- Synthesis of [6,6,m]-Tricyclic Compounds via [4+2] Cycloaddition with Au or Cu Catalyst
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We synthesized [6,6,6]- and [6,6,7]-tricyclic compounds via intramolecular [4+2] cycloaddition by gold or copper catalysts. Substrates for cyclization were prepared by coupling reactions between eight types of diyne and four types of aromatic moieties. We have successfully synthesized eleven tricyclic compounds.
- Kang, Juyeon,Ham, Seunghwan,Seong, Chaehyeon,Oh, Chang Ho
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supporting information
p. 1039 - 1043
(2021/05/05)
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- Oxidation of alcohols to aldehydes with bromoisobutyrate and dimethyl sulfoxide
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We have developed an efficient oxidation of primary alcohols to aldehydes with ethyl bromoisobutyrate and dimethyl sulfoxide. Diaryl ketone can also be prepared under this reaction system.
- Wu, Fei-Yue,Chen, Xiao-Hui,Zhou, Hai-Mei,Li, Jia-Qin,Cui, Hai-Lei
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supporting information
(2021/09/29)
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- Bromination of phenyl ether and other aromatics with bromoisobutyrate and dimethyl sulfoxide
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Bromoisobutyrate has been used for the first time as a general brominating source for the direct bromination of a diverse of simple phenyl ethers. Aromatic ethers bearing various substituents could be compatible in this reaction system delivering brominated arenes in moderate to good yields. The reaction system can also be expanded to bromination of phenols and unactivated arene. This process can be regarded as an alternative for the well-established bromination systems for bromoarene synthesis.
- Li, Jia-Qin,Chen, Xiao-Hui,Wang, Xian-Xun,Cui, Hai-Lei
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supporting information
(2021/09/09)
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- Synthesis of Axially Chiral 2,2′-Bisphosphobiarenes via a Nickel-Catalyzed Asymmetric Ullmann Coupling: General Access to Privileged Chiral Ligands without Optical Resolution
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We report an asymmetric homocoupling of ortho-(iodo)arylphosphine oxides and ortho-(iodo)arylphosphonates resulting in highly enantioenriched axially chiral bisphosphine oxides and bisphosphonates. These products are readily converted to enantioenriched b
- Zuo, Ziqing,Kim, Raphael S.,Watson, Donald A.
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supporting information
p. 1328 - 1333
(2021/02/01)
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- Assessment of the regioselectivity in the condensation reaction of unsymmetrical o-phthaldialdehydes with alanine
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One approach for the synthesis of isoindolinones, a privileged bioactive heterocyclic core structure, involves a condensation reaction of o-phthaldialdehydes with a suitable nitrogen-containing nucleophile. This fascinating reaction is revisited here in the context of the use of o-phthaldialdehydes that contain additional substituents in the aromatic ring leading to a detailed analysis of the regioselectivity of the reaction. Eleven monosubstituted o-phthaldialdehydes were synthesised and reacted with alanine. The regioselectivity observed across the eleven substrates led to the design of a disubstituted substrate that reacted with very high control. A gram-scale reaction followed by esterification gave one major regioisomer in high yield. In addition, the regioselectivity observed on reaction of two novel monodeuterated substrates led to an increased mechanistic understanding.
- D'Hollander, Agathe C.A.,Westwood, Nicholas J.
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p. 224 - 239
(2017/12/08)
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- A formal total synthesis of anti-Helicobacter pylori agent (+)-spirolaxine methyl ether
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A convergent, formal enantioselective synthesis of anti-Helicobacter pylori agent, (+)-spirolaxine methyl ether 2 has been achieved in high enantiomeric purity starting from commercially available 1,5-pentanediol. The strategy mainly comprises of the Noyori's asymmetric reduction and Brown allylation/Cu-catalyzed lactonization as the key step for the construction of key chiral intermediates, spiroketal 3 and phthalide fragment 4.
- Gadakh, Sunita K.,Sudalai, Arumugam
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- Domino [Pd]-Catalysis: One-Pot Synthesis of Isobenzofuran-1(3H)-ones
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An efficient domino [Pd]-catalysis for the synthesis of isobenzofuran-1(3H)-ones is presented. The strategy shows broad substrate scope and is amenable to o-bromobenzyl tertiary/secondary/primary alcohols. Significantly, the method was applied to the synthesis of antiplatelet drug n-butyl phthalide and cytotoxic agonist 3a-[4′-methoxylbenzyl]-5,7-dimethoxyphthalide.
