2-Naphthol → HCID 136355259, compound

1.4 g (4.4 mmol) of the compound from Step 10.4 was dissolved in 20 mL of water and 1.5 g of hydrochloric acid (32%), the solution was cooled in an ice bath and to it was added over a period of 10 min 0.3 g (4.4 mmol) of sodium nitrite in 2 mL of water. The mixture was allowed to agitate for an additional 30 min after which a solution of 0.63 g (4.4 mmol) of 2-naphthol in 10 mL of isopropanol was added. The pH was adjusted to 8 to 9 by addition of saturated sodium carbonate solution which resulted in coupling with formation of a brown solution. After 1 hour, the solution was evaporated to dryness and, to isolate the pure dye, 80 mL of methanol was added to the residue. After an agitation period of 1 hour at room temperature, the inorganic salts were filtered off. The filtrate was concentrated to about 20% of its original volume and then 30 mL of isopropanol was added to induce crystallization. Cooling in an ice bath, filtration and drying at 40° C. under vacuum gave 1.6 g (67% of the original) of a red-brown product.

1. additionwas added
2. customresulted in coupling with formation of a brown solution
3. customthe solution was evaporated to dryness
4. customto isolate the pure dye, 80 mL of methanol
5. additionwas added to the residue
6. filtrationAfter an agitation period of 1 hour at room temperature, the inorganic salts were filtered off
7. concentrationThe filtrate was concentrated to about 20% of its original volume
8. addition30 mL of isopropanol was added
9. customcrystallization
10. temperatureCooling in an ice bath
11. filtrationfiltration
12. customdrying at 40° C. under vacuum
13. customgave 1.6 g (67% of the original) of a red-brown product

ORD record

ord-7d91867b1e5a4d83a6b81bbf7044415f

Source dataset

uspto-grants-2009_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07517367B2