AU567978B2 - Carminomycinone precursors and analogues and derivatives thereof. - Google Patents

Description

CARMINOMYCINONE PRECURSORS AND ANALOGUES AND DERIVATIVES THEREOF

This invention relates to organic compounds including anthracycl ines and anthracycli nones. In a specific aspect this invention relates to carminomycinone and analogues and derivatives thereof i ncludi ng daunomycinone and analogues and derivatives thereof, to novel organic compounds which are useful in the synthesis of carminomycinone and its analogues and derivatives, to methods of production of organic compounds which are valuable precursors in the production of carminomycinone and its derivati ves and analogues and to methods of production of analogues of anthracyclines.

Reference wil l be made to the accompanyi ng drawi ngs which are structural drawings of various chemical compounds and reaction schemes.

The compounds of formula I are named, according to the substituents borne, as set out below. The three glycosides are i so la te d a nd adm i n i s te re d as s al ts , us ua l l y hydrochlorides. All ami no compounds referred to throughout this specification and cl aims are considered to incl ude salts as well as free bases,

R' R" R"'

Daunomycin CH₃ H alpha-L-daunosaminyl Adriamycin CH₃ OH alpha-L-daunosaminyl Carminomycin H H alpha-L-daunosaminyl Daunomycinone CH₃ H H Adriamycinone CH₃ OH H Carminomycinone H H H

Modified compounds with different glycosidic residues including oligosaccharides, and with di fferent aglycones are known, in particular those where the glycosidic sugar is 4'-deoxy-, 4'-epi-, or N-trifluoroacetyl-daunosamine and/or where the aglycone l acks the oxy substituent at position 4 or 11.

At least the compounds daunomyci n and adriamycin are therapeutically useful. The. other compounds at least have ut i l ity as i ntermedi ates i n the product io n of pharmaceuticals.

The present invention provides compounds of formula III and tautomeric forms thereof wherein:-

R₁ - R₄ are H, alkyl, aryl, alkaryl, halogen, hydroxy, alkoxy, aryloxy, aralkoxy, acyloxy, amino or alkylamino;

Ra is H, halogen, alkoxy, aryloxy or acyloxy; and

R_b is H, halogen, alkoxy, aryloxy or acyloxy.

Provided that if R₁ R₄ and R_a are all, H, R_b is not H or ch lo ro. and provided that if R ₁ - R₄ are al l H and R_a is chloro or bromo R_b is not chloro.

Preferred compounds of formula III are those wherein:-

(a) not all of R₁ - R₄ are H;

(b) R₄ is hydroxy, alkoxy, aralkoxy or acyloxy;

(c) R_a i s H, Br, Cl; and

(d) R_b is H, Br, Cl, methoxy, acyloxy.

The present i nvention also provides compounds of formula IV and tautomeric forms thereof wherein: R₁ is H, alkyl, aralkyl or acyl;

R₂ is H, halogen, alkoxy, aryloxy or acyloxy; or R₃ is H, halogen, alkoxy, aryloxy or acyloxy.

Preferred compounds of formula IV are those where in:-

(a) R₁ is H or methyl;

(b) R₂ is H, Br or Cl; or

(c) R₃ is H, Br, Cl.

The present invention al so provides compounds of formula II and tautomeric forms thereof wherein:- R₁ - R₄ have the meaning given above;

R₈ has the same meaning as given to R₁ - R₄ or may be glycosyloxy;

R₉ and R_{1 2} have the same meaning as given to R₁ - R₄ and alternatively may be al koxycarbonyl, aryloxycarbonyl or carboxy; one of _Rχ or R_b i s hydroxy and the other is H, hal, al koxy, aryloxy or acyloxy;

R _{1 0} and R_{1 1} taken together are oxo or ethylenedioxy (provided that if R _{1 0} and R_{1 1} taken together are ethylenedioxy then i f R₄ is hydrogen or methoxy, R_b is not hydrogen or acetoxy); or R₁₀ is hydroxy; and R_{1 1} is hydroxyalkyl or dihydroxyalkyl or -CO-R₁₅ where R₁₅ is H, alkyl, aryl, aralkyl, hydroxyalkyl.

