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Search for "cyanoketones" in Full Text gives 4 result(s) in Beilstein Journal of Organic Chemistry.
Synthesis of legonmycins A and B, C(7a)-hydroxylated bacterial pyrrolizidines
- Wilfred J. M. Lewis,
- David M. Shaw and
- Jeremy Robertson
Beilstein J. Org. Chem. 2021, 17, 334–342, doi:10.3762/bjoc.17.31
- pyrrolizidines; cyanoketones; legonmycin; vinylogous ureas; Introduction At least 40 members of the large class of pyrrolizidine alkaloids [1][2][3][4] have so far been characterized from bacterial cultures. Of these ‘bacterial pyrrolizidines’, those of the vinylogous urea type are particularly intriguing from
Graphical Abstract
Figure 1: The clazamycins, and selected bacterial pyrrolizidines of the vinylogous urea type. For consistency...
Figure 2: Key species in the biosynthesis of legonmycins A (3) and B (4), and the pyrrolizixenamides A–D (9–12...
Scheme 1: Preparation of the legonmycin core.
Scheme 2: Hypothesis for the oxidative hydrolysis of diacylated pyrrolizidinone 18 (R = iBu).
Scheme 3: Preparation of C(7a)-functionalized pyrrolizinone derivatives and synthesis of legonmycins A and B.
Hypervalent organoiodine compounds: from reagents to valuable building blocks in synthesis
- Gwendal Grelier,
- Benjamin Darses and
- Philippe Dauban
Beilstein J. Org. Chem. 2018, 14, 1508–1528, doi:10.3762/bjoc.14.128
- this issue of atom-economy, the group of Shafir has reported the metal- and base-free arylation of keto-esters and cyanoketones using [bis(trifluoroacetoxy)iodo]arenes ArI(OCOCF3)2 (Scheme 40) [78]. The reaction can also be applied to cyclic 1,3-diones with equal efficiency [79]. Mechanistic studies
Graphical Abstract
Scheme 1: Strategies to address the issue of sustainability with polyvalent organoiodine reagents.
Scheme 2: Functionalization of ketones and alkenes with IBX.
Scheme 3: Functionalization of pyrroles with DMP.
Scheme 4: Catalytic benzoyloxy-trifluoromethylation reported by Szabó.
Scheme 5: Catalytic benzoyloxy-trifluoromethylation reported by Mideoka.
Scheme 6: Catalytic 1,4-benzoyloxy-trifluoromethylation of dienes.
Scheme 7: Catalytic benzoyloxy-trifluoromethylation of allylamines.
Scheme 8: Catalytic benzoyloxy-trifluoromethylation of enynes.
Scheme 9: Catalytic benzoyloxy-trifluoromethylation of allenes.
Scheme 10: Alkynylation of N-(aryl)imines with EBX for the formation of furans.
Scheme 11: Catalytic benzoyloxy-alkynylation of diazo compounds.
Scheme 12: Catalytic asymmetric benzoyloxy-alkynylation of diazo compounds.
Scheme 13: Catalytic 1,2-benzoyloxy-azidation of alkenes.
Scheme 14: Catalytic 1,2-benzoyloxy-azidation of enamides.
Scheme 15: Catalytic 1,2-benzoyloxy-iodination of alkenes.
Scheme 16: Seminal study with cyclic diaryl-λ3-iodane.
Scheme 17: Synthesis of alkylidenefluorenes from cyclic diaryl-λ3-iodanes.
Scheme 18: Synthesis of alkyne-substituted alkylidenefluorenes.
Scheme 19: Synthesis of phenanthrenes from cyclic diaryl-λ3-iodanes.
Scheme 20: Synthesis of dibenzocarbazoles from cyclic diaryl-λ3-iodanes.
Scheme 21: Synthesis of triazolophenantridines from cyclic diaryl-λ3-iodanes.
Scheme 22: Synthesis of functionalized benzoxazoles from cyclic diaryl-λ3-iodanes.
Scheme 23: Sequential difunctionalization of cyclic diaryl-λ3-iodanes.
Scheme 24: Double Suzuki–Miyaura coupling reaction of cyclic diaryl-λ3-iodanes.
Scheme 25: Synthesis of a δ-carboline from cyclic diaryl-λ3-iodane.
