Diphosgene → 3-tert-Butyl-5-isocyanato-1-p-tolyl-1H-pyrazole

HRID 1916804Notes

Reaction equation

[C:1]([C:5]1[CH:9]=[C:8]([NH2:10])[N:7]([C:11]2[CH:16]=[CH:15][C:14]([CH3:17])=[CH:13][CH:12]=2)[N:6]=1)([CH3:4])([CH3:3])[CH3:2].[C:18]([O-])(O)=[O:19].[Na+].O=C(Cl)OC(Cl)(Cl)Cl>C(Cl)Cl>[C:1]([C:5]1[CH:9]=[C:8]([N:10]=[C:18]=[O:19])[N:7]([C:11]2[CH:12]=[CH:13][C:14]([CH3:17])=[CH:15][CH:16]=2)[N:6]=1)([CH3:4])([CH3:3])[CH3:2]

Participants

Conditions

Temperature: 0 °C

Procedure

To a solution of 3-tert-butyl-1-p-tolyl-1H-pyrazol-5-amine (4) (WO 2000043384) (1.00 g, 4.36 mmol) in DCM (90 mL) was added a saturated aq solution of NaHCO3(60 mL). The mixture was stirred vigorously, cooled to 0° C. and diphosgene (2.1 mL, 17.4 mmol) was added in a single portion. After stirring for 1 hr at RT, the layers were separated and the organics dried and evaporated to give a brown oil. The oil was triturated with iso-hexane (5.0 mL) and the solid filtered. The filtrate was concentrated in vacuo to give 3-tert-butyl-5-isocyanato-1-p-tolyl-1H-pyrazole (19) as a light brown oil (1.00 g, 3.92 mmol, 90%). m/z 288 (in MeOH) (M+H+MeOH)+ (ES+).

Workup

stirringAfter stirring for 1 hr at RT
customthe layers were separated
customthe organics dried
customevaporated
customto give a brown oil
customThe oil was triturated with iso-hexane (5.0 mL)
filtrationthe solid filtered
concentrationThe filtrate was concentrated in vacuo

Sources & evidence

ORD record: ord-b2c659a3acd9483d95b4d9a98b93e4be
Source dataset: uspto-grants-2013_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08618140B2

Reaction notes

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