Preferred compounds of formula II are those wherein:-

(a) not al 1 of R₁ - R₄ is H;

(b) R₄ is hydroxy, alkoxy, aralkoxy or acyloxy; (c)(1) R_x is hydroxy; R_b is H, Br,Cl, methoxy;

(i) R₈, R₉ and R ₁₂ are H and R ₁₀ and R _{1 1} taken together are oxo; or (i i) R₈ is hydroxy or glycosyloxy; and R₉ and R_{1 2} are H; and R _{1 0} i s hydroxy; and R _{1 1} i s hydroxyal kyl, dihydroxyalkyl or R_{1 1} i s - CO -R ₁₅ where R_{1 5} is H, alkyl, aryl, aralkyl, hydroxyalkyl; or

(c)( I I) R_x i s H; R_b i s hydroxy; R₈ i s H, hydroxy, glycosyloxy; R₉ and R ₁₂ are H and R₁₀ is hydroxy; and R_{1 1} is -CO- R₁₅ where R₁₅ is H, alkyl, aryl, aralkyl, hydroxyalkyl; or R_{1 1} is hydroxyalkyl, dihydroxyalkyl.

The present invention al so provi des compounds of formula II and tautomeric forms thereof wherein:- (i) R₁-R₃ are H;

R₄ and R_χ taken together are -OSO₂O-;

R₅ is hydroxy, alkoxy, aralkoxy or acyloxy;

R₈-R₁₅ are as defined above. or

(ii) R₁ and R_b taken together are -OSO₂O¬

R₂-R₄ are H R_x is hydroxy, alkoxy, aralkoxy or acyloxy;

R₈-R₁₅ are as defined above.

The present invention also provides the novel compounds 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 19, 20, 21, 22, 23, 24 and 25 of the Reaction Schemes I, I I, I II or V substituted, if desired and where possible, with any one or more of R₁ - R₁₅, R_x, R_a or R_b as defined above.

The present invention provides a method of obtaining a precursor of carmi nomyci none or of daunomyci none or thei r, analogues or derivatives comprising reacting a compound of formul a III with a substituted butadiene under conditions forming the A ring of a compound of formula II and converti ng the group R_b at position 10 in formula III to a hydroxy group which taken with the hydroxy group at position 9 in formula III leads to a system tautomeric with the anthracyclinone chromophore.

The present invention provides a method of obtaining a precursor of carminomycinone or its analogues or derivatives comprising reacting a compound of formula IV with a substituted butadiene under conditions forming the A ring of a compound of formula II and converting the group R₁ in formula IV to H and hydrolysing the bridging sulfate.

If necessary, a compound so obtained is further reacted to obtain a desired compound of formula II.

The present invention also provides a method of obtaining precursors of 4-deoxy carminomycinone, that is of 4-demethoxy daunomycinone, or its analogues or derivatives comprising reacting a compound of formula III, where R₄ is H and R ₁-R₃ and R_b are as defined above, with substituted butadiene under conditions forming the A ring of a compound of formula II and converting the group R_b at position 10 in formula I II to a hydroxy group which taken with the hydroxy group at position 9 in formula III leads to a system tautomeric with the anthracyclinone chromophore.

The present invention also provides a method of obtaining precursors of 12-deoxy carminomycinone or of 12deoxy daunomycinone or their analogues or derivatives comprising reacting a compound of formula III with a substituted butadiene under conditions forming the A ring of a compound of formula II and, where R_b is not already H, converting it to H.

The reaction with the substituted butadiene can be improved if there is a halogen atom, preferably bromine or chlorine atom, at the 2-position of the compounds of formula III or IV.

