 3: Side reaction during the double alkylation of 7 and possible reaction mechanism for the formation o...
Scheme 4: Competition between the formation of 5- and 7-substituted THIQs. Conditions: (a) 6 M HCl, rt.
Scheme 5: Formation of the 4-hydroxy and 4-methoxy-THIQs. Conditions: (a) 6 M HCl or 70% HClO4, rt (see Table 3).
Scheme 6: Competition between the formation of THIQs 10a,o,p and indoles 16a,o,p. Conditions: (a) 70% HClO4, ...
Scheme 7: Competition between 6- and 7-membered ring formation. Conditions: (a) NaBH(OAc)3, CHCl3, rt; (b) 2,...
Scheme 8: Competition between ring formation para- or meta- to an activating group. Conditions: (a) NaBH(OAc)3...
When gold can do what iodine cannot do: A critical comparison
- Sara Hummel and
- Stefan F. Kirsch
Beilstein J. Org. Chem. 2011, 7, 847–859, doi:10.3762/bjoc.7.97
- intermediates will most likely never be matched by electrophilic analogues and will be unique tools for the creation of valuable target compounds. Mechanistic scenarios for alkyne activation. Synthesis of 3(2H)-furanones. Synthesis of furans. Formation of dihydrooxazoles. Variation on indole formation
Graphical Abstract
Scheme 1: Mechanistic scenarios for alkyne activation.
Scheme 2: Synthesis of 3(2H)-furanones.
Scheme 3: Synthesis of furans.
Scheme 4: Formation of dihydrooxazoles.
Scheme 5: Variation on indole formation.
Scheme 6: Formation of naphthalenes.
Scheme 7: Formation of indenes.
Scheme 8: Iodocyclization of 3-silyloxy-1,5-enynes.
Scheme 9: 5-Endo cyclizations with concomitant nucleophilic trapping.
Scheme 10: Reactivity of 3-BocO-1,5-enynes.
Scheme 11: Intramolecular nucleophilic trapping.
Scheme 12: Approach to azaanthraquinones.
Scheme 13: Carbocyclizations with enol derivatives.
Scheme 14: Gold-catalyzed cyclization modes for 1,5-enynes.
Scheme 15: Iodine-induced cyclization of 1,5-enynes.
Scheme 16: Diverse reactivity of 1,6-enynes.
Scheme 17: Iodocyclization of 1,6-enynes.
Scheme 18: Cyclopropanation of alkenes with 1,6-enynes.
Scheme 19: Cyclopropanation of alkenes with 1,6-enynes.
An overview of the key routes to the best selling 5-membered ring heterocyclic pharmaceuticals
- Marcus Baumann,
- Ian R. Baxendale,
- Steven V. Ley and
- Nikzad Nikbin
Beilstein J. Org. Chem. 2011, 7, 442–495, doi:10.3762/bjoc.7.57
- yields (Scheme 9). However, in sumatriptan the indole product resulting from the Fischer synthesis can still react further which leads to the formation of by-products and significantly reduced yields. One way to minimise this was to protect the nitrogen of the sulfonamide group prior to indole formation
Graphical Abstract
Figure 1: Structures of atorvastatin and other commercial statins.
Figure 2: Structure of compactin.
Scheme 1: Synthesis of pentasubstituted pyrroles.
Scheme 2: [3 + 2] Cycloaddition to prepare 5-isopropylpyrroles.
Scheme 3: Regiospecific [3 + 2] cycloaddition to prepare the pyrrole scaffold.
Scheme 4: Formation of the pyrrole core of atorvastatin via [3 + 2] cycloaddition.
Scheme 5: Formation of pyrrole 33 via the Paal–Knorr reaction.
Scheme 6: Convergent synthesis towards atorvastatin.
Figure 3: Binding pocket of sunitinib in the TRK KIT.
Scheme 7: Synthesis of sunitinib.
Scheme 8: Alternative synthesis of sunitinib.
Scheme 9: Key steps in the syntheses of sumatriptan and zolmitriptan.
Scheme 10: Introduction of the N,N-dimethylaminoethyl side chain.
Scheme 11: Japp–Klingemann reaction in the synthesis of sumatriptan.
Scheme 12: Synthesis of the intermediate sulfonyl chlorides 62 and 63.
Scheme 13: Alternative introduction of the sulfonamide.
Scheme 14: Negishi-type coupling to benzylic sulfonamides.
Scheme 15: Heck reaction used to introduce the sulfonamide side chain of naratriptan.
Scheme 16: Synthesis of the oxazolinone appendage of zolmitriptan.
Scheme 17: Grandberg indole synthesis used in the preparation of rizatriptan.
Scheme 18: Improved synthesis of rizatriptan.
Scheme 19: Larock-type synthesis of rizatriptan.
Scheme 20: Synthesis of eletriptan.
Scheme 21: Heck coupling for the indole system in eletriptan.
Scheme 22: Attempted Fischer indole synthesis of elatriptan.
Scheme 23: Successful Fischer indole synthesis for eletriptan.
