Nitric Acid → HCID 21289516, compound

Temperature

-8 °C

2.1 g of ethyl 6-(2-amino-5-thiazolylmethyl)-5,6,7,8-tetrahydro-2-naphthalenecarboxylate was dissolved in 23 ml of phosphoric acid and 12 ml of concentrated nitric acid was added thereto. A solution of 0.46 g of sodium nitrite in 4 ml of water was added dropwise to the mixture. The resulting mixture was stirred at -8° C. for 20 minutes. The reaction mixture was added to a solution of 5.28 g of cuprous chloride in 7 ml of concentrated hydrochloric acid at -5° C. The resulting mixture was stirred at -8° to 0° C. for 1.5 hours and 100 ml of an ice-cold water was added thereto. The mixture was neutralized by adding sodium carbonate and the resulting mixture was extracted with chloroform. The extract was washed with water and dried and then concentrated in vacuo. The residue was dissolved in 15 ml of acetic acid and 14.4 g of zinc powder was added portionwise thereto under heating. The mixture was heated under reflux for 2 hours. After cooling, the insoluble material was removed by filtration. The filtrate was concentrated in vacuo and the residue was dissolved in chloroform. The solution was washed with water, dried and concentrated in vacuo. The residue was purified by silica gel column chromatography using a mixture of methanol and chloroform (2:98 by volume) for elution to give 1.27 g of ethyl 6-(5-thiazolylmethyl)-5,6,7,8-tetrahydro-2-naphthalenecarboxylate as an oil.

1. stirringThe resulting mixture was stirred at -8° to 0° C. for 1.5 hours
2. extractionthe resulting mixture was extracted with chloroform
3. washThe extract was washed with water
4. customdried
5. concentrationconcentrated in vacuo
6. dissolutionThe residue was dissolved in 15 ml of acetic acid
7. addition14.4 g of zinc powder was added portionwise
8. temperatureunder heating
9. temperatureThe mixture was heated
10. temperatureunder reflux for 2 hours
11. temperatureAfter cooling
12. customthe insoluble material was removed by filtration
13. concentrationThe filtrate was concentrated in vacuo
14. dissolutionthe residue was dissolved in chloroform
15. washThe solution was washed with water
16. customdried
17. concentrationconcentrated in vacuo
18. customThe residue was purified by silica gel column chromatography
19. additiona mixture of methanol and chloroform (2:98 by volume)
20. washfor elution

ORD record

ord-e38d26735ca04d4e9a71642ba168cab4

Source dataset

uspto-grants-1988_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04777257