Triethylamine → HCID 14964780, compound

Temperature

-20 °C

17.2 g of t-butyloxycarbonyl-L-proline were dissolved in 160 ml of tetrahydrofuran, cooled to -20° C and treated with 11.1 ml of triethylamine and 7.7 ml of chloroformic acid ethyl ester. The resulting suspension was stirred at -20° C for a further 5 minutes and treated with a suspension, pre-cooled to -20° C, prepared from 13.4 g of β-alanine methyl ester hydrochloride and 13.4 ml of triethylamine in 160 ml of a mixture of dimethylformamide and tetrahydrofuran (1:1). The mixture was stirred for 1 hour at a temperature below -10° C and for a further hour at room temperature, filtered and the filtrate concentrated in vacuo. The oily residue was dissolved in 200 ml of ethyl acetate and washed three times, each time with 5% potassium hydrogen sulphate solution, water, 5% sodium hydrogen carbonate solution and water, and dried over sodium sulphate. The organic phase was concentrated in vacuo and the oily residue crystallised from ether/petroleum ether. Yield: 19.2 g; melting point 70° C; [α]D25 = -39.2° (c = 1 in dimethylformamide).

1. additiontreated with a suspension
2. temperaturepre-cooled to -20° C
3. stirringThe mixture was stirred for 1 hour at a temperature below -10° C and for a further hour at room temperature
4. filtrationfiltered
5. concentrationthe filtrate concentrated in vacuo
6. dissolutionThe oily residue was dissolved in 200 ml of ethyl acetate
7. washwashed three times
8. dry with materialeach time with 5% potassium hydrogen sulphate solution, water, 5% sodium hydrogen carbonate solution and water, and dried over sodium sulphate
9. concentrationThe organic phase was concentrated in vacuo
10. customthe oily residue crystallised from ether/petroleum ether

ORD record

ord-0a17af7ac3ff450387048cae9f4b1594

Source dataset

uspto-grants-1978_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04066635