Scheme 26: Synthesis of N-(aryl)carbazoles from cyclic diaryl-λ3-iodanes.
Scheme 27: Synthesis of carbazoles from cyclic diaryl-λ3-iodanes.
Scheme 28: Synthesis of carbazoles and acridines from cyclic diaryl-λ3-iodanes.
Scheme 29: Synthesis of dibenzothiophenes from cyclic diaryl-λ3-iodanes.
Scheme 30: Synthesis of various sulfur heterocycles from cyclic diaryl-λ3-iodanes.
Scheme 31: Synthesis of dibenzothioheterocycles from cyclic diaryl-λ3-iodanes.
Scheme 32: Synthesis of dibenzosulfides and dibenzoselenides from cyclic diaryl-λ3-iodanes.
Scheme 33: Synthesis of dibenzosulfones from cyclic diaryl-λ3-iodanes.
Scheme 34: Seminal study with linear diaryl-λ3-iodanes.
Scheme 35: N-Arylation of benzotriazole with symmetrical diaryl-λ3-iodanes.
Scheme 36: Tandem catalytic C–H/N–H arylation of indoles with diaryl-λ3-iodanes.
Scheme 37: Tandem N-arylation/C(sp2)–H arylation with diaryl-λ3-iodanes.
Scheme 38: Catalytic intermolecular diarylation of anilines with diaryl-λ3-iodanes.
Scheme 39: Catalytic synthesis of diarylsulfides with diaryl-λ3-iodanes.
Scheme 40: α-Arylation of enolates using [bis(trifluoroacetoxy)iodo]arenes.
Scheme 41: Mechanism of the α-arylation using [bis(trifluoroacetoxy)iodo]arene.
Scheme 42: Catalytic nitrene additions mediated by [bis(acyloxy)iodo]arenes.
Scheme 43: Tandem of C(sp3)–H amination/sila-Sonogashira–Hagihara coupling.
Scheme 44: Tandem reaction using a λ3-iodane as an oxidant, a substrate and a coupling partner.
Scheme 45: Synthesis of 1,2-diarylated acrylamidines with ArI(OAc)2.
(Thio)urea-mediated synthesis of functionalized six-membered rings with multiple chiral centers
- Giorgos Koutoulogenis,
- Nikolaos Kaplaneris and
- Christoforos G. Kokotos
Beilstein J. Org. Chem. 2016, 12, 462–495, doi:10.3762/bjoc.12.48
- -workers disclosed the first enantioselective reaction of α-cyanoketones 118 to α,β-unsaturated trifluoromethyl ketones 119, utilizing a novel organocatalyst that they developed containing a piperazine moiety (S)-120 (Scheme 38) [58]. The reaction proceeded through a Michael addition to the unsaturated
- dihydropyrans 122. They utilized the novel tyrosine-derived tertiary amine-thiourea 123 in quite low catalyst loading to catalyze the reaction between α-cyanoketones 118 and β,γ-unsaturated α-ketoesters 87 (Scheme 39) [59]. Initially a Michael reaction occurs, followed by a hemiacetalization reaction, providing
Graphical Abstract
Scheme 1: Activation of carbonyl compounds via enamine and iminium intermediates [2].
Scheme 2: Electronic and steric interactions present in enamine activation mode [2].
Scheme 3: Electrophilic activation of carbonyl compounds by a thiourea moiety.
Scheme 4: Asymmetric synthesis of dihydro-2H-pyran-6-carboxylate 3 using organocatalyst 4 [16].
Scheme 5: Possible hydrogen-bonding for the reaction of (E)-methyl 2-oxo-4-phenylbut-3-enoate [16].
Scheme 6: Asymmetric desymmetrization of 4,4-cyclohexadienones using the Michael addition reaction with malon...
Scheme 7: The enantioselective synthesis of α,α-disubstituted cycloalkanones using catalyst 11 [18].
Scheme 8: The enantioselective synthesis of indolo- and benzoquinolidine compounds through aza-Diels–Alder re...
Scheme 9: Enantioselective [5 + 2] cycloaddition [20].
Scheme 10: Asymmetric synthesis of oxazine derivatives 26 [21].
Scheme 11: Asymmetric synthesis of bicyclo[3.3.1]nonadienone, core 30 present in (−)-huperzine [22].