- Mahendar, Lodi,Satyanarayana, Gedu
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p. 7685 - 7691
(2016/09/09)
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- Mechanistic studies of copper(I)-catalyzed 1,3-halogen migration
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An ongoing challenge in modern catalysis is to identify and understand new modes of reactivity promoted by earth-abundant and inexpensive first-row transition metals. Herein, we report a mechanistic study of an unusual copper(I)-catalyzed 1,3-migration of 2-bromostyrenes that reincorporates the bromine activating group into the final product with concomitant borylation of the aryl halide bond. A combination of experimental and computational studies indicated this reaction does not involve any oxidation state changes at copper; rather, migration occurs through a series of formal sigmatropic shifts. Insight provided from these studies will be used to expand the utility of aryl copper species in synthesis and develop new ligands for enantioselective copper-catalyzed halogenation.
- Van Hoveln, Ryan,Hudson, Brandi M.,Wedler, Henry B.,Bates, Desiree M.,Le Gros, Gabriel,Tantillo, Dean J.,Schomaker, Jennifer M.
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p. 5346 - 5354
(2015/05/13)
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- Asymmetric total synthesis of paecilomycin E, 10′-epi-paecilomycin e and 6′-epi-cochliomycin C
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The asymmetric total syntheses of naturally occurring resorcylic acid lactone paecilomycin E and two of its structural congeners have been reported in this article. The major highlight of the synthetic venture is the application of the late stage Mitsunob
- Pal, Pratik,Jana, Nandan,Nanda, Samik
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supporting information
p. 8257 - 8274
(2015/01/08)
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- Syntheses of 3,4-benzotropolones by ring-closing metatheses
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Ortho-lithiated styrenes or ortho-lithiated benzaldehyde dimethyl acetals were added to 2,2-dimethoxypent-4-enals 7. The resulting alcohols were carried on to the aromatic dienones 10. These were ring-closed by olefin metathesis. Hydrolysis of the dimethyl ketal moiety and enolization provided the 3,4-benzotropolones 5. Overall, this access comprises 4-6 steps and totaled a 22-81% yield.
- Arican, Deniz,Brückner, Reinhard
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supporting information
p. 2582 - 2585
(2013/07/19)
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- An efficient total synthesis of Benzocamphorin H and its anti-inflammatory activity
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A naturally occurring enynyl-benzenoid, Benzocamphorin H (1), from the edible fungus Taiwanofungus camphoratus (Antrodia camphorata) was characterized by the comprehensive spectral analysis. It displayed potent anti-inflammatory bioactivity and would be v
- Liao, Yu-Ren,Liang, Jun-Weil,Wu, Tian-Shung,Kuo, Ping-Chung,Huang, Shiow-Chyn
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supporting information
p. 6202 - 6204,3
(2012/12/11)
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- Total synthesis and absolute stereochemistry of seragakinone A
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(Chemical Equation Presented) Cyclic transformation: The key transformations of the asymmetric total synthesis of the marine-derived natural product seragakinone A are two N-heterocyclic carbene catalyzed benzoin cyclizations that result in the construction of two rings and a pinacol-type rearrangement to install the angular prenyl substituent.
- Takada, Akiomi,Hashimoto, Yoshimitsu,Takikawa, Hiroshi,Hikita, Katsuyoshi,Suzuki, Keisuke
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p. 2297 - 2301
(2011/04/16)
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- C2-symmetrical bipyridyldiols as promising enantioselective catalysts in Nozaki-Hiyama allylation
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Several new chiral bipyridyldiol ligands that promote the chromium-catalyzed enantioselective addition of allylic halides to aldehydes in up to 99% ee were synthesized. The chromium-catalyzed allylation of aldehydes using ligands 4 and 4a in the presence
- Huang, Xin-Ren,Pan, Xin-Hong,Lee, Gene-Hsian,Chen, Chinpiao
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supporting information; experimental part
p. 1949 - 1954
(2011/10/13)
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- SUBSTITUTED ISOQUINOLINES AND THEIR USE AS TUBULIN POLYMERIZATION INHIBITORS
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The present invention relates generally to substituted isoquinolines and their use as tubulin polymerization inhibitors. In particular, the invention relates to substituted isoquinolines which possess useful therapeutic activity, use of these compounds in methods of therapy and the manufacture of medicaments as well as compositions containing these compounds
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Page/Page column 84
(2011/12/14)
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- Probing the influence of an allylic methyl group in zearalenone analogues on binding to Hsp90
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By the replacement of an acetate with propionate by means of organic synthesis, a range of zearalenone analogues were prepared that feature an allylic methyl group. For the synthesis of the aliphatic region of the analogues, we used an asymmetric alkylati
- Rink, Christian,Sasse, Florenz,Zubrienae -, Asta,Matulis, Daumantas,Maier, Martin E.
