Thiols 2-amino-ethane

Amifostine is hydrolyzed rapidly to 2-[(3-aminopropyl)amino]ethane-thiol (9.64) at the acidic pH of the stomach, and by alkaline phosphatases in various tissues. After intravenous administration to cancer patients, the plasma half-lives were found to be in the order of minutes. This is highly relevant, since most or all pharmacological effects of amifostine can be ascribed to its thiol metabolite. 

The described synthesis of l,4-thiazino[3,2-6][l,4]thiazine (305) <87JA4308> starts with the reaction of aqueous glyoxal (302) with iV-methylguanidinium chloride (303) in water (pH 8). The resulting 2-amino-4,5-dihydro-4,5-dihydroxy-l-methylimidazolium chloride (304) is treated with 2-amino-ethane thiol in H20 (pH 8-9) to give either (305) or (306). The NMR spectrum of the product supports both of the structures (305) and (306) there is only one diastereomer <87JA4308>. 

So far we have discussed various techniques for computing the PMF. The other type of free energy calculation commonly performed is alchemical transformation where two different systems are compared. Such calculations have many applications such as Lennard-Jones fluid with and without dipoles for each particles, comparison of ethanol (CH3CH2OH) and ethane thiol (CH3CH2SH), replacing one amino acid by another in a protein, changing the formula for a compound in drug discovery, etc. 

NSC2H7, Ethane thiol, 2-amino-, cobalt complex, 21 19... 

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