Skip to main content
NCBI home page
ACS Medicinal Chemistry Letters logoLink to ACS Medicinal Chemistry Letters
. 2023 Jul 27;14(8):1073–1078. doi: 10.1021/acsmedchemlett.3c00205

Design, Construction, and Screening of Diversified Pyrimidine-Focused DNA-Encoded Libraries

Mengnisa Seydimemet †,‡, Yixuan Yang ‡, Yuhan Lv §, Jiaxiang Liu ∥, Ziqin Yan ‡, Yujun Zhao ‡,⊥,*, Xuan Wang ‡,*, Xiaojie Lu †,‡,⊥,*
PMCID: PMC10424316  PMID: 37583819

Abstract

graphic file with name ml3c00205_0007.jpg

Pyrimidine is a ubiquitous component in natural products and approved drugs, providing an ideal modular scaffold for generating libraries with drug-like properties. DNA-encoded library technology introduces a novel library modality where each small molecule is covalently linked to a unique oligo tag. This technology offers the advantages of rapidly generating and interrogating large-scale libraries containing billions of members, substantially reducing the entry barrier to their use in both academia and the pharmaceutical industry. In this Letter, we describe the synthesis of three DNA-encoded libraries based on different functionalized pyrimidine cores featuring diversified chemoselectivity and regioselectivity. Preliminary screening of these DNA-encoded libraries against BRD4 identified compounds with nanomolar inhibition activities.

Keywords: DNA-encoded library technology, Pyrimidine-focused DNA-encoded library, BRD4, Affinity screening, Inhibitor

Identifying high-affinity molecules is a primary goal for both the pharmaceutical industry and academia at the outset of a drug discovery project.1 Several tools have been developed for drug discovery, with high-throughput screening (HTS) strategies serving as a cornerstone for potential drug candidate identification. To lower the entry barrier of HTS in both academia and the pharmaceutical industry, scientists developed a genetically encoded technology—DNA-encoded library technology (DELT), a powerful and promising screening platform to find potent ligands for a wide range of therapeutic-relevant targets in a cost-effective and time-efficient manner.2−4

Over the past three decades, DELT has undergone significant development and has increasingly been utilized for hits identification.4 These hit compounds are selected from DNA-encoded libraries (DELs), large-scale collections where each molecule is covalently linked with a unique genetic code. DELs are generated by iterative cycles of DNA-compatible chemistries and enzymatic ligation through a split-and-pool strategy. This synthetic paradigm allows for the generation of large-scale libraries in a cost-effective and time-efficient manner, significantly lowering the barrier to conducting HTS campaigns in the early stage of drug discovery.

To achieve effective DEL selection against specific targets of interest, chemists often strive to create DELs with diverse structures and drug-like properties.5 One synthetic strategy involves utilizing “privileged scaffolds” to produce compound collections with easily accessible building blocks (BBs). The concept of “privileged scaffold” was first introduced by Evans et al. in 1988.6 After several decades of research in both academic and industrial settings, the “privileged scaffold” has been recognized as a unique molecular framework that can be synthetically modified to generate drug candidates with desirable pharmacological characteristics.

Pyrimidine, an aromatic N-heterocycle, is a widely distributed constituent found in natural compounds and plays a significant role in medicinal chemistry (see Figure 1 for some examples).7 Previous publications have highlighted the important binding interactions between pyrimidine-based ligands and protein targets.8−11 The most frequent interaction in pyrimidine-based ligands is the hydrogen bond between the nitrogen atoms in the ring and the amino substituents attached to the pyrimidine nucleus. Theoretically, pyrimidine is a good modular scaffold incorporated into the library members. However, there are limited literature reports on this topic. In contrast, 1,3,5-triazine, which serves as the isosteric substitution for pyrimidine, has found extensive applications in the construction and selection of DELs.12−17 The symmetrical cyanuric chloride serves as a competent starting point to generate trisubstituted triazine derivatives and facilitates the creation of libraries with amine/boronic BBs through the synthetically tractable SNAr substitution reaction/Suzuki coupling reaction. Several triazine-based hit compounds have been identified by DELs. However, this does not imply that the triazine scaffold can serve as a replacement for the pyrimidine core. Alternation of the ring structure would impact the binding interaction of ligands to their targets in certain cases.18 There is a need for the preparation of libraries based on the pyrimidine core.

