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

Participants

Role	Name	HCID	Charge
Reactant	tert-Butanol	HCID 6386	—
Reactant	Triethylamine	HCID 8471	—
Reactant	P,P-Diphenylphosphinic azide	HCID 199401	—
Reactant	4H,5H,6H-pyrrolo[1,2-b]pyrazole-2-carboxylic acid	HCID 11367096	—
Product	tert-Butyl 5,6-Dihydro-4H-pyrrolo[1,2-b]pyrazol-2-ylcarbamate	HCID 86684089	15.5%

Reaction Conditions

Temperature	85 °C

Reaction Steps

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

Provenance & Evidence

DOI	10.6084/m9.figshare.5104873.v1
Patent number	US08754077B2
Source dataset	uspto-grants-2014_06
ORD ID	ord-a14283aa828142b6987f4d02d55e99e9
Source note	uspto-grants-2014_06