Amide Coupling Reaction for the Synthesis of Bispyridine-based Ligands and Their Complexation to Platinum as Dinuclear Anticancer Agents

The overall goal of this procedure is to synthesize multi nuclear platinum anti-cancer complexes based on the structural characteristics of the drug's PPL and BBR 34 64. This is accomplished by first synthesizing bis paridine bridging ligands through the conjugation of iso nic acid and a di amino alkane using an amite coupling reaction. The second step is to re crystallize the ligand from hot water.

Next, the ligand is coordinated to platinum by reaction with trans diamine di chloro platinum.Two. The final step is purification of the metal complexes by fractional precipitation from water using acetone. Ultimately, successive amide coupling and platinum coordination is observed most definitely using proton nuclear magnetic resonance spectroscopy.

The application of this technique is in the design and synthesis of new anti-cancer drugs. We've done this through the combination of particular characteristics of different platinum agents. Generally, individuals new to this research area will struggle with the chemical characterization, particularly how the ligand peaks and the proton NMR change chemical shift and shape upon platinum coordination.

First, dry a three neck, round bottom flask in an oven at 100 degrees Celsius for one hour to ensure that all moisture is removed. Once the flask has cooled to room temperature at 0.5 moles of solid iso acid, in this case, one 10 D amino acan, along with a magnetic stirring bar, cap the necks of the flask with rubber septa and replace the air in the flask with nitrogen through the use of a nitrogen filled balloon. Using a hypodermic needle and syringe, add four to eight milliliters of anhydrous dimethyl sulfoxide to dissolve the solids.

If the solids don't dissolve easily, then heat the solution gently under a stream of running hot water. Next, add seven mole equivalents of triethylamine to the flask. Add one mole of one propyl phospho anhydride, and stir the reaction mixture for five to 12 hours at room temperature for bis perine ligands made using dia amino alkane ligands with 10 or more methylene groups wait for the product to precipitate from solution as the reaction progresses.

Following this, collect each bis paridine ligand by vacuum filtration using a bookner funnel and flask. After transferring the ligand to a beaker, we crystallize the crude material using approximately 400 to 500 milliliters of boiling water per 200 milligrams of ligand. Once the ligand has completely dissolved, add potassium hydroxide to the cooled solution to ensure that the compounds are free bases upon rech crystallization.

Then place the solution in the refrigerator to maximize rech crystallization. At this point, add transat and water to a beaker. Heat the solution to 70 to 80 degrees Celsius to fully dissolve the transplant and produce a clearly strong yellow colored solution.

Add 0.5 moles of the bis perine ligand and stir the solution at temperature until the ligand dissolves to afford a clear solution. After the solution is nearly colorless, turn off the heat and stir at room temperature overnight. Once the reaction is complete, remove the solvent by rotary evaporation teal a yellow colored powder following this, purify the platinum complex by dissolving it in a minimum amount of 50 degrees Celsius water.

Add acetone to the solution until a white precipitate is formed, which appears to be a polymeric form of the metal complex and represents up to 10%of the reaction product. Add an additional 20 to 30 milliliters of acetone until no more precipitate is observed. Remove this precipitate by filtering the contents through a 0.2 micron nylon filter paper under vacuum.

After transferring the solution to a round bottom flask concentrated by rotary evaporation, which will yield a pure product. The bis perine ligands and their respective dinu nuclear platinum complexes are characterized by proton carbon and platinum NMR and electro spray ionization mass spectroscopy. In particular, proton NMR shows resonances that can definitively demonstrate successful amite coupling and platinum coordination.

As the dino alkane chain length increases, many of the methylene resonances become equivalent and fewer peaks are observed due to symmetry in NN prime octane one eight dial bis ISO amide five allophatic resonances would be expected, but the four inner methylene peaks are magnetically equivalent and appear as one resonance around 1.2 ppm. The Amin proton resonance of the uncoupled D amino acan chain is located in the atic region and moves significantly downfield upon coupling to the carboxylic acid. The subsequent amide proton resonance is seen around 8.7 PP M as a relatively broad triplet platinum group.

Coordination to the BIS perine ligands is observed through a downfield shift of the ha resonances and an upfield shift of the HB resonances. Further confirmation of coordination is the observance of platinum coupling on the doublet resonance for the HA protons platinum group. Coordination to the BIS perine ligand can also be observed using platinum NMR.

The Dinu nuclear platinum complexes show a resonance around negative 2300 PP M due to the amino and chloro coordination state. Using this procedure, other amide coupling reactions can be used to generate a large family of new ligands that can be used to synthesize not only dinu nuclear, but tri nuclear platinum drugs.