Figure 1.

Figure 1

Open in a new tab

Representative pharmacological molecules containing a pyrimidine moiety.

Several considerations need to be taken into account when designing a library. The first consideration is the purity of individual library members, which relies on chemical reactivity and efficiency; the second consideration is the quantity of library members, which depends on the substrate scope of the DNA-compatible reactions and the number of commercially available BBs. Figure 2 illustrates two synthetic strategies for pyrimidine-based libraries. One strategy involves in situ cyclization between DNA-tagged α,β-unsaturated ketone and guanidine.19 However, the limited availability of guanidine BBs restricts their use in generating large-scale compound collections. Another strategy involves substitution between the DNA-linked pyrimidine scaffold and nucleophilic BBs, which is more efficient and enables access to large-scale BBs.20,21

Figure 2.

Figure 2

Open in a new tab

Description of previously published work and this work.

To date, no systematic investigation of pyrimidine-based DELs has been reported. Here, we aimed to design and produce pyrimidine-based libraries using a diverse set of pyrimidine reagents, P-I–P-IV. Each of these pyrimidines contains diverse reactive groups, enabling distinctive regioselectivity and chemoselectivity when paired with different BBs. Taking advantage of the combinatorial split-and-pool synthetic strategy, the corresponding pyrimidine-based DELs could be generated with millions of members. Preliminary selection of the DELs against the BRD4 protein, followed by bioactivity confirmation, provides additional evidence of the feasibility and value of this novel platform based on pyrimidine libraries.

We commenced our work with the 2,4,6-trichloropyrimidine reagent P-I. P-I is an inexpensive and synthetically tractable starting material used for the synthesis of amino-pyrimidine derivatives with drug-like properties. This is achieved through sequential displacement of chloride atoms using either SNAr reactions or transition-metal-promoted cross-coupling reactions. Despite the general reactive principle of C4(6) > C2 ≫ C5, P-I suffered from poor site-selectivity in its reaction with nucleophiles.22,23 In 2015, Satz et al. revealed the production of trifunctionalized pyrimidine DELs using P-I as the starting material.21 In their study, the chlorides were sequentially substituted by a Headpiece, amine, and boronic acid/ester at the C4, C2, and C6 positions, respectively. We also conducted an on-DNA experiment between Headpiece and P-I using the standard SNAr protocol, and the reaction progress was monitored by LCMS. The UV absorption spectrum revealed a mixture of 2-DNA pyrimidine isomer A and 4-DNA pyrimidine isomer B (Scheme 1A, Figure S3).

Scheme 1. Library Construction of DEL-A Based on the P-I Scaffold.

Scheme 1

Open in a new tab

We also recognized that isomer B would produce regioisomers in the following SNAr substitution reaction with amines (6-2/6-3). Based on the existing literature and our own experience, we knew that the regioselectivity of SNAr reactions strongly depended on the properties of the amine BBs. Given the diverse nature of BBs employed in DELs, SNAr substitution could potentially take place with either the C2-chloride or the C4-chloride. However, because the DELs were synthesized as pooled mixtures, it is not possible to isolate or purify individual library members. Furthermore, the outcomes of on-DNA reactions are not exact replicas of the off-DNA synthesis, which complicates hit validation. Despite the challenges, we can still obtain fragments with affinity properties that can be utilized in medicinal chemistry optimization.

