In order to develop specific and sensitive immunoassays, carboxylated derivatives of tetrahydrocortisol and tetrahydrocortisone were synthesized. The preparation of the 3-hemisuccinates (23, 27), 21-hemisuccinates (8, 14), 3-hemiglutarates (24, 28), and 21-hemiglutarates (9, 15) of these corticosteroids was carried out starting from cortisol 21-acetate (1). Tetrahydrocortisol monoglucuronides (36, 38) and tetrahydrocortisone monoglucuronides (37, 39) were also prepared.