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supporting information; experimental part
p. 14469 - 14478
(2011/03/21)
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- TREATMENT OR PROPHYLAXIS OF PROLIFERATIVE CONDITIONS
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The invention relates to novel compounds for use in the treatment or prophylaxis of cancers and other proliferative conditions that are for example characterized by cells that express cytochrome P450 1B1 (CYP1B1) and allelic variants thereof. The invention also provides pharmaceutical compositions comprising one or more such compounds for use in medical therapy, for example in the treatment of prophylaxis of cancers or other proliferative conditions, as well as methods for treating cancers or other conditions in human or non-human animal patients. The invention also provides methods for identifying novel compounds for use in the treatment of prophylaxis of cancers and other proliferative conditions that are for example characterized by cells that express CYP1 B1 and allelic variants thereof. The invention also provides a method for determining the efficacy of a compound of the invention in treating cancer.
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Page/Page column 33-34
(2010/11/17)
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- Nucleophilic substitution of nitro groups by [18F]fluoride in methoxy-substituted ortho-nitrobenzaldehydes-A systematic study
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As model reactions for the introduction of [18F]fluorine into aromatic amino acids, the replacement of NO2 by [18F]fluoride ion in mono- to tetra-methoxy-substituted ortho-nitrobenzaldehydes was systematically investigated. Unexpectedly, the highly methoxylated precursors 2,3,4-trimethoxy-6-nitrobenzaldehyde and 2,3,4,5-tetramethoxy-6-nitrobenzaldehyde showed high maximum radiochemical yields (82% and 48% respectively). When the electrophilicity of the leaving group substituted carbon atom is expressed by its 13C NMR chemical shift a good correlation with the reaction rate at the beginning of the reaction (first min) was found (R2 = 0.89), whereas the maximum radiochemical yields correlated much poorer with this electrophilicity parameter. This may be caused by side reactions becoming influencial in the further reaction course. As possible side reactions the demethylation of methoxy groups and intramolecular redox reactions could be detected by HPLC/MS.
- Shen, Bin,L?ffler, Dirk,Reischl, Gerald,Machulla, Hans-Jürgen,Zeller, Klaus-Peter
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experimental part
p. 216 - 224
(2009/07/25)
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- Nucleophilic acylation of o-quinone methides: An umpolung strategy for the synthesis of α-aryl ketones and benzofurans
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The synthesis of α-aryl ketones is accomplished by the direct nucleophilic acylation of o-quinone methide electrophiles. In this process, two reactive intermediates, carbonyl anions and o-quinone methides, are generated in one flask upon treatment of the corresponding thiazolium carbinols and silyl protected phenols with a soluble fluoride source. These intermediates then undergo productive addition reactions to afford the desired α-aryl ketone adducts. This new strategy has been applied to a short synthesis of the natural product demethylmoracin I. Copyright
- Mattson, Anita E.,Scheidt, Karl A.
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p. 4508 - 4509
(2007/10/03)
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- Photoinduced C-Br homolysis of 2-bromobenzophenones and Pschorr ring closure of 2-aroylaryl radicals to fluorenones
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(Chemical Equation Presented) A variety of diversely substituted 2-aroylaryl radicals, generated by photoinduced homolysis of 2-bromoarylketones, is shown to undergo Pschorr cyclization to yield fluorenones in moderate to excellent yields. The photochemical results illustrate that the substituents in the two phenyl rings of the 2-bromobenzophenone skeleton exert a dramatic influence on the reactivity of the derived 2-aroylaryl radicals. The disubstitution by methoxy groups in the radical ring renders the aryl σ-radical highly electrophilic and unreactive for hydrogen abstraction and cyclization. On the other hand, the substituents in the non-radical ring that strongly stabilize the hydrofluorenyl π-radical, formed subsequent to the attack of the 2-aroylaryl radical on the non-radical ring, promote cyclization to furnish fluorenones in excellent isolated yields.
- Moorthy, Jarugu Narasimha,Samanta, Subhas
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p. 9786 - 9789
(2008/03/17)
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- Total synthesis of topopyrones B and D
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(Chemical Equation Presented) We describe a straightforward synthesis of topopyrones B and D, which are potent and selective inhibitors of topoisomerase I. The chemistry should be suitable for additional structure-activity relationship (SAR) work.
- Tan, Jason Samuel,Ciufolini, Marco A.
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p. 4771 - 4774
(2007/10/03)
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- First total synthesis of two resveratrol derivatives
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The total synthesis of two resveratrol derivatives with an isobutyryl substituent is reported for the first time.