Butadienes of particular interest as reagents are those bearing one or more of a 1-R₁₂-substituent, a 2trialkylsilyloxy- or 2-al koxy- or 2 - hydroxyal kyl- or 2oxoalkyl-, or 2-hydroxyoxoalkyl- or 2 -dihydroxyalkylsubstituent, a 3-R₉-substituent, and a 4-R₈-substituent.

The present invention also provides a method of obtaining 5-deoxy daunomycin or 5-deoxy adriamycin or their analogues or deri vati ves comprising either reduction of a compound of formula I or tautomeric forms thereof, where R₁ is not H, or reduction of a compound of formula I I or tautomeric forms thereof, where R₄ is not OH, in either case to give a compound of formula II where R_x is H. REACTION SCHEME I .

The compound 1 in scheme I which is used as a starting material is 1,8-dihydroxy-9,10-anthraquinone (chrysazin) and is avail able as a rel ativel y cheap dyestuff intermediate. The step, compound 1 to compound 2 w as performed i n accordance with the method described in BIOS Report 1484, P.22. Omitting the hydrolytic work-up from this procedure led to compound 24, methylation of which gave compound 25.

The conversion compound 2 to compound 3 was effected in the presence of thionyl chlori de and achieved, in the particular instance, three important requirements (a) - (c).

(a) The 9, 10-anthraquinone compound 2 which is unsuitable for further reaction i n its own ri ght, i s converted into a reacti ve 1,4-anthraqui none. Suitabl e reacti vity of the latter compound results from exposure of the unsubstituted 2,3-double bond of the quinonoid system.

(b) The 1,4-anthraquinone compound 3 has the possibility of reacti ng regiosel ectively, that i s with predictabl e di scrimi nation between positions 2 and 3. This i s because the carbonyl groups 1 and 4 which control such processes are themselves clearly differentiated, being respectively adjacent to a hydroxy and to a chloro substituent.

(c) The conversion of compound 2 into compound 3 is itself regio specific. The potentially competitive process leading to the unwanted isomeric compound was not observed at all.

