(S)-N-Boc-(4-Pyridyl)alanine

off-white to light yellow powder

To 9.6 g (40 mmol) of L-3-(4-pyridyl)alanine.2HCl were added 200 ml of a IN aqueous sodium hydroxide solution and 200 ml of THF. While stirring, 20 ml of di-t-butyl dicarbonate was added dropwise and the mixture was stirred for 2 hours. To the resulting reaction mixture was added 300 ml of water and the resulting mixture was washed with ethyl acetate (2x200 ml). To the aqueous layer was added a 5percent aqueous potassium hydrogen sulfate solution to adjust the pH of the mixture to about 4, and then, the mixture was extracted with n-butanol (4x200 ml). The organic layer was concentrated under reduced pressure. The solid was collected by filtration and dried to obtain 8.0 g of CI 04-1 as white solid. MS (ESI) m/z: 267.2 [M+H]General procedure: To amixture of Boc-Phe-OH (33a) (5 g, 18.9 mmol), ethyl 5-amino-1H-indole-2-carboxylate (34) (3.9 g, 18.9 mmol) and pyridine (5 mL) in CH2Cl2 (50 mL) at -10 C was added POCl3 (2.9 g, 18.9 mmol)dropwise. After addition, the reaction mixture was stirred at 10 C for 2 h when TLC analysisindicated completion of reaction, then H2O (10 mL) was added and the organic layer was separated, washed by hydrochloric acid (1 M, 10 mL), dried by Na2SO4, filtered. The filtrate was evaporated invacuum to get crude 35a as a brown solid, which was used for next step without further purification(6.6 g, 77.6% yield).

Molecular Weight:266.29
XLogP3:1.4
Hydrogen Bond Donor Count:2
Hydrogen Bond Acceptor Count:5
Rotatable Bond Count:6
Exact Mass:266.12665706
Monoisotopic Mass:266.12665706
Topological Polar Surface Area:88.5
Heavy Atom Count:19
Complexity:319
Defined Atom Stereocenter Count:1
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes