JPH0559093A - Production of 3alpha, 7alpha-dihydroxy-12-oxocholanic acid - Google Patents
Production of 3alpha, 7alpha-dihydroxy-12-oxocholanic acidInfo
- Publication number
- JPH0559093A JPH0559093A JP24426391A JP24426391A JPH0559093A JP H0559093 A JPH0559093 A JP H0559093A JP 24426391 A JP24426391 A JP 24426391A JP 24426391 A JP24426391 A JP 24426391A JP H0559093 A JPH0559093 A JP H0559093A
- Authority
- JP
- Japan
- Prior art keywords
- acid
- dihydroxy
- reaction
- oxocholanic
- amount
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
- Steroid Compounds (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、式 で示される３α，７α−ジヒドロキシ−１２−オキソコ
ラン酸の製造法に関する。詳しくは、デヒドロコ−ル酸
を選択的に還元して、簡便かつ高収率に３α、７α−ジ
ヒドロキシ−１２−オキソコラン酸を製造する方法であ
る。BACKGROUND OF THE INVENTION And a method for producing 3α, 7α-dihydroxy-12-oxocholanic acid. More specifically, it is a method for producing 3α, 7α-dihydroxy-12-oxocholanic acid conveniently and in high yield by selectively reducing dehydrocolic acid.
【０００２】[0002]
【従来の技術】３α、７α−ジヒドロキシ−１２−オキ
ソコラン酸は、胆石溶解剤として有用なケノデオキシコ
−ル酸又はウルソデオキシコ−ル酸をコ−ル酸から製造
する際の重要な中間体である。３α、７α−ジヒドロキ
シ−１２−オキソコラン酸をコ−ル酸から化学的に製造
する最も一般的な方法としては、以下の方法が知られて
いる。2. Description of the Prior Art 3α, 7α-Dihydroxy-12-oxocholanic acid is an important intermediate in the production of chenodeoxycolic acid or ursodeoxycolic acid, which is useful as a gallstone solubilizer, from colic acid. .. The following methods are known as the most general methods for chemically producing 3α, 7α-dihydroxy-12-oxocholanic acid from colic acid.
【０００３】すなわち、まず、式 で示されるコ−ル酸をアルコ−ルでエステル化し、一般
式 で示されるコール酸エステルを形成した後、３つの水酸
基のうち３位、７位の水酸基を選択的にアシル化して、
一般式 で示される３α，７α−ジアシロキシ−１２α−ヒドロ
キシコラン酸エステルを合成する。次に、１２位の水酸
基を酸化して で示される３α，７α−ジアシロキシ−１２−オキソコ
ラン酸エステルを得た後アルカリで加水分解し目的物を
得るものである。That is, first, the formula The ester of carboxylic acid represented by After forming the cholate ester represented by, the hydroxyl groups at the 3- and 7-positions of the three hydroxyl groups are selectively acylated,
General formula The 3α, 7α-diacyloxy-12α-hydroxycholanic acid ester represented by is synthesized. Next, oxidize the hydroxyl group at position 12 The compound of interest is obtained by obtaining 3α, 7α-diacyloxy-12-oxocholanic acid ester represented by and then hydrolyzing it with an alkali.
【０００４】かかる従来法では、エステル化、アシル
化、酸化及び加水分解の４工程を必要とし、各工程は反
応、晶出、濾過、乾燥及び濾過液の後処理等多くの煩雑
な操作を含み、工業化にあたっては多大な設備と労力が
必要である、アシル化反応においては、３位と７位の
アシル化の選択性を高めるために低温で１０〜２４時
間、場合によっては３０時間以上も反応しなければなら
ず、その選択性も十分ではない、アシル化反応にはベ
ンゼンやトルエン等の有機溶媒をはじめ大量の有機酸や
その無水物等を使用しなければならず、その回収が困難
である等の欠点があった。The conventional method requires four steps of esterification, acylation, oxidation and hydrolysis, and each step involves many complicated operations such as reaction, crystallization, filtration, drying and post-treatment of the filtrate. , Industrialization requires a lot of equipment and labor. In the acylation reaction, the reaction is carried out at a low temperature for 10 to 24 hours, and in some cases, for 30 hours or more in order to enhance the selectivity of the acylation at the 3- and 7-positions. However, the selectivity is not sufficient, and a large amount of organic acids such as benzene and toluene and organic acids and their anhydrides must be used in the acylation reaction, which makes recovery difficult. There were some drawbacks.
