Potential Corticoid Metabolites: Chemical Synthesis of 3- and 21-Monosulfates and Their Double-Conjugates of Tetrahydrocorticosteroids in the 5α- and 5β-Series

Here, we describe the chemical synthesis of the complete sets of 18 novel 3- and 21-monosulfates and their double-conjugated form of tetrahydrocortisol (THF), tetrahydro-11-deoxycortisol (THS), and tetrahydrocortisone (THE) in the 5α- and 5β-series. The principal reactions involved are: (1) selective protection of a specific hydroxy group in substrates; (2) catalytic hydrogenation at C-5 of Δ4-3-ketosteroids with 10% Pd(OH)2/C to yield 3-oxo-5β-steroids and reductive allomerization with 10% Pd/C to yield 3-oxo-5α-isomers; (3) reduction of the resulting 3-oxo-5β- and 3-oxo-5α-steroids to the corresponding 3α-hydroxy-compounds with Zn(BH4)2 and K-Selectride®, respectively; and (4) sulfation of hydroxy groups at C-3 and/or C-21 in the tetrahydrocorticosteroid derivatives with sulfur trioxide-triethylamine complex.