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Search for "Bischler–Napieralski reaction" in Full Text gives 3 result(s) in Beilstein Journal of Organic Chemistry.
An oxidative amidation and heterocyclization approach for the synthesis of β-carbolines and dihydroeudistomin Y
- Suresh Babu Meruva,
- Akula Raghunadh,
- Raghavendra Rao Kamaraju,
- U. K. Syam Kumar and
- P. K. Dubey
Beilstein J. Org. Chem. 2014, 10, 471–480, doi:10.3762/bjoc.10.45
- – 500085, India 10.3762/bjoc.10.45 Abstract A novel synthetic methodology has been developed for the synthesis of dihydro-β-carboline derivatives employing oxidative amidation–Bischler–Napieralski reaction conditions using tryptamine and 2,2-dibromo-1-phenylethanone as key starting materials. A number of
- dihydro-β-carboline derivatives have been synthesized in moderate to good yields using this methodology. Attempts were made towards the conversion of these dihydro-β-carbolines to naturally occurring eudistomin alkaloids. Keywords: Bischler–Napieralski reaction; dihydro-β-carboline derivatives; dihydro
- . Accordingly eudistomin Y (6) could be obtained by the aromatization of dihydro-β-carboline 12. The dihydro-β-carboline 12 in turn could be synthesized from ketoamide 9 under Lewis acid mediated Bischler–Napieralski reaction. The key intermediate, ketoamide 9 required for the synthesis could easily be accessed
Graphical Abstract
Figure 1: Natural products containing the β-carboline skeletal.
Scheme 1: Retrosynthetic analysis of 6.
Scheme 2: Plausible mechanism of the oxidative amidation for 9.
Scheme 3: Synthesis of α-ketoamide 9.
Scheme 4: Synthesis of dihydroeudistomin Y analogues.
Scheme 5: Plausible mechanism for the formation of 7.
Scheme 6: Rearrangement of 8a into 7a and coupling interactions of 7a.
Figure 2: COSY and HSQC of 8a and 7a.
An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles
- Marcus Baumann and
- Ian R. Baxendale
Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265
- phenylalanine residue as well as through several H-bonds facilitated by the adjacent polar substituents (Figure 8). The reported synthesis of carmegliptin enlists a Bischler-Napieralski reaction utilising the primary amine 2.76 and methyl formate to yield the initial dihydroquinoline 2.77 as its HCl salt
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.
The chemistry of isoindole natural products
- Klaus Speck and
- Thomas Magauer
Beilstein J. Org. Chem. 2013, 9, 2048–2078, doi:10.3762/bjoc.9.243
- moiety was accomplished via deprotection, palladium-catalyzed cyclization–methoxycarbonylation [166] and an acid-catalyzed lactone formation to afford 223. For the generation of the isoindolinone via a Bischler–Napieralski reaction, a chloroacetyl (CA)-protected phenol was essential to avoid competing
Graphical Abstract
Figure 1: a) Structural features and b) selected examples of non-natural congeners.
Scheme 1: Synthesis of isoindole 18.
Scheme 2: Staining amines with 1,4-diketone 19 (R = H).
Figure 2: Representative members of the indolocarbazole alkaloid family.
Figure 3: Staurosporine (26) bound to the adenosine-binding pocket [19] (from pdb1stc).
Figure 4: Structure of imatinib (34) and midostaurin (35).
Scheme 3: Biosynthesis of staurosporine (26).
Scheme 4: Wood’s synthesis of K-252a via the common intermediate 48.
Scheme 5: Synthesis of 26, 27, 49 and 50 diverging from the common intermediate 48.
Figure 5: Selected members of the cytochalasan alkaloid family.
Scheme 6: Biosynthesis of chaetoglobosin A (57) [56].
Scheme 7: Synthesis of cytochalasin D (70) by Thomas [63].
Scheme 8: Synthesis of L-696,474 (78).
Scheme 9: Synthesis of aldehyde 85 (R = TBDPS).
Scheme 10: Synthesis of (+)-aspergillin PZ (79) by Tanis.
Figure 6: Representative Berberis alkaloids.
Scheme 11: Proposed biosynthetic pathway to chilenine (93).
Scheme 12: Synthesis of magallanesine (97) by Danishefsky [84].
Scheme 13: Kurihara’s synthesis of magallanesine (85).
Scheme 14: Proposed biosynthesis of 113, 117 and 125.
Scheme 15: DNA lesion caused by aristolochic acid I (117) [102].
Scheme 16: Snieckus’ synthesis of piperolactam C (131).
Scheme 17: Synthesis of aristolactam BII (104).
Figure 7: Representative cularine alkaloids.
Scheme 18: Proposed biosynthesis of 136.
Scheme 19: The syntheses of 136 and 137 reported by Castedo and Suau.
Scheme 20: Synthesis of 136 by Couture.
Figure 8: Representative isoindolinone meroterpenoids.
Scheme 21: Postulated biosynthetic pathway for the formation of 156 (adopted from George) [143].
Scheme 22: Synthesis of stachyflin (156) by Katoh [144].
Figure 9: Selected examples of spirodihydrobenzofuranlactams.
Scheme 23: Synthesis of stachybotrylactam I (157).
Scheme 24: Synthesis of pestalachloride A (193) by Schmalz.
Scheme 25: Proposed mechanism for the BF3-catalyzed metal-free carbonyl–olefin metathesis [149].
Scheme 26: Preparation of the isoindoline core of muironolide A (204).
Scheme 27: Proposed biosynthesis of 208.
Scheme 28: Model for the biosynthesis of 215 and 217.
Scheme 29: Synthesis of lactonamycin (215) and lactonamycin Z (217).
Figure 10: Hetisine alkaloids 225–228.
Scheme 30: Biosynthetic proposal for the formation of the hetisine core [167].
Scheme 31: Synthesis of nominine (225).
