- Email: [email protected]
Combinatorial Chemistry Online Volume 16, Issue 9, September 2014
Combinatorial Chemistry - An Online Journal 16 (2014) 33–35
Contents lists available at ScienceDirect
Combinatorial Chemistry - An Online Journal journal homepage: www.elsevier.com/locate/comche
Combinatorial Chemistry Online Volume 16, Issue 9, September 2014 N.K. Terrett Ensemble Therapeutics Corp., Cambridge, MA 02139, USA
1. Current literature highlights
R1
1.1. Microwave-assisted polymer-supported synthesis of a constrained peptide backbone mimetic In the search for new therapeutic agents that can interact efficiently with protein–protein and peptide–protein interactions, a successful strategy has been to make molecules that are mimetics of the electronic and conformational properties of the native interacting surface. To hold peptidomimetics in an appropriate conformation, there have been numerous attempts to design and synthesise privileged structures which are constrained mimetics of peptide backbones. A recent paper describes the synthesis of benzimidazolinopiperazinone peptides with full stereochemical control using both conventional and microwave-assisted syntheses [1]. The fused ring system of benzo[4,5]imidazo[1,2-a]pyrazin4(1H)-one (1), can be considered a hybrid of benzimidazole and the hexahydroimidazo[1,2-a]pyrazin-5(1H)-one system, both of which occur in many pharmacologically active compounds. System 1 was prepared by a tandem N-acyliminium ion cyclisation-nucleophilic addition process that has been successfully applied to other diverse heterocyclic systems. Rink amine resin was acylated with Fmoc-a-amino acids under standard DIC-catalysed coupling conditions, and the products (2) following removal of the Fmoc protecting group, were derivatised with 1-fluoro-2-nitrobenzenes. Reduction of the nitro group using sodium dithionite, acylation with a bromoacetate and displacement of the bromide with aminoacetaldehyde dimethyl acetal generated the intermediates 3. Sulphonylation of the free amine with a nosyl or tosyl group was followed by trifluoroacetic acid-catalysed cyclisation of the acetal and cleavage of the Rink resin linker. The initial solution intermediate from this cyclisation was not isolated, as after further time under the same reaction conditions, the desired product 1 was generated by a further intramolecular nucleophilic attack by the aromatic amine onto a cyclic N-acyl-N-aryliminium ion intermediate.
R2' R2
R1
R3
N H
NH
HN Me O
H N O 3
O R2'
OMe R2
R1 N N
CONH 2 H
O
1
N R3
SO2 R
Each step in the reaction sequence was undertaken both with conventional heating and with microwave irradiation. Completing all steps in this process under conventional heating took from 3 to 6 days, depending on the building blocks employed and their reactivity. In contrast, microwave heating contributed a significant reduction in reaction time, with the complete synthesis being completed in a matter of minutes, with no significant impact on chemical yields. It was also demonstrated that the chemistry proceeded with full stereochemical control of the newly formed stereocentres. Overall, this approach provides a novel and effective approach to a peptidomimetic scaffold with considerable utility for library synthesis. 2. A summary of the papers in this month’s issue
No papers this month.
http://dx.doi.org/10.1016/j.comche.2014.08.001
2
O
2.1. Polymer supported synthesis
E-mail: [email protected]
H N
FmocHN
34
N.K. Terrett / Combinatorial Chemistry - An Online Journal 16 (2014) 33–35
2.2. Solution-phase synthesis
2.5. Novel resins, linkers and techniques
Among numerous reactions used to prepare cyclophane derivatives, the Claisen rearrangement reaction is very useful. A recent report describes the preparation of cyclophanes containing an ethylene oxy bridge by a double Claisen rearrangement reaction and ring-closing metathesis reaction as the key steps [2]. A simple and useful methodology for the synthesis of spirocycles in a diversity-oriented manner starting with monocyclic ketones and bicyclic diones has been described. Using readily available starting materials and an operationally simple procedure using ring-closing metathesis with the aid of Grubbs’ first generation catalyst, a library of intricate spirocycles have been prepared in good to excellent yields [3]. Different approaches for the synthesis of 1-benzyloxypyrazin2(1H)-one derivatives from simple amino acids have been investigated. Using this approach, a 33-component library of 1-benzyloxypyrazin-2(1H)-one derivatives, precursors for the synthesis of N-hydroxypyrazinones, has been prepared in moderate to good yields with minimal reaction steps [4]. An efficient one-pot method for the synthesis of highly substituted 5H-[1,3,4]thiadiazolo[3,2-a]pyrimidine-6-carboxylate derivatives has been reported. The reaction proceeded via a microwave irradiation of various aldehydes, 2-aminothiadiazole, and acetoacetate in a multicomponent reaction without any catalyst. Having established optimal conditions, the scope and generality of the method were investigated by preparing a library of these derivatives [5].
