Solvent effects on isomer distributions and relative rates in Friedel–Crafts benzylation and benzoylation of dibenzofuran derivatives

Keumi, Takashi; Nakamura, Masaru; Kitamura, Masao; Tomioka, Naoto; Kitajima, Hidehiko

doi:10.1039/p29850000909

Cited by 5 publications

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“…30] 8) The charge-transfer nitration carried out in acetonitrile also gave a mixture of the almost same composition as that for the thermal nitration (runs 38 and 46). It is worth noting that the nitration with tetranitromethane did not proceed without irradiation.…”

Section: Resultsmentioning

confidence: 96%

Positional reactivity of dibenzofuran in electrophilic substitutions

Keumi¹,

Tomioka²,

Hamanaka³

et al. 1991

J. Org. Chem.

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95; H, 7.31; N, 10.15.4-Amino-5-tert -butyl-rl'-(dimethylamino)bipheny1-3-carbonitrile (8c) was prepared from 0.17 g (0.49 mmol) of 13 in 25 mL of CH3CN by addition of 1 mL of HBF, (40% in ether).After being stirred for 45 min, the solution was treated with lu until an aqueous extract was no longer acidic. The solvent was evaporated, and the residue was several times extracted with ether. The resulting colorless material was recyrstallized from methanol and yielded 70 mg (51%) of 8c: mp 137-138 "C; MS m / z 293 (100, M' ), 278 (28), 263 (10); 'H NMR (90 MHz, CCl,) 6 1.44 (9, 9 H, tert-butyl), 2.95 (s,6 H, N(CH3),), 4.49 (s,2 H, NH,), 6.5-7.6 (m, 6 H, aromatic protons); l R (KBr) 347013390 (NH), 2900 (CH), 2205 (CN). Anal. Calcd for CIOHaN3: C, 77.78; H, 7.90; N, 14.32. Found: C, 77.61; H, 7.71; N, 14.02. Diethyl 2-[3,5-Di-tert-butyl-l-[4-(dimethylamino)-phenyl]-4-imino-2,5-cyclohexadien-1-yllmalonate ( 12). A 2.55-g (16-"01) portion of diethyl malonate was treated with 0.12 g (5.2 "01) of Na dissolved in 20 mL of EtOH. The resulting solution was added to a solution of 4c (from anodic oxidation of 0.28 g (0.86 mmol) of aniline IC) in acetonitrile. After immediate decolorization, the excess of diethylmalonate was evaporated at 100 "C (0.1 Torr). The product 12 was isolated as an oil (yield, 93%): MS m/z 482 (6, M+), 426 (13), 324 (loo), 309 (44), 173 (68); 'H NMR (90 MHz, CDC13), 6 1.13 (t, 6 H, J = 7 Hz, OCH,CH,), 1.31 (8, 18 H, tert-butyl), 2.89 ( 8 , 6 H, N(CH3),), 4.02 (4, J = 7 Hz, OCHzCH3), 4.17 (8, CH(CO0Et)z; the integration of the signals at 4.02 and 4.17 corresponds to 5 H), 6.68 (8, vinylic protons), 6.84 (q, A2Bz, J = 9 Hz, aromatic protons; the integration of the signals between 6.56 and 7.11 corresponds to 6 H), a signal for the NH proton was not found, in CeDe it was detected at 9.98 (9, broad, 1H); IR (KBr) 3400 (NH), 2960 (CH), 1760/1735 (C=O), 1565 (C=N) cm-'. Anal. Calcd for C29H42N204: C, 72.17; H, 8.77; N, 5.80. Found: C, 71.95; H, 8.61; N, 5.72. 1,5-Di-tert -butyl-3-[ 44 dimet hylamino) phenyl]-6-imino-2,4-cyclohexadiene-1-carbonitrile (13) was obtained after addition of a 7% excess of NBu4CN to the electrogenerated solution of 4c (from 0.27 g (0.83 mmol) of IC). It was recrystallized from petroleum ether (30/50), giving yellow crystals (yield, 64%): mp 98 "C dec; MS m / z 349 (1, M+), 324 (2), 293 (loo), 278 (36); 'H NMR (90 MHz, CC1$ 6 1.06 (8, 9 H, tert-butyl), 1.33 (8, 9 H, tert-butyl), 2.99 (9, 6 H, N(CH3),), 5.97 (d, 1 H, J = 2 Hz), 6.60 (d, J = 2 Hz, vinylic protons), 6.91 (9, A2B2, J = 9 Hz, aromatic protons, the integration of the signals between 6.50 and 7.50 corresponds to 5 H), 10.69 (9, broad, 1 H, NH); IR (KBr) 3390 (NH), 2890 (CH), 2225 (CN), 1585/1525 (C=N) cm-' . Anal. Calcd for C23H31N3: C, 79.04; H, 8.94; N, 12.02. Found: C, 79.25; H, 9.12; N, 12.23.Reaction of 4c with Thiophenolate Ion. To a solution of cation 4c (derived from 0.28 g (0.86 mmol) of IC) in acetonitrile were added 1 g of powdered NazCOs and 1 g (9.0 mmol) of thiophenol. From the resulting colorless solution ...

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Section: Resultsmentioning

confidence: 96%