- Su, Ying,Ma, Junying,Peng, Xuanjia,She, Xuegong,Pan, Xinfu,Gao, Jinming
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p. 704 - 705
(2007/10/03)
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- Pyridinium hydrobromide perbromide induces ipsobromodeformylation in o-hydroxy and o-methoxy substituted aromatic aldehydes
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The reaction of o-hydroxy and o-methoxy substituted aromatic aldehydes with PHPB in pyridine gives aromatic bromination products including those arising from ipsobromodeformylation.
- Córdoba, Rubén,Plumet, Joaquín
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p. 9303 - 9305
(2007/10/03)
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- Total synthesis of the calphostins: Application of Fischer carbene complexes and thermodynamic control of atropisomers
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The total syntheses of the potent protein kinase C inhibitors calphostins A, B, C, and D as well as a variety of structural analogues are reported. An aminobenzannulation reaction of an enantiopure chromium Fischer carbene complex is utilized to prepare a pentasubstituted naphthylamine. After optimization of side-chain substituents, conversion of the naphthylamine to an o-naphthoquinone was followed by biomimetic oxidative dimerization using trifluoroacetic acid and air yielding a 1:2 P/M mixture of atropisomeric perylenequinones. Thermal equilibration to a 3:1 P:M atropisomeric ratio and separation of the perylenequinones followed by side chain desymmetrization and functionalization led to the total synthesis of enantio- and diastereomerically pure calphostin C in only twelve steps from commercially available starting materials. In addition, calphostins A, B, D, and several structural analogues were prepared to evaluate biological activities.
- Merlic,Aldrich,Albaneze-Walker,Saghatelian,Mammen
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p. 1297 - 1309
(2007/10/03)
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- Oxygenated dihydrophenanthrenes via quinol acetals: A brief synthesis of orchinol
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The dihydrophenanthrene phytoalexin Orchinol was synthesized in 5 steps from commercially available 3,5-dimethoxybenzaldehyde. The approach utilized a new synthon, p-benzoquinone dibenzylmonoacetal, which served as a phenol 3,4-dication equivalent in an a
- Broering, Teresa J.,Morrow, Gary W.
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p. 1135 - 1142
(2007/10/03)
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- The first synthesis of C-terminal biphenyl moiety of vancomycin
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A successful Palladium catalysed intramolecular coupling of phenyl rings corresponding to amino acids (R)-4-hydroxyphenylglycine and (S)-3,5-dihydroxyphenylglycine of vancomycin is achieved.
- Rama Rao,Chakraborty,Joshi
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p. 4045 - 4048
(2007/10/02)
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- General Method for the Synthesis of Phthalaldehydic Acids and Phthalides from o-Bromobenzaldehydes via Ortho-Lithiated Aminoalkoxides
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A general method for the synthesis of phthalaldehydic acids and phthalides, many of which are key intermediates in natural product synthesis, has been developed. o-Bromobenzaldehydes 1a-f were first protected in situ as α-morpholinoalkoxides by reaction with lithium morpholide.Treatment of the α-morpholinoalkoxides 3a-f with n-butyllithium (to exchange bromine with lithium) followed by sequential treatment with solid CO2 and dilute acid afforded the phthalaldehydic acids 6a-f, respectively.Reduction of 6a-f with NaBH4 in EtOH furnished the phthalides 7a-f, respectively, in nearly quantitative yields.Efficient methods for the synthesis of the o-bromobenzaldehydes 1a-d, which were not readily available, are also described.
- Sinhababu, Achintya K.,Borchardt, Ronald T.
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p. 2356 - 2360
(2007/10/02)
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- Aromatic Hydroxylation. Hydroxybenzaldehydes from Bromobenzaldehydes via Reaction of in Situ Generated, Lithiated α-Morpholinobenzyl Alkoxides with Nitrobenzene
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A general method for the one-step conversion of bromobenzaldehydes to the corresponding hydroxybenzaldehydes has been developed.The method involves in situ protection of the aldehyde function of the bromobenzaldehyde as its lithium morpholinoalkoxide, followed by lithium-bromine exchange, reaction with nitrobenzene at -75 deg C, and a subsequent acidic workup.The method has been applied to the synthesis of 4,5-dimethoxy-3-hydroxy- (1a), 3,5-dimethoxy-2-hydroxy- (2a), 3,5-bis(benzyloxy)-2-hydroxy- (2b), 3,4-dimethoxy-2-hydroxy- (14), 3-hydroxy-4,5-(methylenedioxy)- (16), and 4,5-dimethoxy-2-hydroxybenzaldehydes (18) from the bromobenzaldehydes 4, 12a, 12b, 13, 15, and 17, respectively.
- Sinhababu, Achintya K.,Borchardt, Ronald T.
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p. 1941 - 1944
(2007/10/02)
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