GB1380248A - 3alpha-hydroxy steroids and esters thereof - Google Patents

Abstract

1380248 3α-Hydroxy-steroids and their esters GLAXO LABORATORIES Ltd 16 Dec 1971 [17 Dec 1970] 58545/71 Divided out of 1380246 Heading C2U [Also in Division A5] Steroids of the formula wherein R<SP>1</SP> is H, halogen or C 1-6 alkyl; R<SP>2</SP> is H or C 1-6 alkyl; R<SP>3</SP> is H or C 2-6 alkanoyl or haloalkanoyl; R<SP>4</SP> is H, OH or a C-C double bond or epoxy group in the 9,11-position; R<SP>5</SP> is H when R<SP>4</SP> is epoxy or a double bond or is H or OH when R<SP>4</SP> is H, or is C 1-6 alkyl or allyl when R<SP>4</SP> is OH, or R<SP>4</SP> and R<SP>5</SP> together are oxo (when R<SP>7</SP> is CH 3 ); R<SP>6</SP> is H, halogen or CH 3 , or two methyl groups; R<SP>7</SP> is CH 3 or C 1-6 alkoxy; X is 0 or, when R<SP>7</SP> is CH 3 , ethylenedioxy; and the #<SP>1</SP> and #<SP>8</SP> double bonds are optional; provided that at least one of R<SP>1</SP>, R<SP>2</SP>, R<SP>3</SP> and R<SP>6</SP> is other than H when R<SP>4</SP> and R<SP>5</SP> are oxo or are both H and the 1,2- and 8,9- positions are saturated are prepared and interconverted as follows (1) by acylation of 3α-ols; (2) by hydrolysis of 3-acylates; (3) by ketalization of 20-ones; (4) for 11α-ols, by stereospecific reduction of 11-ones (which are preferably, when R<SP>7</SP> is CH 3 , 20-ketals); (5) for 11α-hydrocarbyl-11#-ols, by alkylation or allylation of 11-ones which, when R<SP>7</SP> is CH 3 , are 20-ketals; (6) for 20-ones, by hydrolysis of 20-ketals; (7) for 16#-methyl compounds, by hydrogenation of 16-methyl-#<SP>16</SP>-analogues, which are prepared from the corresponding 3#-ols containing this grouping, by conversion into a 3#-hydrocarbonsulphonyloxy derivative, reaction with a carboxylic acid salt to give the 3α-acyloxy compound and, when required, hydrolysis of this: (8) for 16α-methyl-20-oxo compounds, by reaction of 16-unsubstituted-#<SP>16</SP>-20-ones with a methyl metal derivative; (9) for 9#,11#-epoxides, by elimination of hydrogen halide from 9α-halo- 11#-ols, these in turn being prepared from the corresponding #<SP>9(11)</SP>-steroids and hypohalous acid sources; (10) for #<SP>9(11)</SP>-steroids of Formula (I), by hydrogenation of corresponding 9(11),16- dienes, themselves prepared as described under (7) for 16-methyl-#<SP>16</SP>-compounds; (11) for #<SP>8</SP>-11-ones and 11#-ols, by dehydrohalogenation of the corresponding 9α-halo steroids which are preferably 3α-acyloxy compounds, the starting materials being prepared, for example, by reacting a 9,11-epoxy compound with a halogen hydracid to give 3α-acyloxy-9α9halo-5α-pregnan-11#-ol and oxidizing this to the 11-one; (12) as an alternative to (11), a 3α-acyloxy-9α: halo-11#-hydroxy-5α-pregnane is dehydrohalogenated to a 3α-acyloxy-11#-hydroxy-5α-pregn- 8-ene and this is oxidized to the corresponding 11-one; (13) for the 11-ones in general, by oxidation of corresponding 11-ols; (14) for 3#- unsubstituted-3α-ols, by stereospecific reduction of 3-ones; (15) for 2α-alkyl compounds, by reaction of corresponding 2α,3α-epoxides with metal alkyls to give 2#-alkyl-3α-ols, followed by oxidation to the 3-ones, equilibration to the 2α-alkyl epimers and stereospecific reduction; (16) for 2α-methyl compounds, from corresponding 2-unsubstituted 3-ones, which if they are pregnanes are 20-ketals, by conversion to 2-hydroxymethylene compounds, reduction of these to 2α-methyl compounds (and some 2#- methyl by-product) and sterospecific reduction of the 3-oxo group of these; (16) as an alternative to (15), 2α-alkyl-3-ones may be reduced to the 3#-ols and these converted to the 3α-ols as in (7); (17) for the 2α-halo compounds, by reaction of the corresponding 2#-halo compounds with an alkali metal halide, the starting materials being obtained by reaction of the corresponding 2α, 3α-epoxides with a hydrogen halide; (18) as an alternative to (17), 2α-halo-3- oxo compounds may be stereospecifically reduced; (19) for #<SP>1</SP>-steroids, by dehydrohalogenation of 2#-halo steroids, a 3α-OH group being possibly protected as a THP-ether; (20) for 3#-alkyl steroids, by reacting the corresponding 3-spiro-2<SP>1</SP>-oxiranes with either a complex metal hydride, to give 3#-methyl products, or with metal alkyls, to give higher homologues, any 11#-OH group formed by reduction of an 11-oxo group being subsequently oxidized; the starting 3-spiro-2<SP>1</SP>-oxiranes being prepared by reaction of the corresponding 3-ones (20-ketal protected) with a trimethyl sulphoxonium halide in presence of an alkali metal hydride or by epoxidation of corresponding 3-methylene compounds; (21) for 3#-alkyl-3α-ols, by reaction of the corresponding 3-ones (20-ketal protected) with an alkyl magnesium halide; (22) for 16α- halo steroids, from the corresponding 16- unsubstituted-#<SP>16</SP>-steroids by reaction with a halogen hydracid, the starting materials being prepared as in (7); (23) for 17-alkoxycarbonyl steroids, by esterification of the corresponding free acids, directly or via reactive derivatives such as the acid halides, the acids being prepared for example, by oxidation of the 17(3-acetyl group of corresponding pregnanes. The steroids are novel with the exception of the esters of the 3α-ols wherein R<SP>4</SP> and R<SP>5</SP> are oxo or are both OH, the 1,2- and 8,9- positions are saturated and R<SP>1</SP>, R<SP>2</SP> and R<SP>6</SP> are all H; and of the compounds wherein R<SP>5</SP> is OH. 3# - Hydroxy - 16 - methyl - 5α pregn - 16 - ene- 11,20-dione is prepared by hydrolysis of the corresponding 3#-acetoxy steroid. 3#-Hydroxy- 5α - pregna - 9(11),16 - dien - 20 - one and 3# - hydroxy - 5α - pregn - 16 - ene - 11,20 - dione are prepared similarly. 2α,3α - Epoxy - 17# - methoxycarbonyl - 5α- androstane is prepared by epoxidation of the corresponding #<SP>2</SP>-steroid. The steroids of the Formula (I) are anaesthetics and may be made up into compositions with a suitable carrier or excipient and a non- ionic surface active agent.