Fluorene 1,3-dimethyl

The direct Suzuki coupling of 2,6-dibromo-DTT 97 with (4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yIIS - -hexy 1-2,2 -hi thiophene 150 and (4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)-9,9-dimethyl-fluorene 152 gave... 

One case of n—5 —n delocalization was demonstrated by Stevenson et al. (2006). The potassinm anion-radical salt of l-(9-methyl-9H-fluoren-9-yl)-4-methyl benzyl is characterized by the delocalization of an nnpaired electron within the fluorenyl moiety only. Its ESR spectrnm completely coincides with the spectrnm of the potassium anion-radical salt of the 9,9-dimethyl fluorene anion-radical in THE However, the cesium anion-radical salt of the fluorenyl methylbenzyl derivative produces the ESR spectrum corresponding to the placement of this cation between the fluorenyl and methylbenzyl moiety. The conditions of n—s—n delocalization appear An unpaired electron spends its time within both fluorenyl and methylbenzyl fragments. The situation is explained in Scheme 3.54. 

If an electron acceptor is available in homogeneous solution, photochemical reaction can be observed. For example, when 2 is excited (X > 350 nm) in anhydrous dimethylsulfoxide (DMSO), methylation occurs, ultimately giving rise to 9,9-dimethyl-fluorene in >80% yield. By analogy with Tolbert s mechanism for photomethylation in DMSO (4), such a process may be initiated by electron transfer to DMSO to form a caged radical-radical anion pair from which subsequent C-S cleavage occurs (eqn 4). 

Rearrangement of gibberellin Ax (IV) to the ketone (V) and oxidation of the latter gave a diketone (VI) which, on dehydrogenation gave 1,7-dimethyl-fluoren-2-ol (VII) whose structure was established by synthesis (13). 

The formation of fluorene and 4-methylfluorene by repeated passage of 2-methyl- and 2,2 -dimethyl-fluorene, respectively, over palladized charcoal at 450° was reported by Orchin.267... 

Trimethyl-phenyl)-iithanol1 /-Hydroxy-5,6-dimethyl-acenaphthen1 9-Hydroxy-fluoren 4... 

S)-N-(9-PHENYLFLUOREN-9-YL) ALANINE AND (S)-DIMETHYL N-(9-PHEN YLFLU0REN-9-YL)ASPARTATE L-Alanlne, N-(9-phenyl-9H-fluoren-9-yl)- and L-Aspartic acid, N-(9-phenyl-9H-fluoren-9-yl>, dimethyl ester)... 

Bromo-9-phenylfluorene 9H-Fluorene, 9-bromo-9-phenyl (9) (55135-66-5) (S)-Dimethyl aspartate hydrochloride Aspartic add, dimethyl ester, hydrochloride, L- (8) L-Aspartic acid, dimethyl ester, hydrochloride (9) (32213-95-9) 9-Methoxy-9-phenylfluorene 9H-Fluorene, 9-methoxy-9-phenyl- (9) (56849-87-7) 9-Phenyl-9-fluorenol Fluoren-9-ol, 9-phenyl- (8) 9H-Fluoren-9-ol, 9-phenyl- (9) (25603-67-2)... 

The electrogenerated radical anions of aromatic hydrocarbons, e.g. DPA, rubrene, fluorene, can also act as reductants towards electro-chemically obtained radical cations which are derivatives of other aromatic compounds such as N,N-dimethyl-/>-phenylenediamine (Wurster s red) 150> (see Section VIII. B.). When a mixture of DPA and a halide such as 99 (DPACI2) or 100 is electrolysed, a bright chemiluminescence is observed the quantum yields are about two orders of magnitude higher than that of the DPA radical anion-radical cation reaction 153>. 

Fluorene-[2,5-di(aminoethoxy)benzene] copolymers 370a,b have been synthesized by Huang and coworkers [437,438] as precursors to the first water-soluble cationic PFs 371, 372a-c (Scheme 2.58). Whereas the neutral polymers 370a,b readily dissolve in common organic solvents such as THF, chloroform, toluene, and xylene (but not in dimethyl sulfoxide (DMSO), methanol, or water) their quaternization produces material 371, which is insoluble in chloroform or THF but completely soluble in DMSO, methanol, and water. For... 