A fluoride-responsive (FR) amino acid that induces amide bond cleavage upon the addition of a fluoride ion has been developed, and has been applied to an FR traceable linker. By the use of an alkyne-containing peptide, introduction of the FR traceable linker onto the peptide was achieved, and subsequent fluoride-induced cleavage of the linker followed by labeling of the released peptide derivative was investigated [10].
2.3. Scaffolds and synthons for combinatorial libraries No papers this month. 2.4. Solid-phase supported reagents Selective formylation of free (N–H) indoles at C3 has been achieved by using formylating species generated from hexamethylenetetramine and silica-supported ceric ammonium nitrate. The use of a catalytic amount of this solid-supported reagent was found to be compatible with a range of substituents on the indoles and generated the corresponding products with good yields. A mechanism for the formylation involving an electron transfer process has been proposed [6]. Au/MgO has proved to be a highly efficient and reusable catalyst for multicomponent coupling reactions at 70 °C. The multisubstituted pyridines that could be synthesised were obtained in high yields and in short reaction times. Following a facile workup, the novel catalyst was readily recovered and reused without any loss of its catalytic activity [7]. Bifunctional palladated rasta resins bearing both phosphino and basic amino groups have been successfully used for Mizoroki–Heck reactions between aryl iodides and alkenes without adding a soluble base. It has been shown that the resin can be easily regenerated after reaction and reused [8]. Graphene supported Pd–Co bimetallic nanoparticles as highly active catalysts have been prepared by a chemical reduction method and used for coupling reactions. By characterisation using X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and Raman spectrum, the composition of resulting Pd–Co material was identified to be alloy structural. The Pd–Co (1:1)/graphene exhibited highest catalytic activity for Sonogashira-type coupling reactions and also exerted satisfactory catalytic activity and stability for Suzuki–Miyaura cross-coupling reactions [9].
2.6. Library applications A knowledge-based library of 2,3-dichlorophenylsulphonyl derivatives of commercially available aryl amines has been synthesised and screened for activity as human CCR4 antagonists. Azabenzimidazolone analogues were all found to be active, with one compound exhibiting whole blood activity, and meeting all the criteria for progression to lead optimisation [11]. The synthesis and biological activity of a library of sixteen 3,4dihydro-1H-quinolin-2-one derivatives, embodying a 3,3-dibenzyl-4-hydroxy pattern and three main sites of structural diversification, has been reported. The compounds were tested for antimicrobial activity, and the minimum inhibitory concentration values of the most active heterocycles were slightly higher than those exhibited by levofloxacin, employed as comparator. The design of the library