Benzo cjfurans

When 2-ethylbenzophenone is brominated as described earlier and the crude product treated with A -phenylmaleimide (refluxing CCI4) and dimethyl acetylenedicarboxylate (refluxing CHCI3), the Diels-Alder adducts 98 (mp 183-184°C, 40% presumably endo, when the H-NMR data are compared with those of 88 and 89) and 99 (mp 126.5-127°C, 57%) are isolated again a benzo [cjfuran (87 R = Me, R — Ph, R = H) is assumed to be an intermediate. ... 

Electron-withdrawing substituents seem to stabilize the benzo[cjfuran system as they do in the analogous benzo[c]thiophene and benzo [c]indole series. l-Cyano-3-phenylbenzo[c]furan (128) was obtained from the aldehyde 127 as stable yellow needles hydrolysis with base yields the carboxylic acid (129). Catalyzed hydrogenation of these cornpounds leads to 1,3-dihydrobenzo[c]furans (130, R = CH2NH2, COOH = Ph). Increased... 

Detailed accounts on the photooxygenation of 1,3-diphenyl-benzo[c]furan (and other benzo [cjfurans " ) reveal a dual mechanistic process. In the high concentration region 138 reacts in its ground state with singlet oxygen (generated either by dye sensitization [Scheme 15,... 

Schonberg et al. reportedly obtained the photodimer in excellent yields when a solution of 138 in diethyl phthalate was heated to 270°C for 30 minutes and then rapidly chilled with ice water (on slow cooling no dimer was obtained see also Mustafa ). These observations could not be substantiated a product obtained in this way (mp 200°C) differed from the photodimer (comparison of IR spectra). The structure of this product is not known. A dimer was also obtained when 1,3-bis(dimethyl-aminophenyl)benzo[c]furan was treated with acetic acid with sulfuric acid it was reconverted to the monomer. . There seem to be no reports concerning the photodimerization of other benzo[cjfurans. As we have found,... 

The parent compound (5), which was first prepared by Eugster and coworkers, is readily available by the tetrazine route. Benzo[cjfuran-... 

In contrast to benzo [cjfuran itself, quinonoid derivatives of benzo [c]-... 

Benzo[cjfuran, 6-amino-1,3-dihydro-1 -phenyl- H NMR, 4, 574 (75JA5160)... 

Oxidative cyclization of 361 and 363 yields ISti-electron analogs of benzo-[cjfuran (362, 364) in solution these possibly exist as several conformers, as do the Diels-Alder adducts obtained with dimethyl acetylenedicar-boxylate." ... 

The first synthesis of a stable benzo[c]furan, namely 1,3-diphenylbenzo-[cjfuran (7a), was reported in 1905. As pointed out by Blicke et... 

Telrahydro-3,5-dihydroxy-5-pentyl-2//,6//,8//-difuro[3,2-/ 3. 4 -cJfuran-6-one, see S-20085 6 /,7,12,12 -Tetrahydro-9.11 -dimethoxy-6,6-dimethyl-8-(3-mcthyl-2-butenyl)-6//-benzo[/ ]naphtho[2,3- /lpyran-3-ol. see H-30044... 

This article aims to review papers that were published in 2013 on reactions and syntheses of furans, tetrahydrofurans, and their derivatives. Reviews published in 2013 covered recent syntheses of furans (13CR1499,13SL2350), and benzo[l) or cjfuran-containing compounds (13CR1614). 

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