Patent GB-959377-A (GB)
Title: Dioxy steroids and processes for their preparation
IPC: C07J5/00
Filed: 1960-09-13
Abstract: The invention comprises steroids of the pregnane series having at the 17, 20 and 21 positions the formula: <FORM:0959377/C2/1> wherein R and R1 represent lower alkyl or aralkyl radicals or, taken together with the carbon atom to which they are attached, a cycloaliphatic ring, and B represents hydrogen or an aralkyl, lower alkyl or lower alkanoyl radical, or, taken with the hydrogen atom attached to C21, an aralkylidene or lower alkylidene radical, and the preparation thereof by reacting 17a , 21-dihydroxy-20-keto-21-b  steroids, wherein b  has the above significance, with compounds of the formula RR1C=Q, wherein R and R1 have the above significance and Q represents O or bis-lower alkoxy, in the presence of a strong acid having a log K of less than 2.25 such as p-toluenesulphonic, sulphuric, hydrochloric and trifluoroacetic acids. By the term "lower" means having not more than 8 carbon atoms.  The above process may be modified in that a product obtained having the above general formula wherein B represents hydrogen may be reacted with a lower alkyl halide, or aralkyl halide, formaldehyde, a lower alkyl aldehyde, an aryl substituted aliphatic aldehyde, a lower alkyl ketone, an aryl substituted aliphatic ketone or an ester of a lower alkanoic acid in the presence of a strong base. The steroids having the above formula may contain a hydroxy or keto group or a group convertible to keto by hydrolysis at the 3-position, a dihydroxyacetone side chain at the 17-position, a hydrogen atom or a hydroxy or keto group at the 11-position, halogen at one or more of the positions 2, 4, 6, 9, 11 and 12, a hydroxy group at one or more of the positions 1, 2, 3, 11 and 12, and unsaturation at any of the positions 1, 4, 5, 6, 7 and 9. Preferred steroids have the general formula: <FORM:0959377/C2/2> and the 1, 2-dihydro analogues thereof, wherein Z represents a hydrogen or halogen atom or a methyl group, D represents a hydrogen atom or a lower alkyl or lower alkylidene group, X represents a hydrogen or halogen atom, Y represents a keto, (H,OH), (H,O-Acy) or (H, halogen) group with the proviso that Y is a halogen atom, X is also a halogen atom or X and Y together represent a 9 (11) double bond, and R, R1 and B have the above significance.  A product containing a 21-hydroxy group may be esterified to form a 21-ester, an 11a -hydroxy group may be oxidised to the corresponding 11-keto compound, and a product containing a 3-keto group may be reacted with ethylene glycol in the presence of small amounts of p-toluenesulphonic acid to form the corresponding 3-ethylene ketal.  A product containing a 9(11)-double bond may be reacted with formic acid, sodium formate and N-chlorosuccinimide to form a 9 a -chloro-11b -formate compound having the structure in the first formula above.  Therapeutic compositions useful in the alleviation of burns and the treatment of certain atopic and contact dermatoses and which may be administered topically contain as the active ingredient a steroid having at the 17, 20 and 21-positions the first formula above.  