4- 1,8-naphthalic anhydride

Wood s metal bath or a mixture (m. p. about 150°) of ten parts of potassium nitrate and seven and one-half parts of sodium nitrite may be used. 

If the heating at 250° is continued until hydrogen sulfide is no longer evolved (about ten hours), the product, after recrys- 

The material comes over between 210° and 215° at 12-13 mm. with the bath at 260°. 

2-Naphthalic anhydride has been prepared by the hydrolysis of the dinitrile of ,2-naphthaIic acid,1 by the oxidation of suitably substituted hydrocarbons or ketones,2 or by the dehydrogenation of the 3,4-dihydro compound with bromine 3 or with sulfur.4 

The crude material is suitable for hydrolysis, and for other reactions, without further purification. The pure diacetate may be obtained by recrystallizing from 150 cc. of hot alcohol. The hot solution is filtered through a fluted filter to remove insoluble impurities. The yield of pure / -nitrobenzaldiacetate is 43-46 g. (47-50 per cent of the theoretical amount), m. p. 125-126°. 

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Naphthalic anhydride [81-84-5] M 198.2, m 274°. Extracted with cold aqueous Na2C03 to remove free acid, then crystd from acetic anhydride. 

A solution of 66.5 g. (1.01 moles) of 85% potassium hydroxide in 300 ml. of water in an 800-ml. beaker is heated to 60-70 , and 100 g. (0.505 mole) of commercial 1,8-naphthalic anhydride (Note 1) is stirred in. The pH of the resultant deep-brown solution is adjusted to a value of 7 (Note 2) with 6N hydrochloric acid and 3N potassium hydroxide. It is treated with 10 g. of decolorizing carbon and filtered. This operation is repeated. The filtrate is concentrated in a 1.5-1. beaker on a steam bath to about 180 ml. The concentrate is cooled to room temperature, 800 ml. of methanol is added with vigorous stirring by hand, and the mixture is cooled to 0-5°. The precipitated dipotassium naphthalate is separated by filtration, washed with 150 ml. of methanol, and dried in a vacuum oven at 150°/150 mm. The dried cream-colorcd salt weighs 130 135 g. (88 92%). 

Suitable 1,8-naphthalic anhydride, m.p. 274-275°, is obtainable from Coaltar Chemicals Corp., 420 Lexington Ave., New York, N. Y. 

The naphthalimide 11.23 is manufactured from acenaphthene by sulphonation, oxidation to the naphthalic anhydride derivative and conversion to 4-methoxy-N-methylnaphthal-imide as outlined in Scheme 11.14. 

The naphthalic anhydride (4-11 g.) is recovered on acidification of the filtrate. This substance is the principal product if the oxidation becomes too vigorous. Naphthalic anhydride may be prepared from the technical grade of acenaphthene. 

The solid is transferred to a 1-1. beaker, and 220 ml. of a 10% solution of sodium carbonate is added. The solution is heated on a steam bath for an hour and filtered hot this operation removes the naphthalic anhydride formed as a by product (Note 3). The residual red solid is then placed in a 2-1. three-... 

Naphthalic acid imide 69 is obtained through air oxidation of acenaphthene 72 with vanadium peroxide as a catalyst. The intermediate, naphthalic anhydride 73, is subsequently reacted with ammonia ... 

This polycyclic pigment, listed in the Colour Index under Constitution Number 507300, is synthesized by condensation of 5,6-diaminobenzimidazolone with a naphthalic anhydride in a high boiling solvent [3] ... 

Excessive activity of the enzyme aldose reductase sometimes accompanies diabetes. The net result is often accumulation of reduced sugars such as galactose in the lens of the eye and ensuing cataract formation. A1 restatin (43), an aldose reductase inhibitor, is one of the first agents found that holds promise of preventing diabetes-induced cataracts. The compound, actually used as its sodium salt, is prepared in straightforward manner by imide formation between 1,8-naphthalic anhydride (41) and glycine. ... 

Naphthalic anhydride, reaction with potassium hydroxide to yield 2,6-naphthalenedicarboxylic add, 40, 71... 

TL4093) or of naphthalic anhydride in the presence of cupric oxide (82GEP3105485), naphtholactones 61 have been obtained. 

The most common compounds from the naphtho[crf]pyran series are naphthalic anhydride and its various derivatives 378 substituted in the naphthalene nucleus. These derivatives are formed on heating naphthalic acids 377, which are obtained on oxidation of the corresponding acenaph-thenes. The syntheses of naphthalic acids 377 and their anhydrides are described in a monograph (66MI1). The interaction between naphthalic acid and sulfur tetrafluoride leads to 2,2,9,9-tetrafluoronaphtho[cd]pyran 379 (73ZOR689). 

Peri-carboxy-substituted /3-diketone 399, obtained from naphthalic anhydride and cyclohexanone, is cyclized by hydrazine to the condensed hetrocyclic system 400 (72TL4533). The most wide-spread representatives... 

There are known methods for constructing a naphtho[ ]-l, 2-diazepine nucleus by ring expansion on interaction of naphtho[crf]pyran derivatives with hydrazines. Thus, the reaction of naphthalic anhydride with hydrazines leads to 3,10-dioxo derivatives of naptho[[Pg.88]

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