provided preliminary insights into the structural requirements for activity of the heterocycles and helped to improve their antibacterial profile [12]. A library of novel bis-heterocycles containing 2-mercaptobenzoxazole-based 1,2,3-triazoles has been synthesised using a click chemistry approach. One compound was discovered to exhibit potent in vivo anti-inflammatory activity and suppressed COX-2 gene expression [13]. References [1] Ventosa-Andrés P, Hradilová L, Krchnˇák V. Privileged structures as peptide backbone constraints: polymer-supported stereoselective synthesis of benzimidazolinopiperazinone peptides. ACS Comb Sci 2014;16(7):359–66. [2] Kotha S, Waghule GT. Diversity-oriented approach to cyclophanes via Claisen rearrangement and ring-closing metathesis as key steps. Tetrahedron Lett 2014;55(30):4264–8. [3] Kotha S, Ali R, Chinnam AK. Diversity-oriented approach to spirocycles via ringclosing metathesis. Tetrahedron Lett 2014;55(32):4492–5. [4] Mai AH, Pawar S, De Borggraeve WM. Synthesis of 1-benzyloxypyrazin-2(1H)one derivatives. Tetrahedron Lett 2014;55(33):4664–6. [5] Zhao B, Xu Y, Deng Q-G, Liu Z, Wang L-Y, Gao Y. One-pot, three component synthesis of novel 5H-[1,3,4]thiadiazolo[3,2-a]pyrimidine-6-carboxylate derivatives by microwave irradiation. Tetrahedron Lett 2014;55(33):4521–4. [6] Tongkhan S, Radchatawedchakoon W, Kruanetr A, Sakee U. Silica-supported ceric ammonium nitrate catalyzed chemoselective formylation of indoles. Tetrahedron Lett 2014;55(29):3909–12. [7] Pagadala R, Maddila S, Moodley V, van Zyl WE, Jonnalagadda SB. An efficient method for the multicomponent synthesis of multisubstituted pyridines, a rapid procedure using Au/MgO as the catalyst. Tetrahedron Lett 2014;55(29):4006–10. [8] Derible A, Yang Y-C, Toy PH, Becht J-M, Le Drian C. A bifunctional palladated rasta resin for Mizoroki–Heck reactions. Tetrahedron Lett 2014;55(31):4331–3. [9] Feng Y-S, Lin X-Y, Hao J, Xu H-J. Pd–Co bimetallic nanoparticles supported on graphene as a highly active catalyst for Suzuki–Miyaura and Sonogashira crosscoupling reactions. Tetrahedron 2014;70(34):5249–53. [10] Yamamoto J, Maeda N, Komiya C, Tanaka T, Denda M, Ebisuno K, et al. Development of a fluoride-responsive amide bond cleavage device that is potentially applicable to a traceable linker. Tetrahedron 2014;70(34):5122–7. [11] Miah AH, Abas H, Begg M, Marsh BJ, O’Flynn DE, Ford AJ, et al. Lead identification of benzimidazolone and azabenzimidazolone arylsulfonamides as CC-chemokine receptor 4 (CCR4) antagonists. Bioorg Med Chem 2014;22(15):4298–311. [12] Ferretti MD, Neto AT, Morel AF, Kaufman TS, Larghi EL. Synthesis of symmetrically substituted 3,3-dibenzyl-4-hydroxy-3,4-dihydro-1H-quinolin-2-ones, as novel quinoline derivatives with antibacterial activity. Eur J Med Chem 2014;81:253–66. [13] Haider S, Alam MS, Hamid H, Shafi S, Dhulap A, Hussain F, et al. Synthesis of novel 2-mercaptobenzoxazole based 1,2,3-triazoles as inhibitors of proinflammatory cytokines and suppressors of COX-2 gene expression. Eur J Med Chem 2014;81:204–17.
