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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: sotirone on September 06, 2021, 03:21:19 AM

Title: Morphine acetylation to Heroin. Why not acetic chloride?
Post by: sotirone on September 06, 2021, 03:21:19 AM

Hello, I am studying for my exam and I have a question my professor has not explained.

She insists that to get Heroin from Morphine we have to use acetic anhydride instead of acetic chloride.
Numerous sources online claim that you can get Heroin from Morphine using acetic chloride but she does not agree.

The question that she may ask on the topic is why can't acetic chloride be used for the preparation of Heroin.

Any ideas?

Title: Re: Morphine acetylation to Heroin. Why not acetic chloride?
Post by: rolnor on September 06, 2021, 05:49:33 AM

It seems as if your professor is wrong, there is no reason you can not use acetyl chloride. You need to be carefull, ice-bath, pyridine, dichloromethane. Acetic anhydride is more simple, just dissolve and boil for a few minutes.

Title: Re: Morphine acetylation to Heroin. Why not acetic chloride?
Post by: rolnor on September 06, 2021, 01:56:14 PM

Its technically a transformation of drugs. But you are right, we should not discuss that here.

Title: Re: Morphine acetylation to Heroin. Why not acetic chloride?
Post by: Borek on September 06, 2021, 02:10:58 PM

OK by my book. We don't discuss recipes, but the chemistry behind reaction, especially without precise practical details, is OK.

Acylation is not in any particular way specific to drugs, it is just one of standard procedures used in organic chemistry.

Title: Re: Morphine acetylation to Heroin. Why not acetic chloride?
Post by: sotirone on September 08, 2021, 02:18:50 PM

She looks to be wrong but I have to find a suitable answer.

Could the answer be that, because morphine is highly basic, the acyl chloride can turn to a ketene?

Title: Re: Morphine acetylation to Heroin. Why not acetic chloride?
Post by: rolnor on September 08, 2021, 03:02:24 PM

Thats why I suggest keeping the reaction cold, and you are right, it will be ketene if to warm. If you dissolve it in acetyl chloride at roomtemp it will be a mess.

Title: Re: Morphine acetylation to Heroin. Why not acetic chloride?
Post by: Meter on September 10, 2021, 11:48:44 AM

Is she mistaking acetyl chloride for something else?

Title: Re: Morphine acetylation to Heroin. Why not acetic chloride?
Post by: wildfyr on September 16, 2021, 08:18:13 PM

Draw her the arrow push and ask to show what step is not possible.