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Design and Synthesis of Mixed Oligomers with Thiophenes, Dithienothiophene S,S-Dioxides, Thieno[3,4]pyrazines and 2,1,3-Benzothiadiazoles: Flipper Screening for Mechanosensitive Systems.

Verolet Q, Soleimanpour S, Fujisawa K, Dal Molin M, Sakai N, Matile S - ChemistryOpen (2015)

Bottom Line: Monomers with large surface area and high quantum yield, that is fluorescent flippers, have been engineered into twisted push-pull oligomers to create membrane probes with high mechanosensitivity and long fluorescence lifetime.Here, the synthesis and characterization of thieno[3,4]pyrazines and 2,1,3-benzothiadiazoles are described in comparison with the original dithienothiophene S,S-dioxides.Dithienothiophene S,S-dioxide flippers are confirmed as the best reported so far, and poor results with single flipper probes support that two flippers are needed for the probe to really "swim", that is, for high mechanosensitivity.

View Article: PubMed Central - PubMed

Affiliation: Department of Organic Chemistry, University of Geneva Quai Ernest Ansermet 30, 1211, Geneva, Switzerland.

ABSTRACT
Monomers with large surface area and high quantum yield, that is fluorescent flippers, have been engineered into twisted push-pull oligomers to create membrane probes with high mechanosensitivity and long fluorescence lifetime. Here, the synthesis and characterization of thieno[3,4]pyrazines and 2,1,3-benzothiadiazoles are described in comparison with the original dithienothiophene S,S-dioxides. Dithienothiophene S,S-dioxide flippers are confirmed as the best reported so far, and poor results with single flipper probes support that two flippers are needed for the probe to really "swim", that is, for high mechanosensitivity.

No MeSH data available.


Reagents and conditions: a) 1. S(SnBu3)2, Pd(PPh3)4, toluene, 130 °C, 12 h, 46 %, 2. nBuLi, CuCl2, Et2O, 0 °C→rt, 57 %,6 3. mCPBA, CHCl3, 40 °C, 12 h, 64 %; b) 1. NBS, CH2Cl2/AcOH (6:4), 1 h, rt, 45 %, 2. 10, Pd(PPh3)4, toluene, 130 °C, 12 h, 52 %, 3. NBS, CH2Cl2/AcOH (6:4), 1 h, rt, 1 h, 96 %, 4. Pd(PPh3)4, 11, toluene, 130 °C, 12 h, 65 %; c) 1. DIBAL, CH2Cl2, −78 °C, 4 h, 2. DMP, CH2Cl2, rt, 1 h, 96 % (2 steps), 3. 13, piperidine, CH3CN, 70 °C, 6 h, 42 %; d) 1. p-TsOH⋅H2O, CH2Cl2, rt, 75 min, 86 %, 2. 15, DMSO, 60 °C, 90 min, 58 %.
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sch01: Reagents and conditions: a) 1. S(SnBu3)2, Pd(PPh3)4, toluene, 130 °C, 12 h, 46 %, 2. nBuLi, CuCl2, Et2O, 0 °C→rt, 57 %,6 3. mCPBA, CHCl3, 40 °C, 12 h, 64 %; b) 1. NBS, CH2Cl2/AcOH (6:4), 1 h, rt, 45 %, 2. 10, Pd(PPh3)4, toluene, 130 °C, 12 h, 52 %, 3. NBS, CH2Cl2/AcOH (6:4), 1 h, rt, 1 h, 96 %, 4. Pd(PPh3)4, 11, toluene, 130 °C, 12 h, 65 %; c) 1. DIBAL, CH2Cl2, −78 °C, 4 h, 2. DMP, CH2Cl2, rt, 1 h, 96 % (2 steps), 3. 13, piperidine, CH3CN, 70 °C, 6 h, 42 %; d) 1. p-TsOH⋅H2O, CH2Cl2, rt, 75 min, 86 %, 2. 15, DMSO, 60 °C, 90 min, 58 %.

Mentions: The synthesis of dithienothiophene probes 1–4 has been described previously (Figure 1).5 Probe 5 was prepared following the procedure used for probe 4 with some modifications (Scheme 1). Bromothiophene 8 was converted into dithienothiophene following reported procedures, and a successive oxidation with meta-chloroperoxybenzoic acid (mCPBA) gave the electron-poor S,S-dioxide 9.5 Two consecutive Stille couplings, first with 10 and finally with 11, gave push–pull chromophore 12. Ester reduction to the primary alcohol, oxidation with Dess–Martin periodinane to the aldehyde, and Knoevenagel condensation with cyanoamide 13 afforded acetal 14 as the pure trans isomer. The final amphiphile, 5, was obtained by aldehyde deprotection and oxime formation with alkoxyamine 15.