The operation compound 2 to compound 3 thus resolves a fundamental problem towards formul ating a regiospecific synthesi s of anthracyclines, namely of being able to use a substituent on one side of the molecule (the hydroxy group of ring D) to discriminate between reactive centres remotely located on the other side of the molecule (positions 2 and 3 of compound 3). In the conversion compound 3 to compound 4 the more exposed of the two hydroxy groups of (3) readi ly undergoes selective protection to give the monoacetate (4). None of the unwanted isomeric monoacetate at the 9-position was observed. Retention of a free hydroxy group at position 9, as in compound 4 was necessary for di rective purposes i n the subsequent step, conversion to the 2-bromo derivative compound 5. None of the unwanted isomeric 3-bromo derivative was observed i n thi s step. (The 2-chloro deri vati ve analogous to (5) has also been obtained and it shows similar chemical behaviour). The bromo derivati ve compound 5 is activated towards regiospecific cycloaddition of 2-trimethylsilyloxybutadiene, a readi ly accessi bl e reagent which i s commercial ly avai labl e. On being heated smooth conversion occurs to the cycloadduct compound 6. Treatment of the cycloadduct compound 6 then effected deacetyl ation and 1,2-el imination of hydrogen bromide to give the 1,4-quinone compound 7. The latter product on being treated with acid affords the tetracycl ic 5,12-quinone compound 8, the desired compound in the synthesis. The conversion compound 7 to compound 8 is an important step in the sequence, permitting hydrolytic removal of the chloro group under conditions sufficiently mild so as not to cause aromatization of ring A. This step provides the necessary complement to the step of compound 2 to compound 3 described above. Having introduced controlled discrimination into the system in the form of the chloro substituent specifical ly placed at position 10 of compound 3, the synthesis requires its replacement by an oxygen substituent once its function has been achieved, i.e., once an A-ring having the correct orientation has been formed. This requirement is accomplished in the conv-ersion of compound 7 to compound 8. In considering the sequence (5) to (6) to (7) to (8), whil st it was possible to isolate the two intermediates compounds 6 and 7 if required, it is more efficient to carry out the entire process (5) to (8) as a one-pot operation. The yield was calculated accordingly. The tetracyclic ketone compound 8 as obtained herein was identical with an authentic sample derived by chemical degradation of natural daunomycin. It i s to be noted that the four steps (2) to (3), (3) to (4), (4) to (5), and (5) to (8), where regiochemical considerations are critical, all proceeded regiospecifically within the limits of detection. Compound 8 can be converted into (±)-daunomycinone by Kende's method and can also be converted into (±)carminomycinone (U.S. Patent Nos. 4,021,457 and 4,070,382). Daunomycinone can be converted i nto adriamycinone (U.S. Patent No. 4,012,448). Glycosylation of these racemic anthracycl i nones with appropri ate derivatives of Ldaunosamine (itself chemically synthesisable in enantiomeric form and commerically available) affords the natural enantiomeric anthracyclines. In summary the conversion (1) to (8) involves five operations and proceeds in a yield of 24% overall. REACTION SCHEME II. A modified synthesis of compound 8 is shown in Reaction Scheme II. It differs from the synthesis in Scheme I in effecting cycloaddition to the 1,4-anthraquinone compound 3 directly, so as to give the new cycloadduct compound 9. This avoi ded the acetylation and bromination steps used in Example I but it suffers from the disadvantage that cycloaddition to compound 3 requires more severe conditions than to the bromo acetate compound 5. Cycloaddition to compound 3. might conceivably have proceeded less regiospecifically than to compound 5, since the bromo substitutent in such systems generally provides a powerful directive influence; however none of the unwanted orientation was observed. The cycloadduct compound 9 is at the oxidation level of a dihydro quinone. Oxidation to the corresponding quinone system is achieved by first protecting the isolated keto group in compound 9 as its acetal compound 10, so as to prevent aromatization of the A-ring during oxidation. Basecatalysed aerial oxidation of compound 10 then gives th e protected quinone compound 11, treatment of which with trif luoroacetic acid as in the last stage of Scheme I again gives the tetracyclic ketone compound 8. REACTION SCHEME III A modified synthesis is shown in Reaction Scheme II I and involves methylation of compound 3 under the defi ned conditions which occurred regiospecifical ly to give the monomethyl ether compound 12, substantially exclusively. In the fol lowi ng stages of the sequence via compound 13 to compound 14 to compound 15 to compound 16 the monomethyl ether compound 12 went through an analogous procedure to that applied to the monoacetate compound 4 in Scheme I. The tetracyclic methoxy ketone compound 16 resulting from this sequence can be converted to (±)-daunomycinone (U.S. Patent Nos. 4,021 ,457 and 4,070,382). There are two advantages of this pathway relati ve to those of Schemes I and II. First the methoxy group at position 4, present i n the natural anthracycl i nes i s incorporated efficiently early in the synthesis rather than at a later poorer-yieldi ng stage. Second the overal l synthesis can be achieved in one less step and with much higher effi ciency. Thus the overal l yield of ( ± )daunomyci none from 1,8-dihydroxyanthraquinone by the pathway of Scheme III i s 4.2% i n eight operations. This compares with a yield of 1.8% in nine operations by Scheme I. REACTION SCHEME IV. Suitable starting material s analogous to compound 2 were made as shown in Reaction Scheme IV. REACTION SCHEME V. Selective reduction of daunomycin 17 under mildly acidic conditions leads to the 5-deoxy compound 20 in yield of 57% and to the 5-deoxy-13-dihydro compound 21 in yield of 25%. Minor modification of this reaction leads to compound 21 in yield of 71% as the sole glycosidic product. Simi lar reduction of adriamycin 26 gives the 5-deoxy compound 22 in yield of 38% and the 5-deoxy-13-dihydro compound 23 in yield of 17%.

