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Search for "tertiary alcohol" in Full Text gives 83 result(s) in Beilstein Journal of Organic Chemistry.
When cyclopropenes meet gold catalysts
- Frédéric Miege,
- Christophe Meyer and
- Janine Cossy
Beilstein J. Org. Chem. 2011, 7, 717–734, doi:10.3762/bjoc.7.82
- acted as a nucleophile, but the corresponding tertiary alcohol 9i was isolated in only modest yield (34%) (Scheme 5) [18]. Additional results were subsequently reported by Lee et al. in a full article in 2010 [19]. Due to their lower nucleophilic character compared to alcohols, phenols could not be used
Graphical Abstract
Scheme 1: General reactivity of cyclopropenes in the presence of gold catalysts.
Scheme 2: Cationic organogold species generated from cyclopropenone acetals.
Scheme 3: Rotation barriers around the C2–C3 bond (M06 DFT calculations).
Scheme 4: Au–C1 bond length in organogold species of type D.
Scheme 5: Gold-catalyzed addition of alcohols or water to cyclopropene 8.
Scheme 6: Gold-catalyzed addition of alcohols to cyclopropene 10.
Scheme 7: Mechanism of the gold-catalyzed addition of alcohols to cyclopropenes.
Scheme 8: Synthesis of tert-allylic ethers from cyclopropenes and allenes.
Scheme 9: Oxidation of the intermediate gold–carbene with diphenylsulfoxide.
Scheme 10: Gold, copper and Lewis acid-catalyzed reactions of cyclopropene 18.
Scheme 11: Mechanism of the Lewis acid-catalyzed reactions of cyclopropene 18.
Scheme 12: Gold-catalyzed rearrangement of vinylcyclopropenes 25.
Scheme 13: Gold-catalyzed rearrangement of cyclopropenes 27 to indenes 28.
Scheme 14: Gold-catalyzed rearrangement of cyclopropenes 29 to indenes 30.
Scheme 15: Gold-catalyzed rearrangement of cyclopropenyl ester 34a.
Scheme 16: Gold-catalyzed reactions of cyclopropenyl esters 34b–34d.
Scheme 17: Gold-catalyzed reactions of cyclopropenylsilane 34e.
Scheme 18: Gold-catalyzed rearrangement of cyclopropenylmethyl acetates.
Scheme 19: Mechanism of the gold-catalyzed rearrangement of cyclopropenes 39.
Scheme 20: Gold-catalyzed cyclopropanation of styrene with cyclopropene 8.
Scheme 21: Representative reactions of carbene precursors on gold metal.
Scheme 22: Intermolecular olefin cyclopropanation with gold carbenes generated from cyclopropenes.
Scheme 23: Gold-catalyzed formation of trienes from cyclopropenes and furans.
Scheme 24: Gold-catalyzed formation of trienes from cyclopropenes and furans.
Scheme 25: Gold-catalyzed formation of trienes from cyclopropenes and furans.
Scheme 26: Gold-catalyzed cycloisomerization of cyclopropene-ene 59.
Scheme 27: Gold-catalyzed cycloisomerization of substituted allyl cyclopropenyl carbinyl ethers 62a–62f.
Scheme 28: Gold-catalyzed cycloisomerization of cyclopropene-enes.
Scheme 29: Gold-catalyzed cycloisomerization of cyclopropene-ynes.
Scheme 30: Formation of products arising from a double cleavage process in the gold-catalyzed cycloisomerizati...
Scheme 31: Gold-catalyzed cycloisomerization of cyclopropene-ynes involving a double cleavage process.
Scheme 32: Gold-catalyzed reaction of cyclopropene-ynes, cyclopropene-enes and cyclopropene-allenes.
Asymmetric synthesis of tertiary thiols and thioethers
- Jonathan Clayden and
- Paul MacLellan
Beilstein J. Org. Chem. 2011, 7, 582–595, doi:10.3762/bjoc.7.68
- Mitsunobu reactions, there is one example of the displacement of a tertiary alcohol by a thiol under Mitsunobu conditions in the literature. La Clair reported the synthesis of the initially assigned structure of natural product hexacyclinol (27, Figure 4) [29]. The reported synthesis entailed Mitsunobu
Graphical Abstract
Figure 1: Seven out of the ten top selling drugs in the USA in 2009 contain sulfur. Figures in italics are to...