Scheme 12: Asymmetric inverse electron-demand Diels-Alder reaction catalyzed by amine-thiourea 34 [23].
Scheme 13: Asymmetric entry to morphan skeletons, catalyzed by amine-thiourea 37 [24].
Scheme 14: Asymmetric transformation of (E)-2-nitroallyl acetate [25].
Scheme 15: Proposed way of activation.
Scheme 16: Asymmetric synthesis of nitrobicyclo[3.2.1]octan-2-one derivatives [26].
Scheme 17: Asymmetric tandem Michael–Henry reaction catalyzed by 50 [27].
Scheme 18: Asymmetric Diels–Alder reactions of 3-vinylindoles 51 [29].
Scheme 19: Proposed transition state and activation mode of the asymmetric Diels–Alder reactions of 3-vinylind...
Scheme 20: Desymmetrization of meso-anhydrides by Chin, Song and co-workers [30].
Scheme 21: Desymmetrization of meso-anhydrides by Connon and co-workers [31].
Scheme 22: Asymmetric intramolecular Michael reaction [32].
Scheme 23: Asymmetric addition of malonate to 3-nitro-2H-chromenes 67 [33].
Scheme 24: Intramolecular desymmetrization through an intramolecular aza-Michael reaction [34].
Scheme 25: Enantioselective synthesis of (−)-mesembrine [34].
Scheme 26: A novel asymmetric Michael–Michael reaction [35].
Scheme 27: Asymmetric three-component reaction catalyzed by Takemoto’s catalyst 77 [46].
Scheme 28: Asymmetric domino Michael–Henry reaction [47].
Scheme 29: Asymmetric domino Michael–Henry reaction [48].
Scheme 30: Enantioselective synthesis of derivatives of 3,4-dihydro-2H-pyran 89 [49].
Scheme 31: Asymmetric addition of α,α-dicyano olefins 90 to 3-nitro-2H-chromenes 91 [50].
Scheme 32: Asymmetric three-component reaction producing 2,6-diazabicyclo[2.2.2]octanones 95 [51].
Scheme 33: Asymmetric double Michael reaction producing substituted chromans 99 [52].
Scheme 34: Enantioselective synthesis of multi-functionalized spiro oxindole dienes 106 [53].
Scheme 35: Organocatalyzed Michael aldol cyclization [54].
Scheme 36: Asymmetric synthesis of dihydrocoumarins [55].
Scheme 37: Asymmetric double Michael reaction en route to tetrasubstituted cyclohexenols [56].
Scheme 38: Asymmetric synthesis of α-trifluoromethyl-dihydropyrans 121 [58].
Scheme 39: Tyrosine-derived tertiary amino-thiourea 123 catalyzed Michael hemiaketalization reaction [59].
Scheme 40: Enantioselective entry to bicyclo[3.2.1]octane unit [60].
Scheme 41: Asymmetric synthesis of spiro[4-cyclohexanone-1,3’-oxindoline] 126 [61].
Scheme 42: Kinetic resolution of 3-nitro-2H-chromene 130 [62].
Scheme 43: Asymmetric synthesis of chromanes 136 [63].
Scheme 44: Wang’s utilization of β-unsaturated α-ketoesters 87 [64,65].
Scheme 45: Asymmetric entry to trifluoromethyl-substituted dihydropyrans 144 [66].
Scheme 46: Phenylalanine-derived thiourea-catalyzed domino Michael hemiaketalization reaction [67].
Scheme 47: Asymmetric synthesis of α-trichloromethyldihydropyrans 149 [68].
Scheme 48: Takemoto’s thiourea-catalyzed domino Michael hemiaketalization reaction [69].
Scheme 49: Asymmetric synthesis of densely substituted cyclohexanes [70].
Scheme 50: Enantioselective synthesis of polysubstituted chromeno [4,3-b]pyrrolidine derivatines 157 [71].
Scheme 51: Enantioselective synthesis of spiro-fused cyclohexanone/5-oxazolone scaffolds 162 [72].
Scheme 52: Utilizing 2-mercaptobenzaldehydes 163 in cascade processes [73,74].
Scheme 53: Proposed transition state of the initial sulfa-Michael step [74].
