606964-89-0Relevant academic research and scientific papers
Diversity oriented synthesis: Substitution at C5 in unreactive pyrimidines by Claisen rearrangement and reactivity in nucleophilic substitution at C2 and C4 in pteridines and pyrido[2,3-d]pyrimidines
Adcock, Jonathan,Gibson, Colin L.,Huggan, Judith K.,Suckling, Colin J.
experimental part, p. 3226 - 3237 (2011/05/19)
Diversity oriented synthesis of fused pyrimidines leads to scaffolds with many biological activities. In the case of the preparation of pyrido[2,3-d]pyrimidines from 2-alkylthiopyrimidines, the formation of a new carbon-carbon bond at C5 is required, a reaction, that is, very limited in scope. However Claisen type rearrangement of simple 4-allylic ethers affords C5 substituted pyrimidines readily; in cases with an ester substituent, rearrangement occurs at room temperature. Subsequent cyclisation to afford 6-methylpyrido[2,3-d]pyrimidin-7(8H)-ones was achieved in high yield. Using allylic ethers derived from 3-chloromethyl-4-arylbut-3-en-2-ones as substrates, a new titanium[IV]chloride catalysed reaction affording 6-arylmethyl-7- methylpyrido[2,3-d]pyrimidines was discovered. In contrast, 2- alkylthiopteridines are readily available. In both cases, substitution at C2 and C4 to generate diversity has been carried out and the reactivity compared; yields of substitution products were generally higher with pteridine substrates. In biological assays unexpected hits were found for activity against the Gram positive bacterium, Nocardia farcinia, and against the parasite Trypanosoma brucei brucei, illustrating the value of diversity oriented synthesis in the discovery of biologically active compounds.
A prototype solid phase synthesis of pteridines and related heterocyclic compounds
Gibson, Colin L.,La Rosa, Salvatore,Suckling, Colin J.
, p. 1909 - 1918 (2007/10/03)
The development of a versatile solid phase synthesis of bicyclic polyaza heterocycles including pteridines, purines, and deazapurines is described. The strategy comprises the linking of a pre-formed pyrimidine through a thioether at the 2 or 4 position to a polystyrene resin, the cyclisation of the second ring, and the direct or oxidative cleavage of the product from the resin by nucleophilic substitution. This provides not only for substituent variation in the second ring, but also for variation at the site of cleavage. Limitations in the scope of the methodology are set by the intrinsic reactivity of pyrimidinyl 2- or 4-thioethers which, whilst undergoing ready nitration at C5, are surprisingly difficult to alkylate and acylate.