Design and Synthesis of Mixed Oligomers with Thiophenes, Dithienothiophene S,S-Dioxides, Thieno[3,4]pyrazines and 2,1,3-Benzothiadiazoles: Flipper Screening for Mechanosensitive Systems.

Verolet Q, Soleimanpour S, Fujisawa K, Dal Molin M, Sakai N, Matile S - ChemistryOpen (2015)

Reagents and conditions: a) 1. S(SnBu3)2, Pd(PPh3)4, toluene, 130 °C, 12 h, 46 %, 2. nBuLi, CuCl2, Et2O, 0 °C→rt, 57 %,6 3. mCPBA, CHCl3, 40 °C, 12 h, 64 %; b) 1. NBS, CH2Cl2/AcOH (6:4), 1 h, rt, 45 %, 2. 10, Pd(PPh3)4, toluene, 130 °C, 12 h, 52 %, 3. NBS, CH2Cl2/AcOH (6:4), 1 h, rt, 1 h, 96 %, 4. Pd(PPh3)4, 11, toluene, 130 °C, 12 h, 65 %; c) 1. DIBAL, CH2Cl2, −78 °C, 4 h, 2. DMP, CH2Cl2, rt, 1 h, 96 % (2 steps), 3. 13, piperidine, CH3CN, 70 °C, 6 h, 42 %; d) 1. p-TsOH⋅H2O, CH2Cl2, rt, 75 min, 86 %, 2. 15, DMSO, 60 °C, 90 min, 58 %.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4522174&req=5

sch01: Reagents and conditions: a) 1. S(SnBu3)2, Pd(PPh3)4, toluene, 130 °C, 12 h, 46 %, 2. nBuLi, CuCl2, Et2O, 0 °C→rt, 57 %,6 3. mCPBA, CHCl3, 40 °C, 12 h, 64 %; b) 1. NBS, CH2Cl2/AcOH (6:4), 1 h, rt, 45 %, 2. 10, Pd(PPh3)4, toluene, 130 °C, 12 h, 52 %, 3. NBS, CH2Cl2/AcOH (6:4), 1 h, rt, 1 h, 96 %, 4. Pd(PPh3)4, 11, toluene, 130 °C, 12 h, 65 %; c) 1. DIBAL, CH2Cl2, −78 °C, 4 h, 2. DMP, CH2Cl2, rt, 1 h, 96 % (2 steps), 3. 13, piperidine, CH3CN, 70 °C, 6 h, 42 %; d) 1. p-TsOH⋅H2O, CH2Cl2, rt, 75 min, 86 %, 2. 15, DMSO, 60 °C, 90 min, 58 %.
Mentions: The synthesis of dithienothiophene probes 1–4 has been described previously (Figure 1).5 Probe 5 was prepared following the procedure used for probe 4 with some modifications (Scheme 1). Bromothiophene 8 was converted into dithienothiophene following reported procedures, and a successive oxidation with meta-chloroperoxybenzoic acid (mCPBA) gave the electron-poor S,S-dioxide 9.5 Two consecutive Stille couplings, first with 10 and finally with 11, gave push–pull chromophore 12. Ester reduction to the primary alcohol, oxidation with Dess–Martin periodinane to the aldehyde, and Knoevenagel condensation with cyanoamide 13 afforded acetal 14 as the pure trans isomer. The final amphiphile, 5, was obtained by aldehyde deprotection and oxime formation with alkoxyamine 15.

Bottom Line: Monomers with large surface area and high quantum yield, that is fluorescent flippers, have been engineered into twisted push-pull oligomers to create membrane probes with high mechanosensitivity and long fluorescence lifetime.Here, the synthesis and characterization of thieno[3,4]pyrazines and 2,1,3-benzothiadiazoles are described in comparison with the original dithienothiophene S,S-dioxides.Dithienothiophene S,S-dioxide flippers are confirmed as the best reported so far, and poor results with single flipper probes support that two flippers are needed for the probe to really "swim", that is, for high mechanosensitivity.

View Article: PubMed Central - PubMed

Affiliation: Department of Organic Chemistry, University of Geneva Quai Ernest Ansermet 30, 1211, Geneva, Switzerland.

ABSTRACT
Monomers with large surface area and high quantum yield, that is fluorescent flippers, have been engineered into twisted push-pull oligomers to create membrane probes with high mechanosensitivity and long fluorescence lifetime. Here, the synthesis and characterization of thieno[3,4]pyrazines and 2,1,3-benzothiadiazoles are described in comparison with the original dithienothiophene S,S-dioxides. Dithienothiophene S,S-dioxide flippers are confirmed as the best reported so far, and poor results with single flipper probes support that two flippers are needed for the probe to really "swim", that is, for high mechanosensitivity.

No MeSH data available.