Dewar, Michael J. S.; Poesche, Werner H. published the artcile< New heteroaromatic compounds. XVIII. Boron-containing analogs of benz[a]anthracene>, Name: 4-Bromoisobenzofuran-1,3-dione, the main research area is .
The amines, 2,3-Ph(H2N)C10H6 (I) and 2-(2-H2NC6H4)C10H7 (II) on treatment with BCl3 and a catalytic amount of AlCl3 in boiling xylene gave the corresponding chloroborazarobenz[a]anthracenes (III, R = Cl) (IV) and (V, R = Cl) (VI). NaNO2 (55 ml., 2M) in concentrated H2SO4 stirred below 25° with addition of 18.8 g. 3,2-O2N(H2N)C10H6 in 670 ml. AcOH (boiled and cooled rapidly to 20°) and the mixture kept 15 min., added with stirring to 38 g. CuBr in 200 ml. 48% HBr and kept overnight, and diluted with H2O yielded 54% 3,2-Br(O2N)C10H6, m. 79-80°. The compound (20.8 g.) and 55 g. PhI stirred 36 hrs. at 110° with 31.8 g. Cu bronze yielded 74% 3,2-Ph(O2N)C10H6 (VII), m. 96.0-6.8° (MeOH). VII (6.0 g.) and 0.2 g. 10% Pd-C in 230 ml. boiling alc. treated gradually with 20 ml. N2H4.H2O and kept 1 hr. yielded quant. I, m. 82.7-3.5° (90% MeOH). I (10 g.) in 160 ml. dry xylene added (N atm.) slowly to 7.0 g. BCl3 in 45 ml. ice-cold xylene and the mixture treated with 0.2 g. AlCl3, the mixture heated to 140° in 4 hrs. and the temperature maintained 16 hrs., cooled and taken up in 750 ml. 2:1 Et2O-C6H6, the H2O-washed and dried (MgSO4) solution evaporated on a steam bath and the residue taken up in 500 ml. hot MeOH, the solution concentrated and kept at -15°, the product recovered from hot MeOH and the purified material (4.2 g.) recrystallized using an efficient dry box gave III (R = OMe) (VIII), m. 159° (evacuated capillary). The mother liquors gave 0.85 g. III (R = 1/2 O), C32H22B2N2O, m. 322°. VIII (1.3 g.) in 40 ml. dry Et2O stirred (H2O-free atm.) at 0° with addition of 12.5 ml. 0.6M MeMgBr and the mixture stirred 24 hrs. with rise of temperature to 20, the filtered solution evaporated and the residue sublimed at 150°/0.005 mm. gave III (R = Me) (VIIIa), m. 160.0-1.3° (petr. ether, b. 60-8°). LiAlH4 (1.35 millimoles) added to 3.86 millimoles VIII in 40 ml. dry Et2O and the mixture refluxed 2 hrs. with 0.45 millimole AlCl3 gave 5,6-borazarobenz[a]anthracene (III, R = H) (IX), m. 139° (decomposition). Cu bronze (46.5 g.), 65.0 g. 2-IC10H7, and 56.0 g. 1,2-Br(O2N)C6H4 stirred 40 hrs. at 110° gave 60% 2-(o-O2NC6H4)C10H7 (X), m. 101° (MeOH). X (9.0 g.) in 450 ml. alc. hydrogenated at 20° and 30 lb./in.2 with 0.3 g. 10% Pd-C and the filtered solution concentrated gave 6.0g. II, m. 95-7°. X (32 g.) and 1.0 g. 10% Pd-C refluxed 1 hr. in 1400 ml. alc. with gradual addition of 45 ml. N2H4.H2C and the filtered solution concentrated gave 22 g. II. II (22.0 g.) in 350 ml. dry xylene added slowly with stirring to 13.0 g. BCl3 in 100 ml. ice-cold xylene and the mixture heated 4 hrs. at 140° with 0.5 g. AlCl3 and stirred 16 hrs. at 140° gave 10.4 g. V (R = 1/2 O) (XI), m. 261-4°, recrystallized from PhMe(C) to give an analytical sample, m. 275.5°. Further concentration of the mother liquors gave a 2nd crop of XI (4.8 g., m. 264-5°), and evaporation of the filtrate yielded 8.6 g. residue (XII), m. 225-47°. The ether XI (12.7 g.) taken up in 500 ml. hot absolute MeOH and concentrated to 350 ml., cooled and the product (10.5 g., m. 174-6°) recrystallized