Prior to preparing the DELs using the pyrimidine core P-I, we performed a substrate scope study (Figure S4 and S12) and a proof-of-concept library synthesis (Figure S18) to validate the feasibility of the designed synthetic route. Scheme 1B illustrates the synthetic routes for the DEL-A. Double-strand DNA starting material 1 (headpiece + primer) was split into individual reaction wells and then enzymatically ligated with a unique cycle 1 tag to afford product 2. The chemical synthesis of cycle 1 involved two routes. The first route involved amidation with 206 Fmoc amino acids under HATU/DIPEA condensation conditions, followed by deprotection using a 10% piperidine solution, resulting in the production of DNA-tagged compound 3-1 containing a primary amino group. The second route involved the coupling of the N-succinimidyl bromoacetate, followed by SN2 substitution with 389 amine BBs under basic conditions, leading to the formation of product 3-2 with a secondary amino group. Subsequently, 3-1 and 3-2 were combined in a single Eppendorf tube and reacted with the 2,4,6-trichloropyrimidine scaffold P-I.

The products resulting from the anchoring of P-I to DNA-tagged compound 3 were labeled 4-1 and 4-2 as regioselective isomers. Following standard pooling, purification, and splitting procedures, the DNA-linked compounds underwent enzymatic ligation with cycle 2 tags, followed by SNAr substitution with 101 amines. It should be noted that the SNAr substitution of 4-DNA-2,6-dichloropyrimidine 5-2 could lead to the formation of regioisomers 6-2 and 6-3. Subsequently, cycle 3 tags and 327 boronic acids/esters were added sequentially to the individual reaction wells after repeating the standard procedures of pooling, purification, and splitting. This process resulted in the generation of the final DEL-A library, which comprised 19.6 million members.

In the next stage of library synthesis, we employed different types of pyrimidine scaffolds, 5-nitro-4,6-dichloropyrimidine P-II and 5-nitro-2,4-dichloropyrimidine P-III, that have distinct reactive handles located in different positions in the pyrimidine ring. These scaffolds offer the advantages of structural diversification due to their ability to incorporate different types of BBs and varied substituent orientations, allowing for the formation of diverse binding interactions with the targets.

The synthetic route of DEL-B is outlined in Scheme 2, where P-II and P-III are first anchored to material 2, containing the DNA sequence of Headpiece, primer, and cycle 1 tag. As evidenced in the literature, the presence of the nitro group substantially enhances the reactivity of the C4-chloride, leading to regioselective SNAr chloride displacement at the C4 position with a regioisomeric excess exceeding 90%.24,25 In this context, the DNA barcodes were preferentially attached to the C4 position of P-II and P-III, resulting in the formation of DNA-linked products 9-1 and 9-2. During the cycle 2 chemical synthesis using 568 amines, both the C6-chloride in 9-1 and the C2-chloride in 9-2 exhibit higher reactivity compared to their counterparts (5-1 and 5-2, respectively); the SNAr substitution could proceed at room temperature. It could be attributed to the electron-deficient nitro group at the C5 position. Moreover, the C5 position could be further diversified with various BBs via distinct DNA-compatible chemistries. After reduction of the nitro group, functionalization of the resulting amino group at the C5 position was achieved through different DNA-compatible reactions, including amidation with carboxylic acids, sulfonylation with sulfonyl chlorides, and reductive amidation with aldehydes. Finally, the DEL referred to as DEL-B was constructed, encompassing a total of 1.8 million compounds.

Scheme 2. Library Construction of DEL-B Based on the P-II and P-III Scaffolds.

Scheme 2

Open in a new tab

In the final synthesis stage, we employed the pyrimidine scaffold P-IV. In comparison to its analogue P-I, P-IV features reactive groups distributed in the same positions of the pyrimidine ring, with a methylsulfonyl group replacing the chloride atom at the C2 position. It would be advantageous to improve the regioselectivity of the SNAr reaction.

We conducted an on-DNA experiment between the Headpiece and P-IV, and mass spectroscopy indicated that the DNA barcode regioselectively displaced the methylsulfonyl group under the standard base condition (Figure S43).20,26 During the production of DEL-C (Scheme 3), the amino group of pooled DNA-tagged compound 3 reacted with P-IV to afford the desired products 15. The subsequent SNAr and Suzuki conditions closely resemble those employed in Scheme 1. Finally, the corresponding DNA-encoded library DEL-C was constructed with a total size of 43.7 million. We combined the selection outcomes of DEL-A and DEL-C to do the comparison, aiding in the confirmation of hit compounds.

