Ammonia → 1,6-Naphthyridine-5,7(6H,8H)-dione

Temperature

-2.5 °C

Tetrahydrofuran (9 vol) is charged to the reactor followed by the starting material ester (1 eq) and a rinse of tetrahydrofuran (1 vol). The mixture is cooled to −2.5±7.5° C. under nitrogen atmosphere then treated with triethylamine (1.35 eq) and later ethyl chloroformate (1.25 eq). The reaction is stirred for 1 h at −2.5±7.5° C. then sampled. On receipt of a successful result the reaction is carefully treated with aq. ammonia, stirred, then water is added. Dilute HCl is added at <5° C. to adjust the pH to 6.5-7.5. The mixture is distilled under vacuum at <40° C. to 12-14 volumes and cooled to 7.5±2.5° C. The suspension is stirred ˜1 h at 7.5±2.5° C. then filtered. The solid is washed with water (1 vol) then offloaded and dried under vacuum (NLT 650 mm of Hg) at 52.5±2.5° C. for 12.0 h.

1. washa rinse of tetrahydrofuran (1 vol)
2. aliquotthen sampled
3. customOn receipt of a successful result the reaction
4. stirringstirred
5. distillationThe mixture is distilled under vacuum at <40° C. to 12-14 volumes
6. temperaturecooled to 7.5±2.5° C
7. stirringThe suspension is stirred ˜1 h at 7.5±2.5° C.
8. filtrationthen filtered
9. washThe solid is washed with water (1 vol)
10. customdried under vacuum (NLT 650 mm of Hg) at 52.5±2.5° C. for 12.0 h.

ORD record

ord-4aa07a65ed7d4c009a4a80faf54fb2c0

Source dataset

uspto-grants-2014_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08633319B2