【０００５】一方、コール酸を酸化して得られる式 で示されるデヒドロコール酸の３位と７位のケト基のみ
を選択的に還元してα−水酸基とすることにより目的物
を得る方法が考えられる。しかし、かかる方法では還元
における選択性が極めて低く、これまでほとんど工業化
に成功した例はない。On the other hand, the formula obtained by oxidizing cholic acid A method is conceivable in which only the keto groups at the 3- and 7-positions of dehydrocholic acid represented by are selectively reduced to form α-hydroxyl groups. However, with such a method, the selectivity in reduction is extremely low, and there have been no examples of successful industrialization so far.
【０００６】[0006]
【発明が解決しようとする課題】本発明は、かかる従来
法の欠点を克服し、コール酸から３α，７α−ジヒドロ
キシ−１２−オキソコラン酸を簡便かつ高収率に製造し
ようとするものである。SUMMARY OF THE INVENTION The present invention is intended to overcome the drawbacks of the conventional method and to produce 3α, 7α-dihydroxy-12-oxocholanic acid from cholic acid simply and in high yield.
【０００７】[0007]
【課題を解決するための手段】本発明者らは、３α，７
α−ジヒドロキシ−１２−オキソコラン酸の製造法につ
いて鋭意研究した結果、コール酸を酸化して得られるデ
ヒドロコール酸から３α，７α−ジヒドロキシ−１２−
オキソコラン酸を高い選択率で製造する方法を見出し本
発明を完成させた。The present inventors have developed 3α, 7
As a result of diligent research on a method for producing α-dihydroxy-12-oxocholanic acid, 3α, 7α-dihydroxy-12-12 was obtained from dehydrocholic acid obtained by oxidizing cholic acid.
The present invention has been completed by finding a method for producing oxocholanic acid with high selectivity.
【０００８】即ち、本発明は、含水溶媒中で白金系触媒
を用いデヒドロコ−ル酸の３位と７位のケト基のみを選
択的に水素化してα−水酸基とすることにより、簡便か
つ高収率に３α、７α−ジヒドロキシ−１２−オキソコ
ラン酸を製造する方法である。That is, according to the present invention, a platinum catalyst is used in a water-containing solvent to selectively hydrogenate only keto groups at the 3- and 7-positions of dehydrocolic acid to form an α-hydroxyl group, which is simple and highly functional. This is a method for producing 3α, 7α-dihydroxy-12-oxocholanic acid in a yield.
【０００９】本発明の製造法によれば、コール酸から３
α，７α−ジヒドロキシ−１２−オキソコラン酸を酸化
と還元の２工程で製造することができる。また、選択的
アシル化を伴う従来法に比べて高い選択率で３α，７α
−ジヒドロキシ−１２−オキソコラン酸を製造すること
ができる。According to the production method of the present invention, 3 is obtained from cholic acid.
α, 7α-Dihydroxy-12-oxocholanic acid can be produced in two steps of oxidation and reduction. In addition, compared with the conventional method involving selective acylation, 3α, 7α has higher selectivity.
-Dihydroxy-12-oxocholanic acid can be prepared.
【００１０】本発明の出発原料となるデヒドロコール酸
は、例えば特公昭５２−３３６３８号公報記載の方法等
により、コール酸の３位、７位及び１２位の水酸基を全
て酸化することにより簡便且つ高収率に得られる。The dehydrocholic acid used as the starting material of the present invention is simply and easily prepared by oxidizing all the hydroxyl groups at the 3-, 7- and 12-positions of cholic acid by the method described in JP-B-52-33638. Obtained in high yield.
