Racemization deduced using amino acids

With the increasing use of amino acid racemization dating, it is important to establish a set of criteria for assessing the reliability of a racemization-deduced age. Below, we have listed information which should be given when a racemization age is reported. 

The first two criteria should be considered a minimum requirement and should always be reported otherwise, the racemization date should be considered meaningless. The second criterion is by far the most important. The d/l amino acid ratio for a particular bone can generally be imequivocally determined (criterion 1). However, the conversion of this ratio into an age estimate can be done only if a suitable calibration value has been determined for the site or locality where the bone was found. The reliability of the date increases with the number of criteria which are fulfilled. In the future, it should eventually be possible to satisfy an additional criterion and report an average racemization age for a sample deduced using several different amino acids. 

Trichloro[l,3,5]triazine has also been attached to the Wang resin. Reaction of the resulting supported dichlorinated triazine with 2-(2-aminoethoxy)ethanol and further treatment again with an excess of 2,4,6-trichIoro[l,3,5]triazine afforded resin 65, which has been shown to be effective in the conversion of carboxylic acids into acid chlorides, using triethylamine as base in dichloromethane or acetone as solvent [78]. The obtained acid chlorides can be easily transformed into ester or amides after removal of the resin by filtration and addition of an alcohol or an amine. From the isolated yields of the esters or amides it could be deduced that the yields of the obtained acid chlorides are around 70-90%. However, a chiral amino acid was completely racemized under this resin treatment. 

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