1-Methoxynaphthalene, reactions with

The reactions of the tetrahalogenobenzynes with alkoxynaphtha-lenes, in accord with the results previously mentioned, result in addition at the 1,4-positions. Thus tetrafluorobenzyne reacts with 1,2,3,4-tetra-fluoro-5-methoxynaphthalene to form (82) in good yield 90>. Reactions with 2,3-dimethoxynaphthalene lead to the formation of the adducts [83, X = F or Cl) 123>. These compounds are relatively unstable and are transformed slowly in the open atmosphere. Thus [83, X = C1) affords the di-ester (84). 

Acetylenedicarboxylic acid, dimethyl ester, 50, 25, 36 Acetylenes, reaction with tri-methylsilyl azide, 50, 109 Acetylenic sulfonium salts, furans from, 53, 3 2-Acetylindane-l,3-dione, 52, 4 2-ACETYL-6-METHOXYNAPHTHALENE, 53, 5... 

In an attempt to obtain further evidence of the mechanism, the behavior of 2-methoxynaphthalene and 2-trimethylsiloxynaphthalene under standard conditions was studied. Neither compound would be expected to take part in an ene reaction, nor involve a Lewis acid-stabilized transition state, and if a reaction did occur, it would suggest a conventional electrophilic aromatic substitution. However, neither compound showed any reaction with DEAD in the presence of LiC104 at room temperature for some... 

We have carried out reactions with other substrates, in particular [3-methoxy-naphthalene. The reaction is remarkably facile and leads to 1-trifluoroacetyl 2-methoxynaphthalene as the only reaction product, in 68 % yield (eqn. 11). In this case, the most reactive position is position 1 (the position para with respect to the methoxy group is now blocked). Reactivity in position 6 has been observed in a limited number of cases, for the acetylation, especially when zeolites are used (ref. 33). 

The benzoylation of 2-methoxynaphthalene (2-MN) 4 with an equimo-lecular amount of BC in the presence of aluminum chloride (5% mol) gives producfs 5, 6, and 7 in 63 25 12 rafio (Table 3.1). With indium trichloride in place of aluminum chloride, compound 5 is obtained in a higher selectivity (88%). On increasing the temperature in the reaction with indium trichloride, the product composition is changed, and compound 6 is the predominant one (84% selectivity). Quite similar results are achieved with iron trichloride, tin tetrachloride, and zinc chloride, while in the case of antimony pentachloride and titanium tetrachloride, compound 5 is the major product. Mechanistic studies show that the reaction involves the isomerization of 5 to 7 and 6. 

Hydroxy-5-methoxynaphthalene underwent a Mannich reaction with cyclohexyl amine and 2 moles of 35% formalin in methanol until reaction was complete leading to an 80% yield of 3-cyclohexyl-2,4-dihydro-7-methoxy-2H-naphth[2,1 -e][1,3]oxazine although secondary amines afforded normal 2-dialkylamino methylation (ref.195). This reaction has been referred to in an earlier Chapter. 

Recently, a simple method for the synthesis of the acid (55) has been described, the key stage of which is the Grignard reaction of l-iodo-6-methoxynaphthalene (2) with the anhydride of 13 -methylcarballylic acid (59) [193, 194]. In this process, seven carbon atoms are introduced into the molecule directly with the formation of the keto diacid (60). Hydrogenoly-... 

A final synthetic effort in the yohimbine alkaloid area concerns the studies reported by Loewenthal and his coworkers (Scheme 3.92) (143). The aim was to develop an efficient method to prepare the bicyclic enone 21, which serves as a key intermediate in the Woodward reserpine synthesis strategy (19). The route for preparation of 21 began with Friedel Crafts reaction of 2-methoxynaphthalene (523) with the oxalyl chloride equivalent 524, a process which afforded the acenaphthenoquinone 525. Oxidative-decarboxylation of 525 yielded the naphthalene-carboxylic acid 526 which was transformed by Birch reduction and esterification to the dihydro-derivative 527. Carboxyla-tion then provided geminal diester 528 which was epoxidized. Sequential lactonization and methylation afforded tricyclic lactone 529. Ester cleavage with subsequent decarboxylation gave lactone 530 which was demethylated to provide 531. While no further effort was given to the development of this... 

