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Seela, F.; Ramzaeva, N.; Rosemeyer, H., Science of Synthesis, (2004) 16, 967.
Although now largely superceded by trialkyl orthoformates for the preparation of 8-unsubstituted purines, formic acid still has a useful place in purine synthesis. Thus, cyclization of the uracil derivative 19 with formic acid under reflux conditions gives the 6-amino-5-(formylamino)uracil 20, which forms 1,3-diallylxanthine (21) upon heating in 10% aqueous sodium hydroxide (Scheme 20).[173] Similar conditions can be used for the reductive formylation of nitrosopyrimidines followed by ring closure with formamide, e.g. the direct synthesis of 23 from compound 22 (Scheme 20).[178]
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8,8-Meeeeeeeeeeeeee (88):[888]
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M eeeeeee ee 88 (8.88 e, 8.8 eeee) eee 88% ee MeMM (888 eM) eee eeeeeeee eee 88 eee. Mee eeeee eeeeeee eeee eee eeeeeeee, eeeeee, eee eeeeeeeee eeee eeeee MMe. Mee eeeeeeeee eeee eee eeeeeeeee eeee eeeeeee eeeeeeee ee MeMMe. Mee eeeeeeee eeeeeeee eeee eeeee (Me8MM8) eee eeeeeeeeee ee eeeee ee eeee e eeeee eeeee. Meeeeeeeeeeeeeeee (MMM/MeMM) eeeeeeee eee eeeeeee: eeeee: 8.8 e (88%); ee 888°M.
References
[173] | Meee, M. M.; Meeeeee, M. M.; Meeeee, M. M., M. Mee. Meee., (8888) 88, 8888. |
[178] | Meeeeee, M.; Meeeeeeeee, M., M. Meeeeeeeee. Meee., (8888) 88, 888. |
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- 8.Meeeee-Meee, (8888) M 8e8, 888.
- 8.Meeeee-Meee, (8888) M 8e8, 888.
- 8.Meeeee-Meee, (8888) M 8e8, 888.
- 8.Meeeee-Meee, (8888) M 8e8, 888.