Hello, this is my first post. I am a biochemist who is well versed in synthetic organic chemistry. I only have a limited knowledge about the use of anabolics as bodybuilding and fitness supplements (although it seems very interesting) but a friend of mine requested my help because apparently a lot of the testosterone on the market today is of doubtful quality, which doesn't surprise me as it comes mostly from China. The Chinese have a very bad reputation when it comes to practically every product they make. I'm not only thinking about impure products, but several analyses of Chinese products over the years, including their pharmaceutical preparations, have shown the presence of dangerous levels of heavy metals (lead, mercury) and contamination with unrelated pharmaceuticals such as cortisones or Viagra.
My friend showed me this write-up of a two-step synthesis of testosterone from DHEA:
https://thinksteroids.com/community/threads/process-of-making-testosterone.134361616/#post-1190547
This write-up is a bit dodgy as it appears to be a synopsis of the chemical literature that have DHEA as precursor or reactant, written by someone who has not done any of this. The first step (reduction of DHEA with sodium borohydride) seems real enough, but the second step I don't believe for a minute that is was actually performed as stated. And everything after that is shoddy, like it was copy/pasted from a patent and adapted by someone who is overly enthousiast.
There is only one way to confirm it, and that is to repeat the preparation, which is what I will report here now.
The first step, the reduction of DHEA with NaBH4 in neutral solution, proceeds as advertised with very high molar yield (>90%). The only difference is that I used ethanol instead of methanol, as it is a much better solvent for DHEA (only half the volume is required), the 5-androstenediol is also removed by filtration:
The product was sufficiently pure to use as is in the next step, but I still made two recrystallisation attempts, using ethanol (methanol is preferred according to the Merck Index) and using acetone/petroleum ether.
The next step is where the "recipe" is false. First it is claimed that activated MnO2 is prepared by boiling ceramics grade manganese dioxide in nitric acid, which is only partially true. Then the author recommends a very shoddy, very unhealthy/dangerous preparation of concentrated nitric acid in the gaseous phase, which he admits he didn't try, but instead he "activated" his pottery grade MnO2 by refluxing with benzene. Here I know he is lying, as this is utterly impossible, and he confuses the preparation of an active form of MnO2 with drying it using benzene (which forms an azeotrope with water, thus efficiently removing it). Next to all this, he performs the oxidation in possibly the worst solvent: pure (glacial) acetic acid. Not only is this a bitch to remove outside laboratory conditions, it smells, it's corrosive and a bad choice for these type of oxidations.
First: about the pottery grade manganese dioxide (pyrolusite). This is a very impure product consisting mostly of beta-MnO2. At least 6 different structural modifications of MnO2 exist, which have a severe impact on reactivity. The pottery grade, beta-MnO2, is the least active and therefore seldomly used as a reagent. We need gamma-MnO2, a partially hydrated and the most reactive form suitable for this type of oxidation (oxidation of allylic alcohols). It is true that "spent" gamma-MnO2 (what is filtrated off after the reaction) can be re-used by re-activating with dilute nitric acid, but this will not turn pottery grade beta-MnO2 into gamma-MnO2. The latter must be prepared beforehand, but luckily the necessary reagents can also be had from the ceramics supply store: potassium permanganate (KMnO4) and manganese sulfate (MnSO4):
The choice of solvent is important and has an impact on the rate of oxidation. Non-polar solvents are preferred, usually chloroform or dichloromethane is the solvent of choice in the existing literature on the type of oxidations. Alternatively acetone, petroleum ether, benzene and diethyl ether can be used. Benzene seems to give consistently lesser yields. Acetic acid is far too polar and a bad choice for these type of reaction. Best would be diethyl ether or petroleum ether. Acetone seemed not the obvious choice, but I have tried it and it seems to give similar results as chloroform. The advantage is that acetone is cheap and readily available and has a low boiling point and is easily removed. Technical grade acetone from the hardware store is ok, I re-use my solvents by destilling instead of evaporating.
Quoted from Quart. Rev. 1959 review on MnO2 oxidations:
The rule is easy as to the proportions of substrate, reagent and solvent to be used: (by weight) 1 part 5-AD, 10 parts gamma-MnO2 and (by volume) 100 parts of acetone. What is most essential to the reaction rate, is the efficiency of stirring. The author of the "recipe" says 6-10 h in acetic acid, he notes "you won't over oxidize since exact molar equivalents are used". First off, you can't overoxidise, simply because the reactivity of MnO2 is limited to oxidising allylic alcohols (eg. 5-AD) to the corresponding unsaturated aldehyde/ketone (eg. testosterone). Even if you use 50 equivalents, testosterone will be the only product as its oxidation potential is selective (at room temperature of course). Secondly, the rate of oxidation is heavily influenced by the rate of stirring. As this is a heterogenous reaction (solid reagens + solution of reactant), stirring permits a constant change in surface of the MnO2 and permits the unoxidised 5-AD in solution to contact fresh dioxide surface continuously. To compare: an oxidation can be over after 24 hours strong stirring while the same yield is obtained after 6-12 days when the mixture was allowed to stand and was shaken by hand a couple of times every day.
