Expeditious Synthesis of 1,2-Diaminoimidazoles under Solvent-Free Conditions

Abstract

1,2-Diaminoimidazoles are obtained in good yields by reaction of 1,2-diaza-1,3-butadienes with cyanamide at 50 °C under solvent-free conditions. These compounds are important intermediates for the synthesis of imidazo[1,2-b][1,2,4]triazines.

Key words

1,2-diaza-1,3-butadienes - 1,2-diaminoimidazoles - hydrazones - Michael additions - cylizations

References

• 1a Grimmet MR. In Comprehensive Heterocyclic Chemistry II, Imidazoles   Vol. 3:  Katritzky AR. Rees CW. Scriven EFV. Pergamon; London: 1996. 
• 1b Kirk KL. J. Org. Chem.  1978,  43:  4381 
• 1c Nishimura T. Kitajiama K. J. Org. Chem.  1979,  44:  818 
• 1d Little TL. Webber SE. J. Org. Chem.  1994,  59:  7299 
• 1e Weinmann H. Harre M. Koenig K. Merten E. Tilstam U. Tetrahedron Lett.  2002,  43:  593 
• 2 Röhrle AN. Schmidhammer H. Helv. Chim. Acta  1998,  81:  1070 
• 3 Khanna IK. Weir RM. Xiang YY. Xu XD. Koszyk FJ. Collins PW. Kobolt CM. Veenhuizen AW. Perkins WE. Casler JJ. Masferrer JL. Zhang YY. Gregory SA. Seibert K. Isakson PC. J. Med. Chem.  1997,  40:  1634 
• 4 Yanagisawa H. Amemiya Y. Kanasaki T. Shimoji Y. Fujimoto K. Kitahara Y. Sada T. Mizuno M. Ikeda M. Miyamoto S. Furukawa Y. Koibe H. J. Med. Chem.  1996,  39:  323 
• 5 Baker GP. Bourne IA. Ford MJ. Foster RWG. Jackson TH. Pannell RW. Whittmore MW. Org. Proc. Res. Dev.  1999,  3:  104 
• 6 Tanaka K. Solvent-free Organic Synthesis   Wiley-VCH Verlag GmbH & Co. KGaA; Weinheim: 2003. 
• 7a Attanasi OA. De Crescentini L. Filippone P. Mantellini F. Santeusanio S. Arkivoc  2002,  xi:  274 
• 7b Attanasi OA. De Crescentini L. Favi G. Filippone P. Giorgi G. Mantellini F. Santeusanio S. J. Org. Chem.  2003,  68:  1947 
• 7c Attanasi OA. Favi G. Filippone P. Stanovnik B. Svete J. Synlett  2003,  995 
• 8a Sommer S. Tetrahedron Lett.  1977,  18:  117 
• 8b Attanasi OA. Filippone P. Mei A. Santeusanio S. Synthesis  1984,  671 
• 8c Attanasi OA. Filippone P. Mei A. Santeusanio S. Synthesis  1984,  873 
• 11a Lalezari I. Levy Y. J. Heterocycl. Chem.  1974,  11:  327 
• 11b Keen BT. Krass DK. Paudler WW. J. Heterocycl. Chem.  1976,  13:  807 
• 11c Povstyanoi MV. Kruglenko VP. Klykov MA. Fiziol. Akt. Veshchestva  1980,  12:  56 
• 11d Ivashchenko AV. Lazareva VT. Prudnikova EK. Ivashchenko SP. Rumyantsev VG. Khim. Geterotsikl. Soedin.  1982,  236 
• 11e Labouta IM. Soliman FSG. Kassem MG. Pharmazie  1986,  41:  812 

9

Analytical data of compound 3a: mp 173-177 °C. IR 3435, 3323, 1739, 1704, 1627 cm^-1. ¹H NMR (DMSO-d ₆): δ = 2.16 (s, 3 H), 3.65 (s, 3 H), 3.68 (s, 3 H), 5.88 (s, 2 H), 10.36 (s, 1 H). ¹³C NMR (DMSO-d ₆): δ = 9.0, 50.5, 52.7, 120.3, 131.4, 148.0, 155.1, 163.3. MS: m/z (%) = 228 (54) [M⁺], 196 (100). Anal. Calcd for C₈H₁₂N₄O₄: C, 42.10; H, 5.30; N, 24.55. Found: C, 42.17; H, 5.28; N, 24.58.

10

Analytical data of compound 4: oil. IR 3310, 2258, 2202 cm^-1. ¹H NMR (DMSO-d ₆): δ = 1.29 (s, 18 H), 2.23 (s, 3 H), 3.66 (s, 3 H), 5.27 (s, 1 H), 10.24 (br s, 1 H). ¹³C NMR (CDCl₃-d ₆): δ = 14.2, 27.9, 29.6, 51.0, 51.5, 82.7, 114.2, 132.8, 144.4, 150.0, 161.9. MS: m/z (%) = 326 (4) [M⁺], 270 (10), 211 (19), 182 (26), 170 (36), 155 (72), 123 (100). Anal. Calcd for C₁₅H₂₆N₄O₄: C, 55.20; H, 8.03; N, 17.17. Found: C, 55.16; H, 8.09; N, 17.15.