Hydrazine hydrate (1:1) → (1R,2R)-2-Hydroxycyclopentanecarboxylic acid hydrazide

To a 200-mL four-necked flask were added 18.47 g (128.1 mmol) of methyl (R,R)-2-hydroxycyclopentanecarboxylate and 75 mL of 2-propanol and stirring was started. Hydrazine monohydrate (12.83 g; 256.2 mmol) was dropped thereinto at 20° C. taking 1 hour and 30 minutes. After the dropping, the mixture was stirred at 85° C. for 15 hours. After the reaction, heating was stopped and the mixture was cooled to room temperature to precipitate the crystals. The crystals were filtered and washed with small amount of 2-propanol. The resulting crystals were dried to give 10.89 g of the title compound. The yield was 59%. Ratio of anti-form to syn-form of the compound was measured by a high-performance liquid chromatography (column: Inertsil ODS-3V) and found that the anti/syn ratio was more than 99/1.

1. stirringAfter the dropping, the mixture was stirred at 85° C. for 15 hours
2. customAfter the reaction
3. temperatureheating
4. customto precipitate the crystals
5. filtrationThe crystals were filtered
6. washwashed with small amount of 2-propanol
7. customThe resulting crystals were dried

ORD record

ord-d85dc5487cd94a0fbeda16aacef20951

Source dataset

uspto-grants-2006_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07038087B2