Nitric Acid → 5-Chloro-1-(4-nitro-phenyl)-1H-tetrazole

Temperature

65 °C

5-Chloro-1-phenyl-1H-tetrazole (500 g, 2.78 mol) was carefully added in one portion to stirred white fuming nitric acid (91.5% HNO3, 2.5 L). The internal temperature of the mixture increased steadily to 65° C. then fell. An aliquot was removed and partitioned between water and dichloromethane. TLC analysis (80:20 hexanes/ethyl acetate) indicated consumption of starting material. The mixture was carefully poured into stirred ice (3 L), water (2 L) and dichloromethane (2 L). The layers were separated and the aqueous was extracted with dichloromethane (2 L). The combined organic phase was washed with 5% aqueous sodium bicarbonate solution (1 L), dried (MgSO4), filtered, and concentrated to a solid. The solid was mixed with 90:10 hexanes/ethyl acetate (3 L) and heated to 65° C. The mixture was cooled overnight (2-5° C.). Filtration afforded a white crystalline solid (544 g, 87%). 1H NMR (CDCl3, 300 MHz) δ 8.51 (d, 9.5 Hz, 2H), 7.91 (d, 8.8 Hz, 2H); mp 96.5° C.; Rf=0.2 (K).

1. customAn aliquot was removed
2. custompartitioned between water and dichloromethane
3. customconsumption of starting material
4. additionThe mixture was carefully poured
5. stirringinto stirred ice (3 L), water (2 L) and dichloromethane (2 L)
6. customThe layers were separated
7. extractionthe aqueous was extracted with dichloromethane (2 L)
8. washThe combined organic phase was washed with 5% aqueous sodium bicarbonate solution (1 L)
9. dry with materialdried (MgSO4)
10. filtrationfiltered
11. concentrationconcentrated to a solid
12. additionThe solid was mixed with 90:10 hexanes/ethyl acetate (3 L)
13. temperatureheated to 65° C
14. temperatureThe mixture was cooled overnight (2-5° C.)
15. filtrationFiltration

ORD record

ord-5456aab091d64518ad11932d9dbf55bb

Source dataset

uspto-grants-2005_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06903218B2