Naphthol analogues

Certain aromatic analogues of natural amino acids can be used as potential fluorescent probes of peptide structure and dynamics in complex environments. The research team of M.L. McLaughlin undertook the gram scale synthesis of racemic 1- and 2-naphthol analogues of tyrosine. The synthesis of the 1-naphthol tyrosine analogue started with the Gattermann formylation of 1-naphthol using the Adams modification to afford the formylated product 4-hydroxy-1-naphthaldehyde in 67% yield. 

This reaction is effected by heating a suspension of beta-naphthol in water vitli equivalent quantities of formaldehyde and sodium bisulfite. The sulfo acid is reported to ciystallize from solution on cooling after acidifica tion with acetic acid. The formation of this sulfonate of a naphthol analogue of saligenin is of particular interest, since monomethylolnaphthols haw never been isolated. 

Many compounds capable of chelation have been tested for antimicrobial properties. Those showing positive results include saHcylaldoxime [94-67-7] l-nitroso-2-naphthol [131-91-9] mercaptobenzothiazol [149-30-4], dimethylglyoxime [95-45-4], saHcylaldehyde [90-02-8], cupferron [135-20-6], phenanthroline [66-71-7], isoniazid [54-85-3], thiosemicarbazones, the sulfur analogue of oxine, and numerous antibiotics (qv) including tetracyclines. Whether these compounds function exclusively, partially, or at all by virtue of their abiHty to chelate is open to debate. 

The same naphthylazo-2-naphthol ligand grouping is present in the 1 1 complex Cl Acid Black 52 (5.53 M = Cr) and its symmetrical 1 2 analogue Black 172 (5.54 M = Cr), which are both widely used in the dyeing of wool. The corresponding 1 1 and 1 2 complexes of trivalent iron (M = Fe) have been synthesised and their properties compared with the... 

Noteworthy among the yellow lakes are those of yellow wood, quercitron, Persian berries, naphthol yellow, auramine, thioflavine, chrysoidine, quinoline yellow, met anil yellow and its analogues. 

This chiral column has been shown successfully to resolve enantiomeric mixtures (or racemates) of aromatic alcohols including l,l -bi-2-naphthol and its analogues (p. 836), aromatic hydroxy (or alkoxy) carboxylic esters and amides, amino acid derivatives, sulphoxides, cyclic imides and amides, lactones, etc. Even this list should not be regarded as limiting. The potential of this method, coupled with the simplicity of operation will undoubtedly be extensively developed and explored in the coming years. 

Tab. 33. Supported iron(lll)-mediated oxidative dimerization of 2-naphthol (68a) and its 6-bromo analogue (68b).

In addition to electrophilic functionalization, the 5,6-double bond of the adducts (see (222)) is reported to undergo high-pressure [4 + 2]-cycloaddition with jV-(2,4-dinitrophenyl)isoquinolinium chloride (223) (Bradsher cycloaddition) to afford the naphthol-substituted isoxazoline (224) (Equation (61)), which was used for the total synthesis of nogalamycin analogues <92JOC644>. 

In an analogous manner, treatment of 4-(2-haloethyl)-phenols and -l-naphthols " with bases produces spiro[2.5]octa-4,7-dien-6-ones and their benzo analogues, respectively. The basic treatments of jS-oxiranyl ketones , esters (equation 13) , nitriles , sulfones and alkynes affords 2-(hydroxymethyl) cyclopropyl derivatives, usually as the sole cyclization product. The cyclization occurs regiospecifically by the intramolecular attack of the anion on the y-carbon in the oxirane ring. Attack of the anion on the 5-carbon in the oxirane, which should lead to the formation of cyclobutanols, usually does not take... 

Various segments were to be inserted, one of which was the OCH2 moiety. The analogue which would have been obtained is shown as structure I in Fig. 7.27. 0-Naphthol was the starting material, but was not immediately available, and rather than waste the day, a-naphthol was used instead. The result was propranolol which has proved a successful drug in the treatment of angina for many years. 

The synthesis of analogues of the spiroketal-containing pyranonaphthoquinone antibiotic griseusin A can be achieved by the regio- and stereoselective hydroxyalkylation of 4,8-dimethoxy-l-naphthol (equation 29). ... 

Because phenol yielded such favorable swelling results, along with the fact that previous analyses of JP-5 fuel indicated that the most abundant oxygenates in the fuel were alkylphenols, it was decided to examine other phenol analogues. Naphthols were included because they contain both the -OH functionality and aromatic or cyclic functionalities, both of which were suspected as being good promoters of swelling. The results are reported in Table III. 

Dihydrofuro[2,3-b]naphthols, derived from 3,7-dihydroxy-2-naphthoic acids are sources of hetero-fused naphtho[2,l-b]pyrans through reaction with propynols. The oxacyclic substituent is equivalent to an alkoxy group and in the only data provided, the /-fused dihydrofuran derivative 45 exhibits a 9 nm red shift to 481 nm compared with the 8-methoxy analogue 46 <99WOP24438>. 

Further studies116 have shown that salicylate (= 2-hydroxybenzoate) analogues or corresponding naphthalene compounds, for instance l-naphthol-4-sulphamoyl-2-carboxylate (188), are also strong inhibitors of the contraluminal influx of 35S042 into proximal tubular cells if they possess —COOH,—S03H or other electronegative or ... 

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