Ammonium Chloride → 3-Amino-5-(2-methoxy-ethyl)-5H-pyrrolo[2,3-b]pyrazine-2-carboxylic acid

To a solution of 3-amino-5-(2-methoxy-ethylamino)-6-trimethylsilanylethynyl-pyrazine-2-carboxylic acid methyl ester (487 mg, 1.51 mmol) in THF (7.6 ml) was added a suspension of KOtBu (356 mg, 3.17 mmol) in THF (7.6 ml) and the reaction mixture was stirred at r.t. for 2 h. At 0° C. solid NH4Cl (848 mg) was added and the mixture stirred for 30 min. After addition of half-saturated NH4Cl solution (15 ml) the mixture was extracted with EtOAc (2×15 ml), the pH of the aq. phase was adjusted the pH to 4 by addition of 1N HCl. The aq. phase was extracted with DCM/EtOH 9:1 (2×100 ml), the combined organic layers were dried with Na2SO4 and evaporated. The residue was filtered through a plug of silica gel (DCM/EtOH 90:10) to provide the title compound as brown powder. This material was used for coupling reactions without further purification.

1. stirringthe mixture stirred for 30 min
2. extractionwas extracted with EtOAc (2×15 ml)
3. additionby addition of 1N HCl
4. extractionThe aq. phase was extracted with DCM/EtOH 9:1 (2×100 ml)
5. dry with materialthe combined organic layers were dried with Na2SO4
6. customevaporated
7. filtrationThe residue was filtered through a plug of silica gel (DCM/EtOH 90:10)

ORD record

ord-d909c39a367e452282f34c74fdc4a2a2

Source dataset

uspto-grants-2014_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08865712B2