Figure 2: Naturally occurring organosulfur compounds glutathione and (R)-thioterpineol.
Figure 3: Methods for the synthesis of chiral tertiary thiol 1.
Scheme 1: Preparation of thioethers 4 from α-hydroxy esters.
Scheme 2: Nucleophilic substitution in α-aryl-α-hydroxy esters.
Scheme 3: Preparation of α,α-dialkylthioethers.
Scheme 4: Preparation of α-cyanothioacetate 12.
Scheme 5: Synthesis of (R)-(+)-spirobrassinin.
Scheme 6: Opening of cyclic sulfamidates with thiol nucleophiles.
Scheme 7: Synthesis of androgen 20.
Scheme 8: Synthesis of (+)-BE-52440A.
Scheme 9: The Mitsunobu reaction.
Scheme 10: Mitsunobu substitution at a quaternary centre.
Figure 4: Initially assigned structure of hexacyclinol.
Scheme 11: Preparation of thioether 29.
Scheme 12: Thioethers 33 prepared from phosphinites 31.
Scheme 13: Preparation of enantiomerically pure thiol 39.
Scheme 14: Thioethers prepared by a modified Mitsunobu reaction.
Scheme 15: Nucleophilic conjugate addition.
Scheme 16: Asymmetric addition to cyclic enones.
Scheme 17: Preparation of thioether 45.
Scheme 18: Catalytic kinetic resolution of the enantiomers of enone 46.
Scheme 19: Organocatalytic conjugate addition to nitroalkenes 49.
Scheme 20: Preparation of β-amino acid 54.
Scheme 21: Sulfur migration within oxazolidine-2-thiones 56.
Scheme 22: Preparation of thiols 62 by self-regeneration of stereocentres.
Scheme 23: Synthesis of (5R)-thiolactomycin.
Scheme 24: Preparation of tertiary thiols and thioethers via α-thioorganolithiums.
Scheme 25: Diastereoselective methylation of organolithium 71.
Scheme 26: Addition to lithiated thiocarbamate 75.
Scheme 27: Configurational lability in unhindered α-lithiothiocarbamates.
Scheme 28: Configurational stability in bulky α-lithiothiocarbamates.
Scheme 29: Asymmetric functionalisation of secondary benzylic thiocarbamates.
Scheme 30: Methylation of lithioallyl thiocarbamates.
Scheme 31: Asymmetric preparation of tertiary allylic thiols.
Scheme 32: Asymmetric preparation of thiols 96 by aryl migration in lithiated thiocarbamates.
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
- and dichloromethane selectively provides tertiary alcohol 183. In subsequent steps this imidazole is alkylated with the tetrazole containing biphenyl appendage, followed by ester hydrolysis and alkylation of the resulting carboxylate with 4-(chloromethyl)-5-methyl-2-oxo-1,3-dioxole to yield olmesartan
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).
Mitomycins syntheses: a recent update
- Jean-Christophe Andrez
Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33
Graphical Abstract
Scheme 1: Aziridine containing natural products.
Scheme 2: Mitomycin structures and nomenclature.
Scheme 3: Base catalysed epimerization of mitomycin B.
Scheme 4: Biosynthesis of mitomycin C (MMC) 7.
Scheme 5: Mode of action of mitomycin C.
Scheme 6: The N–C3–C9a disconnection.
Scheme 7: Danishefsky’s Retrosynthesis of mitomycin K.
Scheme 8: Hetero Diels–Alder reaction en route to mitomycins.
Scheme 9: Nitroso Diels–Alder cycloaddition.
Scheme 10: Frank azide cycloadddition.
Scheme 11: Final steps of mitomycin K synthesis. aPDC, DCM; bPhSCH2N3, PhH, 80 °C; cL-selectride, THF, −78 °C; ...
Scheme 12: Naruta–Maruyama retrosynthesis.
Scheme 13: Synthesis of a leucoaziridinomitosane by nitrene cycloaddition. aAlCl3-Et2O; bNaH, ClCH2OMe; cn-BuL...
Scheme 14: Thermal decomposition of azidoquinone 51.
Scheme 15: Diastereoselectivity during the cycloaddition.
Scheme 16: Oxidation with iodo-azide.
Scheme 17: Williams’ approach towards mitomycins.aDEIPSCl, Imidazole, DCM; bPd/C, HCO2NH4, MeOH; cAllocCl, NaH...