To conclude: the two-step synthesis of testosterone from DHEA is indeed simple and straight-forward, and can be performed outside a lab setting -taking into account of course, adequate safety measures- but I would not recommend anyone without a basic grasp of chemistry and a minimum practical lab experience to perform this as a first synthesis.
I include with this post the papers I used when researching the subject.
My friend showed me this write-up of a two-step synthesis of testosterone from DHEA:
https://thinksteroids.com/community/threads/process-of-making-testosterone.134361616/#post-1190547
This write-up is a bit dodgy as it appears to be a synopsis of the chemical literature that have DHEA as precursor or reactant, written by someone who has not done any of this. The first step (reduction of DHEA with sodium borohydride) seems real enough, but the second step I don't believe for a minute that is was actually performed as stated. And everything after that is shoddy, like it was copy/pasted from a patent and adapted by someone who is overly enthousiast.
There is only one way to confirm it, and that is to repeat the preparation, which is what I will report here now.
The first step, the reduction of DHEA with NaBH4 in neutral solution, proceeds as advertised with very high molar yield (>90%). The only difference is that I used ethanol instead of methanol, as it is a much better solvent for DHEA (only half the volume is required), the 5-androstenediol is also removed by filtration:
In an Erlenmeyer flask of suitable size, 10 gr DHEA was dissolved in 200 ml 93% ethanol (denatured with diethyl ether) with continous stirring on a magnetic stirrer and the flask was placed in a cold waterbath (no ice was necessary). 2.5 gr NaBH4 was added in small portions over the course of 30 minutes, carefully monitoring the temperature, which never rose above 25°C. After a short while 5-androstene-3,17-diol precipitated, another 50ml ethanol was added to facilitate stirring, and the mixture was stirred for another hour. 50ml distilled water was added and the mixture was filtrated. The cake of white crystals was washed well three times with warm distilled water (60°C) to remove borate salts, once with a small amount of cold ethanol, it was sucked as dry as possible (using a Buchner vacuum filtration setup and a refrigerator compressor as the vacuum pump) and dried in an oven at 80-90°C. Yield: 9.2 grams
The product was sufficiently pure to use as is in the next step, but I still made two recrystallisation attempts, using ethanol (methanol is preferred according to the Merck Index) and using acetone/petroleum ether.
The next step is where the "recipe" is false. First it is claimed that activated MnO2 is prepared by boiling ceramics grade manganese dioxide in nitric acid, which is only partially true. Then the author recommends a very shoddy, very unhealthy/dangerous preparation of concentrated nitric acid in the gaseous phase, which he admits he didn't try, but instead he "activated" his pottery grade MnO2 by refluxing with benzene. Here I know he is lying, as this is utterly impossible, and he confuses the preparation of an active form of MnO2 with drying it using benzene (which forms an azeotrope with water, thus efficiently removing it). Next to all this, he performs the oxidation in possibly the worst solvent: pure (glacial) acetic acid. Not only is this a bitch to remove outside laboratory conditions, it smells, it's corrosive and a bad choice for these type of oxidations.
First: about the pottery grade manganese dioxide (pyrolusite). This is a very impure product consisting mostly of beta-MnO2. At least 6 different structural modifications of MnO2 exist, which have a severe impact on reactivity. The pottery grade, beta-MnO2, is the least active and therefore seldomly used as a reagent. We need gamma-MnO2, a partially hydrated and the most reactive form suitable for this type of oxidation (oxidation of allylic alcohols). It is true that "spent" gamma-MnO2 (what is filtrated off after the reaction) can be re-used by re-activating with dilute nitric acid, but this will not turn pottery grade beta-MnO2 into gamma-MnO2. The latter must be prepared beforehand, but luckily the necessary reagents can also be had from the ceramics supply store: potassium permanganate (KMnO4) and manganese sulfate (MnSO4):
In a 6L beaker placed on a hotplate/magnetic stirrer 105 gr KMnO4 was dissolved in 2 liters of distilled water and this was heated with stirring to 60°C. A separately prepared solution of 151 gr MnSO4 in 3 liters of distilled water at 60°C was added to this in a thin stream with strong stirring, and the resulting brown suspension was kept stirring at 60°C for one hour. The gamma-MnO2 thus formed was filtrated (a slight excess of KMnO4 was used to ensure maximum quality, hence the filtrate was purple), and the filter cake washed well with an equal volume of hot water at least 7 times (to ensure removal of permanganate and sulfate ions) and dried in an oven at 110-125°C.