N.K. Terrett / Combinatorial Chemistry - An Online Journal 16 (2014) 33–35
Further reading Papers on combinatorial chemistry or solid-phase synthesis from other journals. Deiss F, Matochko WL, Govindasamy N, Lin EY, Derda R. Flow-through synthesis on teflon-patterned paper to produce peptide arrays for cell-based assays. Angew Chem Int Ed 2014;53(25):6374–7. Ji S, Cao W, Yu Y, Xu H. Dynamic diselenide bonds: exchange reaction induced by visible light without catalysis. Angew Chem Int Ed 2014;53(26):6781–5. Taduri AK, Devi BR. Alum-Cs2CO3 as a new recyclable solid base catalyst for the efficient syntheses of arylidenemalononitriles, esters and arylcinnamic acids in water. Asian J Chem 2014;26(7):1938–42. Dirksen A, Madsen M, Dello IG, Matin MJ, Bacica M, Stankovic N, et al. Parallel synthesis and screening of peptide conjugates. Bioconjugate Chem 2014;25(6):1052–60. Pina AS, Guilherme M, Pereira AS, Fernandes CSFM, Branco RJF, El Khoury G, et al. A tailor-made, ‘‘tag-receptor’’ affinity pair for the purification of fusion proteins. ChemBioChem 2014;15(10):1423–35. Goyal S, Dhanjal JK, Tyagi C, Goyal M, Grover A. Novel fragment-based QSAR modeling and combinatorial design of pyrazole-derived CRK3 inhibitors as potent antileishmanials. Chem Biol Drug Des 2014;84(1):54–62. Miyazaki A, Asanuma M, Dodo K, Egami H, Sodeoka M. A ‘‘catch-and-release’’ protocol for alkyne-tagged molecules based on a resin-bound cobalt complex for peptide enrichment in aqueous media. Chem Eur J 2014;20(26):8116–28. Brust A, Schroeder CI, Alewood PF. High-throughput synthesis of peptide a-thioesters: a safety catch linker approach enabling parallel hydrogen fluoride cleavage. ChemMedChem 2014;9(5):1038–46. Barot KP, Nikolova S, Ivanov I, Ghate MD. Liquid-phase combinatorial library synthesis: recent advances and future perspectives. Comb Chem High Throughput Screening 2014;17(5):417–38. Jee J-E, Ang YL, Cha J, Ang MW, Ling J, Lim J, et al. Combinatorial bead-based peptide libraries improved for rapid and robust screenings. Comb Chem High Throughput Screening 2014;17(6):520–30.
35
Gabizon R, Friedler A. Allosteric modulation of protein oligomerization: an emerging approach to drug design. Front Chem 2014;2:9. Fu J, Lee T, Qi X. The identification of high-affinity G protein-coupled receptor ligands from large combinatorial libraries using multicolor quantum dot-labeled cellbased screening. Future Med Chem 2014;6(7):809–23. Shaabani A, Ghadari R, Arabieh M. Synthesis of a new library of pyrano-phenazine derivatives via a novel three-component protocol. Helv Chim Acta 2014;97(2):228–36. Hay DA, Fedorov O, Martin S, Singleton DC, Tallant C, Wells C, et al. Discovery and optimization of small-molecule ligands for the CBP/p300 bromodomains. J Am Chem Soc 2014;136(26):9308–19. Ogasawara M, Tseng Y-Y, Arae S, Morita T, Nakaya T, Wu W-Y, et al. Phosphine–olefin ligands based on a planar-chiral (p-arene)chromium scaold: design, synthesis, and application in asymmetric catalysis. J Am Chem Soc 2014;136(26):9377–84. Cheneval O, Schroeder CI, Durek T, Walsh P, Huang Y-H, Liras S, et al. Fmoc-based synthesis of disulfide-rich cyclic peptides. J Org Chem 2014;79(12):5538–44. Wilde F, Specker E, Neuenschwander M, Nazare M, Bodtke A, Link A. Tractable synthesis of multipurpose screening compounds with under-represented molecular features for an open access screening platform. Mol Diversity 2014;18(3):483–95. Radulovic NS, Mladenovic MZ, Stojanovic-Radic Z, Bogdanovic GA, Stevanovic D, Vukicevic RD. Synthesis, characterization, and antimicrobial evaluation of a small library of ferrocene-containing acetoacetates and phenyl analogs: the discovery of a potent anticandidal agent. Mol Diversity 2014;18(3):497–510. van de Langemheen H, van Hoeke M, Quarles van Uord HC, Kruijtzer JAW, Liskamp RMJ. Scaolded multiple cyclic peptide libraries for protein mimics by native chemical ligation. Org Biomol Chem 2014;12(25):4471–8. Xiao Y-C, Yue C-Z, Chen P-Q, Chen Y-C. Asymmetric dearomatic Diels–Alder reactions of diverse heteroarenes via p-system activation. Org Lett 2014;16(12):3208–11. Traore M, Doan N-D, Lubell WD. Diversity-oriented synthesis of azapeptides with basic amino acid residues: aza-lysine, aza-ornithine, and aza-arginine. Org Lett 2014;16(13):3588–91. Kumar GG, Kamalneet K, Shikha S, Vinod K. Isolation of 4-hydroxythiazoline. A solid phase study in Hantzsch thiazole reaction. Res J Chem Environ 2014;18(2):38–44.
