Racemic diastereoisomers of 1-amino-2-hydroxycyclopentanecarboxylic acid

The synthesis and characterization of the two diastereoisomeric forms of 1-amino-2-hydroxycyclopentanecarboxylic acid have been accomplished. A previously reported synthesis produced a racemic mixture of the threonine analog trans-2-hydroxy-1-aminocyclopentanecarboxylic acid (trans with respect to the hydroxy and carboxyl group). The alternate allothreonine analog was produced by conversion of cyclopentene oxide to trans-2-methoxycyclopentanol, followed by oxidation to 2-methoxycyclopentanone and conversion to a hydantoin. Fractional crystallization of the hydantoin sample, followed by hydrolysis, produced cis-2-hydroxy-1-aminocyclopentanecarboxylic acid (cis with respect to the hydroxy and carboxyl group) in high purity. Neither of the isomeric forms significantly inhibited the growth of the bacterial strains examined nor were they effective in inhibiting Jensen sarcoma cells in tissue culture.