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Search for "tropinone" in Full Text gives 5 result(s) in Beilstein Journal of Organic Chemistry.
Icilio Guareschi and his amazing “1897 reaction”
- Gian Cesare Tron,
- Alberto Minassi,
- Giovanni Sorba,
- Mara Fausone and
- Giovanni Appendino
Beilstein J. Org. Chem. 2021, 17, 1335–1351, doi:10.3762/bjoc.17.93
- Guareschi” [42]. Triacetonamine bears a certain similarity to tropinone (9), the heterocyclic core of tropane alkaloids, and the one-pot preparation from acetone and ammonia reminds of, and anticipates by two decades, the Robinson synthesis of tropinone and the Willstätter synthesis of the corresponding 2
Graphical Abstract
Figure 1: Icilio Guareschi (1847–1918). (Source: Annali della Reale Accademia di Agricoltura di Torino 1919, ...
Scheme 1: Vitamin B6 (pyridoxine, 1), gabapentin (2), and thymol (3).
Figure 2: Baliatico (Nursing) by Francesco Scaramuzza (275 cm × 214 cm, Parma, Complesso Museale della Pilott...
Figure 3: Schiff’s fictitious report on the foundation of the Gazzetta Chimica Italiana (Image reproduced fro...
Scheme 2: Reaction of thymol (3) with chloroform under the basic conditions of the Guareschi–Lustgarten react...
Figure 4: The chemistry building of Turin University in a historical picture. Note, that one of the “mysterio...
Scheme 3: Triacetonamine (6) and the related compounds phorone (7), α-eucaine (8), and tropinone (9).
Scheme 4: Taxonomy of the Guareschi pyridone syntheses.
Scheme 5: The catalytic cycle of the “1897 reaction”.
Scheme 6: Resonance forms of the radical 10.
Figure 5: The wet chamber used by Guareschi to restore parchments (Gorrini, G. L'incendio della R. Biblioteca...
Figure 6: The Guareschi mask. (Servizio Chimico Militare. L'opera di Icilio Guareschi precursore della masche...
Figure 7: Guareschi’s bust at the Dipartimento di Scienza e Tecnologia del Farmaco of Turin University. Permi...
Efficiency Effsyn of complex syntheses as multicomponent reactions, its algorithm and calculations based on concrete criteria
- Heiner Eckert
Beilstein J. Org. Chem. 2019, 15, 1425–1433, doi:10.3762/bjoc.15.142
- synthesis steps yn (Equation 1). An extreme example for the impact of the overall yield is the tropinone synthesis by Willstätter (yoa = 0.75%) [7][8] compared to the Robinson–Schöpf synthesis (yoa = 90%) [9][10]) using a double Mannich reaction, a multicomponent reaction (MCR) [11][12][13]. The Mannich-3CR
- impact the synthesis steps n have on the efficiency Effsyn of the synthesis. The range of profitable to useful syntheses decreases drastically with increasing synthesis steps n. The detrimental impact of a greater number of steps n is shown in the above-mentioned tropinone synthesis by Willstätter (yoa
Graphical Abstract
Scheme 1: Case study of a complex synthesis, parallel reactions. 10 possible synthesis STMs in green, other 1...
Scheme 2: Ordered reactions of the above complex synthesis to a main reaction set and connected parallel reac...
Scheme 3: Section A–J case study of Scheme 2 with operations of yoa calculation.
Scheme 4: Sequential synthesis and fragment linking of a decapeptide with comparison of results in Equations ...
Scheme 5: U-4CR with 17 precursors in the total synthesis of Et-743 (1) [14].
Scheme 6: Synthesis of 4 as key step of (+)-20S-camptothecin (3) total synthesis.