17a , 21- Dihydroxy -20-keto-steroids are prepared by treating the steroids having at the 17, 20 and 21-positions the first formula above with aqueous acid. The product may or may not retain the group represented by the symbol B at the 21-position. corresponding 2a -methyl compound, and treating this compound with refluxing acetic acid.  9a , 11b -Dichloro -16- methylene-1, 4-pregnadiene-17a , 21-diol-3, 20-dione is prepared by treating 16-methyl-5, 16-pregnadiene-3b -ol-20-one with alkaline hydrogen peroxide, acetylating the resulting 16b -methyl-16, 17-oxido -5- pregnene-3b -ol-20-one treating the resulting corresponding 3-acetate with hydrogen bromide to form 16-methylene-5-pregnene-3b , 17a -diol-20-one 3-acetate, treating this compound with bromine, hydrogen bromide and acetic acid to form a 5, 6, 2-tribromo substituted compound, treating this compound with sodium iodide and then potassium acetate to form 16-methylene-5-pregnene-3b , 17a , 21-triol-20-one 3, 21-diacetate, oxidising this compound with a growing culture of Flavobacterium dehydrogenans var. hydrolyticum to form 16-methylene -4- pregnene-17a , 21-diol-3, 20-dione, 11b -hydroxylating this compound with a growing culture of Curvularia lunata to form 16-methylene-hydrocortisone, dehydrogenating this compound with a growing culture of Bacillus sphaericus to form 16-methylene-prednisolone, acetylating this compound to form the corresponding 21-acetate (this compound is also obtainable by 21-acetylating 16-methylene-hydrocortisone and dehydrogenating the resulting 21-acetate with Bacillus sphaericus), treating the 21-acetate with p-toluene sulphonyl chloride and pyridine to form 16-methylene-1, 4, 9 (11)-pregnatriene-17a , 21-diol-3, 20-dione 21-acetate, treating this compound with lithium chloride and N-chlorosuccinimide, and hydrolysing the resulting 9a , 11b -dichloro -16- methylene-1, 4-pregnadiene-17a , 21-diol-3, 20-dione 21-acetate. Prednisolone is prepared by converting pregnane-11b , 17a , 21-triol-3, 20-dione to the corresponding 17a , 21-isopropylidenedioxy by the method referred to in the first paragraph above, brominating the product to form 2, 4-dibromo-17a , 21-isoproylidene-dioxy-pregnane -11b -ol-3, 20-dione, refluxing this compound with dimethyl-formamide to form the corresponding 1, 4-pregnadiene, and hydrolysing the 17a , 21-isopropylidene grouping with refluxing acetic acid.  17a , 21-Dihydroxy -4- pregnene-3, 20-dione is prepared by oxidising the 17a , 21-isopropylidenedioxy derivative of 5(6)-pregnene-3b , 17a , 21-triol-20-one with chromium trioxide in pyridine and cleaning the resulting 17a , 21-isopropylidenedioxy -4- pregnene-3, 20-dione with acetic acid. Cortisone is prepared by oxidising 17a , 21-isopropylidenedioxy -5- pregnene-3b -ol-11, 20-dione with aluminium isopropoxide in cyclohexanone to form 17a , 21-isopropylidenedioxy -4- pregnene-3, 11, 20-trione and cleaning this compound as in the previous paragraph.  2a -Methyl-hydrocortisone is prepared by treating the 17a , 21-isopropylidenedioxy derivative of hydrocortisone with benzaldehyde under alkaline conditions to form 17a , 21-isopropylidenedioxy-21-benxylidene -4- pregnene-11b -ol-3, 20-dione, treating this compound with diethyl oxalate in the presence of sodium methoxide to form the corresponding 2-ethyloxalyl compound, treating this compound with methyl iodide in the presence of potassium t-butoxide to form the resulting 9a , 11b -dichloro -16- methylene-1, 4-pregnadiene-17a , 21-diol-3, 20-dione 21-acetate.  9a -Chloro-1, 4-pregnadiene-11b , 17a , 21-triol-3, 20-dione 11b -formate is prepared by treating 9a -chloro-1, 4-pregnadiene-11b , 17a , 21-triol-3, 20-dione 11b -formate 21-acetate with methanolic perchloric acid.  9a -Chloro-16a -methyl-1,4-pregnadiene-11b , 17a , 21-triol-3, 20-dione 11b -formate is prepared by treating 16a -methyl-1, 4, 9 (11)-pregnadiene-17a , 21-diol-3, 20-dione 21-acetate with formic acid, sodium formate, N-chlorosuccinimide and hydrochloric acid, and treating the resulting 9a -chloro-16a -methyl-1, 4-pregnadiene-11b , 17a , 21-triol-3, 20-dione 11b -formate 21-acetate with methanolic perchloric acid.  The corresponding 16b -methyl and 16a -ethyl compounds are prepared by similar methods.  Specification 959,378 is referred to.