Extended reduction of 17 gi ves the 5, 7-bi sdeoxy compound 19 in yield of 88%. Compound 19 is also obtained by reduction of the known 7-deoxy daunomycinone 18.

The present invention will be further illustrated with the aid of the following examples.

EXAMPLE I

Preparation of 1 ,4,5-Trihydroxy-9, 10-anthracenedione

(compound 2) and of the C_yclic Sulfate (compound 25).

1 , 8-Di hydroxy-9, 10-a nt hracenedione (chrysazi n) (compound 1) (6.85g) was added slowly to a stirred solution of 80% oleum (137g) containing boric acid (3.56g) maintained at 27° i n an oil bath. The resulting purple mixture was stirred for 14 days, then carefully diluted to 83% sulfuric acid by addi tion to ice (56g) contai ned in a very wel l cooled flask. The resulting blue mixture was then heated at 140° for 80 mi n under an air condenser. The mixture was cooled to room temperature then diluted into ice-cold water (600ml) with stirring. The suspension was heated to 90° on a steam bath, cooled and filtered through pulped filter paper on a Buchner funnel. The cake was washed with di stil led water (200ml) then dried under reduced pressure, prior to exhaustive extraction with hot ethyl acetate (1000ml). The extracts were fi ltered and evaporated to give a dark red solid which was recrystallized from acetic acid to give the product (compound 2) as red needles, (5.76g, 79%).

Alternatively, the purple mi xture from the foregoing reaction was added to sufficient ice to cause precipitation. Extr ac ti on w i th di ch lo rometh an e an d prep arat iv e chromatography of the extract on si l ica gel 60 w ith chloroform as eluant gave the product (compound 24). A sample of thi s compound (10 mg) was stirred with an excess of methyl iodide in chloroform (3 ml) in the presence of si lver oxide (36 mg) for 72 h. at room temperature. The mixture was then filtered and the filtrate evaporated. The residue was chromatographed on silica gel G with chloroform as eluant to give the product (compound 25) (10 mg, 98%). EXAMPLE 2 Preparation of 10-Chloro-8,9-dihydroxy-1,4-anthracenedione (compound 3). 1,4, 5-Trihydroxy-9,10-anthracenedione (compound 2) (670 mg) was refluxed in freshly distilled thionyl chloride (7ml) for 40 h while bei ng protected from moi sture. The excess thionyl chloride was evaporated and the residue was taken up in dichloromethane and al lowed to stand overnight. The crystals which separated were fi ltered off and dried. The mother liquor. was applied to a column of silica gel type 60 and eluted with chloroform then chloroform/acetone/acetic acid (95: 5:1). The separated purple band was added to the crystals obtained above to give a combined yield of purpleblack product (compound 3) (586 mg, 81%). EXAMPLE 3 Preparation of 8-Acetoxy-10-chloro-9-hydroxy-1,4anthracenedione (compound 4). 10-Chioro-8,9-dihydroxy-1,4-anthracenedione (compound 3) (180mg) wa s d is so lv ed wi th st irri ng i n dry tetrahydrofuran ( 15 ml ) at room temperature. Acetic anhydride (20 drops) and pyridine (15 drops) were added to the sol ution which was then sti rred for 48 h. Acidified water was added and the suspension was extracted with dichloromethane. The combined organic layers were dried and evaporated, and the residue was column ch roma togr ap hed on silica gel 60 (100 g) with chloroform /acetone mixture as the eluant. The major red band gave the product (compound 4) as a red soli d (17.7 mg,. 85%). EXAMPLE 4 Preparation of 8-Acetoxy-2-bromo-10-chloro-9-hydroxy-1,4anthracenedione (compound 5). 8-Acetoxy-10-chloro-9-hydroxy-1,4-anthracenedione (compound 4) (52 mg). was warmed in acetic acid (2 ml) in a round bottom flask. The mixture was cooled and to thi s was added a solution of bromine (28 mg) in acetic acid (0.1 ml) with stirring. After 1.5h the yellow solution was evaporated to gi ve a dark yellow sol id which was boi led wi th ethanol (5 ml) for 3 min on a water bath. The red mi xture was cool ed, di luted with water and extracted into dichioromethane. Ev aporat io n gave a red s ol i d whi ch was col umn chromatographed on silica gel 60 with chloroform as eluant. The mobile red band was recovered to give the product (compound 5) as a red crystalline solid (64 mg, 98%). EXAMPLE 5 Preparation of 7,10-Dihydro-4,6,11-trihydroxy-5,9,12 (8H)naphthacenetri one (compound 8). 8-Acetoxy-2-bromo-10-chloro-9-hydroxy-1,4anthracenedione (compound 5) (20 mg) was treated wi th 2trimethylsilyloxy-1,3-butadiene (72 mg) in refluxing benzene (2.5 ml) under nitrogen for 6 h. The benzene was evaporated under reduced pressure and the residue (compound 6) was dissolved in trifluoromethanesulfonic acid (0.5 ml) at room temperature with stirring for 10 min. The blue solution was th en qu en ch ed w i th i ce water a nd ext racted w it h dichloromethane. The combined organic extract was dried and evaporated to a purple solid (compound 7). This was taken up in trifluoroacetic acid (5 ml) and heated at reflux under a nitrogen atmosphere for 60 min. The orange solution was then diluted with water and extracted with dichloromethane. The dried organic layers were chromatographed on si lica gel layers containing 2% oxalic acid in toluene/ethyl acetate (90:10). The orange band Rf=0.46 was recovered to give the product (compound 8) as a red soli d (7.5 mg, 45%). EXAMPLE 6 Preparation of 3,4,4a, 12a-Tetrahydro-11-chlloror6,7di hydroxy-2, 5,12(1H)-naphthacenetri one (compound 9). 10-Chioro-8,9-dihydroxy-1,4-anthracenedione (compound 3) (100 mg), 2-methoxy-1,3-butadiene (564 mg) and dry benzene (10 ml) were heated in a sealed tube for 4 h at 130°. After cool ing the crude solution was preparativel y chromatographed on silica gel layers containing oxalic acid (2%) with chloroform as el uant. The major yellow band was recovered to gi ve the product (compound 9) as a yel low crystalline solid (85 mg, 68%) EXAMPLE 7