Contents lists available at ScienceDirect
Combinatorial Chemistry - An Online Journal journal homepage: www.elsevier.com/locate/comche
Combinatorial Chemistry Online Volume 16, Issue 9, September 2014 N.K. Terrett Ensemble Therapeutics Corp., Cambridge, MA 02139, USA
1. Current literature highlights
R1
1.1. Microwave-assisted polymer-supported synthesis of a constrained peptide backbone mimetic In the search for new therapeutic agents that can interact efficiently with protein–protein and peptide–protein interactions, a successful strategy has been to make molecules that are mimetics of the electronic and conformational properties of the native interacting surface. To hold peptidomimetics in an appropriate conformation, there have been numerous attempts to design and synthesise privileged structures which are constrained mimetics of peptide backbones. A recent paper describes the synthesis of benzimidazolinopiperazinone peptides with full stereochemical control using both conventional and microwave-assisted syntheses [1]. The fused ring system of benzo[4,5]imidazo[1,2-a]pyrazin4(1H)-one (1), can be considered a hybrid of benzimidazole and the hexahydroimidazo[1,2-a]pyrazin-5(1H)-one system, both of which occur in many pharmacologically active compounds. System 1 was prepared by a tandem N-acyliminium ion cyclisation-nucleophilic addition process that has been successfully applied to other diverse heterocyclic systems. Rink amine resin was acylated with Fmoc-a-amino acids under standard DIC-catalysed coupling conditions, and the products (2) following removal of the Fmoc protecting group, were derivatised with 1-fluoro-2-nitrobenzenes. Reduction of the nitro group using sodium dithionite, acylation with a bromoacetate and displacement of the bromide with aminoacetaldehyde dimethyl acetal generated the intermediates 3. Sulphonylation of the free amine with a nosyl or tosyl group was followed by trifluoroacetic acid-catalysed cyclisation of the acetal and cleavage of the Rink resin linker. The initial solution intermediate from this cyclisation was not isolated, as after further time under the same reaction conditions, the desired product 1 was generated by a further intramolecular nucleophilic attack by the aromatic amine onto a cyclic N-acyl-N-aryliminium ion intermediate.
R2' R2
R1
R3
N H
NH
HN Me O
H N O 3
O R2'
OMe R2
R1 N N
CONH 2 H
O
1
N R3
SO2 R
Each step in the reaction sequence was undertaken both with conventional heating and with microwave irradiation. Completing all steps in this process under conventional heating took from 3 to 6 days, depending on the building blocks employed and their reactivity. In contrast, microwave heating contributed a significant reduction in reaction time, with the complete synthesis being completed in a matter of minutes, with no significant impact on chemical yields. It was also demonstrated that the chemistry proceeded with full stereochemical control of the newly formed stereocentres. Overall, this approach provides a novel and effective approach to a peptidomimetic scaffold with considerable utility for library synthesis. 2. A summary of the papers in this month’s issue
No papers this month.
http://dx.doi.org/10.1016/j.comche.2014.08.001
2
O
2.1. Polymer supported synthesis
E-mail: [email protected]
H N
FmocHN
34
N.K. Terrett / Combinatorial Chemistry - An Online Journal 16 (2014) 33–35
2.2. Solution-phase synthesis
2.5. Novel resins, linkers and techniques
Among numerous reactions used to prepare cyclophane derivatives, the Claisen rearrangement reaction is very useful. A recent report describes the preparation of cyclophanes containing an ethylene oxy bridge by a double Claisen rearrangement reaction and ring-closing metathesis reaction as the key steps [2]. A simple and useful methodology for the synthesis of spirocycles in a diversity-oriented manner starting with monocyclic ketones and bicyclic diones has been described. Using readily available starting materials and an operationally simple procedure using ring-closing metathesis with the aid of Grubbs’ first generation catalyst, a library of intricate spirocycles have been prepared in good to excellent yields [3]. Different approaches for the synthesis of 1-benzyloxypyrazin2(1H)-one derivatives from simple amino acids have been investigated. Using this approach, a 33-component library of 1-benzyloxypyrazin-2(1H)-one derivatives, precursors for the synthesis of N-hydroxypyrazinones, has been prepared in moderate to good yields with minimal reaction steps [4]. An efficient one-pot method for the synthesis of highly substituted 5H-[1,3,4]thiadiazolo[3,2-a]pyrimidine-6-carboxylate derivatives has been reported. The reaction proceeded via a microwave irradiation of various aldehydes, 2-aminothiadiazole, and acetoacetate in a multicomponent reaction without any catalyst. Having established optimal conditions, the scope and generality of the method were investigated by preparing a library of these derivatives [5].