Scheme 3. Library Construction of DEL-C Based on the P-IV Scaffold.

Scheme 3

Open in a new tab

The libraries DEL-A–DEL-C were subsequently screened against a variety of protein targets. In this Letter, we present the selection and validation results with BRD4 targets. After the affinity selection, PCR amplification, and next-generation sequencing, the outcomes were depicted using three-dimensional cubic scatter plots. Each dot in the plot represents a compound encoded through the informatics-based filter, while the lines of dots represent two common BBs. Each highlighted line in the plots of Scheme 4 represents a combination of cycle 2 BBs and cycle 3 BBs. We applied methylamine to replace the cycle 1 BB and DNA tag, and the corresponding off-DNA compounds were resynthesized and validated by an activity assay. Scheme 4A illustrates the selection outcome of DEL-C. The off-DNA synthesis of M-1 based on the pyrimidine core P-IV exhibited the same regioselectivity as the on-DNA synthesis. M-1 exhibited BRD4BD1 and BRD4BD2 binding Ki values of 0.91 and 1.44 μM, respectively, in the fluorescence polarization assays.

Scheme 4. Selection Outcome of DEL-A–DEL-C and Activity Validation of M-1–M-3.

Scheme 4

Open in a new tab

Scheme 4B illustrates the selection outcome of DEL-A, and two combinations of BBs were chosen for subsequent off-DNA synthesis and validation. As discussed above, the trichloropyrimidine P-I features low regioselectivity in the on-DNA synthesis. However, we obtained regioselective products M-2 and M-3 in the off-DNA synthesis, in which the methylamine and amine selectively displaced the C4-chloride and C2-chloride, respectively. Both M-2 and M-3 exhibited selective inhibition of BRD4BD1, with binding Ki values in the submicromolar range, whereas their binding Ki values to BRD4BD2 were more than 100-fold weaker.

Although M-1–M-3 shared the same pyridone substructure, DEL-A and DEL-C offered distinct selection outcomes, and the cycle 2 BBs and substituent positions potentially influenced the binding selectivity of BRD4BD1 and BRD4BD2. This observation is intriguing and warrants further investigation. In an attempt to investigate the impact of different substituent orientations on binding with targets, we conducted syntheses of products with various orientations. However, despite altering the synthetic routes, we failed to obtain the target compounds. The work of optimization is ongoing, and we hope to show the validation results in a subsequent manuscript.

In summary, we recognized the value of integrating the drug-like pyrimidine moiety into DNA-encoded libraries and the potential importance of the positions of DNA barcodes and substituents. In this study, we employed efficient DNA-compatible chemistries to synthesize large-scale DNA-encoded pyrimidine libraries comprising 65.3 million members. Through affinity selection with the BRD4 protein, these DELs have demonstrated their capability to yield promising binders. The validation of our design assumptions in the DELs and the successful outcomes provide a foundation for future library construction.

Acknowledgments

X.L. thanks NSFC-91953203 and NSFC-92253305 for financial support of this work. X.W. thanks Lingang Laboratory (Grant No. LG-QS-202206-09) and National Key Research and Development Program of China (2022YFC2804400) for financial support of this work. Y.Z. acknowledges financial support from the National Natural Science Foundation of China (grants 82073682 and 82273759).

Glossary

Abbreviations

DELT

DNA-encoded library technology

DEL

DNA-encoded library

BB

building block

Supporting Information Available

The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsmedchemlett.3c00205.

  • Materials and methods; UV/mass spectra for DNA-linked compounds; NMR spectra for small molecules; and the coinjection experiment (PDF)

Author Contributions

# M.S. and Y.Y. contributed equally to this work.

The authors declare no competing financial interest.

