Functionalization of unactivated carbons in 3α,6‐ and 3α,24‐dihydroxy‐5β‐cholane derivatives by dimethyldioxirane

Abstract

Direct remote functionalization of unactivated carbons by dimethyldioxirane (DMDO) was examined for 3alpha,6- and 3alpha,24-dihydroxy-5beta-cholane derivatives. DMDO oxidation of stereoisomeric methyl 3alpha,6-diacetoxy-5beta-cholanoates caused the direct, unexpected 14alpha- and 17alpha-hydroxylations, in analogy with that of the 5alpha-H analogs, regardless of the differences in stereochemical configuration of the A/B-ring junction and of the acetoxyl groups at C-3 and C-6. On the other hand, the ester derivatives of 3alpha,24-dihydroxy-5beta-cholane with DMDO were transformed into the corresponding 5beta-, 14alpha-, and 17alpha-hydroxy compounds, whereas the ether derivatives yielded the 5beta-hydroxy, 3-oxo, and C-24 oxidized products, accompanied by their dehydrated ones.

Relative inhibitory activity of bile acids against 12-O-tetradecanoylphorbol-13-acetate-induced inflammation, and chenodeoxycholic acid inhibition of tumour promotion in mouse skin two-stage carcinogenesis

“…The following bile acid derivatives used in this study were synthesized in our laboratory: 4 , 26 , 34 , 35 and 44 ; 9 5 and 8 ; 10 6 ; 11 7 , 23 , 28 , 36 , 40 , 41 , 45 , 46 and 48 ; 12 14 and 37 ; 13 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 38 , 39 , 49 and 50 ; 14 and 47 15 . The other compounds ( 12 , 13 , 29 , 30 and 31 ) were from our laboratory collection.…”

A comparative study of remote oxy-functionalization of unactivated carbons in 5β-steroids by dimethyldioxirane and 2,6-dichloropyridine N-oxide / ruthenium-porphyrin / HBr

“…1 Our previous papers have reported the utility of dimethyldioxirane (DMDO; see Figure 1) as an effective oxygen-donating reagent against unactivated carbons in 5β-steroids. [2][3][4] However, the use of DMDO appears to be limited to oxidizing C-20~-23 side-chain carbons in 5β-cholanoic acid derivatives. Meanwhile, a number of metalloporphyrins closely related to the iron porphyrin complex (heme) present in the active center of cytochrome P-450, has also been reported as attractive oxidant systems for oxidation reactions.…”

Relative inhibitory activity of bile acids against 12-<I>O</I>-tetradecanoylphorbol-13-acetate-induced inflammation, and chenodeoxycholic acid inhibition of tumour promotion in mouse skin two-stage carcinogenesis

“…Chemicals TPA was purchased from Chemicals for Cancer Research Inc. (Minnesota, USA). Compounds 1,2,3,9,10,11,24,25,27,32,33,42 and 43, and 7,12-dimethylbenz[a]anthracene (DMBA), indometacin and hydrocortisone were obtained from Sigma Chemical Co. (St Louis, MO, USA). Acetone, chloroform and methanol were obtained from Wako Pure Chemical Industries Ltd (Osaka, Japan).…”

“…The following bile acid derivatives used in this study were synthesized in our laboratory: 4, 26, 34, 35 and 44; [9] 5 and 8; [10] 6; [11] 7, 23, 28, 36, 40, 41, 45, 46 and 48; [12] 14 and 37; [13] 15,16,17,18,19,20,21,22,38,39,49 and 50; [14] and 47. [15] The other compounds (12,13,29,30 and 31) were from our laboratory collection.…”