Scheme 54: Asymmetric thiochroman synthesis via dynamic kinetic resolution [75].
Scheme 55: Enantioselective synthesis of thiochromans [76].
Scheme 56: Enantioselective synthesis of chromans and thiochromans synthesis [77].
Scheme 57: Enantioselective sulfa-Michael aldol reaction en route to spiro compounds [78].
Scheme 58: Enantioselective synthesis of 4-aminobenzo(thio)pyrans 179 [79].
Scheme 59: Asymmetric synthesis of tetrahydroquinolines [80].
Scheme 60: Novel asymmetric Mannich–Michael sequence producing tetrahydroquinolines 186 [81].
Scheme 61: Enantioselective synthesis of biologically interesting chromanes 190 and 191 [82].
Scheme 62: Asymmetric tandem Henry–Michael reaction [83].
Scheme 63: An asymmetric synthesis of substituted cyclohexanes via a dynamic kinetic resolution [84].
Scheme 64: Three component-organocascade initiated by Knoevenagel reaction [85].
Scheme 65: Asymmetric Michael reaction catalyzed by catalysts 57 and 211 [86].
Scheme 66: Proposed mechanism for the asymmetric Michael reaction catalyzed by catalysts 57 and 211 [86].
Scheme 67: Asymmetric facile synthesis of hexasubstituted cyclohexanes [87].
Scheme 68: Dual activation catalytic mechanism [87].
Scheme 69: Asymmetric Michael–Michael/aldol reaction catalyzed by catalysts 57, 219 and 214 [88].
Scheme 70: Asymmetric synthesis of substituted cyclohexane derivatives, using catalysts 57 and 223 [89].
Scheme 71: Asymmetric synthesis of substituted piperidine derivatives, using catalysts 223 and 228 [90].
Scheme 72: Asymmetric synthesis of endo-exo spiro-dihydropyran-oxindole derivatives catalyzed by catalyst 232 [91]....
Scheme 73: Asymmetric synthesis of carbazole spiroxindole derivatives, using catalyst 236 [92].
Scheme 74: Enantioselective formal [2 + 2] cycloaddition of enal 209 with nitroalkene 210, using catalysts 23 ...
Scheme 75: Asymmetric synthesis of polycyclized hydroxylactams derivatives, using catalyst 242 [94].
Scheme 76: Asymmetric synthesis of product 243, using catalyst 246 [95].
Scheme 77: Formation of the α-stereoselective acetals 248 from the corresponding enol ether 247, using catalys...
Scheme 78: Selective glycosidation, catalyzed by Shreiner’s catalyst 23 [97].
Approaches towards the synthesis of 5-aminopyrazoles
- Ranjana Aggarwal,
- Vinod Kumar,
- Rajiv Kumar and
- Shiv P. Singh
Beilstein J. Org. Chem. 2011, 7, 179–197, doi:10.3762/bjoc.7.25
- -component synthesis and ring transformations provide useful synthetic routes to 5-aminopyrazoles. Pharmacologically active 5-aminopyrazoles. General equation for the condensation of β-ketonitriles with hydrazines. Reaction of hydrazinoheterocycles with α-phenyl-β-cyanoketones (4). Condensation of
Graphical Abstract
Figure 1: Pharmacologically active 5-aminopyrazoles.
Scheme 1: General equation for the condensation of β-ketonitriles with hydrazines.
Scheme 2: Reaction of hydrazinoheterocycles with α-phenyl-β-cyanoketones (4).
Scheme 3: Condensation of cyanoacetaldehyde (7) with hydrazines.
Scheme 4: Synthesis of 5-aminopyrazoles and their sulfonamide derivatives.
Scheme 5: Synthesis of 5-aminopyrazoles, containing a cyclohexylmethyl- or phenylmethyl- sulfonamido group at...
Scheme 6: Regioselective synthesis of 3-amino-2-alkyl (or aryl) thieno[3,4-c]pyrazoles 19.
Scheme 7: Solid supported synthesis of 5-aminopyrazoles.
Scheme 8: Synthesis of 5-aminopyrazoles from resin supported enamine nitrile 25 as the starting material.
Scheme 9: Two-step “catch and release” solid-phase synthesis of 3,4,5-trisubstituted pyrazoles.