【００１１】本発明で用いられる含水溶媒としてはメタ
ノール、エタノール、ノルマルプロパノール若しくはイ
ソプロパノール又はこれらの混合物からなるものが用い
られる。含水溶媒量には特に制限はなく、例えば原料の
１０倍から１５倍量（ｖ／ｗ）が用いられる。また、含
水率は原料を溶解できる条件であれば特に制限はなく、
例えば１０〜５０ｗｔ％のものが用いられる。As the water-containing solvent used in the present invention, those comprising methanol, ethanol, normal propanol or isopropanol or a mixture thereof are used. The amount of the water-containing solvent is not particularly limited and, for example, a 10-fold to 15-fold amount (v / w) of the raw material is used. The water content is not particularly limited as long as it can dissolve the raw materials,
For example, 10 to 50 wt% is used.
【００１２】本発明で用いられる白金系触媒としては酸
化白金、アルミナ担持白金、活性炭担持白金等が挙げら
れる。触媒量（担持型触媒の場合は担持されている金属
量）は原料に対して１〜５０ｗｔ％の範囲が良く、好ま
しくは５〜１０ｗｔ％である。また、反応促進剤として
酢酸やリン酸等の弱酸性物質を溶媒に対して１〜５ｗｔ
％加えてもよい。Examples of the platinum-based catalyst used in the present invention include platinum oxide, alumina-supported platinum and activated carbon-supported platinum. The catalyst amount (the amount of supported metal in the case of a supported catalyst) is preferably in the range of 1 to 50 wt% with respect to the raw material, and preferably 5 to 10 wt%. Also, a weakly acidic substance such as acetic acid or phosphoric acid is used as a reaction accelerator in an amount of 1 to 5 wt% with respect to the solvent.
% May be added.
【００１３】水素化反応は水素圧５〜５０ｋｇ／ｃｍ2
が良く、好ましくは１０〜３０ｋｇ／ｃｍ2 である。反
応温度は０〜１００℃が良く、好ましくは１０〜６０℃
である。反応時間は３〜１２時間が良く、好ましくは５
〜８時間である。The hydrogenation reaction is carried out at a hydrogen pressure of 5 to 50 kg / cm.2
Good, preferably 10-30 kg / cm2 Is. Anti
The reaction temperature is preferably 0 to 100 ° C, preferably 10 to 60 ° C.
Is. The reaction time is 3 to 12 hours, preferably 5
~ 8 hours.
【００１４】[0014]
［実施例１］デヒドロコール酸２０ｇ、酸化白金２ｇを
メタノール３００ｍｌ（含水率５０ｗｔ％）に懸濁させ
た後、オートクレーブ中にて水素圧２０ｋｇ／ｃ ｍ2で
室温下、５時間反応させた。反応終了後触媒を濾別し、
濾液から減圧蒸留によりメタノールを除去して水溶液と
した後、希硫酸で中和して結晶を析出させ、これを濾過
乾燥した。得られた乾燥結晶量は２０ｇであった。液体
クロマトグラフィー分析による目的物（３α，７α−ジ
ヒドロキシ−１２−オキソコラン酸）の含有率は８８ｗ
ｔ％であり、その他の不純物の含有率はコール酸、３α
−ヒドロキシ−７，１２−ジオキソコラン酸がそれぞれ
７．０、５．０ｗｔ％であった。 Example 1 20 g of dehydrocholic acid and 2 g of platinum oxide
Suspended in 300 ml of methanol (water content 50 wt%)
Then, the hydrogen pressure in the autoclave is 20 kg / c. m2so
The reaction was carried out at room temperature for 5 hours. After completion of the reaction, the catalyst is filtered off,
Methanol was removed from the filtrate by vacuum distillation to obtain an aqueous solution.
After that, neutralize with dilute sulfuric acid to precipitate crystals, which are filtered.
Dried. The amount of dried crystals obtained was 20 g. liquid
Chromatographic analysis of the desired product (3α, 7α-di-
Hydroxy-12-oxocholanic acid) content is 88w
The content of other impurities is cholic acid, 3α
-Hydroxy-7,12-dioxocholanic acid is
It was 7.0 and 5.0 wt%.
【００１５】［実施例２］実施例１において、反応温度
を８０℃、反応時間を３時間に変更した以外は全て同じ
条件で反応した。得られた結晶量は１９．５ｇであっ
た。液体クロマトクラフィー分析による目的物の含有率
は８２ｗｔ％であり、その他の不純物の含有率はコール
酸、３α−ヒドロキシ−７，１２−ジオキソコラン酸が
それぞれ１６．０、０．２ｗｔ％であった。[Example 2] The reaction was carried out under the same conditions as in Example 1, except that the reaction temperature was changed to 80 ° C and the reaction time was changed to 3 hours. The amount of crystals obtained was 19.5 g. The content rate of the target substance by liquid chromatography analysis was 82 wt%, and the content rates of other impurities were 16.0 and 0.2 wt% for cholic acid and 3α-hydroxy-7,12-dioxocholanic acid, respectively. ..
