Carbon Dioxide → HCID 20468446, compound

To a solution of 5-fluoro-4-amino-pentanoic acid (6.75 g, 50 mmoles) in conc. sulfuric acid (49 g, 0.5 moles) is added a solution of hydrazoic acid in chloroform (1.14 N, 44 mL) at 40° C. with vigorous stirring. Heating and stirring are continued until the end of carbon dioxide evolution (6 hours). The reaction mixture is poured into water (500 mL), heated to boiling and the sulfate is precipitated with barium chloride (105 g in 400 mL of water). After cooling to room temperature, barium sulfate is removed by filtration (celite) and the excess barium ions are precipitated by dropwise addition of 2 N sulfuric acid until no further precipitation occurs. After filtration (celite), evaporation gives a solid residue which is recrystallized from methanol/acetone to give 1-fluoro-2,4-diaminobutane dihydrochloride (2HCl, 4.7 g, 53%) as white, slightly hygroscopic crystals, Mp 135° C.

1. temperatureHeating
2. temperatureheated
3. customthe sulfate is precipitated with barium chloride (105 g in 400 mL of water)
4. custombarium sulfate is removed by filtration (celite)
5. customthe excess barium ions are precipitated by dropwise addition of 2 N sulfuric acid until no further precipitation
6. filtrationAfter filtration (celite), evaporation
7. customgives a solid residue which
8. customis recrystallized from methanol/acetone

ORD record

ord-a8126bb37ec54911b22730f5b19de206

Source dataset

uspto-grants-1984_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04435425