Syntheses of stable isotope-labeled 6β-hydroxycortisol, 6β-hydroxycortisone, and 6β-hydroxytestosterone

A method is described for the preparation of two types of multi-labeled 6beta-hydroxycortisol containing either five deuterium atoms at C-19 methyl and C-1 methylene or four C-13 atoms at C-1, C-2, C-4, and C-19 in addition to the five deuterium atoms for use as analytical internal standards for gas chromatography-mass spectrometry (GC-MS). BMD derivatives of [1,1,19,19,19-H-2(5)]cortisone and [1,2,4,19-C-13(4),1,1,19,19,19-H-2(5)]cortisone (cortisone-H-2(5)-BMD and cortisone-C-13(4), H-2(5)-BMD) were first synthesized via indan synthon method starting from optical active 11-oxoindanylpropionic acid and labeled isopropenyl anion([1,1,3,3,3 1,3,3,3-H-2(5)]- or [1,3-C-13(2),1,1,3,3,3-H-2(5)] isopropenyl anion). The labeled isopropenyl anion was prepared from commercially available [1,1,1,3,3,3-H-2(6)]- or [1,3-C-13(2),1,1,1,3,3,3-H-2(6)]acetone. Ultraviolet (UV) irradiated autoxidation at C-6 position of 3-ethyl-3,5-dienol ether derivatives of the labeled cortisone-BMDs gave 6beta-hydroxy-[1,1,19,19,19-H-2(5)]cortisone-BMD and 6beta-hydroxy-[1,2,4,19-C-13(4),1,1,19,19,19-H-2(5)]cortisone-BMD, respectively, as a mixture of 6beta- and 6alpha-epimers in a ratio of 4:1. Separation of 6beta- and 6alpha-epimers by thin-layer chromatography (TLC) and subsequent hydrolysis of the BMD group at C-17 gave pure labeled 6beta-hydroxycortisone. After protecting the keto group at C-3 of the labeled 6beta-hydroxycortisone-BMD as semicarbazone, reduction of 11-keto group with NaBH4 and subsequent removal of the C-3 and C-17 protecting groups gave 6beta-hydroxy-[1,1,19,19,19-H-2(5)]cortisol (6beta-hydroxycortisol-H-2(5)) and 6beta-hydroxy-[1,2,4,19-C-13(4),1,1,19,19,19-H-2(5)] cortisol (6beta-hydroxycortisol-C-13(4), H-2(5)), respectively, as a mixture of 6beta- and 6alpha-epimers (6beta:6alpha = 4.4:1). The isotopic compositions of 6beta-hydroxycortisol-H-2(5) and 6beta-hydroxycortisol-C-13(4), H-2(5) were 90.9 and 92.1 at.%, respectively. Furthermore, 6beta-hydroxy-[1alpha,16,16,17alpha-H-2(4)]testosterone was synthesized by the UV irradiated autoxidation at C-6 position of 3-ethyl-3,5-dienol ether derivative of deuterium-labeled testosterone ([1alpha,16,16,17alpha-H-2(4)]testosterone) obtained by using catalytic deuteration and hydrogen-deuterium exchange reactions. (C) 2003 Elsevier Inc. All rights reserved.