Supplementary Material

ml3c00205_si_001.pdf (9.2MB, pdf)

References

  1. Brown D. G.; Bostrom J. Where Do Recent Small Molecule Clinical Development Candidates Come From?. J. Med. Chem. 2018, 61 (21), 9442–9468. 10.1021/acs.jmedchem.8b00675. [DOI] [PubMed] [Google Scholar]
  2. Sunkari Y. K.; Siripuram V. K.; Nguyen T. L.; Flajolet M. High-power screening (HPS) empowered by DNA-encoded libraries. Trends Pharmacol. Sci. 2022, 43 (1), 4–15. 10.1016/j.tips.2021.10.008. [DOI] [PubMed] [Google Scholar]
  3. Satz A. L.; Brunschweiger A.; Flanagan M. E.; Gloger A.; Hansen N. J. V.; Kuai L.; Kunig V. B. K.; Lu X.; Madsen D.; Marcaurelle L. A.; Mulrooney C.; O’Donovan G.; Sakata S.; Scheuermann J. DNA-encoded chemical libraries. Nat. Rev. Methods Primers 2022, 2 (1), 3. 10.1038/s43586-021-00084-5. [DOI] [Google Scholar]
  4. Gironda-Martinez A.; Donckele E. J.; Samain F.; Neri D. DNA-Encoded Chemical Libraries: A Comprehensive Review with Succesful Stories and Future Challenges. ACS Pharmacol. Transl. Sci. 2021, 4 (4), 1265–1279. 10.1021/acsptsci.1c00118. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Pikalyova R.; Zabolotna Y.; Volochnyuk D. M.; Horvath D.; Marcou G.; Varnek A. Exploration of the Chemical Space of DNA-encoded Libraries. Mol. Inf. 2022, 41 (6), e2100289 10.1002/minf.202100289. [DOI] [PubMed] [Google Scholar]
  6. Evans B. E.; Rittle K. E.; Bock M. G.; DiPardo R. M.; Freidinger R. M.; Whitter W. L.; Lundell G. F.; Veber D. F.; Anderson P. S.; Chang R. S.; Lotti V. J.; Cerino D. J.; Chen T. B.; Kling P. J.; Kunkel K. A.; Springer J. P.; Hirshfield J. Methods for drug discovery: development of potent, selective, orally effective cholecystokinin antagonists. J. Med. Chem. 1988, 31 (12), 2235–2246. 10.1021/jm00120a002. [DOI] [PubMed] [Google Scholar]
  7. Nadar S.; Khan T. Pyrimidine: An elite heterocyclic leitmotif in drug discovery-synthesis and biological activity. Chem. Biol. Drug Des. 2022, 100 (6), 818–842. 10.1111/cbdd.14001. [DOI] [PubMed] [Google Scholar]
  8. Cao S.; Tan C.; Fei A.; Hu G.; Fu M.; Lv J. Insights into pralsetinib resistance to the non-gatekeeper RET kinase G810C mutation through molecular dynamics simulations. J. Mol. Model. 2023, 29 (1), 24. 10.1007/s00894-022-05429-9. [DOI] [PubMed] [Google Scholar]
  9. Ayati A.; Moghimi S.; Toolabi M.; Foroumadi A. Pyrimidine-based EGFR TK inhibitors in targeted cancer therapy. Eur. J. Med. Chem. 2021, 221, 113523 10.1016/j.ejmech.2021.113523. [DOI] [PubMed] [Google Scholar]
  10. Juhas M.; Zitko J. Molecular Interactions of Pyrazine-Based Compounds to Proteins. J. Med. Chem. 2020, 63 (17), 8901–8916. 10.1021/acs.jmedchem.9b02021. [DOI] [PubMed] [Google Scholar]
  11. Zhao B.; Xiao Z.; Qi J.; Luo R.; Lan Z.; Zhang Y.; Hu X.; Tang Q.; Zheng P.; Xu S.; Zhu W. Design, synthesis and biological evaluation of AZD9291 derivatives as selective and potent EGFR(L858R/T790M) inhibitors. Eur. J. Med. Chem. 2019, 163, 367–380. 10.1016/j.ejmech.2018.11.069. [DOI] [PubMed] [Google Scholar]
