Reaction #302881

Reaction equation

TFA

(2S)-2 Benzyloxycarbonylamino-5-oxo-heptanedioic acid 1-benzyl ester 7-ethyl ester

resorcinol

ether

→

L-(7-hydroxycoumarin-4-yl) ethylglycine

Yield 50.0%

Solvents

methanesulfonic acid

water

CH3CN

Conditions

Workup

1. 1
   Temperaturewas cooled to −30° C
2. 2
   WashThe precipitate was washed with cold ether
3. 3
   workup.DISSOLUTIONdissolved in water
4. 4
   Filtrationfiltered
5. 5
   OtherL-(7-hydroxycoumarin-4-yl)ethylglycine was purified by reverse phase HPLC
6. 6
   Otherto afford a brown solid in 50% yield (YMC AA12S052503WT column, 12 ml/min flow rate
7. 7
   Otherover the course of 12 min

Procedure

(2S)-2 Benzyloxycarbonylamino-5-oxo-heptanedioic acid 1-benzyl ester 7-ethyl ester from the previous step (2.35 g, 5 mmol) was added slowly to resorcinol (3 g, 25 mmol) in methanesulfonic acid (20 ml) and stirred for two hours at room temperature. Five volumes of ether were then added to the mixture and was cooled to −30° C. The precipitate was washed with cold ether, dissolved in water, filtered, and lyophilized. L-(7-hydroxycoumarin-4-yl)ethylglycine was purified by reverse phase HPLC to afford a brown solid in 50% yield (YMC AA12S052503WT column, 12 ml/min flow rate, from 10% to 90% CH3CN, 0.1% TFA (w/v) in water, over the course of 12 min). 1H-NMR (DMSO): δ 2.06 (s, 2H), 2.70-2.90 (m, 2H), 3.82-4.0 (m, 1H), 6.06 (s, 1H), 6.75 (dd, J=8.8, 2.4, 1H), 6.82 (d, J=2.4, 1H), 7.62 (d, J=8.8, 1H), 8.17 (s, 3H). LC-MS (ESI) calc. for C13H14NO5 (M+H+) 264.08 Da, obsd. 264.0 Da.

Source