3K47:
reference: Design, synthesis, and X-ray crystal structures of 2,4-diaminofuro[2,3-d]pyrimidines as multireceptor tyrosine kinase and dihydrofolate reductase inhibitors., Gangjee A, Li W, Lin L, Zeng Y, Ihnat M, Warnke LA, Green DW, Cody V, Pace J, Queener SF, Bioorg Med Chem. 2009 Oct 15;17(20):7324-36. Epub 2009 Aug 22. PMID: 19748785

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