1- Naphthol, 5,6,7,8-tetrahydro

Very few physical measurements have been performed on tetrahydronaphthalene with a view to establishing the bond structure of its aromatic ring. The dipole moment measurements on 2,3-dibromo-5,6,7,8-tetrahydronaphthalene [4] have not been interpreted satisfactorily. However, Arnold and Evans [5] have shown that the acidities of 6-nitro- 3,4-xylenol, 6-nitro-5-indanol, and 3-nitro-5,6,7,8-tetrahydro-2-naphthol are virtually the same. Hence, the aromatic bonds in question in all three compounds must have nearly identical double-bond character, thus precluding any appreciable Mills-Nixon effect. 

The starting materials required for preparing the 2,3-disubstituted tetrahydronaphthalenes were 5,6,7,8-tetrahydro-2-naphthol (obtainable from tetrahydronaphthalene) and methyl 3-hydroxy-2-naphthoate, which was reduced to the known tetrahydro ester (Vc) and the latter saponified to the known tetrahydroacid. 

The starting material for the 1,2-disubstituted tetrahydro-naphthalenes was 5,6,7,8-tetrahydro-2-naphthol. This compound was converted in low yield to the known Via by the Reimer-Tiemann reaction. VI6 and Vic both were prepared from 1-bromo-2-methoxy-5,6,7,8-tetrahydronaphthalene. Although VI6 was prepared according to the method of O Farrell et al. [3], we obtained a much higher yield,... 

Eydroxy-5,6,7,8-tetrahydro-l-napMhaldehyde was prepared [7] by the Reimer-Tiemann reaction cn 5,6,7,8-tetrahydro- 2-naphthol. Three recrystallizations from aqueous alcohol afforded a very low yield of pure aldehyde, m.p. 86-8-87-8° (spectral sample) lit. m.p. 86-87° [7J. 

Phenolannelation. Methyl vinyl ketone (and substituted vinyl ketones) undergo Robinson annelation with the /(-keto sulfoxide (1) to afford the 5,6,7,8-tetrahydro-2-naphthol (2) with loss of hcn/cnesnlfenic acid. Sodium methoxide is used as base, and the reaction proceeds at 0 - 25°. 

Phenol annelation.1 This modified methyl vinyl ketone can be used for synthesis of 5,6,7,8-tetrahydro-2-naphthol or 5-indanol by reaction with the lithium enolate of cyclohexanone or cyclopentanone, respectively. The former reaction is formulated in equation (I). 

In compounds with both saturated and aromatic rings, the former appears to be the most readily hydroxylated. For example, the major oxidation products of tetralin (5,6,7,8-tetrahydronaphthalene) in the rabbit are 1- and 2-tetralol, whereas only a trace of the phenol, 5,6,7,8-tetrahydro-2-naphthol, is formed (Figure 10.1D). 

Diels-Alder and Michael addition reactions have been prominent. For the synthesis of 5,6,7,8-tetrahydro-2-naphthol, the lithium enolate of cyclohexanoe in tetrahydrofuran with 3-phenylthiobut-3-en-2-one at -70 C initially and then... 

Asymmetric oxidative dimerisation of S(+)-3,4,8-trimethyl-5,6.7,8-tetrahydro-2-naphthol in ether with potassium ferricyanide in aqueous 0.2M sodium hydroxide was effected by stirring at ambient temperature for 2 hours to afford the S,S-(+)-trans dimer in 62% yield (ref. 14). 

This chapter describes our recent advances on the utilization of polymer-modified laccase complexes in aqueous systems towards the oxidation/polymerization of naturally hydro-phobic steroidal compounds, Equilin (EQ) and 17-P-estradiol (P-EST). We elucidate the kinetic and synthetic aspects of the process with the model compoimd 5,6,7,8-tetrahydro-2-naphthol (THN). The nano-reactor system is composed of linear poly(ethylene oxide)-dendritic poly(benzyl ether) diblock copolymer (G3-PE013k) and laccase isolated from Trametes versicolor. Other advantages of the complex in comparison to the native enzyme are its recyclability, enhanced stability, activity, and overall simplicity in product harvesting and isolation. A principle of action of the complex is suggested based on these findings and is further supported by the biphasic solid-liquid nature of the reaction medium, which exhibits continuous influx of starting material and steady solid product expulsion. Comparative experiments with linear-linear poly(styrene)-Woc -poly(ethylene oxide) copolymer under identical conditions do not evince formation of a... 

ABSTRACT. Selective formylation of phenol at the 4-position is achieved by using 3-cyclodextrin as catalyst in the reaction of phenol with chloroform in aqueous alkali. The reactions of 1,3-dihydroxybenzene and indol, respectively, in the place of phenol give 2,4-dihydroxybenz-aldehyde and indole-3-aldehyde in virtually 100% selectivies and high yields. The reactions of para-substituted phenols, 4-methylphenol and 5,6,7,8-tetrahydro-2-naphthol, instead of phenol, effect the selective dichloromethylation at the para-positions. Selective carboxylation of phenol at the 4-position is achieved in the reaction of phenol with carbon tetrachloride in aqueous alkali by using 3-cyclodextrin and copper powder as catalyst. 

Formylations of phenol, resorcinol and indole, dichloromethylations of 4-methylphenol and 5,6,7,8-tetrahydro-2-naphthol, carboxylation of phenol, and allylation of 2,4,6-trimethylphenol proceed site-selec-tively in high yields by using 3-cyclodextrin as catalyst. The formation of ternary inclusion complex composed of cyclodextrin, substrate, and dichlorocarbene, trichloromethyl cation or allyl cation in the reaction mixture is an important factor of the site-selective reactions. The cyclodextrin is also effective by limiting the molecular size of the reaction intermediate. 

The naphthalene derivative 2f was obtained by sodium borohydride reduction of the corresponding acid. While a direct reaction of 5,6,7,8-tetrahydro-2-naphthol le with formaldehyde led to 2-hydroxymethyl derivative 4e in 20% yield, similar hydroxymethylation of 5-indanol Id failed. The corresponding compound 4d was accessible via rather complicated reaction pathway consisting of the bromination... 

An efficient procedure for the synthesis of 2-methoxyestradiol was found by the same authors, based on Cp lr moiety.5,6,7,8-Tetrahydro-2-naphthol and /3-estradiol gave 7 -arene complexes with [Cp"lt(Solv)3](BF4)2 as described above. In the case of the complexed hormone, the Cp Ir moiety coordinates the A-ring either a (metal down) or /3 (metal up) relative to the Me group at C(13). The novel iridium cyclohexadienone compound of the complexed steroid was then oxidized by iodine to produce 2-methoxyestradiol, an anticancer agent which possesses important antitumor effects in vivo, in 60% overall yield from /3-estradiol. ... 

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