Diisopropylamine → Diethyl 2,6-bis(trifluoromethyl)-4-chloro-3,5-pyridinedicarboxylate

To a cold (-78° C. ) solution of LDA, from 0.0155 mol of n-BuLi, 0.0157 mol (2.2 ml) of diisopropylamine and 30 ml of dry DME was added a solution of 3.2 g (0.01 mol) of product of Example 9 in 5 ml of DME. The resulting purple solution was stirred for 5 minutes and treated with 4 ml of ethyl chloroformate. The mixture was stirred at -78° C. for minutes, the cooling bath was removed, and the reaction mixture was stirred for an additional 30 minutes, then poured into water. The mixture was extracted with ether. The ether extract was washed with 50 ml of 3N HCl, dried, and concentrated. The residue was kugelrohr distilled at 53 Pa. The low bp distillate (pot temperature 50°-60° C. ) was identified as ethyl N,N-diisopropylurethane. The higher bp distillate (pot temperature 100° C. ) was 1.64 g of a solid which was recrystallized from hexane at low temperature to give 1.2 g (30%) of product; mp 76°-77° C.

1. stirringThe mixture was stirred at -78° C. for minutes
2. customthe cooling bath was removed
3. stirringthe reaction mixture was stirred for an additional 30 minutes
4. additionpoured into water
5. extractionThe mixture was extracted with ether
6. extractionThe ether extract
7. washwas washed with 50 ml of 3N HCl
8. customdried
9. concentrationconcentrated
10. distillationThe residue was kugelrohr distilled at 53 Pa
11. customThe low bp distillate (pot temperature 50°-60° C. )
12. customThe higher bp distillate (pot temperature 100° C. )
13. customwas recrystallized from hexane at low temperature

ORD record

ord-cf7010a3ad5045d490c8986d448bc5bf

Source dataset

uspto-grants-1989_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04797149