How would you calculate theorectical yield? And a detailed mechanism for 1,4-dih

Question

How would you calculate theorectical yield?

And a detailed mechanism for 1,4-dihydropyridine formation

Place the following in a 25-mL round-bottomed flask equipped with a magnetic stir bar: methyl acetoacetate (810 mu L) OR ethyl acetoacetate (960 mu L); ammonium acetate (430 mg) and 36% wt. aqueous formaldehyde (280 mu L). Add all liquid reagents with an automatic delivery pipette. Clamp the flask in a room-temperature water bath, attach an air condenser, and heat the mixture gradually to 80degree C with vigorous stirring. After 10 minutes at 80degree C stirring will stop due to accumulation of solid product. Once this occurs, remove the flask from the water bath. Add 5 mL of distilled water to the flask and use a glass rod to break up the solid product and grind it into a fine powder. Isolate the crude product via vacuum filtration and wash thoroughly with distilled water (10 mL). Recrystallize the crude solid product from 95% ethanol (use a 50-mL Erlenmeyer flask). Let the flask cool to room temperature and then place in an ice bath for 10 minutes to ensure complete precipitation. Isolate the purified solid via vacuum filtration. Weigh and calculate the percentage yield for the reaction. Take appropriate physical measurements (mp, IR,^1H,^13C NMR spectra) to ascertain the purity of your compound, comparing with literature data where possible.

Explanation / Answer

I'm not very sure of the reaction you are taking place, therefore, I cannot give you the detailed mechanism, however I can tell you how you can calculate the theorical yield.

1. With the volumes you have, convert that into mass (use the densities values of those reactants): m = d*V. The volume should be in mL (or cm3 which is the same).
2. With the masses obtained, calculate the number of moles of each reactant (moles = m/MW). Look for the molecular weight of each reactant.
3. Determine the limiting reactant, by stechiometry of the reaction. the limiting reactant will tell you how many moles of the product desired you are producing (If the relation of reactant:product is 1:1 then the moles of limiting reactant will be equal to the mole of product)
4. With the moles previously obtained from the limiting reactant, calculate the mass of product (m = moles * MW) and look for the molecular weight.

Then with this, the theorical yield is calculated.

Hope this helps

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