Editing Synthesis Lipophilic Polyamines (section)

=== <br>'''2-bromoacetamido-olean:'''<br>  ===

1. Haloacetamido-alkane or alkenes:&nbsp;'''Oleylamine''' (18C, 油胺,十八烯胺, MW 267.49, 70% from Aldrich,0.813g/ml,&nbsp; O-7805-500g), palmitylamine (16 C), stearylamine (18C) is reacted with chloroacetic chloride or chloroacetic bromide or bromoacetic chloride or&nbsp;'''bromoacetic bromide''' (MW 201.84, 2.317g/ml) in the presence of a '''triethylamine''' (TEA) base in '''Dichloromethane''' '''CH2Cl2'''. The resulted N-haloacetamido-alkane or alkenes is purified by chromatograph on '''silica gel''' ('''Hexane''':'''ethyl acetate''' 15:85).&nbsp; 

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Inside a chemical hood because Bromoacetyl bromide is a lachrymator. Excessive amount of moisture in the glassware or reactants will result in a low yield.

Add&nbsp;Oleylamine (267.49/(0.7*0.813*1000)==0.47 ml==&gt; 1 mmole) to dry dichloromethane (2 ml), add triethylamine (0.14 ml, 1 mmol) on ice. <br>

Add bromoacetyl bromide (201.84/(0.98*2.317*1000), 89 ul--&gt; 1 mmole)&nbsp; in 0.5 ml of dichloromethane (ice-cold) to Oleylamine solution on ice dropwise <strike>over 20min</strike> using a glass microsyringe

Stire for a further30 min&nbsp; on ice.<br>

React o/n at room temperature.<br>

Transfer the mixture to a separatory funnel. Add 20 ml of dichloromethane and wash the organic phase with two 10 ml portions of 1 M aqueous HCl, then with 10 ml of a saturated solution of NaHCO3 and finally with 10 ml of water.<br>

Dry the organic phase in an Erlenmeyer flask with anhydrous sodium sulfate. Add approx 5 g of anhydrous sodium sulfate&nbsp;to the solution in the flask, swirl it and then allow to stand for 5 min. Remove sodium sulfate by gravity filtration using a glass funnel and fluted filter paper. <br>

Concentrate under reduced pressure. Evaporate the solvents under vacuum at 40 °C using a rotary evaporator.<br>

Purify the crude product&nbsp; by chromatography on silica gel: Pack a chromatography column (3 cm i.d. times 30 cm length) with silica gel (30 g) and wash with dichloromethane under pressure until no air is present in the silica gel. Load the product dissolved in a small amount of dichloromethane (1–2 ml) on top of the column and allow it to soak into the column. Then elute the column with dichloromethane under a slight pressure and collect 10 ml fractions. <br>

Identify fractions containing the product using thin-layer chromatography (TLC; retention factor of the product using dichloromethane as an eluent (Rf) = xx).

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Reaction type: Nucleophilic Acylation<br> 

[[Image:Bromoacetyl bromide.png]]+ [[Image:Oleylamine.png]]--&gt; 

[[Image:2-bromoacetamido-olean.png]]<br> 

'''Bromoacetyl bromide''': http://www.sigmaaldrich.com/catalog/product/aldrich/b56412, B56412-5G, $36.20, B56412-100G, $64.70, B56412-500G $143.00<br> 

Alfa Aesar BROMOACETYL BROMIDE 98+% 500 g bottle A19580-36 $86.98 https://us.vwr.com/store/catalog/product.jsp?catalog_number=AAAA19580-36,&nbsp; <br> <br><br> 

'''Oleylamine''': http://www.sigmaaldrich.com/catalog/product/aldrich/o7805, O7805-5G, $32.60, O7805-100G, $36.10, O7805-500G, $111.50<br> 

TCI America&nbsp;: https://us.vwr.com/store/catalog/product.jsp?catalog_number=TCO0059-500ML 500 mL O0059-500ML TCO0059-500ML (500ml) $59.93<br> 

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2. Acryloylamido alkane or alkenes: Oleylamine is treated with acryloyl chloride in the presence of TEA in CH2Cl2. The resulted acryloylamido-olean is purified by chromatograph on silica gel (Hexane:ethyl acetate 10:90).<br><br> 