【００１６】［実施例３］実施例１において、酸化白金
量を１ｇ、反応時間を８時間にした以外は全て同じ条件
で反応した。得られた結晶量は１９．９ｇであった。液
体クロマトグラフィー分析による目的物の含有率は８７
ｗｔ％であり、その他の不純物の含有率はコール酸、３
α−ヒドロキシ−７，１２−ジオキソコラン酸がそれぞ
れ５．５、６．５ｗｔ％であった。Example 3 The reaction was carried out under the same conditions as in Example 1, except that the amount of platinum oxide was 1 g and the reaction time was 8 hours. The amount of crystals obtained was 19.9 g. The content rate of the target substance by liquid chromatography analysis is 87.
wt%, other impurities content is cholic acid, 3
The amounts of α-hydroxy-7,12-dioxocholanic acid were 5.5 and 6.5 wt%, respectively.
【００１７】［実施例４］実施例１において、水素圧を
５０ｋｇ／ｃｍ2、反応時間を３時間に変更した以外は
全て同じ条件で反応した。得られた結晶量は１９．４ｇ
であった。液体クロマトグラフィー分析による目的物の
含有率は８０ｗｔ％であり、その他の不純物の含有率は
コール酸、３α−ヒドロキシ−７，１２−ジオキソコラ
ン酸がそれぞれ１２．０、６．２ｗｔ％であった。Example 4 The reaction was carried out under the same conditions as in Example 1 except that the hydrogen pressure was changed to 50 kg / cm 2 and the reaction time was changed to 3 hours. The amount of crystals obtained is 19.4 g.
Met. The content rate of the target substance by liquid chromatography analysis was 80 wt%, and the content rates of other impurities were 12.0 and 6.2 wt% for cholic acid and 3α-hydroxy-7,12-dioxocholanic acid, respectively.
【００１８】［実施例５］実施例１において、水素圧を
５ｋｇ／ｃｍ2、反応時間を８時間に変更した以外は全
て同じ条件で反応した。得られた結晶量は１９．９ｇで
あった。液体クロマトグラフィー分析による目的物の含
有率は８６．５ｗｔ％であり、その他の不純物の含有率
はコール酸、３α−ヒドロキシ−７，１２−ジオキソコ
ラン酸がそれぞれ５．５、７．０ｗｔ％であった。Example 5 The reaction was carried out under the same conditions as in Example 1, except that the hydrogen pressure was changed to 5 kg / cm 2 and the reaction time was changed to 8 hours. The amount of crystals obtained was 19.9 g. The content ratio of the target substance by liquid chromatography analysis was 86.5 wt%, and the content ratio of other impurities was 5.5 wt% and 3.0 wt% of cholic acid and 3α-hydroxy-7,12-dioxocholanic acid, respectively. It was
【００１９】［実施例６］実施例１において、触媒をア
ルミナ担持白金（担持率３ｗｔ％）３０ｇ、反応温度を
６０℃に変更した以外は全て同じ条件で反応した。得ら
れた結晶量は１９．７ｇであった。液体クロマトグラフ
ィー分析による目的物の含有率は８２．０ｗｔ％であ
り、その他の不純物の含有率はコール酸、３α−ヒドロ
キシ−７，１２−ジオキソコラン酸がそれぞれ７．５、
６．９ｗｔ％であった。Example 6 The reaction was carried out under the same conditions as in Example 1, except that the catalyst was 30 g of platinum supported on alumina (supporting rate 3 wt%), and the reaction temperature was changed to 60 ° C. The amount of crystals obtained was 19.7 g. The content ratio of the target substance by liquid chromatography analysis is 82.0 wt%, and the content ratio of other impurities is 7.5% for cholic acid and 3α-hydroxy-7,12-dioxocholanic acid, respectively.
It was 6.9 wt%.
