Hydrogen Bromide → HCID 178462155, compound

3.27 g (7 mmol) of (1R)-1-[(N-benzyloxycarbonyl-L-histidyl-L-alanyl)amino]-ethylphosphonic acid were ground to a powder and then stirred vigorously at room temperature for 6 hours with a mixture of 15 ml of 45% hydrogen bromide in glacial acetic acid and 5 ml of glacial acetic acid. 75 ml of diethyl ether were added to precipitate a gum which was washed by decantation with a further 75 ml of diethyl ether. The residual gum was dissolved in 50 ml of methanol and two 3 ml portions of propylene oxide were added to the stirred solution to give a solid. The mixture was left to stand overnight and the solid was then filtered off and washed successively with methanol and diethyl ether to give 2.47 g of crude product of melting point 220°-230° C. (decomposition). Recrystallisation from a mixture of 50 ml of water and 125 ml of ethanol gave 2.02 g (87%) of (1R)-1-(L-histidyl-L-alanylamino)-ethylphosphonic acid of melting point 242°-245° C. (decomposition); [α]36520 =-166° (c=0.5% in water).

1. customto precipitate a gum which
2. washwas washed by decantation with a further 75 ml of diethyl ether
3. dissolutionThe residual gum was dissolved in 50 ml of methanol
4. additiontwo 3 ml portions of propylene oxide were added to the stirred solution
5. customto give a solid
6. waitThe mixture was left
7. filtrationthe solid was then filtered off
8. washwashed successively with methanol and diethyl ether
9. customto give 2.47 g of crude product of melting point 220°-230° C. (decomposition)
10. customRecrystallisation
11. additionfrom a mixture of 50 ml of water and 125 ml of ethanol

ORD record

ord-c8e347c56dbd4bc2949990104019813f

Source dataset

uspto-grants-1981_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04250085