Naphthol ethers

In attempting to extend the method to other activated aromatics, it was found that pyrroles give mixtures of 2- and 3-substituted products, and that naphthol ethers and benzo[6]thiophene fail to react. 

In the past several years a number of reports have appeared describing cardiovascular and diuretic effects associated with benzo[ Jthiophene derivatives. Among these was the study of the benzo[6 Jthiophene analog (371) of the j8 -adrenergic blocking agent propanolol, which is the a -naphthol ether. The compounds showed comparable activity, showing that benzo[6 Jthiophene may function as a bioisostere of naphthalene also. 

Naphthyl methylethers are easily converted to methylnaphthols, 5). The a-isomer forms 2- and 4-methyl-a-naphthol, the j3-isomer only l-methyl- 3-naphthol. Ethers with alkyl groups other than methyl sometimes show side reactions due to fragmentation of the migrating group. For example, n-pro-pylphenylether yields mainly ortho- and para-n-propylphenol, but also some ethylphenols and cresols 14). 

Coupling reactions with diazo compounds which are very sensitive to alkali often are most successful when pyridine is used as an acidfixing agent. This is especially true in the preparation of secondary polyazo dyes with l-amino-2-naphthol ethers or their sulfonic acids as intermediates. ... 

If one considers that in the modifications, in place of the hydrocarbons, ethers, mono- and poly-add phenols, naphthalene, thiophene, diphenyl,naphthol-ethers, and many other compounds can be used, the great value of the Friedel-Crafts reaction will be readily understood. 

The hydroxynaphthaldehydes can be synthesised by lithiation of naphthol ethers and later converted to benzocoumarins. The linear benzocoumarin 59 is of special interest, since its synthesis by other methods is not readily achieved... 

Hydrolysis of phenol and naphthol ethers with concentrated hydrochloric adds shows that meta derivatives decompose the least and para derivatives the most and that addic groups increase the stability., ... 

This reagent readily coupled various naphthol-ethers to the corresponding binaphthyls in good yields, yet, these substrates were more efficiently homo-coupled using iron(III) chloride-based reagents. 

A soln. of p-chlorobenzenediazonium hexafluorophosphate in dimethylform-amide added slowly with stirring at — 5° to a mixture of n-butylamine, powdered Na-carbonate, and dimethylformamide, warmed to 0°, and stirred a few min. until a negative test is obtained with 2-naphthol, ether added, filtered, the filtrate washed and dried, this soln. of the resulting crude l-(n-butyl)-3-(4-chlorophenyl)triazene (Y ca. 100% when isolated) treated with ethereal 3,5-dinitrobenzoic acid, and kept 1-2 hrs. at 25° until Ng-evolution ceases n-butyl 3,5-dinitrobenzoate. Y 63-73%.— Triazenes may be used as alkylating agents for carboxylic acids, phenols, mercaptans, and certain alcohols. F. e. s. E. H. White and H. Scherrer, Tetrah. Let. 1961, 758. 

Chem. Descrip. PEG-13 3-naphthol ether Ionic Nature Nonionic CAS 35545-57-4... 

Alkyl and aryl-alkyl halides form 2-naphthyl ethers with 2-naphthol. 

Heat together under reflux 1 g. of 2-naphthol, 3 ml. of 10% NaOH solution and 0 5 ml. of the halide (e.g. benzyl chloride) for 30 minutes. Cool, shake w ith about 10 ml, of water and filter off the solid ether. Recrystallise from ethanol m.p. 101 5 ... 

Almost insoluble in cold water. Higher alcohols (including benzyl alcohol), higher phenols (e.g., naphthols), metaformaldehyde, paraldehyde, aromatic aldehydes, higher ketones (including acetophenone), aromatic acids, most esters, ethers, oxamide and domatic amides, sulphonamides, aromatic imides, aromatic nitriles, aromatic acid anhydrides, aromatic acid chlorides, sulphonyl chlorides, starch, aromatic amines, anilides, tyrosine, cystine, nitrocompounds, uric acid, halogeno-hydrocarbons, hydrocarbons. 