Scheme 10: Synthesis of pyrazolo[5,1-d][1,2,3,5]tetrazine-4(3H)-ones.
Scheme 11: Synthesis of the 5,5-ring system, imidazo[1,2-b]pyrazol-2-ones.
Scheme 12: Synthesis of 5-amino-3-(pyrrol-2-yl)pyrazole-4-carbonitrile.
Scheme 13: Synthesis of N-(1,3-diaryl-1H-pyrazol-5-yl)benzamide.
Scheme 14: Synthesis of 3,7-bis(arylazo)-6-methyl-2-phenyl-1H-imidazo[1,2-b]pyrazoles.
Scheme 15: Synthesis of 3,5-diaminopyrazole.
Scheme 16: Synthesis of 5-amino-4-cyanopyrazole and 5-amino-3-hydrazinopyrazole.
Scheme 17: Synthesis of 3,5-diaminopyrazoles with substituted malononitriles.
Scheme 18: Synthesis of 3,5-diamino-4-oximinopyrazole.
Scheme 19: Synthesis of 4-arylazo-3,5-diaminopyrazoles.
Scheme 20: Synthesis of 3- or 5-amino-4-cyanopyrazoles.
Scheme 21: Synthesis of triazenopyrazoles.
Scheme 22: Synthesis of 5(3)-aminopyrazoles.
Scheme 23: Synthesis of 3-substituted 5-amino-4-cyanopyrazoles.
Scheme 24: Synthesis of 2-{[(1-acetyl-4-cyano-1H-pyrazol-5-yl)amino]methylene}malononitrile.
Scheme 25: Synthesis of 5-aminopyrazole carbodithioates and 5-amino-3-arylamino-1-phenylpyrazole-4-carboxamide...
Scheme 26: Synthesis of 5-amino-4-cyanopyrazoles.
Scheme 27: Synthesis of thiazolylpyrazoles.
Scheme 28: Synthesis of 5-amino-1-heteroaryl-3-methyl/aryl-4-cyanopyrazoles.
Scheme 29: Synthesis of 5-amino-3-methylpyrazole-4-carboxamide.
Scheme 30: Synthesis of 4-acylamino-3(5)-amino-5(3)-arylsulfanylpyrazoles.
Scheme 31: Synthesis of 5-amino-1-aryl-4-diethoxyphosphoryl-3-halomethylpyrazoles.
Scheme 32: Synthesis of substituted 5-amino-3-trifluoromethylpyrazoles 114 and 118.
Scheme 33: Solid-support synthesis of 5-N-alkylamino and 5-N-arylaminopyrazoles.
Scheme 34: Synthesis of 5-amino-1-cyanoacetyl-3-phenyl-1H-pyrazole.
Scheme 35: Synthesis of 3-substituted 5-amino-1-aryl-4-(benzothiazol-2-yl)pyrazoles.
Scheme 36: Synthesis of 5-amino-4-carbethoxy-3-methyl-1-(4-sulfamoylphenyl)pyrazole.
Scheme 37: Synthesis of inhibitors of hsp27-phosphorylation and TNFa-release.
Scheme 38: Synthesis of the diglycylpyrazole 142.
Scheme 39: Synthesis of 5-amino-1-aryl-4-benzoylpyrazole derivatives.
Scheme 40: Synthesis of 4-benzoyl-3,5-diamino-1-(2-cyanoethyl)pyrazole.
Scheme 41: Synthesis of the 5-aminopyrazole derivative 150.
Scheme 42: Synthesis of 3,5-diaminopyrazoles 153.
Scheme 43: Synthesis of 5-aminopyrazoles derivatives 155 via lithiated intermediates.
Scheme 44: Synthesis of 5-amino-4-(1,2,4-oxadiazol-5-yl)-pyrazoles 157.
Scheme 45: Synthesis of a 5-aminopyrazole with anticonvulsant activity.
Scheme 46: Synthesis of tetrasubstituted 5-aminopyrazole derivatives.
Scheme 47: Synthesis of substituted 5-aminopyrazoles from hydrazonoyl halides.
Scheme 48: Synthesis of 3-amino-5-phenylpyrazoles from isothiazoles.
Scheme 49: Synthesis of 5-aminopyrazoles via ring transformation.
