cas 6267-34-1, 4-BROMO-3,5-DIMETHYLANISOLE

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A Mild Heteroatom (O -, N -, and S -) Methylation Protocol Using Trimethyl Phosphate (TMP)-Ca(OH) 2Combination
A mild heteroatom methylation protocol using trimethyl phosphate (TMP)-Ca(OH)2combination has been developed, which proceeds in DMF, or water, or under neat conditions, at 80 °C or at room temperature. A series of O-, N-, and S-nucleophiles, including phenols, sulfonamides, N-heterocycles, such as 9H-carbazole, indole derivatives, and 1,8-naphthalimide, and aryl/alkyl thiols, are suitable substrates for this protocol. The high efficiency, operational simplicity, scalability, cost-efficiency, and environmentally friendly nature of this protocol make it an attractive alternative to the conventional base-promoted heteroatom methylation procedures.
Tang, Yu,Yu, Biao
(2022/03/27)

Mechanistic studies of adamantylacetophenones with competing reaction pathways in solution and in the crystalline solid state
Photochemical reactions in crystals occur under conditions of highly restricted molecular mobility such that only one product is generally obtained, even when there are many others that can be observed in the gas phase or in solution. A series of 2-(1-ada
Hipwell, Vince M.,Garcia-Garibay, Miguel A.
p. 11103 - 11113
(2019/09/30)

Environmentally benign indole-catalyzed position-selective halogenation of thioarenes and other aromatics
Halogenated aromatic compounds are the cores of many pharmaceutical, agricultural and chemical products but they are commonly prepared using electrophilic halogenation reactions in non-green chlorinated solvents under harsh conditions. A separate problem happens in the aromatic halogenation of thioarenes because they readily undergo oxidative side-reactions. Herein we report an environmentally benign electrophilic bromination of aromatics using an indole-catalytic protocol, which is suitable for a wide range of substrates including thioarenes.
Shi, Yao,Ke, Zhihai,Yeung, Ying-Yeung
supporting information
p. 4448 - 4452
(2018/10/17)

Substituents Have a Large Effect on Photochemical Generation of Benzyl Cations and DNA Cross-Linking
Photoactivated DNA interstrand cross-linking agents have a wide range of biological applications. Recently, several aryl boronates have been reported to induce DNA interstrand cross-link (ICL) formation via carbocations upon photoirradiation. Herein, we synthesized a series of new bifunctional phenyl compounds to test the generality of such a mechanism, and to understand how the chemical structure influences carbocation formation and the DNA cross-linking process. These compounds efficiently form DNA ICLs via generated benzyl cations upon 350 nm irradiation. The DNA cross-linking efficiency and the pathway for carbocation generation depend on both the aromatic substituents and the leaving groups. Bromine as a leaving group facilitates the DNA cross-linking process in comparison with trimethyl ammonium salt. Both electron-donating and -withdrawing substituents induce bathochromic shifts, which favor photoinduced DNA ICL formation. For the bromides, the benzyl cation intermediates were generated through oxidation of the corresponding benzyl radicals. However, for the ammonia salts, the benzyl cations were formed through two pathways: either through oxidation of the benzyl radicals or by direct heterolysis of the C?N bond. Photoinduced C?N homolysis to form benzyl radicals occurred with compounds having donating substituents, whereas direct heterolysis of the C?N bond occurred with those bearing withdrawing substituents. The adducts formed between 1 a and four natural nucleosides were characterized, indicating that the alkylation sites for the photogenerated benzyl cations are dG, dA, and dC.
Fan, Heli,Sun, Huabing,Peng, Xiaohua
p. 7671 - 7682
(2018/05/14)

