Helvetica Chimica Acta – Vol. 97 (2014)
983
Ethyl 1,4-Dihydro-2-methyl-4-(3,4,5-trimethoxyphenyl)pyrimido[1,2-a]benzimidazole-3-carboxylate
(4f). Light solid. Yield: 89%. IR (KBr): 3235, 1707, 1654, 1621, 1594, 1253, 1083, 739. 1H-NMR
(400 MHz): 1.20 (t, J ¼ 7.2, Me); 2.47 (s, Me); 3.57 (s, Me); 3.70 (s, 2 Me); 4.04 (q, J ¼ 7.2, CH2); 6.40 (s,
CH); 6.65 – 7.44 (m, 6 arom. H); 10.78 (s, NH). 13C-NMR (100 MHz): 14.6; 19.0; 56.2; 56.4; 59.8; 60.3;
98.2; 104.8; 110.6; 117.2; 120.6; 122.2; 132.0; 137.3; 138.2; 142.7; 146.0; 147.1; 153.1; 165.7. MS (70 eV):
423.
Ethyl 4-(Anthracen-9-yl)-1,4-dihydro-2-methylpyrimido[1,2-a]benzimidazole-3-carboxylate (4g).
1
Light solid. Yield: 82%. IR (KBr): 3235, 1703, 1655, 1619, 1578, 1249, 1084, 735. H-NMR (400 MHz):
0.35 (t, J ¼ 7.2, Me); 2.47 (s, Me); 3.55 (q, J ¼ 7.2, CH2); 6.21 – 9.19 (m, 14 arom. H); 11.10 (s, NH).
13C-NMR (100 MHz): 13.6; 52.1; 59.2; 98.6; 110.0; 117.2; 119.1; 120.3; 121.8; 123.0; 125.12; 125.17; 125.6;
126.7; 127.4; 129.4; 129.7; 130.4; 130.9; 131.5; 131.7; 131.8; 132.8; 165.7. MS (70 eV): 433.
Ethyl 4-(3-Chlorophenyl)-1,4-dihydro-2-methylpyrimido[1,2-a]benzimidazole-3-carboxylate (4h).
1
Light solid. Yield: 96%. IR (KBr): 3237, 1698, 1657, 1616, 1578, 1260, 1088, 731. H-NMR (400 MHz):
1.17 (t, J ¼ 7.2, Me); 2.47 (s, Me); 4.03 (q, J ¼ 7.2, CH2); 6.48 (s, CH); 6.96 – 7.45 (m, 8 arom. H); 10.90 (s,
NH). 13C-NMR (100 MHz): 14.5; 19.1; 55.7; 59.9; 97.7; 110.3; 117.3; 120.8; 122.4; 126.1; 127.6; 128.2;
130.9; 131.8; 133.3; 142.7; 144.9; 145.8; 147.5; 165.5. MS (70 eV): 367. Anal. calc. for C20H18ClN3O2
(367.8288): C 65.31, H 4.93, N 11.42; found: C 65.78, H 4.86, N 11.24.
Ethyl 4-(2,3-Dichlorophenyl)-1,4-dihydro-2-methylpyrimido[1,2-a]benzimidazole-3-carboxylate
(4j). Light solid. Yield: 91%. IR (KBr): 3236, 1705, 1660, 1620, 1575, 1259, 1082, 743. 1H-NMR
(400 MHz): 1.07 (t, J ¼ 7.2, Me); 2.42 (s, Me); 4.01 (q, J ¼ 7.2, CH2); 6.83 (s, CH); 6.97 – 7.55 (m, 7 arom.
H); 11.01 (s, NH). 13C-NMR (100 MHz): 14.5; 19.2; 59.8; 96.3; 109.6; 117.5; 120.9; 122.5; 128.5; 129.1;
129.8; 130.3; 130.6; 132.0; 132.5; 142.5; 145.6; 148.1; 165.3. MS (70 eV): 401. Anal. calc. for C20H17Cl2N3O2
(402.2739): C 59.71, H 4.26, N 10.45; found: C 59.17, H 3.87, N 10.69.