Preparation of Ethylene Acetal of 3, 4, 4a, 12a-Tetrahydro-11chloro-6, 7-dihydroxy-2, 5, 12(1H)-naphthacenetrione (compound 10).

A sol ution of 3,4,4a, 12a-tetrahydro-11-chloro-6,7dihydroxy-2,5, 12(1H)-naphthacenetrione (compound 9) (17 mg), P -toluenesulfonic acid (4 mg) and ethylene glycol (140 mg) i n dry benzene (5 ml) was boi led under refl ux for 4h with azeotropic removal of water. Recovery of the product by partitioning with chloroform and aqueous sodium bicarbonate (5%), drying of the organic phase and evaporation under reduced pressure gave the product (compound 10) which was recrystallized from dichloromethane and light petroleum as yellow needles (18 mg, 95%).

EXAMPLE 8 Preparation of Ethylene Acetal of 3, 4-Dihydro-11-chloro6,7-dihydroxy-2,5,12(1H)-naphthacenetrione (compound 11).

Oxygen was bubbled through a solution of ethylene acetal of 3,4,4a, 12 a-tetrahydro-11-chloro-6,7-dihydroxy2,5,12 (1H)-naphthacenetrione (compound 10) (15 mg in 5 ml 1M aqueous sodium hydroxide) and dim ethyl sul foxi de (20 ml) for 30 min. The purple solution was then acidified with aqueous acetic acid and extracted with chloroform. The combi ned extracts were washed with water, dried and evaporated under reduced pressure to give a residue which was chromatographed on a sil ica gel layer contai ni ng oxalic aci d (2%) with toluene/ethyl acetate (ratio 7:3) as el uant. The major pur-ple band was recovered to give the product (compound 11) as black needles from dichloromethane/.light petrol eum (11 mg, 73%).