Zwitterionic-Salt-Catalyzed Site-Selective Monobromination of Arenes
A zwitterionic-salt-catalyzed electrophilic monobromination of arenes with high regioselectivity has been developed. Under mild reaction conditions, a wide range of monobrominated aromatic compounds can be obtained in excellent yields. The reaction can be operated using an extremely low catalyst loading (0.05 mol %) with the inexpensive brominating agent N-bromosuccinimide. The versatility of this catalytic protocol has been demonstrated by the scale-up reaction with a 0.01 mol % catalyst loading to provide the selectively halogenated compound in quantitative yield.
Xiong, Xiaodong,Tan, Fei,Yeung, Ying-Yeung
supporting information
p. 4243 - 4246
(2017/08/23)

COLORING COMPOSITION, INKJET INK, FABRIC PRINTING METHOD, AND DYED OR PRINTED FABRIC
PROBLEM TO BE SOLVED: To provide a coloring composition having excellent light resistance and excellent storage stability, inkjet ink comprising the coloring composition, a fabric printing method, and a dyed or printed fabric. SOLUTION: The present invent
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Paragraph 0262; 0263; 0264

(2017/06/02)

NOVEL COMPOUND, COLORING COMPOSITION FOR DYEING OR TEXTILE PRINTING, INK JET INK, METHOD OF PRINTING ON FABRIC, AND DYED OR PRINTED FABRIC
Provided are a compound represented by any one of Formulae (1) to (3) (for example, the following compound), a coloring composition for dyeing or textile printing including the compound, an ink jet ink including the coloring composition for dyeing or text
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Paragraph 0408; 0409

(2017/05/10)

A Divergent Approach to the Diastereoselective Synthesis of 3,3-Disubstituted Oxindoles from Atropisomeric N-Aryl Oxindole Derivatives
3,3-Disubstituted oxindoles were divergently synthesized by diastereoselective transformations including nucleophilic addition, alkylation, and cycloaddition using common, axially chiral N-aryl oxindoles. Notably, high diastereoselectivities (up to >95:5) were observed with ortho-monosubstituted N-aryl oxindoles to give various oxindole scaffolds, and facile removal of the p-(benzyloxy)aryl moiety in axially twisted amides was achieved by a mild, two-step sequence.
Nakazaki, Atsuo,Mori, Ayako,Kobayashi, Susumu,Nishikawa, Toshio
supporting information
p. 3267 - 3274
(2016/11/29)

(S) - 2 - (2,3-dihydrobenzo-furan-3-yl) acetic acid derivatives, its preparation process and its use in medicine
The invention relates to an (S)-2-(2,3-dihydrobenzofuran-3-radical) acetic acid derivative, a preparation method of the derivative, a medicine composition containing the derivative and the application of the derivative serving as a therapeutic agent, particularly GPR40/FFA1, and particularly provides the (S)-2-(2,3-dihydrobenzofuran-3-radical) acetic acid derivative shown in a general formula (I), and pharmaceutically acceptable salts of the derivative or a prodrug of the derivative. The compound is an agonist of a GPR40/FFA1 receptor and has a good preventive and therapeutic effect on lots of GPR40-mediated diseases, especially diabetes mellitus. The invention also provides a preparation method of the compound.
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Paragraph 0179-0185

(2016/10/08)

Electrophilic aryl-halogenation using N-halosuccinimides under ball-milling
We report here a methodology of chemo- and regio-selective aryl bromination and iodination using respective N-halosuccinimides at room temperature in the absence of any solvents, catalyst/additives under ball-milling condition. However, for chlorination ceric ammonium nitrate was used as additive. The coupled product succinimide, produced from the reactions, was recycled via regeneration of NBS. This methodology works with the electron-donor substituted or unsubstituted arenes.
Bose, Anima,Mal, Prasenjit
supporting information
p. 2154 - 2156
(2015/03/18)

Electrophilic aryl-halogenation using N-halosuccinimides under ball-milling
We report here a methodology of chemo- and regio-selective aryl bromination and iodination using respective N-halosuccinimides at room temperature in the absence of any solvents, catalyst/additives under ball-milling condition. However, for chlorination ceric ammonium nitrate was used as additive. The coupled product succinimide, produced from the reactions, was recycled via regeneration of NBS. This methodology works with the electron-donor substituted or unsubstituted arenes.
Bose, Anima,Mal, Prasenjit
supporting information
p. 2154 - 2156
(2014/04/03)