  12. Li L.; Su M.; Lu W.; Song H.; Liu J.; Wen X.; Suo Y.; Qi J.; Luo X.; Zhou Y. B.; Liao X. H.; Li J.; Lu X. Triazine-Based Covalent DNA-Encoded Libraries for Discovery of Covalent Inhibitors of Target Proteins. ACS Med. Chem. Lett. 2022, 13 (10), 1574–1581. 10.1021/acsmedchemlett.2c00127. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Ding Y.; Belyanskaya S.; DeLorey J. L.; Messer J. A.; Joseph Franklin G.; Centrella P. A.; Morgan B. A.; Clark M. A.; Skinner S. R.; Dodson J. W.; Li P.; Marino J. P. Jr.; Israel D. I. Discovery of soluble epoxide hydrolase inhibitors through DNA-encoded library technology (ELT). Bioorg. Med. Chem. 2021, 41, 116216 10.1016/j.bmc.2021.116216. [DOI] [PubMed] [Google Scholar]
  14. Taylor D. M.; Anglin J.; Park S.; Ucisik M. N.; Faver J. C.; Simmons N.; Jin Z.; Palaniappan M.; Nyshadham P.; Li F.; Campbell J.; Hu L.; Sankaran B.; Prasad B. V. V.; Huang H.; Matzuk M. M.; Palzkill T. Identifying Oxacillinase-48 Carbapenemase Inhibitors Using DNA-Encoded Chemical Libraries. ACS Infect. Dis. 2020, 6 (5), 1214–1227. 10.1021/acsinfecdis.0c00015. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Wu Z.; Graybill T. L.; Zeng X.; Platchek M.; Zhang J.; Bodmer V. Q.; Wisnoski D. D.; Deng J.; Coppo F. T.; Yao G.; Tamburino A.; Scavello G.; Franklin G. J.; Mataruse S.; Bedard K. L.; Ding Y.; Chai J.; Summerfield J.; Centrella P. A.; Messer J. A.; Pope A. J.; Israel D. I. Cell-Based Selection Expands the Utility of DNA-Encoded Small-Molecule Library Technology to Cell Surface Drug Targets: Identification of Novel Antagonists of the NK3 Tachykinin Receptor. ACS Comb. Sci. 2015, 17 (12), 722–731. 10.1021/acscombsci.5b00124. [DOI] [PubMed] [Google Scholar]
  16. Deng H.; O’Keefe H.; Davie C. P.; Lind K. E.; Acharya R. A.; Franklin G. J.; Larkin J.; Matico R.; Neeb M.; Thompson M. M.; Lohr T.; Gross J. W.; Centrella P. A.; O’Donovan G. K.; Bedard K. L.; van Vloten K.; Mataruse S.; Skinner S. R.; Belyanskaya S. L.; Carpenter T. Y.; Shearer T. W.; Clark M. A.; Cuozzo J. W.; Arico-Muendel C. C.; Morgan B. A. Discovery of highly potent and selective small molecule ADAMTS-5 inhibitors that inhibit human cartilage degradation via encoded library technology (ELT). J. Med. Chem. 2012, 55 (16), 7061–7079. 10.1021/jm300449x. [DOI] [PubMed] [Google Scholar]
  17. Clark M. A.; Acharya R. A.; Arico-Muendel C. C.; Belyanskaya S. L.; Benjamin D. R.; Carlson N. R.; Centrella P. A.; Chiu C. H.; Creaser S. P.; Cuozzo J. W.; Davie C. P.; Ding Y.; Franklin G. J.; Franzen K. D.; Gefter M. L.; Hale S. P.; Hansen N. J.; Israel D. I.; Jiang J.; Kavarana M. J.; Kelley M. S.; Kollmann C. S.; Li F.; Lind K.; Mataruse S.; Medeiros P. F.; Messer J. A.; Myers P.; O’Keefe H.; Oliff M. C.; Rise C. E.; Satz A. L.; Skinner S. R.; Svendsen J. L.; Tang L.; van Vloten K.; Wagner R. W.; Yao G.; Zhao B.; Morgan B. A. Design, synthesis and selection of DNA-encoded small-molecule libraries. Nat. Chem. Biol. 2009, 5 (9), 647–654. 10.1038/nchembio.211. [DOI] [PubMed] [Google Scholar]