A fluoride-responsive (FR) amino acid that induces amide bond cleavage upon the addition of a fluoride ion has been developed, and has been applied to an FR traceable linker. By the use of an alkyne-containing peptide, introduction of the FR traceable linker onto the peptide was achieved, and subsequent fluoride-induced cleavage of the linker followed by labeling of the released peptide derivative was investigated [10].
2.3. Scaffolds and synthons for combinatorial libraries No papers this month. 2.4. Solid-phase supported reagents Selective formylation of free (N–H) indoles at C3 has been achieved by using formylating species generated from hexamethylenetetramine and silica-supported ceric ammonium nitrate. The use of a catalytic amount of this solid-supported reagent was found to be compatible with a range of substituents on the indoles and generated the corresponding products with good yields. A mechanism for the formylation involving an electron transfer process has been proposed [6]. Au/MgO has proved to be a highly efficient and reusable catalyst for multicomponent coupling reactions at 70 °C. The multisubstituted pyridines that could be synthesised were obtained in high yields and in short reaction times. Following a facile workup, the novel catalyst was readily recovered and reused without any loss of its catalytic activity [7]. Bifunctional palladated rasta resins bearing both phosphino and basic amino groups have been successfully used for Mizoroki–Heck reactions between aryl iodides and alkenes without adding a soluble base. It has been shown that the resin can be easily regenerated after reaction and reused [8]. Graphene supported Pd–Co bimetallic nanoparticles as highly active catalysts have been prepared by a chemical reduction method and used for coupling reactions. By characterisation using X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and Raman spectrum, the composition of resulting Pd–Co material was identified to be alloy structural. The Pd–Co (1:1)/graphene exhibited highest catalytic activity for Sonogashira-type coupling reactions and also exerted satisfactory catalytic activity and stability for Suzuki–Miyaura cross-coupling reactions [9].
2.6. Library applications A knowledge-based library of 2,3-dichlorophenylsulphonyl derivatives of commercially available aryl amines has been synthesised and screened for activity as human CCR4 antagonists. Azabenzimidazolone analogues were all found to be active, with one compound exhibiting whole blood activity, and meeting all the criteria for progression to lead optimisation [11]. The synthesis and biological activity of a library of sixteen 3,4dihydro-1H-quinolin-2-one derivatives, embodying a 3,3-dibenzyl-4-hydroxy pattern and three main sites of structural diversification, has been reported. The compounds were tested for antimicrobial activity, and the minimum inhibitory concentration values of the most active heterocycles were slightly higher than those exhibited by levofloxacin, employed as comparator. The design of the library provided preliminary insights into the structural requirements for activity of the heterocycles and helped to improve their antibacterial profile [12]. A library of novel bis-heterocycles containing 2-mercaptobenzoxazole-based 1,2,3-triazoles has been synthesised using a click chemistry approach. One compound was discovered to exhibit potent in vivo anti-inflammatory activity and suppressed COX-2 gene expression [13]. References [1] Ventosa-Andrés P, Hradilová L, Krchnˇák