Reductive alkylation of urea: A practical route to substituted ureas

Tetrahedron Letters

Volumn 39, Issue 10, 1998, Pages 1107-1110

  Xu, Daqiang ^a   Ciszewski, Lech ^a   Li, Tangqing ^a   Repič, Oljan ^a   Blacklock, Thomas J ^a  

^a NOVARTIS PHARMA AG   (Switzerland)

Author keywords

[No Author keywords available]

Indexed keywords

UREA;

ALKYLATION; ARTICLE; NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY; REDUCTION; SYNTHESIS;

EID: 0032485312     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(97)10816-4     Document Type: Article

References (15)

1. (1) Vishnyakova, T. P.; Golubeva, I. A.; Glebova, E. V. Russ. Chem. Rev. Engl. Transl. 1985, 54, 249; and the references cited therein.
2. (2) Katritzky, A. R.; Pleynet, D. P. M.; Yang, B. J. Org. Chem. 1997, 62, 4155.
3. (3) Armstrong III, J. D.; Wolfe, C. N.; Keller, J. L.; Lynch, J.; Bhupathy, M.; Volante, R. P.; Devita, R. J. Tetrahedron Lett. 1997, 38, 1531.
4. (4) Abdel-Magid, A. F.; Carson, K. G.; Harris, B. D.; Maryanoff, C. A.; Shah, R. D. J. Org. Chem. 1996, 61, 3849, and references cited therein.
5. (5) (a) Kato, T.; Chiba, T.; Sasaki, M.; Yakugaku, D.; Yakugaku, Z. J. Pharm. SOS. JAR. 1981, 101, 182.
6. (b) Butler, A. R.; Hussain, I.; Leitch, E. J. Chem. Soc. Perkin Trans. II 1980, 106.
7. (c) Gompper, R.; Noth, H.; Rattay, W.; Schwarzensteiner, M.; Spes, P.; Wagner, H. Angew. Chem. Int. Ed. Engl. 1987, 26, 1039.
8. (6) Although acetyl chloride and trimethylsilyl chloride were interchangable as dehydrating agent, trimethylsilyl chloride generally offered cleaner reaction mixtures (but not necessarily higher yields) and was used in obtaining the results shown in the two tables.
9. (7) (a) S. Chen; Coward, J. K. Tetrahedron Lett. 1996, 37, 4335;
10. (b) Yuan, C.; Chen, S.; Wang, G. Synthesis, 1991, 490;
11. (c) Yuan, C.; Wang, G.; Chen, S. Synthesis, 1990, 522.
12. (8) (a) Sisko, J.; Mellinger, M.; Sheldrake, P.; Baine, N. H. Tetrahedron Lett. 1996, 37, 8113;
13. (b) Zavayalov, S. I.; Kulikova, L. B. Khim-Farm Zh. 1992, 26, 88.
14. (9) The mono-/di-ratio did not show significant change from 10 equivalents to 20 equivalents of urea. However, 20 equivalents of urea is recommended to ensure the general applicability of the method.
15. (10) However, 1.2 to 1.5 equivalents of one of the starting reagents (depends on their availability) were normally used to ensure convenient reaction times.