【００２０】［実施例７］実施例１において、触媒を活
性炭担持白金（担持率３ｗｔ％）６０ｇ、反応時間を１
２時間に変更した以外は全て同じ条件で反応した。得ら
れた結晶量は１９．９ｇであった。液体クロマトグラフ
ィー分析による目的物の含有率は８５．３ｗｔ％であ
り、その他の不純物の含有率はコール酸、３α−ヒドロ
キシ−７，１２−ジオキソコラン酸がそれぞれ３．５、
９．０ｗｔ％であった。[Embodiment 7] In Embodiment 1, the catalyst is 60 g of platinum supported on activated carbon (supporting ratio is 3 wt%), and the reaction time is 1
All were reacted under the same conditions except that the time was changed to 2 hours. The amount of crystals obtained was 19.9 g. The content rate of the target substance by liquid chromatography analysis is 85.3 wt%, and the content rate of other impurities is 3.5% for cholic acid and 3α-hydroxy-7,12-dioxocholanic acid, respectively.
It was 9.0 wt%.
【００２１】［実施例８］実施例１において、メタノー
ルをエタノール、含水率を５０ｗｔ％に変更した以外は
全て同じ条件で反応した。得られた結晶量は１９．９ｇ
であった。液体クロマトグラフィー分析による目的物の
含有率は９２．０ｗｔ％であり、その他の不純物の含有
率はコール酸、３α−ヒドロキシ−７，１２−ジオキソ
コラン酸がそれぞれ７．０、１．０ｗｔ％であった。Example 8 The reaction was carried out under the same conditions as in Example 1, except that methanol was changed to ethanol and the water content was changed to 50 wt%. The amount of crystals obtained is 19.9 g.
Met. The content rate of the target substance by liquid chromatography analysis is 92.0 wt%, and the content rate of other impurities is 7.0% and 1.0 wt% of cholic acid and 3α-hydroxy-7,12-dioxocholanic acid, respectively. It was
【００２２】［実施例９］実施例１において、メタノー
ルをノルマルプロパノール、含水率を１０ｗｔ％に変更
した他は全て同じ条件で反応した。得られた結晶量は１
９．８ｇであった。液体クロマトグラフィー分析による
目的物の含有率は８８．０ｗｔ％であり、その他の不純
物の含有率はコール酸、３α−ヒドロキシ−７，１２−
ジオキソコラン酸がそれぞれ２．０、１０．０ｗｔ％で
あった。Example 9 The reaction was carried out under the same conditions as in Example 1, except that methanol was changed to normal propanol and the water content was changed to 10 wt%. The amount of crystals obtained is 1
It was 9.8 g. The content rate of the target substance by liquid chromatography analysis is 88.0 wt%, and the content rate of other impurities is cholic acid, 3α-hydroxy-7,12-
Dioxocholanic acid was 2.0 and 10.0 wt%, respectively.
【００２３】［実施例１０］実施例１において、メタノ
ールをイソプロパノール、含水率を４０ｗｔ％に変更し
た以外は全て同じ条件で反応した。得られた結晶量は２
０．０ｇであった。液体クロマトグラフィー分析による
目的物の含有率は８６．０ｗｔ％であり、その他の不純
物の含有率はコール酸、３α−ヒドロキシ−７，１２−
ジオキソコラン酸がそれぞれ１．５、１２．５ｗｔ％で
あった。Example 10 The reaction was carried out under the same conditions as in Example 1, except that methanol was changed to isopropanol and the water content was changed to 40 wt%. The amount of crystals obtained is 2
It was 0.0 g. The content rate of the target substance by liquid chromatography analysis is 86.0 wt%, and the content rate of other impurities is cholic acid, 3α-hydroxy-7,12-
Dioxocholanic acid was 1.5 and 12.5 wt%, respectively.
【００２４】[0024]
【発明の効果】本発明の製造法によれば、選択的アシル
化を伴う従来法に比べ、少ない工程数で且つ高い選択率
でコール酸から３α，７α−ジヒドロキシ−１２−オキ
ソコラン酸を製造することができる。EFFECTS OF THE INVENTION According to the production method of the present invention, 3α, 7α-dihydroxy-12-oxocholanic acid is produced from cholic acid in a smaller number of steps and with higher selectivity than in the conventional method involving selective acylation. be able to.