Synthesis of deuterated benzopyran derivatives as selective COX-2 inhibitors with improved pharmacokinetic properties
We designed a series of specifically deuterated benzopyran analogues as new COX-2 inhibitors with the aim of improving their pharmacokinetic properties. As expected, the deuterated compounds retained potency and selectivity for COX-2. The new molecules possess improved pharmacokinetic profiles in rats compared to their nondeuterated congeners. Most importantly, the new compounds showed pharmacodynamic efficacy in several murine models of inflammation and pain. The benzopyran derivatives were separated into their enantiomers, and the activity was found to reside with the S-isomers. To streamline the synthesis of the desired S-isomers, an organocatalytic asymmetric domino oxa-Michael/aldol condensation reaction was developed for their preparation.
Zhang, Yanmei,Tortorella, Micky D.,Wang, Yican,Liu, Jianqi,Tu, Zhengchao,Liu, Xiaorong,Bai, Yang,Wen, Dingsheng,Lu, Xin,Lu, Yongzhi,Talley, John J.
p. 1162 - 1166
(2014/12/10)

BILATERALLY-SUBSTITUTED TRICYCLIC COMPOUNDS FOR THE TREATMENT OF HUMAN IMMUNODEFICIENCY VIRUS TYPE-1 (HIV-1) INFECTION AND OTHER DISEASES
The invention relates to bilaterally-substituted tricyclic compounds and pharmaceutical compositions containing them, for use as medicaments. Due to their ability to interact with an internal RNA loop and to mimic a protein a-helix these compounds are effective in the treatment and/or prevention of HIV-1 (Human Immunodeficiency Virus-1) infection and other diseases such as those caused by other RNA viruses and by gram-positive and gram-negative bacteria, or infectious or chronic diseases responsive to inhibition of DNA transcription, or infectious or chronic diseases where these compounds can be used to modulate the function of RNA internal loops, or infectious or chronic diseases where these compounds can be used as agonists or inhibitors of a-helical proteins in interaction with other biomolecules.
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(2014/09/03)

Structure-based design of an RNA-binding p-terphenylene scaffold that inhibits HIV-1 rev protein function
Rev(ersing) RNA binding: RNA-binding inhibitors based on a bilaterally substituted p-terphenylene scaffold (green) project their substituents in a broad spatial angle and reproduce the interactions of a protein α-helix (red) embedded in its RNA receptor.
Gonzalez-Bulnes, Luis,Ibanez, Ignacio,Bedoya, Luis M.,Beltran, Manuela,Catalan, Silvia,Alcami, Jose,Fustero, Santos,Gallego, Jose
supporting information
p. 13405 - 13409
(2014/01/06)

GLUCAGON RECEPTOR MODULATORS
The present invention provides a compound of Formula (I) or a pharmaceutically acceptable salt thereof wherein R1, R2, R3, A1, A2, A3, A4, L, B1, B2, B3 and B4 are as defined herein. The compounds of Formula I have been found to act as glucagon antagonists or inverse agonists. Consequently, the compounds of Formula I and the pharmaceutical compositions thereof are useful for the treatment of diseases, disorders, or conditions mediated by glucagon.
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Page/Page column 36

(2012/08/27)

A highly active and selective palladium pincer catalyst for the formation of α-aryl ketones via cross-coupling
Several air and moisture stable Pd(ii) pincer complexes were synthesized via oxidative addition of Pd(0) to novel PheBox pincer ligand precursors. Low loadings (1 mol%) of the Pd complex [t-BuPhebox-Me2]PdBr are capable of efficiently promoting the selective α-monoarylation of a variety of ketones with numerous aryl bromides in only 1 h at 70°C with 82-99% yields.
Bugarin, Alejandro,Connell, Brian T.
supporting information; experimental part
p. 7218 - 7220
(2011/08/09)