EXAMPLE 9 Preparation of 7,10-Dihydro-4,6, 11-trihydroxy-5,9,12(8H) -naphthacenetrione- (compound 8).

A solution of ethylene acetal of 3,4-dihydro-11-chloro6, 7-dihydroxy-2,5,12(1H)-naphthacenetrione (compound 11) (4 mg) in trifluoroacetic acid (2 ml) was heated at 80° under reflux for 1 h. The solution was cooled, di luted with distil led water (10 ml) and extracted with ethyl acetate. The combined organic l ayers were washed with di stil led water, dried and evaporated to give the crude product (compound 8) which was recrystallized from ethyl acetate as brown microcrystals (2.5mg 74%). EXAMPLE 10 Preparation of 10-Chloro-9-hydroxy-8-methoxy-1,4anthracenedione (compound 12). 10-Chloro-8,9-dihydroxy-1 ,4-anthracenedione (compound 3) (100 mg) was di ssolved with sti rring in dry dimethyl sulfoxide (25 ml) under a nitrogen atmosphere. Sodium hydride (80% dispersion, 28.5 mg) was added to the solution in one aliquot. The resulting dark blue solution was stirred for 5 min then methyl iodi de (156 mg, 0.1 ml) was added i n one lot. Stirri ng was conti nued for 10 min then another aliquot of methyl iodide (0.1 ml) was added to the mixture. After a further 5 min the dark bl ue solution was quenched w ith i ce-cold phosphate buffer (pH7) to give a red suspension which was extracted with chloroform. The combined organic extracts were dried and evaporated to a crude solid which was chromatographed on a column of silica gel 60 with chloroform as el uant. The mobile red band gave the product (compound 12) as a red sol id (84 mg, 88%). This yield was calculated after allowing for recovered starting material (10 mg). EXAMPLE 11 Preparation of 2-Bromo-10-chloro-9-hydroxy-8-methoxy-1,4anthracenedione (compound 13). 10-Chloro-9-hydroxy-5-methoxy-1,4-anthracenedione (compound 12) (50 mg) was dissolved in acetic acid (5 ml) to saturation by warming. The mixture was cooled to room temperature before addition of bromine (27 mg) in acetic acid (0.15 ml). The mixture was stirred for 120 min. then excess acetic acid was evaporated under reduced pressure. The crude soli d dibromide was di ssolved in ethanol (5 ml) containing boron trifluoride etherate (5 drops) and heated at reflux for 20 min. The resulting red-purple sol ution which deposited some crystals was cooled and diluted with distil led water (20 ml). After standi ng overnight, the precipitated red-black sol id was fil tered off to gi ve the product (compound 13) (58 mg, 91%). EXAMPLE 12 Preparation of 7, 10-Dihydro-6,11-dihydroxy-4-methoxy-5,9,12 (8H)-naphthacenetrione (compound 16). 2-Bromo-10-chloro-9-hydroxy-8-methoxy-1,4anthracenedione (compound 13) (55 mg) was dissolved i n dry benzene under nitrogen at reflux. 2-Trimethylsilyloxy-1,3butadiene (212 mg) in benzene (0.5 ml) was added and the mi xture was refl uxed for 12.5 h altogether. Excess benzene was evaporated under reduced pressure to give a dark red s o l i d ( com po u n d 14) w h i c h w a s d i s so l ved i n trifluoromethanesulfonic acid at room temperature with stirring under a nitrogen atmosphere. After 20 min.. the dark bl ue sol ution was quenched with ice and extracted with dichloromethane. The combined organic extracts were dried and evaporated to dryness under reduced pressure. The residue (compound 15) was dissolved in trifluoroacetic acid (5 ml) and refl uxed under nitrogen for 90 min. The dark red solution was dil uted with cold disti lled water and then extracted with