Ammonium Chloride → (2S,5R)-2-[2-(2-Chloro-phenyl)-ethyl]-5-isopropyl-3,6-dimethoxy-2-methyl-2,5-dihydro-pyrazine

A solution of (R)-(−)-2,5-dihydro-3,6-dimethoxy-2-isopropyl-5-methylpyrazine (1.0 g, 5.0 mmol) in tetrahydrofuran (23 ml) was cooled to −70° C., then tert.butyllithium (1.7 M in pentane, 3.26 ml, 5.55 mmol) was added and the mixture was stirred for 1 hour. A solution of 1-(2-bromo-ethyl)-2-chlorobenzene (1.44 g, 6.56 mmol) in tetrahydrofuran (10 ml) was added slowly and the mixture was stirred overnight at −70° C. At room temperature saturated ammonium chloride solution was added and the mixture was extracted three times with ether. The combined organic layers were dried (MgSO4), filtered and evaporated. The residue was purified by column chromatography (SiO2, heptane/EtOAc=1:1 to yield an orange solid, (1.22 g, 72%); MS (ISP): 337.1; 339.1 ((M+H)+.).

1. stirringthe mixture was stirred overnight at −70° C
2. extractionthe mixture was extracted three times with ether
3. dry with materialThe combined organic layers were dried (MgSO4)
4. filtrationfiltered
5. customevaporated
6. customThe residue was purified by column chromatography (SiO2, heptane/EtOAc=1:1
7. customto yield an orange solid, (1.22 g, 72%)

ORD 기록

ord-1f8d0e6aa34744169bd4ce39625a625d

출처 데이터셋

uspto-grants-2013_12

DOI

10.6084/m9.figshare.5104873.v1

특허 번호

US08604061B2