Role of substitution on the photophysical properties of 5,5′-diaryl-2,2′-bipyridine (bpy*) in [Ir(ppy) 2(bpy*)]PF6 complexes: A combined experimental and theoretical study
The synthesis of a family of 4′-functionalized 5,5′-diaryl-2, 2′-bipyridines (bpy*; 6a-6g) is reported. These ligands were reacted with the dimer [(ppy)2IrCl]2 (ppyH = 2-phenylpyridine) and afforded, after subsequent counterion exchange, a new series of luminescent cationic heteroleptic iridium(III) complexes, [(ppy)2Ir(bpy*)] PF6 (8a-8g). These complexes were characterized by electrochemical and spectroscopic methods. The crystal structures of two of these complexes (8a and 8g) are reported. All of the complexes except for 8c and 8f exhibit intense and long-lived emission in both 2-MeTHF and ACN at 77 K and room temperature. The origin of this emission has been assigned by computational modeling to be an admixture of ligand-to-ligand charge-transfer [3LLCT; π(ppy) → π*(bpy*)] and metal-to-ligand charge-transfer [ 3MLCT; dπ(Ir) → π*(bpy*)] excited states that are primarily composed of the former. The luminescent properties for 8a-8c are dependent upon the functionalization at the 4′ position of the aryl substituents affixed to the diimine ligand, while those for 8d-8g are essentially independent because of an electronic decoupling of the aryls and bpy due to the substitution of o,o-dimethyl groups on the aryls, causing a near 90° angle between the aryl and bipyridyl moieties. A combined density functional theory (DFT)/time-dependent DFT study was conducted in order to understand the origin of the transitions in the absorption and emission spectra and to predict accurately emission energies for these complexes.
Ladouceur, Sebastien,Fortin, Daniel,Zysman-Colman, Eli
scheme or table
p. 5625 - 5641
(2010/08/04)

EMISSIVE ARYL-HETEROARYL ACETYLENES
Disclosed herein are compounds represented by a formula: R1—O-A-C≡C-D, where R1, A, and D are defined as described herein. Compositions and light-emitting devices related thereto are also disclosed.
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(2010/12/29)

TWISTED PI-ELECTRON SYSTEM CHROMOPHORE COMPOUNDS WITH VERY LARGE MOLECULAR HYPERPOLARIZABILITIES AND RELATED COMPOSITIONS AND DEVICES
Unconventional twisted π-electron system electro-optic (EO) chromophores/compounds, compositions and related device structures. Crystallographic analysis of several non-limiting chromophores reveals, for instance, large ring-ring dihedral twist angles and
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(2010/12/26)

The first total synthesis of lactonamycin, a hexacyclic antitumor antibiotic
The total synthesis of lactonamycin has been achieved. The synthesis includes sequential intramolecular conjugate addition of alcohols to the acetylenic ester, stereoselective glycosylation of the tertiary alcohol, and Michael-Dieckmann type cyclization w
Tatsuta, Kuniaki,Tanaka, Hiroaki,Tsukagoshi, Hitomi,Kashima, Takafumi,Hosokawa, Seijiro
scheme or table
p. 5546 - 5549
(2010/11/03)

Synthesis of arylbromides from arenes and Nbromosuccinimide bromosuccinimide (NBS) in acetonitrile - A convenient method for aromatic bromination
Regioselective and chemoselective electrophilic bromination of a wide series of activated arenes using N-bromosuccinimide (NBS) in acetonitrile occurs readily. Environmentally friendly conditions, large substrate scope, and ease of synthesis enhance the utility of this method over other electrophilic bromination conditions.
Zysman-Colman, Eli,Arias, Karla,Siegel, Jay S.
experimental part
p. 440 - 447
(2009/12/01)

Synthesis of novel structurally simplified estrogen analogues with electron-donating groups in ring A
A library of 25 novel estrogen analogues were prepared in five to eight steps from mostly commercially available substituted anisoles via bromination, formylation, Corey-Fuchs reaction, elimination, and Sonogashira reaction. Georg Thieme Verlag Stuttgart.
Tietze, Lutz F.,Vock, Carsten A.,Krimmelbein, Ilga K.,Nacke, Linda
experimental part
p. 2040 - 2060
(2009/12/27)

