1,4,5,8-Naphthalenetetracarboxylic acid → 1,3-Dioxo-1H,3H-naphtho(1,8-cd)pyran-6,7-dicarboxylic acid

Participants

Role	Name	HCID	Charge
Reactant	1,4,5,8-Naphthalenetetracarboxylic acid	HCID 31422	—
Reactant	Disodium	HCID 141233	—
Solvent	Water	HCID 962	—
Solvent	[2-adenin-9-yl-5-[[[[5-(3-carbamoyl-4H-pyridin-1-yl)-3,4-dihydroxy-tetrahydrofuran-2-yl]methoxy-oxido-phosphoryl]oxy-oxido-phosphoryl]oxymethyl]-4-hydroxy-tetrahydrofuran-3-yl] phosphate	HCID 12598259	—
Product	1,3-Dioxo-1H,3H-naphtho(1,8-cd)pyran-6,7-dicarboxylic acid	HCID 132336	97%

Reaction Steps

After cooling to a temperature of 20° to 30° C., the suspension, which was present after the letting down, of the tetrasodium salt of naphthalene-1,4,5,8-tetracarboxylic acid (NTC) was worked up by a process analogous to that described in Example 3 c) , by a procedure in which the disodium salt of NTC was first formed by acidification to pH 4.8 to 4.5 and was isolated, this salt was then dissolved in water by conversion into the tetrasodium salt, insoluble impurities were separated off by filtration, and the 1,8-monoanhydride of NTC was then precipitated by acidification with hydrochloric acid and was isolated. 13.1 kg of naphthalene-1,4,5,8-tetracarboxylic acid 1,8-monoanhydride of 96% purity, corresponding to a yield of 97% of theory, were obtained.

Provenance & Evidence

DOI	10.6084/m9.figshare.5104873.v1
Patent number	US05254796
Source dataset	uspto-grants-1993_10
ORD ID	ord-20723f5bb0344f3383d0149c69f6c215
Source note	uspto-grants-1993_10