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Search for "nitro reduction" in Full Text gives 4 result(s) in Beilstein Journal of Organic Chemistry.
Palladium nanoparticles supported on chitin-based nanomaterials as heterogeneous catalysts for the Heck coupling reaction
- Tony Jin,
- Malickah Hicks,
- Davis Kurdyla,
- Sabahudin Hrapovic,
- Edmond Lam and
- Audrey Moores
Beilstein J. Org. Chem. 2020, 16, 2477–2483, doi:10.3762/bjoc.16.201
- stabilizing dispersed metal nanoparticle catalysts, along with increased solubility in aqueous media. Very recently, we have shown that these bio-based nanomaterials could stabilize highly disperse Au species on the surface of these nanocrystals to create a highly active catalyst for aromatic nitro reduction
Graphical Abstract
Scheme 1: Pathway for the formation of ChNC and subsequently ChsNCs from bulk chitin.
Figure 1: TEM micrographs of (a) ChNCs and (b) ChsNCs. Both samples were stained and prepared on glow-dischar...
Scheme 2: Catalyst fabrication method for the deposition of Pd NPs onto chitin (PdNP@ChNC) and chitosan (PdNP...
Figure 2: TEM micrographs of (a) PdNP@ChNCs and (b) PdNP@ChsNCs. The samples were placed on glow discharged T...
Figure 3: High-resolution X-ray photoelectron spectroscopy of the Pd 3d region of (a) PdNP@ChNC and (b) PdNP@...
Continuous-flow synthesis of primary amines: Metal-free reduction of aliphatic and aromatic nitro derivatives with trichlorosilane
- Riccardo Porta,
- Alessandra Puglisi,
- Giacomo Colombo,
- Sergio Rossi and
- Maurizio Benaglia
Beilstein J. Org. Chem. 2016, 12, 2614–2619, doi:10.3762/bjoc.12.257
- synthetically relevant intermediates (precursors of baclofen and boscalid). Keywords: chemoselectivity; continuous processes; flow synthesis; nitro reduction; trichlorosilane; Introduction The reduction of nitro compounds to amines is a fundamental transformation in organic synthesis. The nitration of
- . Flow chemistry has recently emerged as a powerful technology in synthetic chemistry [12] as it can reduce risks associated to the use of hazardous chemicals and favors reaction scale-up [13][14][15][16][17]. The possibility to efficiently perform nitro reduction in continuo would make the
- 91% and 93%, respectively, by using a residence time of 10 minutes only (when a residence time of 5 minutes was used a slightly lower yield was obtained – 81% for amine 2g). We then applied the trichlorosilane-mediated continuous-flow nitro reduction to the synthesis of advanced precursors of
Graphical Abstract
Scheme 1: Continuous flow reduction of 4-nitrobenzophenone using a 0.5 mL PTFE flow reactor.
Scheme 2: Continuous flow reduction of aromatic nitro compounds.
Scheme 3: Continuous-flow reduction of aliphatic nitro compounds.
Scheme 4: Synthesis of 2-(4’-chlrophenyl)aniline (4) with a 5 mL flow reactor.
Scheme 5: Synthesis of intermediate 6, a direct precursor of the drug baclofen.
Scheme 6: Continuous-flow reduction of 1a and in-line extraction.
Amyloid-β probes: Review of structure–activity and brain-kinetics relationships
- Todd J. Eckroat,
- Abdelrahman S. Mayhoub and
- Sylvie Garneau-Tsodikova
Beilstein J. Org. Chem. 2013, 9, 1012–1044, doi:10.3762/bjoc.9.116
- . Subsequent nitro reduction, reductive methylation, methyl ether cleavage, and pegylation gave the nonlabeled precursors 39a–c. The [18F]-label was introduced by using the standard [K/K222]18F in DMSO and acetonitrile reaction conditions (Scheme 3B) [16]. The [Re]- and [99mTc]-labeled flavone complexes 30a
- representative synthesis of stilbene 46a is shown (Scheme 4B). Initial Wadsworth–Emmons reaction between diethyl (4-nitrobenzyl)phosphonate (47) and 4-methoxybenzaldehyde (48) constructed the stilbene core 49. The target compound 46 was formed from a straightforward sequence of nitro reduction, reductive
- by subsequent radioiodination of compound 53 (Scheme 5B) [47]. The 1,2,4-oxadiazole core of [125I]51c was obtained by DCC/HOBt-mediated condensation of 4-bromobenzamidoxime (54) and p-nitrobenzoic acid (55). Subsequent nitro reduction, reductive methylation, and radioiodination gave [125I]51c (Scheme
Graphical Abstract
Figure 1: Structures of A. dyes originally used to stain Aβ and B. newer scaffolds explored for the developme...
Scheme 1: General synthetic strategies (Gs) used to introduce A. 18F, B. 11C, C. 99mTc/Re, and D. 123I and 125...
Scheme 2: A. Structures of radiolabeled chalcone analogues discussed. B.–D. Synthetic schemes for the prepara...
Scheme 3: A. Structures of the radiolabeled flavone and aurone analogues discussed. B. Synthetic scheme for t...
Scheme 4: A. Structures of the radiolabeled stilbene analogues discussed. B. Synthetic scheme for the prepara...
Scheme 5: A. Structures of the diphenyl-1,3,4- and diphenyl-1,2,4-oxadiazoles discussed. B.,C. Synthetic sche...
Figure 2: Structures of the radiolabeled benzothiazole analogues discussed.
Scheme 6: A.–F. Synthetic schemes for the preparation of [11C]56b, [11C]56c, 57, 58a,b, 61, and [18F]65a–d.
Scheme 7: A. Structures of the [Re]- and [99mTc]-labeled benzothiazole analogues discussed. B.,C. Synthetic s...
Figure 3: Structures of the radiolabeled benzoxazole analogues discussed.
Scheme 8: A.–E. Synthetic schemes for the preparation of 94, [123I]95e, 96–98.
Figure 4: Structures of the radiolabeled benzofuran analogues discussed.
Scheme 9: A.–E. Synthetic schemes for the preparation of 121, [125I]122a, 123a,b, 125a,b, and 126.
Scheme 10: A. Structures of the radiolabeled imidazopyridine analogues discussed. B. Synthetic scheme for the ...
Scheme 11: Synthetic scheme for the preparation of the benzimidazole 146.
Figure 5: Structures of the quinolines discussed.
Scheme 12: Synthetic scheme for the preparation of the naphthalene analogues 152 and 160a,b.
Scheme 13: A. Structures of the radiolabeled analogues resulting from the combination of various scaffolds. B.,...
Scheme 14: A.–C. Synthetic schemes for the preparation of radiolabeled probes with unique scaffolds.
Scheme 15: A. Structures of the oxazine-derived fluorescence probes discussed. B. Synthetic scheme for the pre...
Figure 6: Structure of THK-265 (190).
Scheme 16: Synthetic scheme for the preparation of quinoxaline analogue 191.
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
- antagonist candesartan (204, Atacand) is formed from an advanced diaminobenzene derivative, which in turn is prepared by a tin-mediated nitro reduction to form a highly substituted diaminobenzene (Scheme 41). This general strategy involving initial alkylation of 207 is often employed to control the
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).
