Hydrochloric Acid → 2,4,5,6-Tetrahydrocyclopenta[c]pyrazol-3-amine

HRID 352420Notizen

Reaktionsgleichung

Reaktionsgleichung von HRID 352420
[C:1]1(=[N:6][NH:7][C:8]([NH2:10])=S)[CH2:5][CH2:4][CH2:3][CH2:2]1.C(NC(C)C)(C)C.[Li].Cl.S.[OH-].[Na+]>O1CCCC1>[NH:6]1[C:1]2[CH2:5][CH2:4][CH2:3][C:2]=2[C:8]([NH2:10])=[N:7]1

Komponenten

7

Edukt 5

HCID 313Hydrochloric AcidHCID 402Hydrogen SulfideHCID 14798Sodium HydroxideHCID 690102Cyclopentanone thiosemicarbazoneHCID 45051747Lithium diisopropylamine

Produkt 1

HCID 227120592,4,5,6-Tetrahydrocyclopenta[c]pyrazol-3-amineAusbeute 62,2 %

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 8028TetrahydrofuranLösungsmittel

Versuchsvorschrift

5.3 g of cyclopentanone thiosemicarbazone is carefully added at 0° C. to a solution of lithium diisopropylamine in 200 ml of tetrahydrofuran (from 29 ml of diisopropylamine and 81 ml of 1.6 M n-butyllithium), whereby the temperature rises to 30° C. Then, it is stirred for 2 hours at room temperature. Then, 150 ml of 4N hydrochloric acid is carefully added in drops (exothermic, H2S development), and the mixture is refluxed for 30 minutes. Then, it is cooled to 5° C. and set at pH 14 with sodium hydroxide solution. The aqueous phase is extracted three times with tetrahydrofuran/ethyl acetate 95:5. The crude product is purified by column chromatography on silica gel with 1 l of ethyl acetate and 1 l of ethyl acetate/methanol 9:1 with the addition of 3% triethylamine. 2.58 g of 1,4,5,6-tetrahydro-cyclopentapyrazol-3-yl-amine with a melting point of 116-120° C. is obtained.

Aufarbeitung

  1. customrises to 30° C
  2. temperaturethe mixture is refluxed for 30 minutes
  3. temperatureThen, it is cooled to 5° C.
  4. extractionThe aqueous phase is extracted three times with tetrahydrofuran/ethyl acetate 95:5
  5. customThe crude product is purified by column chromatography on silica gel with 1 l of ethyl acetate and 1 l of ethyl acetate/methanol 9:1 with the addition of 3% triethylamine

Quellen und Nachweise

ORD-Eintrag
ord-afae7f681e3748d8ab9a8e2228a47be7
Quelldatensatz
uspto-grants-2004_06
Patentnummer
US06747046B2

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