2,7-Dihydroxynaphthalenes, reaction

The Bucherer carbazole synthesis was pivotal in the preparation of the first hexahelicene 37a. Reaction of 2,7-dihydroxynaphthalene 35 with phenylhydrazine and sodium bisulfite afforded helicene 37a although in low yield. More recently, the synthesis was extended to the preparation of 37b using 2,5-dimethylphenylhydrazine 36b. ... 

Eaton RW, PJ Chapman (1992) Bacterial metabolism of naphthalene construction and use of recombinant bacteria to study ring cleavage of 1,2-dihydroxynaphthalene and subsequent reactions. J Bacteriol 174 7542-7554. 

Antia et al. [96] proposed a colorimetric method comprising a concentration step and a reaction with 2,7-dihydroxynaphthalene. This method has a detection limit of 0.1 mg/1. Methods comprising concentration by adsorption on alumina, followed by elution and colour development, yielded a detection limit of 5 ng/1 [97,98]. These methods have not been too successful in hands other than those of the original authors, possibly because of the amount of manipulation necessary in the analysis. 

Glycerol can be oxidized to formaldehyde by periodic acid and the formaldehyde measured spectrophotometrically at 570 nm after reaction with chromotropic acid, or fluorimetrically after the addition of diacetylacetone and ammonia. The chromotropic acid reagent consists of 8-dihydroxynaphthalene-3,6-disulphonic acid dissolved in 50% sulphuric acid. 

If the introduction of the protecting group takes place through an irreversible reaction, then the chemoselective protection of one of two identical mutually interacting groups may be a critical step in the synthetic sequence. For instance, the monoprotection of 2,3-dihydroxynaphthalene (17) as the corresponding methyl... 

The first heterohelicene (72) ever made was obtained by Fuchs and Niszel 56) in 1927 by heating 2,7-dihydroxynaphthalene with phenylhydrazine and sodium-hydrogen sulphite. The reaction was also investigated by Zander57). 

The reaction of 1,3-dihydroxynaphthalene with 3,3-dimethylacrylic acid in the presence of phosphorus oxychloride and zinc chloride yields only 9-hydroxy-2,2-dimethyl-benzo[/]chroman-4-one (585). 2,7-Dihydroxynaphthalene similarly yields the angular ben-zochromanone (586) rather than the alternative linear product (79RRC59). 

Among the Ti02 powders, P25, which contains a 30% rutile phase and has a 43 m2/g surface area, showed the highest activity, as shown in Fig. 11.8. In this system, only three kinds of oxidized compounds (2-formylcinnamaldehyde and 1,3- and 1,4-dihydroxynaphthalene) among 10 possible isomers were obtained.81) Furthermore, no mono-hydroxylated compounds, i.e., 1- and 2-naphthol. were detected in the reaction products. Quantum efficiencies of the reactions were determined at around 365 nm. After photoirradiation for 1 h, the quantum efficiencies were determined to be 14.6% and 5.8% for the production of 2-formylcinnamaldehyde and 1,3-dihydroxynaphthalene, respectively. The efficiency was determined on the assumption that 4 holes are necessary to form one oxidized naphthalene molecule. 

The zwitterion X5-spirosilicate bis[2,3-naphthalendiolato][2-(dimethylammonio)phe-nyl]silicate (56 isolated as 57 = 56-1/2 MeCN) was synthesized by reaction of [2-(dimethylamino)phenyl]dimethoxyorganosilanes with 2,3-dihydroxynaphthalene in acetonitrile at room temperature. Reaction of 57 or of [2-(dimethylamino)phenyl]trimetho-xysilane with water in acetonitrile yielded the cage-like silasesquioxane 58 (R = 2 — Me2NCgH4). The crystal structures of 57 and 58 were studied by X-ray diffraction. In addition, 57 and 58 were characterized by solid-state 29Si CPMAS NMR142 (Figure 34). 

One of the most widely used photochromic compounds for sunglasses is prepared easily as follows reaction of 2,7-dihydroxynaphthalene with a mixture of sodium nitrite and sulfuric acid... 

