Naphtho furan derivative

The pyrolytic reactions of pentafluorophenyl and heptafluoro-2-naphthyl propargyl ethers give product mixtures containing benzo- and naphtho[6]furan derivatives, resulting from initial Claisen rearrangement followed by further intra- and intermolecular reactions.31 34... 

On condensation of peri-hydroxynaphthaldehydes with the Fischer base (82KGS1501) or with 1,3,3-trimethylisobenzofurylium perchlorate (86DOK639), 2-substituted heterocyclic 2//-naphtho[6c]furan derivatives... 

Naphtho[bc]furan derivatives are formed from peri-hydroxy-naphthylbenzyl ketone 49 by acidic or basic catalysis (83ZOR41I ... 

The naphtho[l,2-Z>]furan derivative (282) occurs in the dark green velvety mycelial mat produced upon cultured growth of the ascomycete Roesleria pallida. This compound which exhibits strong blue fluorescence was isolated from the green extracts of the fungus and the struc-... 

Van Eijk, G.W. A Naphtho[l,2-Z>]furan Derivative from the Fungus Roesleria pallida, Phytochem. 10, 3263 (1971). 

Rhodococcus sp. Strain WU-K2R A Rhodococcus strain capable of sulfur-specific desulfurization of benzothiophene, naphthothiophene (NT), and some of their alkyl derivatives was reported [35]. The metabolites of BT desulfurization were BT sulfone, benzo[c][l,2]oxanthiin S-oxide, benzo[c][l,2]oxanthiin S,S-dioxide, o-hydroxystyrene, 2,(2 -hydroxyphenyl)ethan-l-al, and benzofuran. The NT metabolites were NT sulfone, 2 -hydroxynaphthyl ethene, and naphtho[2,l-b]furan [35], The exact biochemical pathway was not determined, however, part of the pathway for BT desulfurization was speculated to be similar to Paenibacillus All-2. 

Oxidation of several 1,1-bisphenols 78 with IBD gives spirobenzofuran derivatives of general formula 79 (Eq. 21). This approach, when applied to benzylidine l.l -bisnaphthols 80, leads to a stereospecific cyclization, thereby forming the less hindered naphtho[2,l-fi]furan-2(l//)-spiro-r-(2//)-naphthalene-2 -ones (82) [80JCS(P1)1978,80JCS(P1)1986]. The conversion 80 to 82 probably occurs through intermediate 81 (Scheme 25). 

Rifampicin Rifampicin is 5,6,9,17,19,21-hexahydroxy-23-methoxy-2,4,12,16,18,20,22-heptamethyl-8-[Af-(4-methyl-l-piperaz inyl)-formamidoyl]-2,7-(epoxypentadeca-l,11-13-trienimino)-naphtho-[2,l-b] furane-l,ll(2H)dion-21 acetate (32.7.8). It is a semisynthetic derivative of rifamicin B, which is synthesized by the actinomycete Streptomyces medit-eranei (Nocardia mediteranei), and was introduced into medical practice in 1968. Rifampicin is described in Chapter 32. 

Reaction of Grignard reagents on 3(2H)- and 2(3/7)-benzofuranones yields 3-alkyl, 2-aryl (and 2,3-diaryl)benzofurans. A number of 3-substituted benzofuran derivatives result from the reaction of Grignard reagents on 3(2H)-benzofuranones.239,276 The method has also been applied in the naphtho[2,3-6] series.685 Substituted 2,3-diphenylbenzo-furans (352) have been obtained in the same way from 3-phenyl-2(3//)-benzofuranones (350) by dehydration (in boiling AcOH) of the intermediate hemiacetals (351).762,763... 

In Table II are compiled the results of a number of experiments with styryl and stilbenyl derivatives of furans and benzo[h]- and naphtho-[h]furans. 

The nomenclature of peri-naphthalene heterocycles does not follow a common principle. In many original papers, the names of heterocyclic systems are derived from the corresponding peri-annelated hydrocarbon derivatives (1,2-diazaacenaphthylene, 1-oxaphenalene, etc.), from monoheterocycles with an indication of linked positions (naphtho[l,8-6c]furan, naphtho[l,8-de]azepine, etc.), and from benzoannelated heterocycles (benzo[o/]indole, benzo[heterocyclic systems and some compounds have trivial names, for instance, perimidine, naph-thostyryl, and naphtholactone. Moreover, it is necessary to remember some peculiarities in the electronic structure of peri-annelated heterocycles, namely the absence of independent existance of the 7r-closed-loop monoheterocycles which could be a fragment of peri-annelated heterocyclic systems. Therefore, the separation of a heterocycle from the united 7r-system is impossible. In this case, the simplest structure and the tt-electron unit is the whole peri-heterocyclic nucleus. 

Crounse and Desai29 showed further that 2-(/>-tolyl)benzo[6]furan with Schiff s base derived from terephthalaldehydic acid and aniline gives, on treatment with excess potassium r-butoxide, the corresponding stilbene carboxylic acid. Schiff s base derived from phthalaldehydic acid and aniline exists30 as the 3-anilinophthalide (40). Nevertheless, this also reacts similarly with, for example, the naphthofuran (39) to form 2-(2 -carboxystilben-4-yl)naphtho [ 1,2-6]furan (41).29 Analogous car-... 

Similar results are found with 2-allyloxy-l-chloro-naphthalene, that affords the diphenylphosphine (98% yield) and trimethylstannane (84% yield) of (l,2-dihydro-naphtho[2,l-Z>]furan-l-ylmethyl) derivatives. 

Synthetically, compound 152 was prepared by the Friedel-Crafts procedure from furan-3,4-dicarbonyl chloride and a tetralin derivative (85JCR (S)338). 1,4-Dihydro-l,4-epoxy-5,8-naphthoquinone, when treated with 3,6-di(2-pyridyl)-l,2,4,5-tetrazine, yielded the quinone 153 (75JCS(P1)1339) derivatives of 153 are also known (74CC1034). The parent compound (153) is a stable derivative of the unstable isobenzofuran. Finally, 3-acetyl-2-furyl-1,4-benzo- (or -naphtho-) quinones are isomerized photochemically in aprotic solvents into the quionones 154 (66HCA1806). 

Reaction with Quinones and Naphthoquinones. Naphth-acene-5,12-diones and naphtho[2,3-c]furan-4,9-diones can be obtained by Mn(OAc)3-promoted reaction between 2-benzoyl-1,4-naphthoquinones and 1,3-dicarbonyls (eq 32). Electron-withdrawing groups on the benzoyl moiety will favor the naph-thofurane derivatives. Higher selectivity is also observed as the size of the 1,3-dicarbonyl substituent (R) increases. Naphthofu-ranes will also be favored in neutral solvents or if the reagents are heated with sodium acetate prior to the reaction with Mn(OAc)3. In contrast, naphthacenediones will be favored if the reaction is carried out in formic acid. An intramolecular variant of this reaction exists and furnishes the naphthacenediones in higher yield, only trace amounts of naphthofuranes are observed (eq 33). ... 

A remarkable ring closure of polyenic acetals can be performed in a highly stereospecific manner with SnCl4 to form polycyclic products with a multiplicity of asym. centers. 3-Alkyl-4-halogeno-tetrahydropyrans can be obtained by a novel reaction of olefins with paraformaldehyde and hydrogen halides . 1,3-Diphenyl-naphtho[2,3-c]furan, the first known stable 2,3-naphthoquinonoid, is an extremely reactive diene component in Diels-Alder syntheses . A modified Pechmann coumarin synthesis uses enamine derivatives of yS-ketoacids without catalyst. ... 

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