Trifluoroacetic acid → 7-Amino-2-(2-furyl)-5-[2-(4-pivaloyloxyphenyl)ethyl]amino[1,2,4]-triazolo[1,5-a][1,3,5]triazine

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7-Amino-2-(2-furyl)-5-[2-(4-hydroxyphenyl)ethyl]amino[1,2,4]-triazolo[1,5-a][1,3,5]triazine (1 g, prepared as described in Example 81) was suspended in dichloromethane (20 ml) and trifluoroacetic acid (20 ml) was added with stirring. Pivaloyl chloride (0.4 ml) was added dropwise at ambient temperature. The mixture was stirred for 2 hours and then the dichloromethane and trifluoroacetic acid was removed in vacuo. The residue was purified by chromatography on silica (100 g) eluting with dichloromethane containing methanol (5.0% v/v). The solid obtained (1.2 g) was crystallised from toluene and finally from isopropanol (25 ml) to give 7-amino-2-(2-furyl)-5-[2-(4-pivaloyloxyphenyl)ethyl]amino[1,2,4]-triazolo[1,5-a][1,3,5]triazine as a solid; m.p. 208°-210° C.; microanalysis, found: C, 59.6; H, 6.1; N, 21.7%; C21H24N7O3 0.5 C3H7OH requires C, 59.9; H, 6.0; N, 21.7%; NMR 1.06(d, ca 3H, (CH3)2CHOH), 1.3(s, 9H, CH3C), 2.9(t, 2H, CH2Ar), 3.55 (t, 2H, CH2N), 3.80(heptet, ca 0.5 H, (CH3)2CHOH), 6.68(dd, 1H, furyl-4H), 7.01 and 7.30 (A2B2 pattern, 4H, phenyl-H), 7.08 (d, 1H, furyl-3H) and 7.82(d, 1H, furyl-5H); m/e 422 (M+H)+.

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