Ultralarge hyperpolarizability twisted π-electron system electro-optic chromophores: Synthesis, solid-state and solution-phase structural characteristics, electronic structures, linear and nonlinear optical properties, and computational studies
This contribution details the synthesis and chemical/physical characterization of a series of unconventional twisted π-electron system electro-optic (EO) chromophores. Crystallographic analysis of these chromophores reveals large ring-ring dihedral twist
Kang, Hu,Facchetti, Antonio,Jiang, Hua,Cariati, Elena,Righetto, Stefania,Ugo, Renato,Zuccaccia, Cristiano,Macchioni, Alceo,Stern, Charlotte L.,Liu, Zhifu,Ho, Seng-Tiong,Brown, Eric C.,Ratner, Mark A.,Marks, Tobin J.
p. 3267 - 3286
(2008/02/01)

Novel flavors, flavor modifiers, tastants, taste enhancers, umami or sweet tastants, and/or enhancers and use thereof
The present invention relates to the discovery that certain non-naturally occurring, non-peptide amide compounds and amide derivatives, such as oxalamides, ureas, and acrylamides, are useful flavor or taste modifiers, such as a flavoring or flavoring agents and flavor or taste enhancer, more particularly, savory (the “umami” taste of monosodium glutamate) or sweet taste modifiers,—savory or sweet flavoring agents and savory or sweet flavor enhancers, for food, beverages, and other comestible or orally administered medicinal products or compositions.
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Page/Page column 97

(2008/06/13)

Efficient synthesis and structural characteristics of zwitterionic twisted π-electron system biaryls
(Chemical Equation Presented) A series of unconventional twisted π-electron system molecules has been synthesized via Suzuki cross-coupling of two sterically hindered arenes. Crystallographic analysis of these molecules reveals a large ring-ring dihedral
Kang, Hu,Facchetti, Antonio,Stern, Charlotte L.,Rheingold, Arnold L.,Kassel, W. Scott,Marks, Tobin J.
p. 3721 - 3724
(2007/10/03)

THYROID HORMONE ANALOGUES AND METHODS FOR THEIR PREPARATION
Thyroid hormone analogues are disclosed. Methods of using such analogues and pharmaceutical compositions containing them are also disclosed, as are novel procedures for their preparation.
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Page/Page column 21

(2010/02/11)

NITROGENOUS HETEROCYCLIC DERIVATIVE HAVING 2,6-DISUBSTITUTED STYRYL
The invention provides a novel nitrogen-containing heterocyclic derivative having 2,6-disubstituted styryl and a pharmaceutically acceptable salt thereof, and a pharmaceutical composition comprising the nitrogen-containing heterocyclic derivative and a pharmaceutically acceptable salt thereof, in particular, a pharmaceutical composition effective as a sodium channel inhibitor, having an excellent analgesic action especially on neuropathic pain with minimized side effects.
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Page/Page column 15

(2010/02/14)

New 2,2′-substituted 4,4′-dimethoxy-6,6′-dimethyl[1, 1′-biphenyls], inducing a strong helical twisting power in liquid crystals
Based on the stabilisation of the molecular motion by the chiral residue, novel optically active biphenylic chiral dopants for nematic liquid crystals were developed. This molecular congestion was obtained by introducing mesogenic residues on the 2,2′-positions of the chiral biphenyl; this led to a novel molecular architecture that was found to be efficient. The synthesised optically active biphenyls were characterised with very short cholesteric pitches when used as chiral dopants in nematic liquid crystals. The synthesis of the enatiomerically pure biphenyl dopants and their preliminary physicochemical characterisations are described.
Holzwarth, Richard,Bartsch, Richard,Cherkaoui, Zoubair,Solladie, Guy
p. 3931 - 3935
(2007/10/03)