V. Privileged structures as peptide backbone constraints: polymer-supported stereoselective synthesis of benzimidazolinopiperazinone peptides. ACS Comb Sci 2014;16(7):359–66. [2] Kotha S, Waghule GT. Diversity-oriented approach to cyclophanes via Claisen rearrangement and ring-closing metathesis as key steps. Tetrahedron Lett 2014;55(30):4264–8. [3] Kotha S, Ali R, Chinnam AK. Diversity-oriented approach to spirocycles via ringclosing metathesis. Tetrahedron Lett 2014;55(32):4492–5. [4] Mai AH, Pawar S, De Borggraeve WM. Synthesis of 1-benzyloxypyrazin-2(1H)one derivatives. Tetrahedron Lett 2014;55(33):4664–6. [5] Zhao B, Xu Y, Deng Q-G, Liu Z, Wang L-Y, Gao Y. One-pot, three component synthesis of novel 5H-[1,3,4]thiadiazolo[3,2-a]pyrimidine-6-carboxylate derivatives by microwave irradiation. Tetrahedron Lett 2014;55(33):4521–4. [6] Tongkhan S, Radchatawedchakoon W, Kruanetr A, Sakee U. Silica-supported ceric ammonium nitrate catalyzed chemoselective formylation of indoles. Tetrahedron Lett 2014;55(29):3909–12. [7] Pagadala R, Maddila S, Moodley V, van Zyl WE, Jonnalagadda SB. An efficient method for the multicomponent synthesis of multisubstituted pyridines, a rapid procedure using Au/MgO as the catalyst. Tetrahedron Lett 2014;55(29):4006–10. [8] Derible A, Yang Y-C, Toy PH, Becht J-M, Le Drian C. A bifunctional palladated rasta resin for Mizoroki–Heck reactions. Tetrahedron Lett 2014;55(31):4331–3. [9] Feng Y-S, Lin X-Y, Hao J, Xu H-J. Pd–Co bimetallic nanoparticles supported on graphene as a highly active catalyst for Suzuki–Miyaura and Sonogashira crosscoupling reactions. Tetrahedron 2014;70(34):5249–53. [10] Yamamoto J, Maeda N, Komiya C, Tanaka T, Denda M, Ebisuno K, et al. Development of a fluoride-responsive amide bond cleavage device that is potentially applicable to a traceable linker. Tetrahedron 2014;70(34):5122–7. [11] Miah AH, Abas H, Begg M, Marsh BJ, O’Flynn DE, Ford AJ, et al. Lead identification of benzimidazolone and azabenzimidazolone arylsulfonamides as CC-chemokine receptor 4 (CCR4) antagonists. Bioorg Med Chem 2014;22(15):4298–311. [12] Ferretti MD, Neto AT, Morel AF, Kaufman TS, Larghi EL. Synthesis of symmetrically substituted 3,3-dibenzyl-4-hydroxy-3,4-dihydro-1H-quinolin-2-ones, as novel quinoline derivatives with antibacterial activity. Eur J Med Chem 2014;81:253–66. [13] Haider S, Alam MS, Hamid H, Shafi S, Dhulap A, Hussain F, et al. Synthesis of novel 2-mercaptobenzoxazole based 1,2,3-triazoles as inhibitors of proinflammatory cytokines and suppressors of COX-2 gene expression. Eur J Med Chem 2014;81:204–17.
N.K. Terrett / Combinatorial Chemistry - An Online Journal 16 (2014) 33–35
Further reading Papers on combinatorial chemistry or solid-phase synthesis from other journals. Deiss F, Matochko WL, Govindasamy N, Lin EY, Derda R. Flow-through synthesis on teflon-patterned paper to produce peptide arrays for cell-based assays. Angew Chem Int Ed 2014;53(25):6374–7. Ji S, Cao W, Yu Y, Xu H. Dynamic diselenide bonds: exchange reaction induced by visible light without catalysis. Angew Chem Int Ed 2014;53(26):6781–5. Taduri AK, Devi BR. Alum-Cs2CO3 as a new recyclable solid base catalyst for the efficient syntheses of arylidenemalononitriles, esters and arylcinnamic acids in water. Asian J Chem 2014;26(7):1938–42. Dirksen A, Madsen M, Dello IG, Matin MJ, Bacica M, Stankovic N, et al. Parallel synthesis and screening of peptide conjugates. Bioconjugate Chem 2014;25(6):1052–60. Pina AS, Guilherme M, Pereira AS, Fernandes CSFM, Branco RJF, El Khoury G, et