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 ...
The positional reactivity order in Friedel-Crafts benzoylation and benzylation of dibenzofuran (DB F) is found t o be 2 > 3 > 1 2 4. Both the partial rate factors and the positional selectivity for the benzylation of DBF are very l o w compared with those of benzoylation. In competitive benzoylation of 1,2,3,4tetramethyldibenzofuran (TMD) versus DBF, a large solvent effect has been observed on the relative rate (TMD versus DBF) as well as on the isomer ratio of 8t o 7-benzoyl-TMD, which appears to be due to the difference in solvation of the intermediate o-complex leading to each of the products. I n contrast, in the case of competitive benzylation of T M D versus DBF, neither solvent effect on the relative rate nor any isomer ratio was observed. The nature of the transition state determining the relative rate and the positional reactivity for benzylation has been deduced from these results.
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Untersucht wird die Friedel‐Crafts‐Benzylierung und ‐Benzoylierung von Dibenzofuran (DBF) und 1,2,3,4‐Tetramethyl‐DBF.
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