fischer esterification

[emdub27]

I've been lurking around here for a while, this is my first post because it is the first thing I haven't been able to find by searching. Thank you all for the knowledge i have aquired. I have done fina conversions and also syno to test base. I am now interested in the fischer reaction to add esters to test base. I am looking at acetate(just because acs acetic acid is easy to aquire from www.carolina.com. .) propionate and enanthate if I can find someone to sell me propionic and heptanoic or enanthic acid. I have read Chemo's post on adding esters to tren using the fischer reaction and have been told it will work on test. questions are

1) My primary question is when the post states "Reaction must be carried out in the presence of excess amounts of organic acid and also a mineral acid catalyst (HCl or H2SO4). " How much organic acid is considered an excess? i.e. How many ml organic acid (such as acetic) per gram of test?

2) What strength hcl to use? The only acs reagent grade I can find is 12.1M, 38.7% also www.carolina.com

3) What size filter paper to use after precipitation of the esterfied test? www.carolina.com has ahlstrom 74(2.0um), 613(6.0um) and 615(25.0um) they are very reasonably priced and should be way better than coffee filters

4) Are radiation sterilized syringe filters OK? www.carolina.com also lists corning brand syringe filters in 20 and 45 um for $3.00

Thanks Bros. you have already helped me out a lot

[Chemo]

...
1) My primary question is when the post states "Reaction must be carried out in the presence of excess amounts of organic acid and also a mineral acid catalyst (HCl or H2SO4). " How much organic acid is considered an excess? i.e. How many ml organic acid (such as acetic) per gram of test?

2) What strength hcl to use? The only acs reagent grade I can find is 12.1M, 38.7% also www.carolina.com

3) What size filter paper to use after precipitation of the esterfied test? www.carolina.com has ahlstrom 74(2.0um), 613(6.0um) and 615(25.0um) they are very reasonably priced and should be way better than coffee filters

4) Are radiation sterilized syringe filters OK? www.carolina.com also lists corning brand syringe filters in 20 and 45 um for $3.00

Thanks Bros. you have already helped me out a lot

1. Since it is acting as a catalyst anything over a 1:1 molar ratio is excess. The general rule is more catalyst = faster reaction...but even this has a limited return if too much is used. Try not to go above a 2 or 3 over molar ratio to keep the reaction under control and thus produce the highest quality product. Remember, this is eventually going to be injected. You have no room to dick the recipe.

2. Don't be concerned with concentration...be extremely concerned with purity.

3. Pore size does not matter when washing the filter cake. As long as the pores are sufficiently small as to retain active material and allow water to pass freely it will suffice. Also, make sure the medium used is conducive to getting the wet or semi-dry patty off!

4. Yup...and eventual final prep I would use the 20 mic

Chemo

[jmh80]

Good to see you around, Chemo. Thought you were gone for good?

[Chemo]

Bro, I'm never gone for good...always lurking.

[rebelhead]

I've been lurking around here for a while, this is my first post because it is the first thing I haven't been able to find by searching. Thank you all for the knowledge i have aquired. I have done fina conversions and also syno to test base. I am now interested in the fischer reaction to add esters to test base. I am looking at acetate(just because acs acetic acid is easy to aquire from www.carolina.com. .) propionate and enanthate if I can find someone to sell me propionic and heptanoic or enanthic acid. I have read Chemo's post on adding esters to tren using the fischer reaction and have been told it will work on test. questions are

1) My primary question is when the post states "Reaction must be carried out in the presence of excess amounts of organic acid and also a mineral acid catalyst (HCl or H2SO4). " How much organic acid is considered an excess? i.e. How many ml organic acid (such as acetic) per gram of test?

2) What strength hcl to use? The only acs reagent grade I can find is 12.1M, 38.7% also www.carolina.com

3) What size filter paper to use after precipitation of the esterfied test? www.carolina.com has ahlstrom 74(2.0um), 613(6.0um) and 615(25.0um) they are very reasonably priced and should be way better than coffee filters

4) Are radiation sterilized syringe filters OK? www.carolina.com also lists corning brand syringe filters in 20 and 45 um for $3.00

Thanks Bros. you have already helped me out a lot

You can make glacial acetic acid from vinegar. I would not order acetic anhydride. Any amount ordered is reported. It is definately on the watched list.

[jmh80]

Why is anhydride reported?

[rebelhead]

Why is anhydride reported?

It can be used in the manufacture of just about every recreational drug known to man. It is the main reagent used to make heroin(diACETYLmorphine).

[jmh80]

Interesting. I worked at a chem. plant that used anhydride as the reactant with wood pulp.

[rebelhead]

Interesting. I worked at a chem. plant that used anhydride as the reactant with wood pulp.

Well acetic anhydride would be the prefered reagent in the esterfication of the OH group in steroid molecules, since the reaction goes to completion with the anhydrides and equalibrium with the others. This process is pretty basic as far as chemical reactions go and most organic chemistry text books would have the basic reaction for this outlinned within it under esterfication of alcohols.

[boby-at]

hm does this process do not alter the stereoconfiguration (alpha/beta)

[CROWLER]

Bro, I'm never gone for good...always lurking.

You still lurking?