Solvent Effects in the Reactions of N-Bromosuccinimide with Toluene, Fluorene and Acenaphthene; Evidence for a Polar Mechanism in Propylene Carbonate

Ross, Sidney D.; Finkelstein, Manuel; Petersen, Raymond C.

doi:10.1021/ja01549a053

Cited by 78 publications

(27 citation statements)

References 5 publications

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“…Synthesis of 4-butylthio-1,8-naphthalic anhydride (4) Compounds 2, 3 and 4 were prepared according to Ross et al, Grayshan et al and Middleton and Parrick [10][11][12].…”

Section: Synthesis Of Intermediates Monomer and Copolymermentioning

confidence: 99%

Synthesis of a novel fluorescent coloured copolymer based on 4‐butylthio‐1,8‐naphthalimide

Safabakhsh

Khosravi

Gharanjig

et al. 2012

Coloration Technology

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A novel fluorescent coloured copolymer based on naphthalimide was prepared. Acenaphthene was brominated and oxidised to prepare 4-bromo-1,8-naphthalic anhydride and further reacted with butanethiol, 2-aminoethanol and acryloyl chloride, in order to obtain a new polymerisable fluorescent dye. The synthesised dyes were characterised by differential scanning calorimetry, absorption spectroscopy (Fourier Transform-infrared, proton and carbon nuclear magnetic resonance, ultravioletvisible spectroscopy) and fluorimetry. Molar extinction coefficients and wavelength maxima were obtained by examining the dye solution in ethanol. The solvatochromic effects of the prepared dyes have also been investigated. Finally, the dye was copolymerised with methyl methacrylate and an intrinsically coloured copolymer was obtained. The photophysical characteristics of the obtained copolymer have also been considered. It is assumed that 99% of the copolymerised dye is chemically bonded to polymer chains. The fluorescent characteristics of the copolymer in the solid state were determined by fluorometer and it was found that it has relatively high fluorescent intensity. The physical properties of the synthesised copolymer have been evaluated by differential scanning calorimetry and gel permeation chromatography.

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“…Synthesis of 4-butylthio-1,8-naphthalic anhydride (4) Compounds 2, 3 and 4 were prepared according to Ross et al, Grayshan et al and Middleton and Parrick [10][11][12].…”

Section: Synthesis Of Intermediates Monomer and Copolymermentioning

confidence: 99%

Synthesis of a novel fluorescent coloured copolymer based on 4‐butylthio‐1,8‐naphthalimide

Safabakhsh

Khosravi

Gharanjig

et al. 2012

Coloration Technology

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“…Et,O (80 ml) was heated to reflux for 2.5 h. After addition of Et,O (100 ml) and filtration, a soln. of 2-bromofluoren-9-one (37.56 g, 145.0 mmol) [30] in abs. toluene (1 1) was added, and the mixture was heated to reflux for 65 h. The cooled (r.t.) soh.…”

Section: H-c(9)mentioning

confidence: 99%

Analogs of Cinchona Alkaloids Incorporating a 9,9′‐Spirobifluorene Moiety

Winter-Werner¹,

Diederich²,

Gramlich³

1996

Helvetica Chimica Acta

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Dedicated to Professor V/adimir Pre/og on the occasion of his 90th birthday (6.111.96)The Cinchona alkaloid analogs (+)-and (-)4 with a quinuclidine-2-methanol residue attached to C(2) of a 9,9'-spirobifluorene moiety were prepared as a racemic mixture by reacting lithiated 2-bromo-9,9'-spirobifluorene 7 with (2-ethoxycarbonyl)quinuclidine (&)-6 to give ketone (+)-ti, followed by diastereoselective reduction with diisobutylaluminum hydride (DIBAL-H). The absolute configuration at C(9) and C(8), i.e., at the methanol bridge and the adjacent quinuclidine C-atom, in the two enantiomers of 5 is identical to the configuration at the corresponding centers in (-)-quinine (1) and (+)-quinidine (2), respectively. For the optical resolution of (&)-5, a chiral stationary phase for HPLC was prepared by covalently bonding quinine via a thiol spacer to a silica-gel surface. The enantiomer separation was accomplished at an OL value of 1.61 with (+)-5 being eluted last, in agreement with 'H-NMR studies in CDCl, which showed that (+)-5 underwent a more stable host-guest association with quinine than (-)-.5. 'H{ 'H} Nuclear Overhauser effect (NOE) difference spectroscopical analysis of the host-guest associations with quinine in CDCI,, combined with computer-model examinations, allowed the assignment of the absolute configurations as (+)-(8R,9S)-5 and (-)-(SS,SR)-5. A detailed conformational analysis displayed excellent agreement between the results of computational methods (Monte Carlo multiple minimum simulations, analyses of the total energy as a function of the flexible dihedral angles in the molecule) and 'H{'H)-NOE difference spectroscopical data. It was found that (-)-5 and (+)-5 differ significantly in their conformational preference from their natural counterparts quinine (1) and quinidine (2). Whereas the natural alkaloids prefer the 'open' conformation, with the quinuclidine N-atom pointing away from the quinoline ring, analog (+)-5 adopts preferentially (by ca. 4 kcal mol-l) a 'closed' conformation, in which the quinuclidine N-atom points into the cleft of the 9,Y-spirobifluorene moiety. Since the basic quinuclidine N-atom in the 'closed' conformation is sterically shielded from forming strong H-bonds, the new Cinchona alkaloid analogs form less stable host-guest associations via H-bonding than quinine or quinidine.