Picrates of p-naphthyl alkyl ethers. Alkyl halides react with the sodium or potassium derivative of p-naphthol in alcoholic solution to yield the corresponding alkyl p-naphthyl ethers (which are usually low m.p. solids) and the latter are converted by alcoholic picric acid into the crystalline picrates ... 

Mix together 1 0 g. of pure p-naphthol and the theoretical quantity of 50 per cent, potassium hydroxide solution, add 0-5 g. of the halide, followed by sufficient rectified spirit to produce a clear solution. For alkyl chlorides, the addition of a little potassium iodide is recommended. Heat the mixture under reflux for 15 minutes, and dissolve any potassium halide by the addition of a few drops of water. The p-naphthyl ether usually crystallises out on cooling if it does not, dilute the solution with 10 per cent, sodium hydroxide solution untU precipitation occurs. Dissolve the p-naphthyl ether in the minimum volume of hot alcohol and add the calculated quantity of picric acid dissolved in hot alcohol. The picrate separates out on cooling. Recrystallise it from rectified spirit. 

Naphthyl methyl ether (nerolin). Use 36 0 g. of p-naphthol, 10-5 g. of sodium hydroxide in 150 ml. of water, and add 31 -5 g. (23 -5 ml.) of dimethyl sulphate whilst the mixture is cooled in ice. Warm for 1 hour at 70-80°, and allow to cool. Filter oflF the naphthyl methyl ether at the pump, wash with 10 per cent, sodium hydroxide solution, then liberally with water, and drain thoroughly. Recrystallise from benzene or methylated spirit. The yield is 33 g., m.p. 72°. 

The enone 807 is converted into the dienol triflatc 808 and then the conjugated diene 809 by the hydrogenolysis with tributylammonium for-mate[689,690]. Naphthol can be converted into naphthalene by the hydrogenolysis of its triflate 810[691-693] or sulfonates using dppp or dppf as a ligand[694]. Aryl tetrazoyl ether 811 is cleaved with formic acid using Pd on carbon as a catalyst[695]. 

Naphthalenol. 1-Naphthol, a-naphthol, or l-hydroxynaphthalene/P(9-/j5 -iJ forms colorless needles, mp 96°C, bp 288°C, which tend to become colored on exposure to air or light. It is almost insoluble in water, but readily soluble in alcohol, ether, and benzene. 1-Naphthol and 2-naphthol are found in coal tar (56). 

Methyl-2-naphthylamlne (2) A mixture ol 1 methyl 2 naphthol 1 (7 8 g, 50 mmol), NaHSOs (10 g 0 1 mol) 28% NH4OH (40 mL) and water (10 mL) was healed to 200 205°C lor 48 (1 The cooled solution was made alkaline with NaOH solution and extracted with EI2O The dned ether solution was treated with HCI gas to allord 2 hydrochlonde which was littered treated with alkali and extracted with El20 Evaporation ol the solvent gave 7 2 g ol 2 (S3%), mp 46 SQ C Recrysiallized from petroleum ether (bp 60 70°C) mp 49 50°C... 

Zn, HOAc, 25°, 1 h, 88-96% yield. Phenacyi andp-bromophenacyl ethers of phenols are stable to 1 % ethanolic alkali (reflux, 2 h), and to 5 N sulfuric acid in ethanol-water. The phenacyi ether, prepared from /3-naphthol, is cleaved in 82% yield by 5% ethanolic alkali (reflux, 2 h). 

The naphthols differ from the phenols of the henzene senes in foiming ethers after the manner of aliphatic alcohols, viz, by the action of sulphuric acid on a mixture of the naphthol and the alcohol, which the other phenols do not,... 

Naphthalene, 216 Naphthalene picrate, 217 Naphthalene sulphonaie ofsodiiim, 218-/ J-Naphthol, 219 Naphthol yellow, 224 /i Naphthyl acetate, 222 /j-Naphthyl methyl ether, 220 /-Nitracetanilide, 153 w-Nitraniline, 154 /-Nitraniline, 153 Nitric acid (fuming), 22 NitroVienzene, 142 w-Nitrobenzoic acid, 200 Nitrogen, qualitative e rimation, 2 quantitative estimation, 13 Nitrophenol, 183 Nitrosohenzene, 146 /-Nitrosodimethylaniline, 157 Niirosoplienol, 159... 

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