Scheme 24: Mechanistic rationale for the Bischler–Möhlau reaction.
Scheme 25: Bischler-type indole synthesis used in the fluvastatin sodium synthesis.
Scheme 26: Palladium-mediated synthesis of ondansetron.
Scheme 27: Fischer indole synthesis of ondansetron.
Scheme 28: Optimised Pictet–Spengler reaction towards tadalafil.
Figure 4: Structures of carvedilol 136 and propranolol 137.
Scheme 29: Synthesis of the carbazole core of carvedilol.
Scheme 30: Alternative syntheses of 4-hydroxy-9H-carbazole.
Scheme 31: Convergent synthesis of etodolac.
Scheme 32: Alternative synthesis of etodolac.
Figure 5: Structures of imidazole-containing drugs.
Scheme 33: Synthesis of functionalised imidazoles towards losartan.
Scheme 34: Direct synthesis of the chlorinated imidazole in losartan.
Scheme 35: Synthesis of trisubstituted imidazoles.
Scheme 36: Preparation of the imidazole ring in olmesartan.
Scheme 37: Synthesis of ondansetron.
Scheme 38: Alternative route to ondansetron and its analogues.
Scheme 39: Proton pump inhibitors and synthesis of esomeprazole.
Scheme 40: Synthesis of benzimidazole core pantoprazole.
Figure 6: Structure of rabeprazole 194.
Scheme 41: Synthesis of candesartan.
Scheme 42: Alternative access to the candesartan key intermediate 216.
Scheme 43: .Medicinal chemistry route to telmisartan.
Scheme 44: Improved synthesis of telmisartan.
Scheme 45: Synthesis of zolpidem.
Scheme 46: Copper-catalysed 3-component coupling towards zolpidem.
Figure 7: Structure of celecoxib.
Scheme 47: Preparation of celecoxib.
Scheme 48: Alternative synthesis of celecoxib.
Scheme 49: Regioselective access to celecoxib.
Scheme 50: Synthesis of pazopanib.
Scheme 51: Syntheses of anastrozole, rizatriptan and letrozole.
Scheme 52: Regioselective synthesis of anastrozole.
Scheme 53: Triazine-mediated triazole formation towards anastrozole.
Scheme 54: Alternative routes to 1,2,4-triazoles.
Scheme 55: Initial synthetic route to sitagliptin.
Figure 8: Binding of sitagliptin within DPP-IV.
Scheme 56: The process route to sitagliptin key intermediate 280.
Scheme 57: Synthesis of maraviroc.
Scheme 58: Synthesis of alprazolam.
Scheme 59: The use of N-nitrosoamidine derivatives in the preparation of fused benzodiazepines.
Figure 9: Structures of itraconazole, ravuconazole and voriconazole.
Scheme 60: Synthesis of itraconazole.
Scheme 61: Synthesis of rufinamide.
Scheme 62: Representative tetrazole formation in valsartan.
Figure 10: Structure of tetrazole containing olmesartan, candesartan and irbesartan.
Scheme 63: Early stage introduction of the tetrazole in losartan.
Scheme 64: Synthesis of cilostazol.
Figure 11: Structure of cefdinir.
Scheme 65: Semi-synthesis of cefdinir.
Scheme 66: Thiazole syntheses towards ritonavir.
Scheme 67: Synthesis towards pramipexole.
Scheme 68: Alternative route to pramipexole.
Scheme 69: Synthesis of famotidine.
Scheme 70: Efficient synthesis of the hyperuricemic febuxostat.
Scheme 71: Synthesis of ziprasidone.
Figure 12: Structure of mometasone.
Scheme 72: Industrial access to 2-furoic acid present in mometasone.
Scheme 73: Synthesis of ranitidine from furfuryl alcohol.
Scheme 74: Synthesis of nitrofurantoin.
Scheme 75: Synthesis of benzofuran.
Scheme 76: Synthesis of amiodarone.
Scheme 77: Synthesis of raloxifene.
Scheme 78: Alternative access to the benzo[b]thiophene core of raloxifene.
Scheme 79: Gewald reaction in the synthesis of olanzapine.
Scheme 80: Alternative synthesis of olanzapine.
Figure 13: Access to simple thiophene-containing drugs.
Scheme 81: Synthesis of clopidogrel.
Scheme 82: Pictet–Spengler reaction in the preparation of tetrahydrothieno[3,2-c]pyridine (422).
Scheme 83: Alternative synthesis of key intermediate 422.
Figure 14: Co-crystal structures of timolol (left) and carazolol (right) in the β-adrenergic receptor.
Scheme 84: Synthesis of timolol.
Scheme 85: Synthesis of tizanidine 440.
Scheme 86: Synthesis of leflunomide.
Scheme 87: Synthesis of sulfamethoxazole.
Scheme 88: Synthesis of risperidone.
Figure 15: Relative abundance of selected transformations.
Figure 16: The abundance of heterocycles within top 200 drugs (5-membered rings).
