3- Methoxy-2-naphthoic acid

Hydroxy-l-naphthoic acid 1-Naphthoic acid 3- Hydroxy-2-naphthoic acid 3- Methoxy-2-naphthoic acid 6-Ethoxy-2-naphthoic acid 4- Hydroxybenzoic acid 1- Hydroxy-2-naphthoic acid 2- Naphthoic acid 6-Hydroxy-2-naphthoic acid 6-Methoxy-2-naphthoic acid 6-Propoxy-2-naphthoic acid 2,6-Naphthalene dicarboxylic acid... 

In a similar manner, 3,4-dihydro-2-naphthoic acid, m.p. 111-114° (corr.), and 7-methoxy-3,4-dihydro-2-naphthoic acid, m.p. 149-150.5° (corr.), have been obtained in 35% yields. 

This method of preparation is essentially that used by Robinson and Crowley for the preparation of 6-methoxy-3,4-dihydro-2-naphthoic acid. They first used concentrated sulfuric acid but found that this reagent caused sulfonation. 

Fig. 5. Correlation of rate data (log A ) for the methoxy-dechlorination of substituted 4-chloroquinolmes with the acid strengths (logiC ) of 1-naphthoic acids.

A methoxyaldehyde, m.p. 52-53°, of unassigned structure is reported in the patent literature [6] as the product from the reaction of 2-methoxy-5,6,7,8-tetrahydronaphthalene with N-methylformanilide and phosphorus oxychloride. This reaction in our hands gave a 50% yield of methoxyaldehyde (VII), m.p. 51 6-52°, whioh was oxidized with potassium permanganate in acetone solution to 3-methoxy-5,6,7,8-tetrahydro-2-naphthoic acid. The structure of the latter was established by mixture m.p. with an authentic sample prepared [7] by converting 3-hydroxy-5,6,7,8-tetrahydro-2-naphthoic acid to the... 

Beams and Manders reported (177) the synthesis of the tricyclic dione 349 via two different synthetic routes. The Australian chemists utilized an approach analogous to one developed earlier by Masamune (178) during the synthesis of atisine and kaurene. They prepared tetrahydro-7-methoxy-2-naphthoic acid (350) from 7-methoxytetral-l-one by published procedures. 

Methoxy-l-naphthoic acids (107 R = H, OMe) have been reduced with lithium or sodium in ammonia, with no loss of the ortho methoxy substituent being reported. Thus, in the presence of ethanol the 1,4-dihydro acids (108 R = H) are obtained, while reduction in the absence of a proton source and quenching with methyl iodide affords the alkylated acids (108 R = H, OMe, R = Me). The conditions used for the reductive alkylation in the earlier examples (Na/NH3/-70 C) would enhance retention of the... 

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>. 

The particular value of the method is for converting methyl and polymethyl derivatives of polycyclic aromatic compounds into mono- and poly-carboxylic acids. For instance, 1-methylnaphthalene with a 42% excess of aqueous sodium dichromate solution in an autoclave at 240-250° gives 95% of 1-naphthoic acid in 18 h 2-methylnaphthalene with a 55% excess gives a 93% yield of 2-naphthoic acid the methyl group in fluoro-, bromo-, chloro-, nitro-, and methoxy-toluene as well as in xylenes and heterocycles can usually be oxidized smoothly to a carboxyl group. An excess of Na2Cr207 acts as a buffer and favors smooth reaction. With 1.5 moles of Na2Cr207 the reaction occurs in accord with the equation ... 

Na added in small pieces with Dry Ice-acetones cooling under Ng to a suspension of 20.2 g. 5,6,7,8-tetrahydro-2-methoxy-l-naphthoic acid in liq. NHg-abs. ether until a blue color persists, then methyl iodide added during 10 min. 18.9 g. crude l,4,5,6,7,8-hexahydro-2-methoxy-l-methylnaphthoic acid. - No hydroxylic proton donor is required. F. e. s. M. D. Bachi et al., J. Org. Chem. 34, 126 (1969). 

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