Reacción #80264

Ecuación de reacción

8-(N-Cbz-amino)-1,3-octanediol

Diisopropylethylamine

4,4-dimethoxytrityl chloride

tetrahydrofuran

→

8-(N-Cbz-amino)-3-hydroxy-1-(4,4'-dimethoxytrityloxy)octane

Disolventes

pyridine

Condiciones de reacción

Tratamiento posterior

1. 1
   Otroevaporated in vacuo
2. 2
   workup.DISSOLUTIONredissolved in anhydrous pyridine (200 mL)
3. 3
   Temperaturacooled in an ice bath
4. 4
   workup.STIRRINGStirring
5. 5
   workup.ADDITIONafter the addition
6. 6
   OtroThe mixture was evaporated in vacuo
7. 7
   Otropurified by column chromatography on silica gel
8. 8
   Lavadoeluting with 20:80:1 ethyl acetate
9. 9
   OtroEvaporation of the appropriate fractions

Procedimiento

8-(N-Cbz-amino)-1,3-octanediol (4, 25 g, 85 mmoles ) was dissolved in anhydrous pyridine (200 mL), evaporated in vacuo and redissolved in anhydrous pyridine (200 mL). Diisopropylethylamine (38.1 mL, 88 mmoles) and 4-dimethylaminopyridine (170 mg) were added. The mixture was stirred under nitrogen and cooled in an ice bath while adding 4,4-dimethoxytrityl chloride (30 g, 88 mmoles) in tetrahydrofuran (200 mL) dropwise over 1.5 hours. Stirring was continued for 15 minutes after the addition was complete. The mixture was evaporated in vacuo and purified by column chromatography on silica gel, eluting with 20:80:1 ethyl acetate:cyclohexane:triethylamine, then 50:50:1 ethyl acetate:cyclohexane:triethylamine and finally, 100:1 ethyl acetate:triethylamine. Evaporation of the appropriate fractions gave 8-(N-Cbz-amino)-3-hydroxy-1-(4,4'-dimethoxytrityloxy)octane (44 g) as a crisp foam. Mass Spectrum: (M+K)+ @m/z 636. 8-(N-Cbz-amino)-3-hydroxy-1-(4,4'-dimethoxytrityloxy)octane (28.4 g, 47.6 mmoles) was dissolved in methanol (200 mL) and hydrogenated over 10% palladium on carbon (2.84 g) @45 psi hydrogen for 2.5 hours. After filtration and evaporation in vacuo there remained 8-(N-Cbz-amino)-1,3-octanediol (21.5 g). Mass Spectrum: (M+K)+ @m/z 502.

Fuente