Ethyl 1,4-Dihydro-2-methyl-4-pentylpyrimido[1,2-a]benzimidazole-3-carboxylate (4k). Light solid.
Yield: 88%. IR (KBr): 3240, 1702, 1661, 1620, 1571, 1255, 1082, 739. 1H-NMR (400 MHz): 0.702 (t, J ¼
7.2, Me); 1.01 – 1.19 (m, 3 CH2); 1.67 – 1.78 (m, CH); 1.96 – 2.05 (m, CH); 2.39 (s, Me); 4.14 (q, J ¼ 7.2,
CH2); 5.6 (t, CH); 7.07 – 7.46 (m, 4 arom. H); 10.50 (s, NH). 13C-NMR (100 MHz): 14.1; 14.8; 19.1; 22.3;
22.7; 31.3; 34.0; 52.1; 59.8; 96.1; 109.8; 117.3; 120.6; 122.0; 131.9; 142.7; 147.2; 148.4; 165.9. MS (70 eV):
327. Anal. calc. for C19H25N3O2 (327.4207): C 69.70, H 7.70, N 12.83; found: C 69.56, H 7.62, N 12.96.
Ethyl 4-Ethyl-1,4-dihydro-2-methylpyrimido[1,2-a]benzimidazole-3-carboxylate (4l). Light solid.
Yield 82%. IR (KBr): 3235, 1681, 1656, 1621, 1574, 1256, 1091, 738. 1H-NMR (400 MHz): 0.519 (t, J ¼ 7.2,
Me); 1.27 (t, J ¼ 7.2, Me); 1.69 – 1.80 (m, CH); 2.03 – 2.15 (m, CH); 2.41 (s, Me); 4.14 (q, J ¼ 7.2, CH2);
5.62 (t, J ¼ 4.0, CH); 7.07 – 7.47 (m, 4 arom. H); 10.50 (s, NH). 13C-NMR (100 MHz): 7.5; 14.7; 19.1; 26.8;
52.7; 59.8; 95.4; 109.8; 117.3; 120.6; 122.0; 131.8; 142.8; 147.3; 148.7; 166.0. MS (70 eV): 285. Anal. calc. for
C16H19N3O2 (285.3410): C 67.35, H 6.71, N 14.73; found: C 67.23, H 6.66, N 15.00.
We are grateful to Bu-Ali Sina University, Center of Excellence in Development of Environmentally
Friendly Methods for Chemical Synthesis (CEDEFMCS), for financial support.
REFERENCES
[1] P. Laszlo, in ꢂOrganic Reactions: Simplicity and Logicꢃ, Wiley-VCH, New York, 1995.
[2] C. O. Kappe, Curr. Opin. Chem. Biol. 2002, 6, 314.
[3] A. Dçmling, I. Ugi, Angew. Chem., Int. Ed. 2000, 39, 3168.
´
[4] ꢂMulticomponent Reactionsꢃ, Eds. J. Zhu, H. Bienayme, Wiley-VCH, Weinheim, 2005.
[5] K. Undheim, T. Benneche, in ꢂComprehensive Heterocyclic Chemistry IIꢃ, Eds. A. R. Katritzky,
C. W. Rees, E. V. F. Scriven, Pergamon Press, London, Vol. 6, 1996, Chapt. 2, pp. 93 – 231.
[6] D. J. Brown, R. F. Evans, W. B. Cowde, in ꢂThe Pyrimidinesꢃ, Eds. E. C. Taylor, A. Weissberger, John
Wiley & Sons, New York, Vol. 52, 1994.
[7] M. Johar, T. Manning, D. Y. Kunimoto, R. Kumar, Bioorg. Med. Chem. 2005, 13, 6663.
[8] N. Azas, P. Rathelot, S. Djekou, F. Delmas, A. Gellis, C. Di Giorgio, P. Vanelle, P. Timon-David, Il
Farmaco 2003, 58, 1263.