tert-Butanol → tert-Butyl 5,6-Dihydro-4H-pyrrolo[1,2-b]pyrazol-2-ylcarbamate

HRID 407829Notes

Reaction equation

HRID 407829 reaction equation
[N:1]1[N:2]2[CH2:11][CH2:10][CH2:9][C:3]2=[CH:4][C:5]=1C(O)=O.C([N:14]([CH2:17]C)CC)C.C1C=CC(P(N=[N+]=[N-])(C2C=CC=CC=2)=[O:26])=CC=1.[C:36]([OH:40])([CH3:39])([CH3:38])[CH3:37]>>[N:1]1[N:2]2[CH2:11][CH2:10][CH2:9][C:3]2=[CH:4][C:5]=1[NH:14][C:17](=[O:26])[O:40][C:36]([CH3:39])([CH3:38])[CH3:37]

Participants

5

Reactant 4

HCID 6386tert-ButanolHCID 8471TriethylamineHCID 199401P,P-Diphenylphosphinic azideHCID 113670964H,5H,6H-pyrrolo[1,2-b]pyrazole-2-carboxylic acid

Product 1

HCID 86684089tert-Butyl 5,6-Dihydro-4H-pyrrolo[1,2-b]pyrazol-2-ylcarbamateYield 15.5%

Conditions

Temperature
85 °C

Procedure

A 25-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser was charged with 162a (197.6 mg, 1.3 mmol), tert-butanol (5.0 mL), triethylamine (262.6 mg, 2.6 mmol), and DPPA (550 mg, 2.0 mmol). The system was subjected to three cycles of vacuum/nitrogen flush and heated at 85° C. for 5 h. It was then cooled to room temperature and purified with Combiflash (A: 1% NH4HCO3/water, B: acetonitrile) to afford 162b (45 mg, 15.5%) as a yellow solid. MS-ESI: [M+H-56]+ 168.3

Workup

  1. customA 25-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser
  2. customflush
  3. temperatureIt was then cooled to room temperature
  4. custompurified with Combiflash (A: 1% NH4HCO3/water, B

Sources & evidence

ORD record
ord-a14283aa828142b6987f4d02d55e99e9
Source dataset
uspto-grants-2014_06
Patent number
US08754077B2

Reaction notes

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