  18. Tasso B.; Spallarossa A.; Russo E.; Brullo C. The Development of BTK Inhibitors: A Five-Year Update. Molecules 2021, 26 (23), 7411. 10.3390/molecules26237411. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Wu R.; Gao S.; Du T.; Cai K.; Cheng X.; Fan J.; Feng J.; Shaginian A.; Li J.; Wan J.; Liu G. Exploring Aldol Reactions on DNA and Applications to Produce Diverse Structures: An Example of Expanding Chemical Space of DNA-Encoded Compounds by Diversity-Oriented Synthesis. Chem. Asian. J. 2020, 15 (23), 4033–4037. 10.1002/asia.202001105. [DOI] [PubMed] [Google Scholar]
  20. Ding Y.; DeLorey J. L.; Clark M. A. Novel Catalyst System for Suzuki-Miyaura Coupling of Challenging DNA-Linked Aryl Chlorides. Bioconjugate Chem. 2016, 27 (11), 2597–2600. 10.1021/acs.bioconjchem.6b00541. [DOI] [PubMed] [Google Scholar]
  21. Satz A. L.; Cai J.; Chen Y.; Goodnow R.; Gruber F.; Kowalczyk A.; Petersen A.; Naderi-Oboodi G.; Orzechowski L.; Strebel Q. DNA Compatible Multistep Synthesis and Applications to DNA Encoded Libraries. Bioconjugate Chem. 2015, 26 (8), 1623–1632. 10.1021/acs.bioconjchem.5b00239. [DOI] [PubMed] [Google Scholar]
  22. Large J. M.; Torr J. E.; Raynaud F. I.; Clarke P. A.; Hayes A.; Stefano F.; Urban F.; Shuttleworth S. J.; Saghir N.; Sheldrake P.; Workman P.; McDonald E. Preparation and evaluation of trisubstituted pyrimidines as phosphatidylinositol 3-kinase inhibitors. 3-Hydroxyphenol analogues and bioisosteric replacements. Bioorg. Med. Chem. 2011, 19 (2), 836–851. 10.1016/j.bmc.2010.12.006. [DOI] [PubMed] [Google Scholar]
  23. Montebugnoli D.; Bravo P.; Brenna E.; Mioskowski C.; Panzeri W.; Viani F.; Volonterio A.; Wagner A.; Zanda M. Traceless solid-phase synthesis of 2,4,6-chlorodiamino and triaminopyrimidines. Tetrahedron 2003, 59 (36), 7147–7156. 10.1016/S0040-4020(03)01097-4. [DOI] [Google Scholar]
  24. Metzger A.; Qin L.-Y.; Cole A. G.; Saionz K. W.; Brescia M.-R.; Gstach H.; Wareing J. R.; Zimmermann J.; Brill W. K. D.; Baldwin J. J.; Dolle R. E.; Henderson I. Combined solution-phase and solid-phase synthesis of 2-amino-7,8-dihydropteridin-6(5H)-ones. Tetrahedron Lett. 2009, 50 (50), 7082–7085. 10.1016/j.tetlet.2009.10.005. [DOI] [Google Scholar]
  25. Cole A. G.; Metzger A.; Ahmed G.; Brescia M.-R.; Chan R. J.; Wen J.; O’Brien L.; Qin L.-Y.; Henderson I. Solid-phase synthesis of N-9-substituted 2,8-diaminopurines. Tetrahedron Lett. 2006, 47 (50), 8897–8900. 10.1016/j.tetlet.2006.10.050. [DOI] [Google Scholar]
  26. Moon Y.-C.; Baiazitov R.; Du W.; Lee C.-S.; Hwang S.; Almstead N. Chemoselective Reactions of 4,6-Dichloro-2-(methylsulfonyl)pyrimidine and Related Electrophiles with Amines. Synthesis 2013, 45 (13), 1764–1784. 10.1055/s-0033-1338853. [DOI] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

ml3c00205_si_001.pdf (9.2MB, pdf)

Articles from ACS Medicinal Chemistry Letters are provided here courtesy of American Chemical Society

RESOURCES