Ethyl isothiocyanate → 4,4-Dimethyl-4,5-dihydro-pyrazole-1-carbothioic acid ethylamide

HRID 1484435Notes

Reaction equation

HRID 1484435 reaction equation
[CH3:1][C:2]1([CH3:7])[CH2:6][N:5]=[N:4][CH2:3]1.[CH2:8]([N:10]=[C:11]=[S:12])[CH3:9]>C(O)C>[CH2:8]([NH:10][C:11]([N:4]1[CH2:3][C:2]([CH3:7])([CH3:1])[CH:6]=[N:5]1)=[S:12])[CH3:9]

Participants

4

Reactant 2

HCID 10966Ethyl isothiocyanateHCID 137429344,4-Dimethyl-4,5-dihydro-3H-pyrazole

Product 1

HCID 866776074,4-Dimethyl-4,5-dihydro-pyrazole-1-carbothioic acid ethylamideYield 80%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

10 g (1 mol equiv.) 4,4-Dimethyl-4,5-dihydro-3H-pyrazole (synthesized as described in WO 2008/034863) and 11.6 mL (1.3 mol equiv.) ethyl isothiocyanate were added to 100 mL ethanol. The reaction mixture was refluxed for 1 hour. Silica gel was added and volatiles were removed in vacuo. Purification by flash chromatography on silica gel (Et2O:PA=1:2) afforded 15.2 g (80%) of 4,4-dimethyl-4,5-dihydro-pyrazole-1-carbothioic acid ethylamide. 1H NMR (400 MHz, CDCl3) δ 1.19-1.30 (m, 9H), 3.63-3.72 (m, 2H), 3.93 (s, 2H), 6.74 (s, 1H), 7.14 (br.s., 1H).

Workup

  1. temperatureThe reaction mixture was refluxed for 1 hour
  2. additionSilica gel was added
  3. customvolatiles were removed in vacuo
  4. customPurification by flash chromatography on silica gel (Et2O:PA=1:2)

Sources & evidence

ORD record
ord-823ba5ced5784b1891208707c6a7952d
Source dataset
uspto-grants-2016_08
Patent number
US09422244B2

Reaction notes

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