BaSO4 in hydrogenation ( continuation)

[java]

A continuation of  BaSO4 Hydrogenation......

Post 359159 (missing)

(Chicken: "BaSO4 in hydrogenation", Stimulants)

I have one question , is the method now documented throughout the thread and verified by someone's continous dream for 17 years WizardX work on a aromatic primary alcohol, namely R-Phenylalaninol ......I would like to skip the chlorination (halogenation ) procedure  if at all possible and reduce to the alkane........java

[UncleFester]

check out

Patent US6399828

. They also explain why my method for hydrogenation gives a low octane product...the sulfate salt of ephedrine...pseudo...etc is not very suitable, and gives about 14% conversion. Check it out..it's a good read, and confirms my idea that the hydrogenolysis of the acetic ester is the best way to go, but they got it right...but they took more than one crack at it, and didn't have to do cop dodging while playing. Excellent patent.

[java]

I saw this one sometimes back [

Post 367468

(Regis: "The most interesting CTH reaction ever documented?", Novel Discourse)]but never thought it may be used on the reduction of the phenylalaninol to the amphetamine, I will read it closer.....thanks , ...java

[UncleFester]

read closely...it's good.

[WizardX]

pseudoephedrine acetic ester is best made with acetic anhydride. Acetic anhydride is a powerful acetylating reagent and will give excellent yields of pseudoephedrine acetic ester. Acetyl chloride is another powerful acetylating reagent.

pseudoephedrine + GAA + H2SO4 gives pseudoephedrine sulphate ester + some pseudoephedrine acetic ester.

The sulphate ester is not a good leaving group compared to the perchlorate, acetic, phosphate pseudoephedrine esters.

[java]

I have one question , is the method now documented .....  work on a aromatic primary alcohol, namely R-Phenylalaninol ......I would like to skip the chlorination (halogenation ) procedure  if at all possible and reduce to the alkane.......

I guess my initial question remains unanswered, although looking back at Regis

Post 367468

(Regis: "The most interesting CTH reaction ever documented?", Novel Discourse)original posting of 

Patent US6399828

,  as suggested by UncleFester gave me hope but I think I see, not sure however, why it won't work on my particular project.

pseudoephedrine acetic ester is best made with acetic anhydride. Acetic anhydride is a powerful acetylating reagent and will give excellent yields of pseudoephedrine acetic ester. Acetyl chloride is another powerful acetylating reagent.

pseudoephedrine + GAA + H2SO4 gives pseudoephedrine sulphate ester + some pseudoephedrine acetic ester.

The sulphate ester is not a good leaving group compared to the perchlorate, acetic, phosphate pseudoephedrine esters.

This procedure is the one I was questioning .....thanks WizardX is this primarily for Benzyl alcohol's or can it be applied to a primary aliphatic arene alcohol?

I have some concerns about the method affecting the unprotected -NH2 in my phenylalaninol alcohol. Since on the application with both ephedrine and Pseudoephedrine the _NH2 group has a CH3 giving it some shield against some reactivity with the acetic anhydride although slight since it's a very acidic environment.......java

[UncleFester]

The procedure I used to make the acetic acid ester was to heat ephedrine with acetic acid plus some sulfuric acid, and that was the ruination of the method...along with using sulfuric acid as the electrolyte for the catalytic hydrogenation. That guaranteed that ALL of the ephedrine would be in the form of the sulfate salt. The patent does clear up this matter, and gives good directions for making the ester from acetic anhydride, along with a few methods of hydrogenation. The one using ammonium formate as the hydrogen donor to the Palladium is especially interesting. It is well known that attmpting to hydrogenate sulfate esters is a losing deal, but the info that the sulfate salt of the ephedrine only gives 14% conversion is very useful news.

[readyeddie]

Would the sulfuric drops still be needed to form the ester with the anhydride?

Would a few ml's of glacial help the yeilds any?

Time to dig out that ingot and the sodium borohydride:)

[UncleFester]

They used ephedrine plus acetic anhydride in acetic acid solvent.

[readyeddie]

[WizardX]

This procedure is the one I was questioning .....thanks WizardX is this primarily for Benzyl alcohol's or can it be applied to a primary aliphatic arene alcohol?

Java: I see no reason why not? Another route is to chlorinate the primary aliphatic arene alcohol, then use this procedure,

http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0650

[java]

WizardX .....as I been spending lots of time to break the curse of Phenylalanine, reading through the archives I ran into this reference..... I included the study but can also be read in

Post 523004

(java: "Hydrogenolysis of Phenylalaninol.....", Serious Chemistry)
Hydrogenolysis of Diaryl and Aryl Alkyl Ketones and Carbinols by sodium Borohydride and anhydrous Aluminum(III) chloride

AoiOno, Nobuko Suzuki, Junko Kamimur

as it can be used to reduce the ephedrine, pseudoephedrine and phenylpropanolamine to their respective hydrocarbon.......thanks to psychokitty for the reference......java

[WizardX]

Phenylalaninol synthesis routes.

http://www.orgsyn.org/orgsyn/prep.asp?prep=v76p0110

http://www.orgsyn.org/orgsyn/prep.asp?prep=cv7p0530

Reduction of the -CH2-OH to -CH3 on the phenylalaninol can be done as discussed with HI/RP, catalytic hydrogenation, or other reductive reagents.