Naphthalic anhydrides condensation

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] ... 

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... 

Fig. 13.144 (1) sulfonation, (2) chromate oxidation to give the naphthalic anhydride (64), (3) condensation with A-methylamine, and (4) replacement of the sulfonic acid group in a reaction with methoxide. This process gives C.I. Fluorescent Brightener 162. 

When acenaphthylene and naphthalic anhydride are produced together, separation may be effected by passing the vapors through a condenser maintained at a temperature of 100° to 200° C., at which temperature the anhydride condenses while the acenaphthylene and acenaphthene pass to a condenser at room temperature. Acenaphthylene may be separated from acenaphthene with sodium bisulfite. 

Thus, condensation of aromatic bis-phenols with two-foid molar amounts of 4-chloroformyl(naphthalic anhydride) in organic solvents in the presence of bases yielded bisfesteranaphthalic anhydrides). Scheme 27 [120]. 

Condensation of 4-chloroformyl (naphthalic anhydride) with resotcine 95 120... 

Another way of rendering PNI soluble is to use various bis(naphthalic anhydrides) of less condensed structure when compared with DPTA and DNTA [19, 21, 27, 69-82]. Interaction of bis(naphthalic anhydride) with 1,12-diaminododecane (Scheme 1.15) leads to the formation of PNI very soluble in methylene chloride and chloroform [69]. 

Since the dye is patented, it is probable that it is represented by one of the five examples in the patent. The most likely possibility is example 3, the condensation product from 4-amino-l,8-naphthalic acid anhydride with cyclohexylamine, or example 4, the sulfonation product of this compound. 

These data reveal a logical pathway to a possible enhancement in thermal and chemical stability of polyheteroarylenes, Le. in the above mentioned reactions a replacement of bis(phthalic anhydrides) by bi naphthalic) ones the structure of which would determine the formation of systems containing six-membered imide rings - either isolated ones or those condensed with other heterocyclic moieties. 

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