Acetic Acid → 1-(4-Ethoxy-2,6-difluorobenzyl)-1,4,5,6-tetrahydrocyclopenta[c]-pyrazole-3-carboximidamide

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Reaction Steps

7.73 g of 1-(4-ethoxy-2,6-difluorobenzyl)-1,4,5,6-tetrahydrocyclopenta[c]-pyrazole-3-carbonitrile 1-1-1 (25.5 mmol, 1.00 eq) were suspended in 100 mL methanol. 7.65 mL sodium methanolate in methanol (2.23 g, 41.3 mmol, 1.62 eq.) were added at rt. The reaction mixture was stirred for 4 h at rt. 2.36 mL acetic acid (2.45 g, 41.3 mmol, 1.62 eq.) and 2.05 g ammonium chloride (38.2 mmol, 1.50 eq.) were added and the reaction mixture was stirred at 50° C. for two days. The mixture was concentrated in vacuo and the residue was filtered off and washed with methanol. The filtrate was suspended in water and aqueous hydrochloric acid (4N). DCM was added, the aqueous layer was washed with DCM twice. To the aqueous layer aqueous sodiumhydroxid solution (2N) was added to reach pH 12. The aqueous layer was extracted with DCM/isopropanol (4:1) three times. The united organic layers were dried over a silicone filter, concentrated in vacuo to provide 2.67 g (7.99 mmol, 31.3%) of analytically pure target compound.

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