Scheme 18: Synthesis of pyrrolidones by homoconjugate addition.
Scheme 19: Homoconjugate addition on the fully functionalized substrate.
Scheme 20: Introduction of the olefin.
Scheme 21: Retrosynthesis of N–C9a, N–C3 bond formation.
Scheme 22: Synthesis of the pyrrolo[1,2]indole 82 using N-PSP activation.aAc2O, Py; bAc2O, Hg(OAc)2, AcOH, 90%...
Scheme 23: Synthesis of an aziridinomitosane. am-CPBA, DCM then iPr2NH, CCl4 reflux; bK2CO3, MeOH; cBnBr, KH; d...
Scheme 24: Oxidation products of a leucoaziridinomitosane obtained from a Polonovski oxidation.
Scheme 25: Polonovski oxidation of an aziridinomitosane. am-CPBA; bPd/C, H2; cDimethoxypropane, PPTS.
Scheme 26: The C1–C9a disconnection.
Scheme 27: Ziegler synthesis of desmethoxymitomycin A.aIm2C=O, THF; bNH3; cTMSOTf, 2,6-di-tert-butylpyridine, ...
Scheme 28: Transformation of sodium erythorbate.aTBDMSCl; bNaN3; cPPh3; d(Boc)2O, DMAP; eTBAF; fTf2O, Pyr.
Scheme 29: Formation of C9,C10-unsaturation in the mitomycins. am-CPBA, DCM; bO3, MeOH; cMe2S; dKHMDS, (EtO)3P...
Scheme 30: Fragmentation mechanism.
Scheme 31: Michael addition-cyclisation.
Scheme 32: SmI2 8-endo-dig cyclisation.
Scheme 33: Synthesis of pyrrolo[1,2-a]indole by 5-exo-dig radical cyclization.
Scheme 34: The C9–C9a disconnection.
Scheme 35: Intramolecular nitrile oxide cycloaddition.
Scheme 36: Regioselectivity of the INOC.
Scheme 37: Fukuyama’s INOC strategy.
Scheme 38: Synthesis of a mitosane core by rearrangement of a 1-(1-pyrrolidinyl)-1,3-butadiene.
Scheme 39: Sulikowski synthesis of an aziridinomitosene. aPd(Tol3P)2Cl2, Bu3SnF, 140; bH2, Pd/C; cTFAA, Et3N; d...
Scheme 40: Enantioselective carbene insertion.
Scheme 41: Parson’s radical cyclization.
Scheme 42: Cha’s mitomycin B core synthesis.
Scheme 43: The N-aromatic disconnection.
Scheme 44: Kishi retrosynthesis.
Scheme 45: Kishi synthesis of a starting material. aallyl bromide, K2CO3, acetone, reflux; bN,N-Dimethylanilin...
Scheme 46: Kishi synthesis of MMC 7. aLDA, THF, −78 °C then PhSeBr, THF, −78 °C; bH2O2, THF-EtOAc; cDIBAL, DCM...
Scheme 47: Acid catalyzed degradation of MMC 7.
Scheme 48: In vivo formation of apomitomycin B.
Scheme 49: Advanced intermediate for apomitomycin B synthesis.
Scheme 50: Remers synthesis of a functionalized mitosene. aTMSCl, Et3N, ZnCl2 then NBS; bAcOK; cNH2OH; dPd/C, H...
Scheme 51: Coleman synthesis of desmethoxymitomycin A. aSnCl2, PhSH, Et3N, CH3CN; bClCO2Bn, Et3N; cPPh3, DIAD,...
Scheme 52: Transition state and pyrrolidine synthesis.
Scheme 53: Air oxidation of mitosanes and aziridinomitosanes.
Scheme 54: The C9-aromatic disconnection.
Scheme 55: Synthesis of the aziridine precursor. aLHMDS, THF; bNaOH; c(s)-α-Me-BnNH2, DCC, HOBT; dDIBAL; eK2CO3...
Scheme 56: Synthesis of 206 via enamine conjugate addition.
Scheme 57: Rapoport synthesis of an aziridinomitosene.
Scheme 58: One pot synthesis of a mitomycin analog.
Scheme 59: Synthesis of compound 218 via intramolecular Heck coupling. aEtMgCl, THF, then 220; bMsCl, Et3N; cN...