Determination of the relative configuration of tropinone and granatanone aldols by using TBDMS ethers
- Ryszard Lazny,
- Aneta Nodzewska,
- Katarzyna Sidorowicz and
- Przemyslaw Kalicki
Beilstein J. Org. Chem. 2012, 8, 1877–1883, doi:10.3762/bjoc.8.216
- relative configurations of tert-butyldimethylsilyl (TBDMS) ethers of all four diastereomers of the aldols of tropinone (8-methyl-8-azabicyclo[3.2.1]octan-3-one), as well as of granatanone (9-methyl-9-azabicyclo[3.3.1]nonan-3-one), were determined from NMR data, and from the observed interconversion of the
- diastereomers (exo,anti to endo,syn and exo,syn to endo,anti). The exo forms invert to endo isomers in the presence of silica gel. The relative configuration of a new isomer of tropinone aldol accessible synthetically through the direct solventless reaction of tropinone and benzaldehyde in the presence of water
- isomerization; granatanone; stereoselective reaction; tropinone; Introduction Enantiomerically pure, and racemic, diastereomerically pure aldols of tropinone have been used as key intermediates in stereoselective syntheses of natural tropane alkaloids and their analogues [1], including the unnatural enantiomer
Graphical Abstract
Figure 1: The exo and the endo substituents at the α-carbon (C-2 by tropane numbering) of the tropinone or gr...
Scheme 1: Typical preparation of representative tropinone and granatanone aldols [3,17,20].
Scheme 2: Sterically and stereoelectronically favored trajectory for the approaching electrophile (E) and att...
Scheme 3: Preparation of TBDMS derivatives of all diastereomers of tropinone and granatanone aldols (included...
Figure 2: Approximate representations of likely conformations of tropinone aldols and their TBDMS ethers in s...
Figure 3: X-ray structure of aldol exo,syn-3 synthesized by direct, solventless reaction of tropinone with be...
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
- to a β-aminoacid, and a tropinone-type unit bound to a 1,2,4-triazole ring. Relatively simple and straightforward chemical transformations are used to assemble the main fragments of maraviroc such as amide bond formation and reductive amination (Scheme 57) [86]. The triazole ring incorporation is
- achieved at an early stage by N-acylation of the tropinone fragment 287 with 2-methylpropanoyl chloride (288). The resulting amide 289 is then converted to the corresponding imidoyl chloride 290 using phosphorous pentachloride in dichloromethane (which proved to be superior to phosphoryl chloride) followed
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).
Radical cascades using enantioenriched 7-azabenzonorbornenes and their applications in synthesis
- David M. Hodgson and
- Leonard H. Winning
Beilstein J. Org. Chem. 2008, 4, No. 38, doi:10.3762/bjoc.4.38
- therefore stoichiometric hydroboration was examined. The timely work of Laschat and co-workers in an analogous tropinone system [29] suggested the application of diisopinocampheylborane (Ipc2BH) [30][31], which with cycloadduct 14 at 0 °C gave alcohol 15 in 84% yield (68% at −10 °C, Scheme 3). HPLC analysis
Graphical Abstract
Scheme 1: Cyclopropylmethyl–homoallyl and nortricyclyl–norbornenyl radical systems.
Scheme 2: Deoxygenation-rearrangement-electrophile trapping.
Figure 1: Radical SOMO/α-nitrogen lone-pair interaction in the rearranged radical 7.
Figure 2: Other products obtained from xanthate 5 by tandem deoxygenation–rearrangement–electrophile trapping....
Scheme 3: Asymmetric hydroboration–oxidation of alkenes 14, 16 and 18.
Scheme 4: Deoxygenation–rearrangement–isomerisation of xanthates 20 and 23.
Scheme 5: Deoxygenation–rearrangement–electrophile trapping of xanthates 20 and 23.
Scheme 6: 2-Azabenzonorbornene as a masked pyrrolidine.
Scheme 7: Ring-opening–hydration–oxidation of azacycle 8.
Scheme 8: Preparation of trisubstituted pyrrolidine (+)-36.
Scheme 9: Preparation of pyrrolidine diester (+)-35 from Vince’s lactam 37.
Scheme 10: Acid-catalysed ring-opening–oxidation of azacycle (+)-8.
Scheme 11: Birch reduction of (+)-8 and 10.
