Regioselective Mannich-type C-nucleosidations of pyrroline derivatives 3 and 8 with 7-carba-purines and 4-aminopyrimidines occur under mild conditions to afford C(8)- and C(5)-azanucleosides, respectively.
The synthesis of a series of diversely substituted pyrimidines under solvent-free conditions in good yields is described. Under microwave irradiation, a variety of nucleophilic substrates containing the N–C–N unit with β-dicarbonyl compounds, ethyl cyanoacetate, malononitrile, and chalcones was cyclized to give pyrimidines. A combinatorial type approach for a one-step synthesis has been developed where
2,4-Substituted flavins (isoalloxazines) bearing an NH2-group in 8-position were found to be stable and easily accessible. In particular the 2- and 4-imino-, resp. 2,4-diimino-compounds are similar to riboflavin in colour and fluorescence, but readily water-soluble. The chemical behaviour of this new class of flavins is discussed.
Prebiotic Origin of Pre‐RNA Building Blocks in a Urea “Warm Little Pond” Scenario
作者:C. Menor Salván、Marcos Bouza、David M. Fialho、Bradley T. Burcar、Facundo M. Fernández、Nicholas V. Hud
DOI:10.1002/cbic.202000510
日期:2020.12.11
water enriched with urea would have been an efficient source for the formation of noncanonical pyrimidines. In the presence of aldose sugars, bases from these pools could react with the sugars through spontaneous glycosylation, ultimately concentrating de novo nucleosides through aggregation. We demonstrate how such a setting could lead to noncanonical nucleosides on a prebiotic Earth.
5,6-Diaminocytidine, a Versatile Synthon for Pyrimidine-Based Bicyclic Nucleosides
作者:Kallanthottathil G. Rajeev、Arthur D. Broom
DOI:10.1021/ol0064765
日期:2000.11.1
This communication describes a convenient, facile, and high-yield synthesis of 3-(beta-D-ribofuranosyl)isoguanine and its 8-methylderivative, as well as nucleoside analogues of pteridines, from a common precursor, 5,6-diaminocytidine. 5,6-Diamino-2',3', 5'-tri-O-benzoylcytidine was synthesized from 4, 6-diamino-2-oxopyrimidine in three steps.