from MeOH (C) gave V (R = OMe) (XIII), m. 183-4° (evacuated capillary). The filtrate evaporated and the residue combined with XII, the mixture recrystallized from absolute MeOH to give 4.80 g. XIII, and the filtrate evaporated in vacuo gave a dark brown oil with an ultraviolet spectrum identical with that of XIII and containing no other bands. XIII (2.6 g.) stirred at 20° in 100 ml. dry Et2O with dropwise addition of 15 ml. M MeMgBr in Et2O and the mixture stirred 2 hrs., the filtered solution diluted with moist Et2O and shaken with H2O, the organic layer dried over CaCl2 and evaporated yielded 87% product, m. 136-40°, sublimed at 120°/0.1 mm. to give V (R = Me) (XIV), m. 141-3°. XIII (1.00 g.) stirred at 0° in 30 ml. dry Et2O with gradual addition of 1.00 millimole LiAlH4 (standardized Et2O solution) and the mixture refluxed 2 hrs. with 0.04 g. AlCl3, the filtered solution evaporated and the residue sublimed at 120°/0.005 mm. gave 65% V (R = H) (XV), m. 136.5-7.0° (decomposition). XIII (2.0 g.) in 20 ml. hot AcOH treated with 10 ml. concentrated HCl and the mixture cooled quickly to 5°, diazotized with 0.60 g. NaNO2 in a min. of H2O and kept 2 hrs., added with stirring to 300 ml. boiling H2O and the mixture boiled 30 min., kept overnight and the precipitate recrystallized twice from PhMe(C) gave 64% 6-hydroxy-6,5-boroxarobenz[a]-anthracene (XVI), m. 279.5-81.0°. The cyclization of II to V rather than to a borazachrysene illustrated very clearly the large steric requirements of the Friedel-Crafts reaction. The charge transfer spectra of the complexes formed by III and V with tetracyanoethylene (XVII) were determined in CHCl3. No difficulty was encountered with the Me or MeO derivatives, VIII, VIIIa, XIII, or XIV, all of which gave stable colorations with XVII, but the parent compounds, IX and XV, reacted rapidly with the acceptor. XV in CHCl3 and XVII in CHCl3 initially gave a green mixture rapidly changing to violet before fading and forming a white precipitate The ultraviolet spectrum of the final colorless solution was identical with that of XIII, suggesting that EtOH in the CHCl3 was forming V (R = OEt) and precipitating (NC)2CHCH(CN)2. The wave lengths of the charge transfer spectra of XVII complexes are given (compound and wave lengths of charge transfer band in A given): IX, 614; VIII, 627; VIIIa, 620; XV, 690, 477; XIII, 701, 500; XIV, 704, 486. The π-electron distribution in these compounds is probably too uneven for first-order perturbation theory to be applicable. The ultra violet spectra of IX and XV in methylcyclohexane and alc.-free CHCl3, and of VIII, XIII, VIIIa, and XIV in CHCl3 were tabulated with the spectrum of benz[a]anthracene (XVIII) in methylcyclohexane listed for comparison. The estimated band maximum (mμ of π-π transitions in methyl cyclohexane for XVIII, IX, and XV were tabulated. The spectra of IX and XV are very similar to that of XVIII, the main difference being an increase in intensity of the α-bands in the hetero aromatics, in accordance with theory.
Journal of the American Chemical Society published new progress about Entropy. 82-73-5 belongs to class bromides-buliding-blocks, and the molecular formula is C8H3BrO3, Name: 4-Bromoisobenzofuran-1,3-dione.
Referemce:
Bromide – Wikipedia,
bromide – Wiktionary