Acetyl chloride → HCID 11658392, compound

Temperature

15 °C

13.9 g Crude Boc-prolinal (70 mmol; Omega Chem, freshly distilled) were dissolved in 110 ml methanol and cooled to ˜15° C. A solution of 11.0 g (140 mmol) acetyl chloride in 30 ml methanol was added all at once and the yellowish solution was stirred at RT for 1 h (gas evolution). 66.9 g Trimethyl orthoformate (630 mmol) were now added and the reaction mixture was stirred at RT for 42 h. The solvent and the excess of the orthoester were removed by rotary evaporation (40° C./≧10 mbar) and the resulting 14.0 g beige, crystalline residue was crystallized from 300 ml hot ethyl acetate yielding after stirring at 0° C. for 17 h 8.9 g (70%) white needles, [α]D=−15.4 (CHCl3; c=1). 1H-NMR:

1. distillationOmega Chem, freshly distilled)
2. dissolutionwere dissolved in 110 ml methanol
3. stirringthe reaction mixture was stirred at RT for 42 h
4. customThe solvent and the excess of the orthoester were removed by rotary evaporation (40° C./≧10 mbar)
5. customthe resulting 14.0 g beige, crystalline residue was crystallized from 300 ml hot ethyl acetate yielding
6. stirringafter stirring at 0° C. for 17 h 8.9 g (70%) white needles, [α]D=−15.4 (CHCl3; c=1)

ORD record

ord-757243efed2d4bacb5edc15efd26281f

Source dataset

uspto-grants-2007_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07312343B2