They next studied the asymmetric oxidative polymerization of achiral 2,3-dihydroxynaphthalene (Scheme 42). The polymerization of this monomer with CuCl2-(-)-sparteine complex resulted in a low yield and gave a low molecular weight oligomer, whereas the polymerization with CuCl-(S)-Phbox quantitatively gave a polymer with Mn of 10 600-15 300. The enantioselectiv-ity attained in this polymerization, however, was estimated to be low, with 43% ee from the model reaction [169]. When vanadyl sulfate (VOSO -Phbox complex was used instead of the copper catalyst system, the enantioselectivity was improved up to 80% ee [170]. Asymmetric cross-coupling polymerization of two kinds of naphthol derivatives was also reported [171,172]. 

The reaction of N3P3C16 with catechol (8), 2,3-dihydroxynaphthalene (11), 1,8-dihydroxynaphthalene (17), 2,2-dihydroxybiphenyl (11), and several aliphatic diols (21, 399) gives spirocyclic derivatives. A typical example is... 

The reaction of dibenzoylacetylene and enol systems, such as acetylacetone, 5,5-dimethylcyclohexane-l,3-dione, 1-naphthol, 2-naphthol, 2,7-dihydroxynaphthalene, or 8-hydroxyquinoline in the presence of triphenylphosphine, leads to tetrasubstituted furans in 65-83% yield (Equation 115) <2002TL4503>. DABCO-catalyzed reaction of a-bromocarbonyl compounds with DMAD also yields highly substituted furans <2005JOC8204>. 

The reaction of di- and polysulfonic acids can usually be carried out so that the replacement of the sulfo groups by hydroxyls takes place stepwise (partial alkali fusion). Thus, phenol-m-sulfonic acid is obtained from benzene-m-disulfonic acid under mild conditions, while resorcinol is formed under more vigorous conditions (see page 144) similarly, naphthalene-l,5-disulfonie acid yields, first, l-naphthol-5-sulfonic acid, then l,5 dihydroxynaphthalene, both valuable azo dye... 

Replacement of the sulfo group by hydrogen instead of by hydroxyl, simultaneously forming sulfate instead of sulfite. This reaction is usually only an unimportant side reaction, but in certain cases it may become the main reaction. Thus, alkali fusion of 2,3-dihydroxynaphthalene-6-sulfonic acid does not give the expected 2,3,6-trihydroxynaphthalene, but instead, 2,3-dihydroxynaphthalene. 

Amidonaphthol-4 6-disulphonic acid (K acid) yields with mercuric chloride or acetate unstable red compounds, to vrhich no formulae have been assigned the same result is obtained with its mono and dibenzoyl derivatives. 1 8-Amidonaphthol-3 6-disulphonic acid (H acid) and 1 8-amidonaphthol-4-sulphonic acid give,colours and reactions similar to K acid, but these compounds are even more readily decomposed. Constancy of composition has not been obtained in the case of 1 8-dihydroxynaphthalene-3 6-disulphonie acid (chromotrope acid), the derived compounds being orange in colour. ... 

Dihydroxynaphthalene-3 6-disulphonio acid, reaction with mercuric salts, 158.. aa-Di-iodomercuri camphor, 198. 

A. 2,7-Bis(diethylcarbamoyloxy)naphthalene.2 Into a dry, 1-L, three-necked, round-bottomed flask, equipped with a mechanical stirrer and a condenser, are added 2,7-dihydroxynaphthalene (49,7 g, 0.310 mol, Note 1) and pyridine (700 mL, Note 2) under nitrogen. A dry, 200-mL pressure-equalizing dropping funnel fitted with a rubber septum is installed and charged with N,N-diethylcarbamoy chloride (120 mL, 0.900 mol Note 3). After the reaction flask is cooled in an ice bath for 30 min, N,N-diethylcarbamoy chloride is added within 5 min to the vigorously stirred mixture. The ice bath is removed and the dark-brown solution is warmed to room temperature. The dropping funnel is removed under a stream of nitrogen and a thermometer is installed. 

The solution is heated to 100°C ( 5°C) for 2 days. TLC indicates a complete reaction (Si02, 2,7-dihydroxynaphthalene, Rf = 0.46 acetone/hexane 40/60). After the flask is cooled in an ice bath, hydrochloric acid (6 M, 250 mL) is poured into it over 10 min with vigorous stirring. A light-brown solid is formed. The brown mixture is poured into a 3-L... 

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