Scheme 60: Elaboration of indole 223. aEt3N, Ac2O; bAcOH; cSOCl2, Et3N; dNaN3, DMF; eH2SO4, THF; fK2CO3, MeOH; ...
Scheme 61: C9-C9a functionalization from indole.
Scheme 62: Synthesis of mitomycin K. a2 equiv. MoO5.HMPA, MeOH; bPPh3, Et3N, THF-H2O; cMeOTf, Py, DCM; dMe3SiCH...
Scheme 63: Configurational stability of mitomycin K derivatives.
Scheme 64: Epimerization of carbon C9a in compound 227b.
Scheme 65: Corey–Chaykovsky synthesis of indol 235.
Scheme 66: Cory intramolecular aza-Darzens reaction for the formation of aziridinomitosene 239.
Scheme 67: Jimenez synthesis of aziridinomitosene 242.
Scheme 68: Von Braun opening of indoline 244.
Scheme 69: C9a oxidation of an aziridinomitosane with DDQ/OsO4.
Scheme 70: Synthesis of epi-mitomycin K. aNaH, Me2SO4; bH2, Pd/C; cMitscher reagent [165]; d[(trimethylsilyl)methyl...
Scheme 71: Mitomycins rearrangement.
Scheme 72: Fukuyama’s retrosynthesis.
Scheme 73: [2+3] Cycloaddition en route to isomitomycin A. aToluene, 110 °C; bDIBAL, THF, −78 °C; cAc2O, Py.; d...
Scheme 74: Final steps of Fukuyama’s synthesis.
Scheme 75: “Crisscross annulation”.
Scheme 76: Synthesis of 274; the 8-membered ring 274 was made using a crisscross annulation. a20% Pd(OH)2/C, H2...
Scheme 77: Conformational analysis of compound 273 and 275.
Scheme 78: Synthesis of a mitomycin analog. aNa2S2O4, H2O, DCM; bBnBr (10 equiv), K2CO3, 18-crown-6 (cat.), TH...
Scheme 79: Vedejs retrosynthesis.
Scheme 80: Formation of the azomethine ylide.
Scheme 81: Vedejs second synthesis of an aziridinomitosene. aDIBAL; bTPAP, NMO; c287; dTBSCl, imidazole.
Scheme 82: Trityl deprotection and new aziridine protecting group 300.
Scheme 83: Ene reaction towards benzazocinones.
Scheme 84: Benzazocenols via homo-Brook rearrangement.
Scheme 85: Pt-catalyzed [3+2] cycloaddition.
Scheme 86: Carbonylative lactamization entry to benzazocenols. aZn(OTf)2, (+)-N-methylephedrine, Et3N, TMS-ace...
Scheme 87: 8 membered ring formation by RCM. aBOC2O, NaHCO3; bTBSCl, Imidazole, DMF; callyl bromide, NaH, DMF; ...
Scheme 88: Aziridinomitosene synthesis. aTMSN3; bTFA; cPOCl3, DMF; dNaClO2, NaH2PO4, 2-methyl-2-butene; eMeI, ...
Scheme 89: Metathesis from an indole.
Scheme 90: Synthesis of early biosynthetic intermediates of mitomycins.
A stable enol from a 6-substituted benzanthrone and its unexpected behaviour under acidic conditions
- Marc Debeaux,
- Kai Brandhorst,
- Peter G. Jones,
- Henning Hopf,
- Jörg Grunenberg,
- Wolfgang Kowalsky and
- Hans-Hermann Johannes
Beilstein J. Org. Chem. 2009, 5, No. 31, doi:10.3762/bjoc.5.31
- unexpected behaviour of this adduct under acidic conditions. Results and Discussion Syntheses Benzanthrone (1) was treated with biphenyl-2-yl lithium (Scheme 1). After work-up and chromatography the surprisingly stable enol 4 was obtained in 56% yield. However, no formation of the tertiary alcohol 5 could be
Graphical Abstract
Scheme 1: Behaviour of benzanthrone (1) towards phenylmagnesium chloride (a), phenyl lithium (b), and bipheny...
Figure 1: 1H NMR spectra (200 MHz) of 4 in CDCl3 solution and time dependence.
Scheme 2: Proposed mechanism for the formation of 4 and its oxidation to 7.
Scheme 3: Conversion of the enol 4 under acidic conditions and reaction products.
Scheme 4: Proposed mechanism for the formation of spiro compound 11 and bicyclo[4.3.1]decane derivative 12.