Claims (1)
−ル、ノルマルプロパノ−ル若しくはイソプロパノ−ル
又はこれらの混合物からなる含水溶媒中白金系触媒の存
在下で水素化することを特徴とする３α，７α−ジヒド
ロキシ−１２−オキソコラン酸の製造法。1. Dehydrocholate is hydrogenated in the presence of a platinum-based catalyst in a water-containing solvent consisting of methanol, ethanol, normal propanol, isopropanol or a mixture thereof. A method for producing 3α, 7α-dihydroxy-12-oxocholanic acid.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24426391A JPH0559093A (en) | 1991-08-30 | 1991-08-30 | Production of 3alpha, 7alpha-dihydroxy-12-oxocholanic acid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24426391A JPH0559093A (en) | 1991-08-30 | 1991-08-30 | Production of 3alpha, 7alpha-dihydroxy-12-oxocholanic acid |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0559093A true JPH0559093A (en) | 1993-03-09 |
Family
ID=17116153
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP24426391A Pending JPH0559093A (en) | 1991-08-30 | 1991-08-30 | Production of 3alpha, 7alpha-dihydroxy-12-oxocholanic acid |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0559093A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2018194426A1 (en) * | 2017-04-20 | 2018-10-25 | 대웅바이오 주식회사 | Method for preparing bile acid derivative by using continuous flow reaction |
-
1991
- 1991-08-30 JP JP24426391A patent/JPH0559093A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2018194426A1 (en) * | 2017-04-20 | 2018-10-25 | 대웅바이오 주식회사 | Method for preparing bile acid derivative by using continuous flow reaction |
| CN110799519A (en) * | 2017-04-20 | 2020-02-14 | 大雄Bio株式会社 | Method for preparing bile acid derivative by using continuous flow reaction |
| US11053275B2 (en) | 2017-04-20 | 2021-07-06 | Daewoong Bio Inc. | Method for bile acid derivative by using continuous flow reaction |
| CN110799519B (en) * | 2017-04-20 | 2023-02-28 | 大雄Bio株式会社 | Method for preparing bile acid derivative by continuous flow reaction |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109762043B (en) | Chenodeoxycholic acid and preparation method thereof | |
| WO2021012673A1 (en) | Method for preparing trenbolone acetate | |
| DE2429040C2 (en) | Steroid haptens, processes for their production and their use | |
| NO132558B (en) | ||
| JPH0559093A (en) | Production of 3alpha, 7alpha-dihydroxy-12-oxocholanic acid | |
| JP3834836B2 (en) | Method for producing alicyclic polycarboxylic acid ester | |
| JPH01193246A (en) | Production of 2,3-dichloropyridine | |
| US2418603A (en) | Method of preparing estradiol from equilin and intermediates obtained thereby | |
| US2615902A (en) | Chemical compounds and processes for preparing the same | |
| RU2333916C1 (en) | Method for obtaining betulonic acid | |
| TWI651297B (en) | Process for the preparation of bis[4-(6-acryloyloxyhexyl)phenyl]cyclohexane-1,4-dicarboxylate | |
| JPH0768163B2 (en) | Process for producing cyclopentenone derivative | |
| US4337206A (en) | Process for preparing high purity ursodeoxycholic acid | |
| CN110072873B (en) | Industrial method for synthesizing nomegestrol acetate | |
| US2554986A (en) | Synthesis of pregnenolone | |
| US2705719A (en) | Preparation of aromatic steroids and intermediates therefor | |
| US2881192A (en) | Method of isolating and purifying keto steroids and new keto steroid compounds | |
| JPH0316333B2 (en) | ||
| CN111138509B (en) | Preparation method of obeticholic acid | |
| JPS61218591A (en) | 2,9-dioxatricyclo(4,3,1,03,7)decane | |
| JPS6160078B2 (en) | ||
| JP2007517778A (en) | Process for producing 7-ethyl-10-hydroxycamptothecin | |
| US2538109A (en) | Reduction of 12-ketosteroids to 12-hydroxysteroids | |
| US2339281A (en) | Derivatives of sapogenins and their preparation | |
| US2823213A (en) | Organic compounds |