Novel thiophene amidines, compositions thereof, and methods of treating complement-mediated diseases and conditions
Disclosed is a method for treating the symptoms of an acute or chronic disorder mediated by the classical pathway of the complement cascade, comprising administering to a mammal in need of such treatment a therapeutically effective amount of a compound of Formula I or a solvate, hydrate or pharmaceutically acceptable salt thereof; wherein R1, R2, R3, R4 and R7 are defined in the specification, Z is SO or SO2, and Ar is an aromatic or heteroaromatic group as defined herein.
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(2008/06/13)

NOVEL THIOPHENE AMIDINES, COMPOSITIONS THEREOF, AND METHODS OF TREATING COMPLEMENT-MEDIATED DISEASES AND CONDITIONS
Disclosed is a method for treating the symptoms of an acute or chronic disorder mediated by the classical pathway of the complement cascade, comprising administering to a mammal in need of such treatment a therapeutically effective amount of a compound of Formula (I) or a solvate, hydrate or pharmaceutically acceptable salt thereof; wherein R1, R2, R3, R4 and R7 are defined in the specification, Z is SO or SO2, and Ar is an aromatic or heteroaromatic group as defined herein.
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Page 258

(2010/02/05)

An enantiospecific approach to 8,9-seco-C-aromatic taxanes
An enantiospecific approach to functionalised C-aromatic-8,9-seco-taxanes starting from the readily available monoterpene (R)-carvone is described.
Srikrishna,Ravi Kumar,Padmavathi
p. 1907 - 1909
(2007/10/03)

Decagram-Scale Synthesis of the Neocarzinostatin Carboxylic Acid
Neocarzinostatin carboxylic acid (2) was synthesized on a 10-g scale in 9 steps and 43% overall yield from 3,5-dimethylanisol (9) (Schemes 5, 7). The hindered bromoarene 23, reached after 3 steps, underwent a high-temperature Heck coupling with ethyl acry
Goerth, Felix Christian,Rucker, Mark,Eckhardt, Matthias,Brueckner, Reinhard
p. 2605 - 2612
(2007/10/03)

Thyroid hormone analogues and methods for their preparation
Thyroid hormone analogues are disclosed. Methods of using such analogues and pharmaceutical compositions containing them are also disclosed, as are novel procedures for their preparation.
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(2008/06/13)

Exploratory studies on the synthesis of the unusual diterpenoid tropone harringtoriolide
Various approaches to the total synthesis of the unusual diterpenoid tropone (2), discovered in the yew species Cephalotaxus harringtonia and C. hainanensis, are described. The rhodium-catalysed intramolecular cyclopropanation reaction of an ary1 ring by
Rogers, Daniel H.,Frey, Barbara,Roden, Francis S.,Russkamp, Friedrich-Wilhelm,Willis, Anthony C.,Mander, Lewis N.
p. 1093 - 1108
(2007/10/03)

Selective thyroid hormone analogs
Selective thyroid hormone agonists are disclosed that are highly selective for the TR beta subtype with high binding affinity. Methods of using such agonists and pharmaceutical compositions containing them are also disclosed, as are novel procedures for
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(2008/06/13)

Practical Synthesis of the Trisubstituted Naphthalene Carboxylic Acid from Neocarzinostatin Chromophore
Neocarzinostatin carboxylic acid (5) has been synthesized in 33% overall yield by a nine-step sequence which is operationally easy enough to be carried out by second-year chemistry students. 3,5-dimethylanisole was brominated in the para and in one benzyl
Rucker, Mark,Brückner, Reinhard
p. 1187 - 1189
(2007/10/03)

SYNTHESIS OF OPTICALLY ACTIVE O,O,O-TRIMETHYLKORUPENSAMINES A AND B
Hydrolysis of benzofuran derivative (10) with concomitant aromatisation produced the biaryl system (11).Subsequent Sharpless asymmetric epoxidation of the cinnamyl alcohol (13) gave atropisomers (14) and (15) conveniently separated by chromatography.Indep
Rao, A. V. Rama,Gurjar, Mukund K.,Ramana, D. Venkata,Chheda, Abhay K.
p. 1 - 6
(2007/10/02)

