Carbon Dioxide → 1,4-Cyclohexane diisocyanate

HRID 2082586Notes

Reaction equation

[C:1](=[O:3])=O.[NH2:4][CH:5]1[CH2:10][CH2:9]C(N)C[CH2:6]1.C([N:14]([CH2:17][CH3:18])[CH2:15]C)C.P(Cl)(Cl)(Cl)=[O:20]>ClCCl>[CH2:18]1[CH:17]([N:14]=[C:15]=[O:20])[CH2:9][CH2:10][CH:5]([N:4]=[C:1]=[O:3])[CH2:6]1

Participants

Conditions

Temperature: -10 °C

Procedure

Carbon dioxide was added subsurface to a dichloromethane (50 mL) solution containing 1,4-diaminocyclohexane (1,4-(NH2)2C6H10) (mixture of cis and trans, 0.04 mol, 4.6 g), N-cyclohexyl-N',N',N",N"-tetraethylguanidine (0.08 mol, 20.4 g) and triethylamine (0.08 mol, 8.0 g) at -10° C. (ice and salt bath) for 1 h at a pressure of 0 psig. The reaction mixture was transferred rapidly via cannula under carbon dioxide to the precooled solution of phosphorus oxychloride (0.08 mol, 12.4 g) in 50 mL dichloromethane. After stirring for ca. 30 min at -10° C. the reaction mixture turned yellow-brown and a ppt formed. The crude reaction was filtered and the filtrate concentrated in vacuo. The residue was extracted with 2×100 mL diethyl ether. The ether layers (light yellow) were concentrated and the residue was distilled under vacuum (ca. 0.1-0.3 torr) collecting product, cis and trans 1,4-cyclohexyl di-isocyanate, at 68°-78 ° C. (3.9 g, 57%) of 96% purity as judged by GC. IR (neat) 2266 cm-1. 1H NMR was also obtained.

Workup

customa ppt formed
customThe crude reaction
filtrationwas filtered
concentrationthe filtrate concentrated in vacuo
extractionThe residue was extracted with 2×100 mL diethyl ether
concentrationThe ether layers (light yellow) were concentrated
distillationthe residue was distilled under vacuum (ca. 0.1-0.3 torr)
customcollecting product, cis and trans 1,4-cyclohexyl di-isocyanate
customat 68°-78 ° C.
custom1H NMR was also obtained

Sources & evidence

ORD record: ord-d986b95435d44fe6b68b77dfeb59257e
Source dataset: uspto-grants-1993_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05189205

Reaction notes

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