[Skay]

What type of reaction mechanism are happening and why?

https://ibb.co/LYHSz4F

[Borek]

Please read the forum rules.

You have to show your efforts and attempts at answering the problem to receive help, this is a forum policy.

[Skay]

So for the first reaction I discovered it was a Fischer esterification.
The second one is a substitution.
but the third one im not completely sure:

In this reaction we have a substitution that involves the nucleophilic substitution of the Cl as leaving group with the new molecule as nucleophile, using the H for creating HCl as a side product. 
We are using K2CO3 (potassium carbonate) that will be CO3-2 as base for counter the HCl, DMF as a polar aprotic solvent and temperature (90C) all of them for forcing the chemical equilibrium of the reaction to the right.

[Orcio_87]

@Skay Third reaction is nucleophilic substitution - with amine as nucleophile.

But I would not say that "HCl is side product". Product is clopidogrel hydrochloride, which can be deprotonated - by amine which is used in reaction or some other base - here it is K₂CO₃. Without K₂CO₃ reaction is still possible to do, but it will need more amine (compound 8 ) as source of base.

[Meter]

Why use HCl for Fischer esterification? Wouldn't the high water content of concentrated HCl give a low yield?

[Orcio_87]

@Meter Dimethyl ether or methyl ether of 13 can be side-product if one will use conc. H₂SO₄ instead.

[rolnor]

Its anhydrous HCl, not HCl(aq)

[Meter]

Its anhydrous HCl, not HCl(aq)

Yes, but in the laboratory, how do you use anhydrous HCl? Isn't that a gas at STP?

[rolnor]

Yes, its a gas. You can make a solution in MeOH or EtOH by slowly mixing a little AcCl in the alcohol. Its a powerfull reaction, do it dropvise!

[Meter]

Yes, its a gas. You can make a solution in MeOH or EtOH by slowly mixing a little AcCl in the alcohol. Its a powerfull reaction, do it dropvise!

Thanks. Good to know.

[Guitarmaniac86]

You can even get 4M HCl in anhydrous 1,4-dioxane too! Very useful reagent!