2.7- Naphthalene diol

Naphthalenic diols may conveniently be classed as dihydric phenols and as such they have been used both synthetically, the synthesis of morphine by M. Gates in 1954 being an example of one application of 2,6-dihydroxynaphthalene. The reaction chemistry of 1,3- and 1,5-isomers has been studied more recently. Naphthalene-1,3-diol in pyridine added to a toluene suspension of solid potassium superoxide under argon foiiowed after 5 mins, by quenching with water gave 2-hydroxy-1,4-naphthaquinone in 60% yield (ref. 193). 

Since 1991 Kricheldorf has published many other articles on liquid crystal polyesterimides. These include two series of thermotropic copoly(esterimides) derived from N-(3 -hydroxyphenyl)trimellitimide and 4-hydroxybenzoic acid or 6-hydroxy-2-naphthoic acid, in which the critical compositions for obtaining mesophases were discovered by varying monomer levels [34]. A series of homopoly(esterimide)s were synthesised from N-(4-carboxyphenyl)trimelliti-mide and various diacetylated linked diphenols. When the diphenol contained an ether or carbonyl linking group, mobile nematic phases were observed. Various naphthalene diols were also employed instead of the diphenol, but only the 2,7-dihydroxy naphthalene produced a nematic phase [35]. 

Despite morphine s phenanthrene core, Gates approach started with manipulation of a naphthalene diol template 37, which after monoprotection, expected a-nitrosylation at the less hindered site, and reduction, gave amine 39, Scheme 2.41 An iron (III)... 

Methyl-l,4-naphthoquinone was obtained in 93% yield from 2-methyl-l,2-naphthalene-diol by oxidation with NaOBr in aqueous-alcoholic sulfuric acid at room temperature.472... 

Complex formation towards 1,8-ANS and 2,7-naphthalene diol 36) has been studi l also for the macrocycles 45 and 46, which are homologous to 47 By affixing a pyridoxamine side chain to 46, the host 58 was obtained. The catalytic activity in the transamination of phenylpyruvate (59) to phenylalanine 60) and of a-ketovalerianic acid 61) to norvaline 62) was studied using this host. 

In this way using the host compound 63 below the CMC value = 2.5 x 10 the complexation of TNS (6) was determined by fluorescence spectroscopy The complex constant is of the same order of magnitude as the one of P-cyclodextrin With 2,7-naphthalene diol (56) as the guest no significant H-NMR highfield shifts could be obtained. The complex constant of 36 nevertheless was determined using the competitive inhibition of TNS. 

In Table 3 some examples are given illustrating the upfield shifts of the aromatic guest protons in the H-NMR spectra, the guest being 2,7-naphthalene diol (36). 

Both hosts 104 and 105 in acndic water K)lution are abk to c mplex polar aromatic guest compounds like 2,7- and 2,6-naphthalene diol 36,82) as is shown by H-NMR upfield shifts. In striking ntrast to 34 and 105 the out/out isomeric host 104 catalyses the H/D exchan of tte 1 H protons of the giKsts 36 and 82. This can be reduced to a more favourable eiKapsulation of the guests in the host 104 compared with 34 and 105, which could lead to an activation of tte 1-position. 

Dimethylphthalic anhydride (I) and 1,4-naphthalene-diol pi) were mixed with BO and heated at 190 0 with stirring, to give 2,3-dimethyl-6,ll-dihydroxy-5,12-naphthacene-quinone (III). (Ill) was refluxed with PCl and POCl, followed by the partial dehydrochlorination with Nal In DMF, to give 2,3-dimethyl-5,6,ll,12-tetrachlQrotetracene (IV). (IV) was heated with Na in HMPA at 100°C for 12 h, to give crude DMTTT (V). (V) was washed with H O, MeOH, sublimed and... 

Many studies selected LC copolyesters as one constituent. We will briefly consider a LC copolyester consisting of three kinds of monomers terephthalic chloride, phenylhydroquinone, and naphthalene diol, with mole fractions 0.5, 0.44, and 0.06, respectively (Khan et al., 1995). Experiments revealed that the melting temperature is around 300 °C and the clearing temperature at approximately 410 °C. One also observed that degradation of the polymer destroys reversibility of the transitions. 

Another way of generating an ansa product is to prepare a cyclophos-phazene precursor that has two non-geminal chlorines in a cis orientation. Such a compound upon reaction with difunctional reagents can lead to ansa produets. Thus, the reaction of oM-ge n-cw-N3P3Cl2(OCH2CF3)4 with the sodium salt of naphthalene diol affords the ansa product (see Eq. 3.23). 

Enzymatic oxidation of naphthalene by bacteria proceeds by way of the intermediate ciy-diol shown. Which prochiral faces of C-1 and C-2 of naphthalene are hydroxylated in this process ... 

Teracasidin Exudates from woody plants, tannin 3 methyl naphthalene 1,8-diol Diopyrosmollis... 

A convenient route to highly enantiomerically enriched a-alkoxy tributylslannanes 17 involves the enanlioselective reduction of acyl stannanes 16 with chiral reducing agents10. Thus reaction of acyl stannanes with lithium aluminum hydride, chirally modified by (S)-l,l -bi-naphthalene-2,2 -diol, followed by protection of the hydroxy group, lead to the desired a-alkoxy stannanes 17 in optical purities as high as 98 % ee. 

Chiral modification of diorganomagnesium compounds with the dilithium salt oi (S)-l,l -bi-naphthalene-2,2 -diol gave reagents with the empirical formula 30. Good to excellent enantiose-lectivities were observed in addition reactions of aliphatic and aromatic reagents to aromatic aldehydes30,31, however, the selectivities were not satisfactory with allylic, vinylic and acetylenic reagents. 

---