N,N-Dimethylacetamide (DMAc), 4-fluorobenzoic acid, 4-fluorobenzoyl chloride, aluminum chloride, 1 -bromonaphthalene, nitrobenzene, ferric chloride, dimethyl sulfone, 4,4 -dihydroxybiphenyl (DHB), and potassium carbonate were obtained from Aldrich and used without purification. 4,4-(Hexafluoroiso-propylidiene)-diphenol (6F-BPA), 9,9-bis(4-hydroxyphenyl)fluorene (HPF), and l,l-bis(4-hydroxyphenyl)-l-phenylethane (Bisphenol AP) were obtained from Ken Seika Corporation and used without purification. 4,4 -Dihydroxydiphenyl sulfone (DHDS) was obtained from Nachem Incorporated and used without purification. 

Buttressing effects are known to raise the barrier to rotation in the biphenyl series by preventing bond angle deformations of a substituent involved in direct interaction in the transition state. Similar effects were found in the 9-arylfluorene series (108). The barrier to rotation of 9-(3-bromo-6-methoxy-2,4-dimethyl-phenyl)fluorene (67, X = H) in chloroform-d at 56.3°C is 25.7 kcal/mol for... 

These conclusions were not applicable when sediment was the source of hydrocarbons. McCain et al. (5) studied the bioavailability of petroleum in sediment to English sole (Parophrys vetu-lus). Sediments rich in alkylated and non-alkylated benzenes and naphthalenes, together with fluorene and phenanthrene, were employed. After 11 days of exposure, samples of skin, muscle, and liver were examined. Fluorene and phenanthrene were not accumulated in the test fish however, significant concentrations of 1-methyl naphthalene, 2-methyl naphthalene, 2,6-dimethyl naphthalene and 1,2,3,4-tetramethylbenzene, were found in skin and liver (Table II) 1-methyl naphthalene and 2-methyl naphthalene were the major components of muscle. In each tissue examined, 1-methyl-naphthalene was the major component 1,2,3,4-tetramethylbenzene occurred in relatively low concentrations in skin and muscle in comparison to naphthalenes containing one and two alkyl groups. 

Oxidation of diphenylmethane in basic solutions involves a process where rate is limited by and equal to the rate of ionization of diphenylmethane. The diphenylmethide ion is trapped by oxygen more readily than it is protonated in dimethyl sulfoxide-text-butyl alcohol (4 to 1) solutions. Fluorene oxidizes by a process involving rapid and reversible ionization in text-butyl alcohol solutions. However, in the presence of m-trifluoromethylnitrobenzene, which readily accepts one electron from the carbanion, the rate of oxygen absorption can approach the rate of ionization. 9-Fluorenol oxidizes in basic solution by a process that appears to involve dianion or carbanion formation. Benzhydrol under similar conditions oxidizes to benzophenone by a process not involving carbanion or dianion formation. 

The hydroperoxide from the more acidic fluorene prefers to react via the decomposition process (Reaction 6 or 7) rather than the reductive reaction with dimethyl sulfoxide (Reaction 3). 

The anion derived from 2,3-dimethyl-l,4-naphthoquinone behaves as a quinone methide and undergoes a [l,4]-cycloaddition with the benzoquinone (193). The product is the xanthene derivative (194) (70JCS(C)722). There is no indication of the formation of the isomeric xanthene. A [l,3]-cycloaddition occurs simultaneously which leads to the fluorene derivative (195). 

Okamura and Katz have determined the pKa of 3H-pyrrolizine by measuring the rate of exchange of its protons with 5 M D20 in dimethyl-formamide containing 1 M triethylamine.115 The value of 29 seems surprisingly high compared with those of indene (18.2), cyclopentadiene (15), and fluorene (22.8). 

Irradiation of l,l,2,2-tetramethyl-l,2-disila (or germa) dibenzocyclohexa-3,5-diene gave rise to 9,9-dimethyl-9-sila (or germa) fluorene (83) by a diradical process92 (equation 31). This silafluorene could also be produced by pyrolysis of dimethyldiphenylsilane93. 

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