Scheme 5: Proposed mechanism for the formation of 13.
Scheme 6: Proposed mechanism for the formation of 18 as a hydride source and further conversion to 7.
Figure 2: Ellipsoid representation (50% level) of compound 7 in the crystal.
Figure 3: Packing diagram of compound 7 viewed parallel to b; hydrogen bonds C-H···O are indicated by dashed ...
Figure 4: Ellipsoid representation (50% level) of compound 11 in the crystal.
Figure 5: Packing diagram of compound 11 viewed perpendicular to the bc plane; hydrogen bonds C-H···π are ind...
Figure 6: Ellipsoid representation (50% level) of compound 13 (d6-DMSO solvate) in the crystal. Hydrogen bond...
Figure 7: Packing diagram of compound 13 viewed parallel to c; DMSO molecules (including their hydrogen bonds...
Facile synthesis of two diastereomeric indolizidines corresponding to the postulated structure of alkaloid 5,9E- 259B from a Bufonid toad (Melanophryniscus)
- Angela Nelson,
- H. Martin Garraffo,
- Thomas F. Spande,
- John W. Daly and
- Paul J. Stevenson
Beilstein J. Org. Chem. 2008, 4, No. 6, doi:10.1186/1860-5397-4-6
- magnesium iodide gave the water soluble tertiary alcohol 1 in 96% yield. 7-Oxoheptanoic acid methyl ester was prepared by the literature procedure [36], by ozonolysis of 1-methoxycycloheptene, and then condensed with the amidoalcohol 1 with azeotropic removal of water to give the N,O-acetal 2 in 71% yield
- this intriguing transformation will be published elsewhere in due course. One-pot dehydration of the tertiary alcohol 3 was accomplished via the mesylate, and in situ elimination with triethylamine to give the diene 4 in 74% yield. Diene 4 smoothly underwent cyclisation to indolizidinone 5 when treated
Graphical Abstract
Figure 1: Subclasses of diastereoisomeric 5,8-disubstituted alkaloids. The absolute stereochemistry of 5,9Z-2...
Scheme 1: Reagents: (i) MeMgI. 96% (ii) PTSA 71%. (iii) TiCl4 CH2Cl2 25 oC 3d 68%. (iv) MsCl, Et3N, THF -40 o...
Figure 2: EIMS spectra of a) natural 5,9E-259B, b) synthetic 7, and c) synthetic minor diastereomer of 7. Str...
Figure 3: Vapor-phase FTIR spectra of a) natural 5,9E-259B, and b) synthetic 7. Structure shown with relative...
The first organocatalytic carbonyl- ene reaction: isomerisation- free C-C bond formations catalysed by H-bonding thio- ureas
- Matthew L. Clarke,
- Charlotte E. S. Jones and
- Marcia B. France
Beilstein J. Org. Chem. 2007, 3, No. 24, doi:10.1186/1860-5397-3-24
- after 3 hours reaction time. A 96% yield of the desired isomerically pure tertiary alcohol was obtained in the presence of 5. In contrast, the uncatalysed background reaction yields just 19%. Reactions monitored by 19F NMR reveal that good conversion (70%) was also possible after 1 hour using 10 mol
Graphical Abstract
Scheme 1: Microwave promoted ene reaction of ethyl trifluoropyruvate with α-methyl styrene.
Scheme 2: Thiourea catalysed ene reaction.
Scheme 3: Asymmetric carbonyl ene reaction mediated by chiral thiourea.
Scheme 4: Reaction between ethyl trifluoropyruvate and various alkenes.
Synthesis of novel (1-alkanoyloxy- 4-alkanoylaminobutylidene)-1,1-bisphosphonic acid derivatives
- Petri A. Turhanen and
- Jouko J. Vepsäläinen
Beilstein J. Org. Chem. 2006, 2, No. 2, doi:10.1186/1860-5397-2-2
- esters like P(O)-O-Me as well as an acyl group at the tertiary alcohol group are stable against enzymatic hydrolysis. [18] However, the latter decomposed gradually due to chemical hydrolysis. Because of the extreme hydrophilic character of HABBPA, its solubility and reactivity in organic solvents is very
Graphical Abstract
Figure 1:
Scheme 1: Preparation of (1-alkanoyloxy-4-alkanoylaminobutylidene)-1,1-bisphosphonic acid derivatives 1a (R =...