al. A tailor-made, ‘‘tag-receptor’’ affinity pair for the purification of fusion proteins. ChemBioChem 2014;15(10):1423–35. Goyal S, Dhanjal JK, Tyagi C, Goyal M, Grover A. Novel fragment-based QSAR modeling and combinatorial design of pyrazole-derived CRK3 inhibitors as potent antileishmanials. Chem Biol Drug Des 2014;84(1):54–62. Miyazaki A, Asanuma M, Dodo K, Egami H, Sodeoka M. A ‘‘catch-and-release’’ protocol for alkyne-tagged molecules based on a resin-bound cobalt complex for peptide enrichment in aqueous media. Chem Eur J 2014;20(26):8116–28. Brust A, Schroeder CI, Alewood PF. High-throughput synthesis of peptide a-thioesters: a safety catch linker approach enabling parallel hydrogen fluoride cleavage. ChemMedChem 2014;9(5):1038–46. Barot KP, Nikolova S, Ivanov I, Ghate MD. Liquid-phase combinatorial library synthesis: recent advances and future perspectives. Comb Chem High Throughput Screening 2014;17(5):417–38. Jee J-E, Ang YL, Cha J, Ang MW, Ling J, Lim J, et al. Combinatorial bead-based peptide libraries improved for rapid and robust screenings. Comb Chem High Throughput Screening 2014;17(6):520–30.
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Gabizon R, Friedler A. Allosteric modulation of protein oligomerization: an emerging approach to drug design. Front Chem 2014;2:9. Fu J, Lee T, Qi X. The identification of high-affinity G protein-coupled receptor ligands from large combinatorial libraries using multicolor quantum dot-labeled cellbased screening. Future Med Chem 2014;6(7):809–23. Shaabani A, Ghadari R, Arabieh M. Synthesis of a new library of pyrano-phenazine derivatives via a novel three-component protocol. Helv Chim Acta 2014;97(2):228–36. Hay DA, Fedorov O, Martin S, Singleton DC, Tallant C, Wells C, et al. Discovery and optimization of small-molecule ligands for the CBP/p300 bromodomains. J Am Chem Soc 2014;136(26):9308–19. Ogasawara M, Tseng Y-Y, Arae S, Morita T, Nakaya T, Wu W-Y, et al. Phosphine–olefin ligands based on a planar-chiral (p-arene)chromium scaold: design, synthesis, and application in asymmetric catalysis. J Am Chem Soc 2014;136(26):9377–84. Cheneval O, Schroeder CI, Durek T, Walsh P, Huang Y-H, Liras S, et al. Fmoc-based synthesis of disulfide-rich cyclic peptides. J Org Chem 2014;79(12):5538–44. Wilde F, Specker E, Neuenschwander M, Nazare M, Bodtke A, Link A. Tractable synthesis of multipurpose screening compounds with under-represented molecular features for an open access screening platform. Mol Diversity 2014;18(3):483–95. Radulovic NS, Mladenovic MZ, Stojanovic-Radic Z, Bogdanovic GA, Stevanovic D, Vukicevic RD. Synthesis, characterization, and antimicrobial evaluation of a small library of ferrocene-containing acetoacetates and phenyl analogs: the discovery of a potent anticandidal agent. Mol Diversity 2014;18(3):497–510. van de Langemheen H, van Hoeke M, Quarles van Uord HC, Kruijtzer JAW, Liskamp RMJ. Scaolded multiple cyclic peptide libraries for protein mimics by native chemical ligation. Org Biomol Chem 2014;12(25):4471–8. Xiao Y-C, Yue C-Z, Chen P-Q, Chen Y-C. Asymmetric dearomatic Diels–Alder reactions of diverse heteroarenes via p-system activation. Org Lett 2014;16(12):3208–11. Traore M, Doan N-D, Lubell WD. Diversity-oriented synthesis of azapeptides with basic amino acid residues: aza-lysine, aza-ornithine, and aza-arginine. Org Lett 2014;16(13):3588–91. Kumar GG, Kamalneet K, Shikha S, Vinod K. Isolation of 4-hydroxythiazoline. A solid phase study in Hantzsch thiazole reaction. Res J Chem Environ 2014;18(2):38–44.