The MnO2 prepared this way was suspended in 10% nitric acid, stirred for 3 hours, filtrated and washed well with several portions of water to remove all traces of acid, and dried again in the oven at 110-125°C. Yield: 174 gr Freshly prepared gamma-MnO2 does not need this treatment, but this is necessary when re-using MnO2 from a previous oxidation.
The choice of solvent is important and has an impact on the rate of oxidation. Non-polar solvents are preferred, usually chloroform or dichloromethane is the solvent of choice in the existing literature on the type of oxidations. Alternatively acetone, petroleum ether, benzene and diethyl ether can be used. Benzene seems to give consistently lesser yields. Acetic acid is far too polar and a bad choice for these type of reaction. Best would be diethyl ether or petroleum ether. Acetone seemed not the obvious choice, but I have tried it and it seems to give similar results as chloroform. The advantage is that acetone is cheap and readily available and has a low boiling point and is easily removed. Technical grade acetone from the hardware store is ok, I re-use my solvents by destilling instead of evaporating.
Quoted from Quart. Rev. 1959 review on MnO2 oxidations:
The most widely used media for the oxidations at room temperature have been saturated hydrocarbons, chlorinated hydrocarbons, benzene, lower alkyl ethers, ethyl acetate, and acetone. Solvents that compete with the substrate for adsorption on the dioxide surface are obviously unsatisfactory, and in our laboratory it has been found that primary and secondary saturated alcohols fall into this category, causing rapid and permanent deactivation of the dioxide. Acetone and ethyl acetate also bring about deactivation but much more slowly, and, in contrast to what happens with alcohols, the activity is restored by drying the dioxide in a high vacuum.
The rule is easy as to the proportions of substrate, reagent and solvent to be used: (by weight) 1 part 5-AD, 10 parts gamma-MnO2 and (by volume) 100 parts of acetone. What is most essential to the reaction rate, is the efficiency of stirring. The author of the "recipe" says 6-10 h in acetic acid, he notes "you won't over oxidize since exact molar equivalents are used". First off, you can't overoxidise, simply because the reactivity of MnO2 is limited to oxidising allylic alcohols (eg. 5-AD) to the corresponding unsaturated aldehyde/ketone (eg. testosterone). Even if you use 50 equivalents, testosterone will be the only product as its oxidation potential is selective (at room temperature of course). Secondly, the rate of oxidation is heavily influenced by the rate of stirring. As this is a heterogenous reaction (solid reagens + solution of reactant), stirring permits a constant change in surface of the MnO2 and permits the unoxidised 5-AD in solution to contact fresh dioxide surface continuously. To compare: an oxidation can be over after 24 hours strong stirring while the same yield is obtained after 6-12 days when the mixture was allowed to stand and was shaken by hand a couple of times every day.
6 gr powdered 5-androstene-3,17-diol was suspended in 600 ml technical grade acetone in a 1L Erlenmeyer flask on a hot plate/mag. stirrer, and the acetone was heated with stirring to boiling. Only a part of the 5-AD dissolved (which is not a problem, as the formed testosterone is much more soluble in acetone then 5-AD, so as the reaction proceeds all 5-AD will eventually dissolve). The heating is shut off, and 60 gr powdered , heat-dried (110-125°C) gamma-MnO2 was added to the hot partial suspension/solution of 5-AD, and the mixture was stirred strongly for 48 hours. The black solids were filtrated and the filter cake extracted repeatedly and thoroughly with small portions of hot acetone. The combined extracts and mother-liquor were reduced to a third of its original volume by distillation. This was filtrated again over a bed of Kieselguhr to remove finely divided traces of MnO2, and the filtrate was distilled until most of the acetone is collected. The concentrate is poured on an evaporating dish, the last solvent is gently evaporated using electric heating. An oily slightly yellow residu is obtained, which crystallised overnight. This is fairly pure testosterone, which should be recrystallised, I'll have to report on that later. About 3 grams was obtained, which seems about right. Best molar yield in the literature, using chloroform as solvent, is 63%.
This was a proof-of-concept, and it does work. I'll follow the next batch with TLC (thin layer chromatography), to ascertain the purity and the reaction time. Also, petroleum ether (aka naphta, waschbenzin) will be tried instead of acetone, 5-AD is also partly soluble in it, better than in acetone even judging from my first trial. And the influence of moderate heat on the oxidation rate, from the literature it seems at 60°C the oxidation power was increased by approx. 60% over the normal rate. Again, with this selective reagent "over-oxidation" is not an issue. Of course, the dioxide has to be washed well and be free of any adsorbed traces of KMnO4, for obvious reasons. And reaction temperatures over 70°C can cause side-reactions in steroid molecules.
To conclude: the two-step synthesis of testosterone from DHEA is indeed simple and straight-forward, and can be performed outside a lab setting -taking into account of course, adequate safety measures- but I would not recommend anyone without a basic grasp of chemistry and a minimum practical lab experience to perform this as a first synthesis.
I include with this post the papers I used when researching the subject.