Another patent apphcation (28) describes the use of zeolite/TUD-1 with optionally a metal function for a variety of reactions. In an example, as-synthesized MCM-22 / TUD-1 was tested for acylation of 2-methoxynaphthalene with acetic anhydride to 2-acetyl-6-methoxynaphthalene at 240°C. After reaction for six hours, conversion of 2-methoxynaphthalene reached 56% with 100% selectivity to 2-acetyl-6-methoxynaphthalene. Other zeolite catalysts were similarly tested, but none were nearly as effective. 

Friedel-Crafts acylation is widely used for the production of aromatic ketones applied as intermediates in both fine chemicals and pharmaceutical industries. The reaction is carried out by using conventional homogenous catalysts, which represents significant technical and environmental problems. The present work reports the results obtained in the Friedel-Crafts acylation of aromatic substrates (anisole and 2-methoxynaphthalene) catalyzed by Beta zeolite obtained by crystallization of silanized seeds. This material exhibits hierarchical porosity and enhanced textural properties. For the anisole acylation, the catalytic activity over the conventional Beta zeolite is slightly higher than with the modified Beta material, probably due to the relatively small size of this substrate and the weaker acidity of the last sample. However, the opposite occurred in the acylation of a bulky substrate (2-methoxynaphthalene), with the modified Beta showing a higher conversion. This result is interpreted due to the presence of a hierarchical porosity in this material, which favors the accessibility to the active sites. 

In contrast, the opposite result was observed when these materials were used in the acylation of a bulky substrate (2-methoxynaphthalene, 2-MN). In this case, l-acetyl-2-metoxynaphthalene (1-A,2-MN) and 6-acetyl-2-metoxynaphthalene (6-A,2-MN) are the main reaction products (Scheme 2). The latter is an intermediate for the preparation of Naproxen (antiinflammatory drug) and, therefore, the most interesting product. Initially, 2-MN acylation leads to 1-A,2-MN (the kinetically controlled product). However, at long times, the selectivity to 6-A,2-MN usually increases due to two secondary reactions transacylation of 1-A,2-MN with a molecule of 2-MN and protodeacylation of 1-A,2-MN yielding 2-MN [7],... 

To a dry flask containing 8 gm (0.329 atom) of magnesium turnings, 150 ml of dry ether, and a crystal of iodine is added dropwise a solution of 50 gm (0.212 mole) of 2-bromo-6-methoxynaphthalene in 150 ml of dry benzene. The reaction mixture is refluxed on a water bath and 2 ml of ethyl bromide is added every hour for 5 hr. After this time, most of the magnesium has reacted, the flask is cooled, and a solution of 37 gm (0.328 mole) of 1-methyl-2-piperidone in 100 ml of ether is added dropwise. After the addition, the reaction mixture is refluxed for 3 hr, cooled, decomposed with dilute hydrochloric acid, the solid hydrochloride of the product, after filtration, reacts with warm aqueous sodium hydroxide, is extracted with ether, dried, and distilled to afford 11.0 gm (20.6%), b.p. 175°C (2.0 mm). 

To a clean reaction vessel add 1-methoxynaphthalene (3.16 g, 20 mmol), benzoyl chloride (2.8 g, 20 mmol), and Envirocat EPZG (0.50 g), which is dried by distillation with tolune prior to the reaction. 

In some cases the reaction is accompanied by a five-membered heterocyclic ring closure. For example, l-nitro-4-methoxynaphthalene 265 reacts with p-tolylpro-penylsulfone to give benzo[/z]quinoline 266 (35%) together with A-hydroxybenzo-pyrrole derivative 267 (14%) (Scheme 77) (00EJO521). Annulation of the pyridine ring may proceed via anion 268, whereas the formation of benzoindole 267 occurs via neutral alkene 269. 

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