Stereoselective total synthesis of topographically constrained designer amino acids: 2',6'-dimethyl-β-methyltyrosines
The constrained aromatic α-amino acid 2',6'-dimethyl-β-methyl tyrosine (Figure 1) was designed to provide specific local constraints to peptides or peptide mimetics. We report here methods for the total asymmetric synthesis of all four stereoisomers. The
Qian,Russell,Boteju,Hruby
p. 1033 - 1054
(2007/10/02)

Hindered organoboron groups in organic chemistry. 27. Preparations and some properties of alkylbis(2,6-dimethyl-4-methoxyphenyl)boranes ((DMP)2BR)
Akylbis(2,6-dimethyl-4-methoxyphenyl)boranes ((DMP)2BR) have been synthesized in an attempt to overcome the limitations of the steric hindrance approach to the production of boron stabilised carbanions. Anion production from (DMP)2BR, followed by alkylations and condensations with aldehydes are reported. Reduction of (DMP)2F with potassium hydride yields the corresponding hydroborate. Attempts to isolate (DMP)2BH were unsuccessful but the borane was readily trapped with alkynes, yielding alkenylboranes. The allyl derivative, (DMP)2BAllyl, was made and some of its reactions were investigated.
Pelter, Andrew,Drake, Robert
p. 13775 - 13800
(2007/10/02)

Nuclear versus Side-Chain Bromination of Methyl-Substituted Anisoles by N-Bromosuccinimide
The reactions of methyl-substituted anisoles with N-bromosuccinimide in CCl4 are reported.In the absence of a catalyst and under irradiation, some of these substrates undergo nuclear bromination in competition with the well-known side-chain bromination.With 2-methylanisole and with 2,6-dimethylanisole, nuclear bromination is not observed, whereas with 3,5-dimethylanisole, nuclear bromination at the 4-position is the dominating reaction.Investigation of the reactivity of several other methyl-substituted anisoles revealed the following general trend: methyl-substituted anisoles are attacked at the position para to the methoxy group rather than at the side chain when (at least) two methyl groups are present at positions 3 and 5.When positions 2 and 6 are both occupied, nuclear bromination is retarded; in 2,6-dimethylanisole and 2,3,6-trimethylanisole, only side-chain bromination is observed.In contrast, in 2,3,5,6-tetramethylanisole, the 4-position is sufficiently reactive to be brominated, because the decrease in reactivity by the presence of two methyl groups at positions 2 and 6 is overruled by the two additional methyl groups at positions 3 and 5; as a result, both nuclear and side-chain bromination occur.The observed chemospecificity can be rationalized by a difference in mechanism: the side-chain bromination is radical reaction, while the nuclear bromination is an electrophilic aromatic substitution reaction, which is so far contrary to expectation, as irradiation had been expected to favor radical processes.
Gruter, Gert-Jan M.,Akkerman, Otto S.,Bickelhaupt, Friedrich
p. 4473 - 4481
(2007/10/02)

The Schmidt reaction of dialkyl acylphosphonates
The scope of the Schmidt rearrangement of ketones has been extended to dialkyl acylphosphonates (11a-11l). Surprisingly, it was found that 11a-11d and 11g, in which the acyl moiety was benzoyl alone or benzoyl bearing an electron-attracting or mildly electron-releasing substituent, yielded an overwhelming portion of products resulting from C-to-N migration of the aryl group (N-arylcarbamoylphosphonates, 12, and N-arylformamides, 15). Contrariwise, the arenecarbonylphosphonates, which carry a powerful electron-releasing p-alkoxy group, yielded products resulting from phosphonate group migration from C to N or elimination (dialkyl N-arenecarbonylphosphoramidates, 13, and arenecarbonitriles, 17, respectively). These counterintuitive results are rationalized by application of the concept of "degree of electron demand" to this area of intramolecular rearrangements. The possible existence of an additional pathway for the Schmidt rearrangement, involving protonation of the iminodiazonium ion, is proposed.
Sprecher, Milon,Kost, Daniel
p. 1016 - 1026
(2007/10/02)

