N,N-di-n-butylformamide dimethyl acetal → HCID 86590003, compound

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Reaction Steps

As described for 8a, with 2b (350 mg, 1 mmol) and N,N-di-n-butylformamide dimethyl acetal (720 μl, 3.1 mmol) in MeOH (7 ml) for 2 h at 40°. After FC (eluant: A→B) two main products were isolated. The faster migrating zone gave 8b as a foam (310 mg, 50%). TLC(B): Rf0.3. UV (MeOH): 235 (22500), 275 (14500), 320 (22100). 1H-NMR ((D6)DMSO): 0.94-0.99 (m, CH2CH3); 1.32-1.44 (m, CH2CH3); 1.59-1.73 (m, CH2CH2); 2.21 (m, H—C(2′)); 2.91 (m, H—C(2′)); 3.32-3.78 (2m, H2—C(5′), NCH2); 3.89 (m, H—C(4′)); 4.40 (m, H—C(3′)); 4.78 (t, J=5.8, HO—C(5′)); 5.19 (d, J=4.4, HO—C(3′)); 6.81 (‘t’, J=6.5, H—C(1′)); 8.69 (s, N═CH); 8.94 (s, N═CH). Anal. calc. for C28H47BrN8O3 (623.6): C, 53.93; H, 7.60; N, 17.97; Found: C, 54.01; H, 7.52; N, 18.05. The slower zone furnished 3-bromo-1-[2-deoxy-β-D-erythro-pentofuranosyl]-N6-((di-n-butylamino)methylene)-1H-pyrazolo [3,4-d]-pyrimidin-4,6-diamine (9b) (75 mg, 16%). TLC(B): Rf0.3. UV (MeOH): 236 (21600), 276 (14000), 320 (21900). 1H-NMR ((D6)DMSO): 0.90-0.96 (m, CH2CH3); 1.30-1.39 (m, CH2CH3); 1.59-1.73 (m, CH2CH2); 2.23 (m, H—C(2′)); 2.89 (m, H—C(2′)); 3.35-3.78 (2m, H2—C(5′), NCH2); 3.84 (m, H—C(4′)); 4.43 (m, H—C(3′)); 4.80 (t, J=5.7, HO—C(5′)); 5.23 (d, J=4.6, HO—C(3′)); 6.40 (s, NH2); 6.81 (‘t’, J=6.4, H—C(1′)); 8.65 (s, N═CH). Anal. calc. for C19H30BrN7O3 (484.4): C, 47.11; H, 6.24; N 20.24; Found: C, 47.23; H, 6.52; N, 20.35.

Provenance & Evidence