Cl.N[N:3]1[CH:7]=[CH:6][CH:5]=[C:4]1[C:8]#[N:9].C(O)(=O)C.[CH:14]([NH2:16])=[NH:15].P([O-])([O-])([O-])=O.[K+].[K+].[K+].N#N>C(O)C>[N:15]1[N:3]2[CH:7]=[CH:6][CH:5]=[C:4]2[C:8]([NH2:9])=[N:16][CH:14]=1
To a stirred suspension of 1-Amino-1H-pyrrole-2-carbonitrile hydrochloride (50 g, 0.35 mol) in absolute ethanol (800 mL) was added formamidine acetate (181.3 g, 1.74 mol) and potassium phosphate (370 g, 1.74 mol). The suspension was heated for 18 hours@78° C. (under N2), then cooled, filtered and concentrated to dryness in vacuo. The residue was mixed with ice water (2 L) and the dark grayish-brown solids were collected by suction filtration. The filter cake was washed with water, sucked dry and the solids were dissolved (on the funnel) with hot ethyl acetate and filtered into a collection vessel. The dark solution was filtered through a long plug of 30/40 Magnesol and the pale yellow filtrate was concentrated to dryness in vacuo to afford a yellow-tinged solid (20.6 g, 44.1% yield). The plug was washed with ethyl acetate/ethanol and the washings were concentrated in vacuo to afford additional material, 10.7 g (23%). Extraction of the aqueous work-up filtrate with ethyl acetate followed by drying, Magnesol filtration and concentration gave another 6.3 g (14%) of clean product, bringing the total recovery to 37.6 g (81%). 1H-NMR (CD3OD): δ 7.72 (s, 1H), 7.52 (dd, 1H, J=2.5, 1.6 Hz), 6.85 (dd, 1H, J=4.5, 1.6 Hz), 6.64 (dd, 1H, J=4.5, 2.7 Hz) LC/MS (+esi): m/z=135.1 [M+H].
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