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“…Some evidence in favor of this mechanism is derived from the trans stereochemistry of the resultant addition products. I t has also been stated (21,22) that when N-bron~osuccinimide reacts in water or alcohols, it is converted by hydrolysis or alcoholysis to hypobromous acid or alltyl hypobromite and this viewpoint is strengthened by Traynham and Pascual's observation (25) that the substitution of aqueous N-bromosuccinimide for aqueous hypobromous acid in reactions with methylene cycloalltanes causes no change in product distribution. If the function of aqueous N-bromosuccinimide is indeed t o generate hypobromous acid, there is good reason t o believe that the mechanism just referred t o is valid, since the extensive work of de la Mare and co-ivorlters (26)(27)(28)(29) on the addition of aqueous hypohalous acids t o olefins has produced convincing evidence in favor of an electrophilic Can.…”

mentioning

confidence: 98%

“…No detailed studies appear t o have been conducted on the mechanism of additions t o double bonds via the use of N-bromoimides in polar solvents (or on the addition reactions which often accoinpany allylic bro~ninations of olefins by N-bromosuccinimide in non-polar solvents). Ilowever, it has been generally assumed that such reactions proceed by a polar mechanism (14,15,18,19,21,23,24) involving attack by a broininium ion or another electrophilic species containing bromine to yield a cyclic bromoniuin ion (14,18,23,24), a pi-complex (14, 25), or a carbonium ion (14,25)) which reacts subsequently with a nucleophile to form the final product. Some evidence in favor of this mechanism is derived from the trans stereochemistry of the resultant addition products.…”

mentioning

confidence: 99%

Cyclohexane Compounds: V. The Reaction of 1-Methoxycyclohexene-2 With Aqueous N-Bromosuccinimide. The 1-Methoxy-2-Bromo-3-Hydroxycyclohexanes

Bannard¹,

Casselman²,

Hawkins³

1965

Can. J. Chem.

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Interaction of 1-methoxycyclohexene-2 and aqueous N-bromosuccinimide gave a mixture of stereoisomeric bromohydrins, which, on treatment with aqueous sodium hydroxide, furnished 1~-methoxy-2a,3a-epoxycyclohexane (I) and la-methoxy-2a,3a-epoxycyclohexane (11) in the ratio 3: 1. The mixture from the N-haloimide-olefin reaction was separated by preparative vapor phase chromatography into three isomeric bromohydrins, la-methoxy-2a-hydroxy-3B-bromocyclohexane (IV), la-methoxy-2a-bromo-3B-hydroxycyclohexane (V), and la-methoxy-2B-bromo-3a-hydroxycyclohexane (VI) in the relative proportions 1:10:4. The 3-bromo isomer IV was identified by comparison with an authentic specimen prepared by the action of hydrobromic acid on the oxide 11. Compounds V and VI were shown to have the indicated structures by deetherification to the corresponding bromodiols VII and VIII in high yield, followed by debromination of the latter to trafzs-and cis-1,3-cyclohexanediol respectively. T h e product distribution is considered in relation to the intervention of electronic and steric factors in a possible mechanism suggested for the reaction between aqueous N-bron~osuccinimide and 1-methoxycyclohewne-2.Several years ago (1) we reported that the action of hydrobroinic acid on the stereoisoineric 1-methoxy-2,3-epoxycyclohexanes I and I1 led t o the formation of la-methoxy-2P-hydroxy-3a-bromocyclohexane (111) and 1a-n~ethoxy-2a-hydroxy-3~-broinocyclohexane (IV) respectively. The structures of these substances were established by a variety of chemical means (1) because we wished t o determine their relationship t o the mixture of bromohydrins resulting froin the action of aqueous N-broinosuccinimide upon l-inethoxycyclohexene-2. The latter bromohydrin mixture furnishes the oxides I and I1 in the ratioof 3 : l on treatment with aqueous sodium hydroxide and since 1,2-halohydrin t o oxide conversions involve a trans ring closure (3,4), it is apparent that the trans oxide I could have arisen from either or both of la-methoxy-2P-hydroxy-3a-brornocyclohexane (111) and la-methoxy-2a-bromo-3p-hydroxycyclohexane (V). Likewise the cis-oxide I1 wouId be formed if the mixture contained either la-methoxy-2a-hydroxy-3P-bromocyclol~exane (IV) or 1a-t~~ethoxy-2~-bromo-3a-hydroxycyclohexane (VI) or both. The present coinrnunication describes the manner in which the conlposition of the bronlohydrin mixture from the olefin-N-haloirnide reaction was determined and provides an unequivocal proof of structure for 1a-methoxy-2a-bromo-3~-hydroxycyclohexane (V) and la-n1etlloxy-2P-brorno-3a-h~.droxycyclohexane (VI).Attempts t o separate the components of the bromohydrin mixture by fractional distillation i n vacz~o and by coluinn chronlatography on alumina were unsuccessful. We therefore explored chemical separations based upon the forillation of crystalline derivatives. In this connection, the possible utility of acetate, p-toluenesulfonate, 2,4-dinitrobenzenesulfenate, dichloroacetate, 3-nitrophthalate, phenylurethane, and naphthylurethane derivatives was examine...

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Solvent Effects in the Reactions of N-Bromosuccinimide with Toluene, Fluorene and Acenaphthene; Evidence for a Polar Mechanism in Propylene Carbonate

Cited by 78 publications

References 5 publications

Synthesis of a novel fluorescent coloured copolymer based on 4‐butylthio‐1,8‐naphthalimide

Synthesis of a novel fluorescent coloured copolymer based on 4‐butylthio‐1,8‐naphthalimide

Analogs of Cinchona Alkaloids Incorporating a 9,9′‐Spirobifluorene Moiety

Cyclohexane Compounds: V. The Reaction of 1-Methoxycyclohexene-2 With Aqueous N-Bromosuccinimide. The 1-Methoxy-2-Bromo-3-Hydroxycyclohexanes

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