3. 1,2-epoxy-3-cis-9-octadecenoxypropane (or oleyl glycidyl ether): Oleyl alcohol in DMSO is treated with crushed KOH pellet and two molar excess of epichlorohydrin at 60° C. for 48 hrs. The resulted epoxypropy oleyl ether is purified by chromatograph on silica gel (Hexane:ethyl acetate 10:90).<br><br> 

4. Other lipid derivatives with a nucleophilic reacting group could also be readily prepared including: reacting iodoacetic chloride, chloroethyl chloroformate, or 2-chloroethyl isothiocyanate with an alkyl or alkenyl amine;<br><br> 

5. Alternatively, 2-chloroethylamine or 2-bromoethylamine reacts with a long chain fatty acid, such as oleic acid, either with the activated acyl chloride or by a dehydrating agent. Commercially available alkyl iodine, bromide, or chloride can also been used. 

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6.&nbsp; Synthesis of Lipophilic Polyamines Using Haloacetamido Olean 

Add '''Polyamine '''(0.1 mmole) in ethanol to '''haloacetamido alkane or alkene''' at varied molar ratio of amino nitrogen to alkylating lipid derivative, followed by 1 equivalent of '''Na2CO3''' to alkylating agents dissolved in small amount of water. Heat the solutions to '''70° C. '''The progress is monitored by TLC test and is completed at the end of '''24-48 '''hrs based on the total consumption of the alkylating agents. The resulted polyamine derivatives are obviously a mixture of analogous with different numbers of lipid chains linked to the polyamine. After evaporation of the solvent, the resulted lipidic polyamines is dissolved in '''methanol-CHCl3''' (1:1 vol/vol) at a concentration of 20 mM according to the original polyamine and stored at −20° C.<br><br> 

7. Synthesis of Lipophilic Polyamines Using Oleyl Glycidyl Ether 

Polyamine (0.1 mmole) in ethanol is added with '''oleyl glycidyl ethe'''r at varied molar ratio of amino nitrogen to alkylating lipid derivative. The solutions are heated to 70° C. The progress is monitored by TLC test and is completed at the end of 48 hrs based on the total consumption of the alkylating agents. The resulted polyamine derivatives are obviously a mixture of analogous with different numbers of lipid chains linked to the polyamine. After evaporation of the solvent, the resulted lipidic polyamines are dissolved in methanol-CHCl3 (1:1 vol/vol) at a concentration of 20 mM according to the original polyamine and stored at −20° C.<br> 

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8. Synthesis of Lipophilic Polyamines Using Acryloylamido-Olean 

Polyamine (0.1 mmole) in ethanol is added with '''acryloylamido-olean''' at varied molar ratio of amino nitrogen to alkylating lipid derivative. The solutions are heated to 70° C. The progress is monitored by TLC test and is completed at the end of 48 hrs based on the total consumption of the alkylating agents. The resulted polyamine derivatives are obviously a mixture of analogous with different numbers of lipid chains linked to the polyamine. After evaporation of the solvent, the resulted lipidic polyamines are dissolved in methanol-CHCl3 (1:1 vol/vol) at a concentration of 20 mM according to the original polyamine and stored at −20° C.<br> 

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9. '''Bromoacetyl lipid-derivative''' can also be conjugated to the polyamines at room temperature, for example 20 oC to 35 oC, at a ratio of lipid to polyamine of 1:1 to 6:1 in methanol for example. Reaction can be completed after 48 hours for example. No additional base is needed.<br> 

In terms of reactivity, the '''haloacetamido compounds are more reactive than epoxy or acryloylamido lipid derivative,''' as the later two require considerable longer reaction time to reach completion at the same reaction temperature than the haloacetamido compounds. Both bromo and chloride derivative are reactive enough under the condition. The bromo compound yielded darker color than the chloro compound, both as lipid intermediates or after reaction to produce lipopolyamines. 

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the reaction by alkylation at elevated temperature is expected to be random modification and the end products should be a mixture of lipopolymers with varied numbers of lipid chains conjugated to the amino groups. Some NH2 may be unmodified; while others may be conjugated with two or three lipid chains. However, it is expected that under the condition that was used, the majority of the lipopolymer should contain a total number of the lipid chains close to the initial ratio of amine to lipid intermediate. As it is difficult to purify individual species of the lipopolycations, the end product was used as is, without purification. However, using known purification methods, such as phase partition, vacuum distillation, size exclusion, ionic exchange or hydrophobic interaction chromatography. 

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