3ꢀSubstitutedꢀ2ꢀtrifluoromethylimidazo[1,2ꢀa]pyridines Russ.Chem.Bull., Int.Ed., Vol. 58, No. 3, March, 2009
Table 2. 1H and 19F NMR spectra of compounds 3a—d, 5a—d and 7a—d in DMSOꢀd6
633
Comꢀ
pound
NMR spectra, δ (J/Hz)
1H
19F
3a
2.17 (s, 3 Н, Me); 7.13 (dd, 1 Н, J1 = 7.5, J2 = 5.4);
7.57 (d, 1 Н, J = 7.5); 8.22 (d, 1 Н, J = 5.4)
8.07, 13.64 (both d, J = 6.1)
3b
3c
3d
5a
2.42 (s, 3 Н, Me); 6.83 (s, 1 H); 7.04, 8.33 (both d, 1 Н, J = 5.4)
2.53 (s, 3 Н, Me); 6.76, 7.06 (both d, 1 Н, J = 8.1); 7.65 (t, 1 Н, J = 8.1)
7.05 (d, 1 Н, J = 9.1); 8.03 (dd, 1 Н, J1 = 9.1, J2 = 2.1); 8.66 (d, 1 Н, J = 2.1)
2.69 (s, 3 Н, Me); 7.06 (t, 1 Н, J = 6.7);
7.22 (d, 1 Н, J = 6.7); 8.13 (d, 1 Н, J = 6.7)
2.54 (s, 3 Н, Me); 7.01 (d, 1 Н, J = 7.2);
7.39 (s, 1 Н); 8.23 (d, 1 Н, J = 7.2)
2.93 (d, 3 Н, Me, J =6.4); 6.88 (d, 1 Н, J = 6.8);
7.34 (dd, 1 Н, J1 = 9.5, J2 = 6.8); 7.51 (br.d, 1 Н, J1 = 9.5)
7.78, 14.63 (both q, J = 7.2)
7.91, 14.99 (both q, J = 7.1)
7.94, 14.74 (both q, J = 7.2)
–71.75 (q, 1 F, J = 10.2);
16.88 (d, 3 F, J = 10.2)
–73.27 (q, 1 F, J = 10.1);
16.81 (d, 3 F, J = 10.1)
–68.12 (q, 1 F, J = 10.5);
16.65 (d, 3 F, CF3, J = 10.5)
–70.72 (qd, J = 10.5, J = 1.5);
16.67 (d, 3 F, J = 10.5)
17.86 (s, CF3)
5b
5c
5d
7a
7b
7c
7d
7.44 (dd, 1 Н, CHAr, J1 = 10.9, J2 = 1.9); 7.59 (d, 1 Н, CHAr
J = 10.9); 8.62 (s, 1 Н, CHAr
,
)
2.51 (s, 3 Н, Me); 4.06 (s, 3 Н, MeO); 6.85 (t, 1 Н, J = 6.6);
7.04 (d, 1 Н, J = 6.6); 8.00 (d, 1 Н, J = 6.6)
2.38 (s, 3 Н, Me); 4.04 (s, 3 Н, MeO); 6.76 (dd, 1 Н, J1 = 7.9,
J2 = 1.1); 7.21 (d, 1 Н, J = 1.1); 8.04 (d, 1 Н, J = 7.9)
2.96 (s, 3 Н, Me); 4.18 (s, 3 Н, MeO); 6.78 (d, 1 Н, J = 6.6);
7.28 (t, 1 Н, J = 6.6); 7.46 (d, 1 Н, J = 6.6)
17.72 (s, CF3)
17.34 (s, CF3)
17.63 (s, CF3)
4.11 (s, 3 Н, MeO); 7.36 (d, 1 Н, J = 9.8);
7.52 (d, 1 Н, J = 9.8); 8.47 (s, 1 Н)
2. S. Langer, S. Arbilla, J. Benavides, B. Seanon, Adv. Biochem.
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1985, 27, 327.
3ꢀFluoroꢀ8ꢀmethylꢀ2ꢀtrifluoromethylimidazo[1,2ꢀa]pyridine (5a),
3ꢀfluoroꢀ7ꢀmethylꢀ2ꢀtrifluoromethylimidazo[1,2ꢀa]pyridine (5b),
3ꢀfluoroꢀ5ꢀmethylꢀ2ꢀtrifluoromethylimidazo[1,2ꢀa]pyridine (5c),
6ꢀbromoꢀ3ꢀfluoroꢀ2ꢀtrifluoromethylimidazo[1,2ꢀa]pyridine (5d)
(general procedure). Trimethyl phosphite (4) (1.24 g, 0.01 mol)
was added with stirring to a solution of hexafluoroacetone
2ꢀpyridylimine 3a—d (0.01 mol) in CH3CN (20 mL). After
completion of the exothermal reaction, the reaction mixture
was refluxed for 1 h and poured into water (50 mL), the mixture
was neutralized with a 5% solution of K2CO3, and the precipitate
was filtered off, and recrystallized from 50% EtOH.
3ꢀMethoxyꢀ8ꢀmethylꢀ2ꢀtrifluoromethylimidazo[1,2ꢀa]pyriꢀ
dine (7a), 3ꢀmethoxyꢀ7ꢀmethylꢀ2ꢀtrifluoromethylimidazo[1,2ꢀa]ꢀ
pyridine (7b), 3ꢀmethoxyꢀ5ꢀmethylꢀ2ꢀtrifluoromethylimidazoꢀ
[1,2ꢀa]pyridine (7c), 6ꢀbromoꢀ3ꢀmethoxyꢀ2ꢀtrifluoromethylꢀ
imidazo[1,2ꢀa]pyridine (7d) (general procedure). A solution
of 3ꢀfluoroꢀ2ꢀtrifluoromethylimidazo[1,2ꢀa]pyridine 5a—d
(0.01 mol) and NaOCH3 (6) (0.6 g, 0.011 mol) in CH3CN
(20 mL) was refluxed for 1 h and poured into water (50 mL). The
precipitate was filtered off and recrystallized from 50% EtOH.
The yields, boiling points, and spectral characteristics
of compounds 3a—d, 5a—d, and 7a—d are summarized in
Tables 1 and 2.
10. K. Burger, K. Geith, K. Gaa, Angew. Chem., 1988, 100, 860.
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Gontar´, Khim. Geterotsikl. Soedinen., 1989, 1699 [Chev.
Heterocycl. Compd. (Engl. Transl.), 1989].
This work was supported by the Russian Foundation
for Basic Research (Project No. 08ꢀ03ꢀ00793ꢀa).
15. V. M. Koshelev, T. D. Truskanova, V. F. Cherstkov, D. V.
Romanov, N. V. Vasil´ev. Izv. Akad. Nauk. Ser. Khim., 2005,
1626 [Russ. Chem. Bull., Int. Ed., 2005, 54, 1675].
References
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Received August 6, 2008