Editing Synthesis of PTDM

== Structure  ==

[[Image:PTDM Structure.jpg]] 

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== Chemicals<br>  ==

Maleic anhydride, furan, 4-dimethyl aminopyridine (DMAP), 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC), methanol, 1,3-Di-Boc-2-(2-hydroxyethyl)guanidine, benzyl alcohol, ethylvinyl ether and trifluoroacetic acid (TFA)&nbsp; reagent grade from Aldrich, Fluka or Acros. The HPLC grade solvents ethyl acetate, pentane and hexane are from Aldrich, Fisher Scientific or Acros and can be used as received. Tetrahydrofuran (THF) (HPLC grade, Fisher Scientific) is distilled from sodium/benzophenone under nitrogen. Dichloromethane (DCM) (HPLC grade, Fisher Scientific) is distilled from CaH2 under nitrogen.<br> 

<br>3rd generation Grubbs catalyst (Dichloro-di(3-bromopyridino)-N,N’-Dimesitylenoimidazolino-Ru=CHPh; G3):&nbsp; Sigma 682330-100MG, $64.80.<br> 

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=== <br>Synthesis of 2:<br>  ===

[[Image:PTDM_fig_1.jpg]]

(i) <br> 

Dissolve maleic anhydride (100 g, 1.02 mol) in 1 L toluene, add 150 mL (140.7 g, 2.05 mol) furan<br> 

Stir the solution for 3 days according to the literature. <br> 

Filter the product (1), wash with hexanes and dry under vacuum. <br> 

A colorless powder should be obtained. 

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(ii) Follow the same procedure as Lienkamp et.al. with minor modifications. <br> 

Dissolve&nbsp; Compound 1, 10 mol% DMAP and 1.9 equivalents of the 1,3-Di-Boc-2-ethyl guanidine in DCM. <br> 

After all components dissolved, cool down the solution to 0 <sup>o</sup>C in an ice bath, and then add 1 equivalent of EDC.<br> 

Stire the solution over night. <br> 

Dilute the reaction mixture with DCM.<br> 

Wash with 10% KHSO4 (3 x 25 mL) and sat. NaHCO3 solution (3x 25 mL). <br> 

Next, dry the organic phase&nbsp; over Na2SO4 and filtered. <br> 

Reduce the volume of solution by vacuum evaporation.<br> 

Purify the product with a short alumina column. <br> 

Vacuum evaporation of the solvent yields the pure product 2. <br> 

The yield ranged from ~80%.<br> 

== Synthesis of monomer 3b:  ==

'''Synthesis of 3a: '''<br> 

[[Image:PTDM_fig_2.jpg]]

Dissolve compound 1 and 1.5 equivalents of the benzyl alcohol&nbsp; in DCM<br> 

Add&nbsp;&nbsp; 10 mol% DMAP.<br> 

Stir the reaction mixture for 3 days.<br> 

Filter the precipitate and vacuum evaporation of residual solvent to yield the pure product 3a. <br> 

The yield is ~70%.<br> 

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'''Synthesis of 3b: '''<br> 

Dissolve one equivalent of compound 3a, two equivalents of methanol and 10% DMAP&nbsp; in 1:1 mixture of DCM:THF. <br> 

After all components dissolved, cool down the solution&nbsp; to 0 oC in an ice bath, and add one equivalent of EDC.<br> 

Stir the solution over night. <br> 

Evaporate al the solvent&nbsp;<br> 

Dissolve reaction mixture in DCM<br> 

Wash with 10% KHSO4 (3 x 25 mL) and sat. NaHCO3 solution (3x 25 mL). <br> 

Dry the organic phase over Na2SO4 and filter.<br> 

Reduce the volume of solution by vacuum evaporation<br> 

Purify the product with a short alumina column. <br> 

Vacuum evaporation of the solvent yieldx the pure product 3b. <br> 

The yield ranged from ~80%.<br> 

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== Synthesis of PTDM-1<br>  ==

'''Synthesis of polymer 4b.'''<br> 

[[Image:PTDM fig 3.jpg]]<br>Dissolve the monomer 2 and G3-catalyst&nbsp; in 1 mL DCM each and subject to three freeze-thaw cycles. <br> 

Add the monomer&nbsp; in one shot to the vigorously stirring catalyst solution at room temperature. <br> 

After 60 min, end-capped the living polymer chain&nbsp; with an excess of ethylvinyl ether (1 mL, 754 mg, 10.5 mmol). <br> 

Stir the solution for 2h. <br> 

After evaporation of the solvent, dissolve the crude product in 1mL THF and precipitated in pentane. <br> 

Stir the pentane solution&nbsp; for an additional 15 min and left standing unperturbed for an hour at 0oC. <br> 

Collect the precipitate by a fine sinter funnel to yield product 4a. <br> 

Dissolve polymer 4a&nbsp; in 2 mL DCM and 2 mL TFA for deprotection. <br> 

After stirring overnight, remove the excess acid&nbsp; by azeotropic distillation with methanol. <br> 

After complete evaporation of the acid, dissove samples&nbsp; in water and dialyze against RO water until the conductivity of water is ~0.1 uS. <br> 

Recover&nbsp; deprotected polymers&nbsp; by lyophilization. <br> 

Store the final deprotected polymer 4b from moisture&nbsp; at 4 ºC.<br><br>

== Synthesis of PTDM-2<br><br>  ==

Synthesis of Polymer 5b.

[[Image:PTDM_fig_4.jpg]]<br>Dissolve monomers 2, 3b and G3-catalyst in 1 mL DCM each and subject to three freeze-thaw cycles. 

First, add the monomer 3b&nbsp; in one shot to the vigorously stirring catalyst solution at room temperature. 

After 5 min, add the monomer 2&nbsp; in the reaction mixture as a second block and reacted for 60 min. 

After 60 min, end-capped the living polymer chain with an excess of ethylvinyl ether (1 mL, 754 mg, 10.5 mmol). 

Stir the solution for 2h. 

After evaporation of the solvent, dissolve the crude product&nbsp; in 1mL THF and precipitate in pentane. 

Stir the pentane solution for an additional 15 min and left standing unperturbed for an hour at 0oC. 

Collect the precipitate&nbsp; by a fine sinter funnel to yield product 5a. 

Dissolve the polymer 5a in 2 mL DCM and 2 mL TFA for deprotection. 

After stirring overnight, remove the excess acid&nbsp; by azeotropic distillation with methanol. 

After complete evaporation of the acid, dissolve samples in water and dialyzed against RO water until the conductivity of water was ~0.1uS. 

Recover&nbsp; deprotected polymers&nbsp; by lyophilization. 

Store the final deprotected polymer 5b&nbsp; protected from moisture at 4 ºC.<br> 

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[[Category:Transfection]] [[Category:Paul]]