Hydrazine hydrate (1:1) → HCID 67033215, compound

Temperature

2.5 °C

A solution of triphosgene (9.44 g, 31.8 mmol) in THF (100 ml) was cooled to 0° C. and piperidine-4-carboxylic acid ethyl ester (10.0 g, 63.6 mmol) was added over 15 minutes while the temperature was maintained between 0-5° C. Then N,N-diisopropyl ethyl amine (33 ml, 191 mmol) was added over 60 minutes. The suspension was stirred for 18 h at rt. The suspension was filtered off and washed with THF (50 ml). The filtrate was transferred into a dropping funnel and added dropwise over 60 minutes to hydrazine monohydrate (9.3 ml, 191 mmol) at 5-10° C. The suspension was stirred for 3 h at 5° C. The reaction mixture was washed twice with brine (100 ml). The aq. layers were extracted with EtOAc (100 ml). The combined organic layers were dried over Na2SO4 and concentrated under vacuo to yield 13.4 g (98%) of the title product as a brown oil. ES-MS m/e: 216.3 (M+H+).

1. filtrationThe suspension was filtered off
2. washwashed with THF (50 ml)
3. customThe filtrate was transferred into a dropping funnel
4. stirringThe suspension was stirred for 3 h at 5° C
5. washThe reaction mixture was washed twice with brine (100 ml)
6. extractionThe aq. layers were extracted with EtOAc (100 ml)
7. dry with materialThe combined organic layers were dried over Na2SO4
8. concentrationconcentrated under vacuo

ORD record

ord-8da4f78d59114553ba7309da581bb571

Source dataset

uspto-grants-2013_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08394834B2