Ring-Substituted y1,2-Bis(4-hydroxyphenyl)ethylenediamine>dichloroplatinum(II) Complexes: Compounds with a Selective Effect on the Hormone-Dependent Mammary Carcinoma
dichloroplatinum(II) complexes with one substituent in the 2-position (CH3, CF3, F, Br, I: meso- and dl-1-PtCl2, meso-(3-5)-PtCl2, meso-(7 and 8)-PtCl2) or two substituents in the 2,6-position (CH3, Cl: meso-2-PtCl2, meso- and dl-6-PtCl2) in both benzene rings were synthesized and tested for estrogenic and toxic activities.Two complexes (meso-6-PtCl2 and meso-7-PtCl2) possess both effects.In comparative tests on estrogen receptor positive and negative mammary tumors in cell culture (MCF 7, ER+ and MDA-MB 231, ER-) and in animals (MXT, ER+ and MXT, ER-, mouse), meso-6-PtCl2 shows a selective effect on the estrogen receptor positive mammary carcinoma.A further increase of efficacy was achieved with the water-soluble (sulfato)platinum(II) derivative (meso-6-PtSO4).On the DMBA-induced hormone dependent mammary carcinoma of the SD rat, meso-6-PtSO4 is significantly more active than its ligand (meso-6) and cisplatin.
Karl, Johann,Gust, Ronald,Spruss, Thilo,Schneider, Martin R.,Schoenenberg, Helmut,et al.
p. 72 - 83
(2007/10/02)

A General Synthetic Approach of Spirovetivanes. The Synthesis of (+/-)-Solavetivone, (+/-)-Hinesol, and Related Compounds
The synthetic procedure leading to preparation of representative compounds, (+/-)-solavetivone and (+)-hinesol, of two classes of spirovetivanes, is described.The procedure involves Diels-Alder reaction of 4-substituted 5,6-dihydro-3,5-dimethylanisoles wi
Murai, Akio,Sato, Shingo,Masamune, Tadashi
p. 2276 - 2281
(2007/10/02)

Π-CYCLIZATION: THE SYNTHESIS OF (+/-)-SOLAVETIVONE AND (+/-)-HINESOL
A general efficient approach leading to the total synthesis of (+/-)-solavetivone, (+/-)-hinesol, and related spirovetivanes, is described.The process involves stereoselective formation of the asymmetric center at C-7 by ?-cyclisation as a key step.
Murai, Akio,Sato, Shingo,Masamune, Tadashi
p. 1033 - 1036
(2007/10/02)

Vinyl Cation Intermediates in Solvolytic and Electrophilic Reactions. 1. Solvolysis of α-Arylvinyl Derivatives
The solvolysis of 16 α-arylvinyl tosylates, bromides, and chlorides has been investigated in various alcohol-water mixtures and in acetic acid at several temperatures.All substrates were substituted with either 2-methyl or 2,6-dimethyl groups to accelerate the rates of reaction.The major or exclusive product isolated in most cases was the acetophenone arising from hydrolysis of the expected enol ethers or acetates during workup.The kinetics were simple first order in the vast majority of cases, with excess base added to prevent side reactions.Leaving group effects, Winstein-Grunwald m values, Schleyer Q values, and effects of solvent nucleophilicity all point to a limiting SN1 ionization generating a vinyl cation intermediate, in which there is little rear-side nucleophilic assistance by solvent.Substituent effects led to ρ values in the range -3.9 to -5.3 vs. ?+.Activation parameters are typical for an SN1 process, and ΔS% is insensitive to the presence of zero, one, or two o-methyl groups, as are the effects of solvent polarity on the rates.The results should therefore be directly comparable with other solvolytic or electrophilic reactions generating formally similar vinyl cation intermediates.
Yates, Keith,Mandrapilias, George
p. 3892 - 3902
(2007/10/02)