Write structures for the products of the following...

Write structures for the products of the following reactions: (a) $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{2} \mathrm{OH}+\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{N}=\mathrm{C}=0 \longrightarrow$ (b) $\mathrm{ClCOCl}+\mathrm{CH}_{3} \mathrm{NH}_{2}$ (excess) $\longrightarrow$ (c) Glycine $\left(\mathrm{H}_{3} \mathrm{NCH}_{2} \mathrm{CO}_{2}^{-}\right)+\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{2} \mathrm{OCOCl} \stackrel{\mathrm{HO}^{-}}{\longrightarrow}$ (d) Product of $(c)+H_{2}, P d \longrightarrow$ (e) Product of $(c)+H B r\left(\text { cold) }, C H_{3} C O_{2} H \longrightarrow\right.$ (f) Urea $+\mathrm{HO}^{-}, \mathrm{H}_{2} \mathrm{O},$ heat

Write structures for the products of the following reactions:
(a) $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{2} \mathrm{OH}+\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{N}=\mathrm{C}=0 \longrightarrow$
(b) $\mathrm{ClCOCl}+\mathrm{CH}_{3} \mathrm{NH}_{2}$ (excess) $\longrightarrow$
(c) Glycine $\left(\mathrm{H}_{3} \mathrm{NCH}_{2} \mathrm{CO}_{2}^{-}\right)+\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{2} \mathrm{OCOCl} \stackrel{\mathrm{HO}^{-}}{\longrightarrow}$
(d) Product of $(c)+H_{2}, P d \longrightarrow$
(e) Product of $(c)+H B r\left(\text { cold) }, C H_{3} C O_{2} H \longrightarrow\right.$
(f) Urea $+\mathrm{HO}^{-}, \mathrm{H}_{2} \mathrm{O},$ heat

Key Concepts

Isocyanate Reactivity

Isocyanates possess a highly electrophilic carbon atom due to the adjacent nitrogen and oxygen atoms, making them prone to nucleophilic attack. When a nucleophile such as an alcohol attacks, the result is the formation of a carbamate linkage, a process that underpins the synthesis of urethanes and various protective groups in organic synthesis.

Carbamate Formation

Carbamate formation involves the reaction of an alcohol with an isocyanate to yield a urethane or carbamate ester. This transformation is a key strategy for constructing protected amino groups in synthesis and is widely used in the development of pharmaceuticals and polymers.

Phosgene Reactivity

Phosgene is a reactive acid chloride that can react with nucleophilic amines to form intermediate carbamoyl chlorides. In the presence of excess amine, these intermediates typically lead to urea derivatives. This reaction showcases the utility of acid chlorides in constructing carbonyl-based functional groups in organic chemistry.

Amine Protecting Groups (Cbz Protection)

Protecting groups like the benzyloxycarbonyl (Cbz) group are used to temporarily mask the reactivity of amines during multi?step synthesis. The installation usually involves the reaction of an amine with a chloroformate derivative, forming a stable carbamate which can be selectively removed later, providing chemoselectivity in complex syntheses.

Catalytic Hydrogenolysis

Catalytic hydrogenolysis is a reduction technique that utilizes hydrogen gas in the presence of a metal catalyst, such as palladium, to cleave benzyl-type protecting groups. This mild deprotection method is particularly valuable because it can remove protecting groups without affecting other sensitive functional groups in the molecule.

Acid-Catalyzed Benzyl Cleavage

Acid-catalyzed benzyl cleavage is an alternative deprotection strategy that employs acid, often under cold conditions, to remove benzyl-based protecting groups. This method is useful when hydrogenation conditions are unsuitable, allowing for selective deprotection in sensitive molecular contexts.

Urea Hydrolysis

Under basic conditions and heat, urea undergoes hydrolysis, a reaction that cleaves the carbon-nitrogen bonds to generate ammonia and carbonate or related species. This process illustrates the susceptibility of certain amide bonds to nucleophilic attack in a strongly basic environment, a principle that is important in both synthetic organic chemistry and biochemical pathways.

Transcript

00:01 Okay, so we're going to get the products with following reactions.

00:02 In the first one, we have proponellic acid with ammonia, and this is done with heat.

00:23 Okay, so the carbostolic acid has a lower pga than ammonia, so it's going to be heaped more as an acid, and ammonia is then going to donate a pair of electrons to form a bond with the hydrogen of propanolc acid, and this is really the only hydrogen it can grab.

00:41 It can't get any from over here.

00:49 The electrons get back to the oxygen, because it's more than the oxygen, because more than the oxygen.

00:51 Oxygen negative so we're going to get this structure and we also have nh4 as well so in the presence of heat at around 200 degrees up 200 degrees celsius we're actually going to get a carbosal acid i mean a um it an amide so if we drop the oxygen and just add this nh2 group we're going to have the loss of water as well see two hydrogens from uh nh4 then the oxygen from the conjugate base of propinoc acid next one is this amide with water and heat so we have a four carbon amide so again a minus this c -o -n -h or c -o -n function group that should be attached to two hydrogens or some r groups but um the amine is more basic than water it's going to depertinate water we're gonna get nh3 which is a weak base so it's a good leaving group but we're also gonna get hydroxide which is a strong base and once that occurs it's going to attack the carbonil carbon and once we get the alkoxid ion it's going to reform the old bond the oxygen to expel ammonia because again it's a weak base so it's a good leaving group so you addition of this ohage group that and we'll get ammonia as a side product x1 is a four carbon ester with sodium hydroxide and heat okay so sodium nitroxide is a strong base and it's going to attack the carbon of carbon directly...

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