dichloromethane. The combined organic layers were dried, evaporated and the crude residue was preparati vely chromatographed on si l ica gel layers containing 2% oxalic acid in toluene/ethyl acetate (80:20). The red-orange band Rf = 0.23-0.35 was recovered to give the product (compound 16) as a red solid (23 mg, 45%). Al ternatively the dark red solid from the foregoing reaction was dissolved in acetic acid (11 ml) containing sodi um acetate (440 mg). The mi xture was stirred under nitrogen for 10 min at room temperature and was then heated at ref lu x for a fu rthe r 5 m in. Extra ct ion w ith dichloromethane gave compound 15 as a red solid. Thi s was converted to compound 16 (14 mg, 30%) as above. EXAMPLE 13 Preparation of (9R)-9-Acetyl-9,12-dihydroxy-4-methoxy7,8,9,10-tetrahydro-6,11- naphthacenedione (compound 19). Daunomycin hydrochioride (compound 17) (20 mg) in dry methanol (20 ml) was catalytically reduced with hydrogen gas and 5% pal ladi um on bari um sulfate (20 mg) 5.5 h at room temperature. Exposure of the mixture to the atmosphere gave a red sol ution which was fi ltered, evaporated and preparatively chromatographed on sil ica gel layers using chloroform/methanol (98:2) as eluant. The red band Rf 0.280.43 gave the product (compound 19) as a red solid (12 mg, 88%). EXAMPLE 14 Preparation of 5-Deoxy Daunomycin (compound 20) and of 5Deoxy-13-dihydro Daunomycin (compound 21 ) A solution of daunomycin hydrochloride (compound 17) (50 mg) in dry methanol (20 ml) containing chloroacetic acid (200 mg) was shaken with hydrogen and Adams catalyst (10 mg) for 50 min at room temperature. The mixture was then filtered, the filtrate diluted with water (50 ml) and washed with dichloromethane to remove non-glycosidic materials, the aqueous residue was then brought to pH 8.5 with aqueous sodium bicarbonate. Extraction with dichloromethane and chromatography on a column of si l ica gel 60 w ith chloroform/methanol/water (100:20:1) as eluant gave 5-deoxy daunomycin (compound 20) (26 mg, 57%) as a dark red sol id. Further elution with chloroform/methanol/water (80:20:1) gave 5-deoxy-13-dihydro daunomycin (compound 21) (12 mg, 25%) as a dark red sol id. EXAMPLE 15 Preparation of 5-Deoxy-13-dihydro Daunomycin (compound 21) A solution of daunomycin hydrochoride (compound 17) (10.4 mg) in dry methanol (6 ml) was shaken with hydrogen and Adams catalyst (8.7 mg) for 70 min at room temperature. The mixture was then fi ltered, the fi ltrate diluted with water (10 ml) and washed with dichloromethane to remove nonglycosidic materials, the aqueous residue was brought to pH 8.5 with aqueous sodium bicarbonate. Extraction with dichloromethane gave 5-deoxy-13-dihydro daunomycin (compound 21) (6.7 mg, 71%) as a dark red sol id. EXAMPLE 16 Preparation of 5-Deoxy Adriamycin (compound 22) and of 5Deoxy-13-dihydro Adriamycin (compound 23). A solution of adriamycin hydrochloride (compound 26) (20 mg) in dry methanol (8 ml) containing chloroacetic acid (80 mg) was shaken with hydrogen and Adams catalyst (5 mg) for 40 min at room temperature. The mixture was fi ltered, the fi ltrate diluted with water (20 ml) and brought to pH 8.5 with aqueous sodium bicarbonate. Extraction with chloroform and chromatography on a column of silica gel 60 with chloroform/methanol/water (80:20:1) as eluant gave 5deoxy adriamycin (compound 22) (7 mg, 38%) as a dark red solid. Further elution gave 5-deoxy-13-dihydro adriamycin (compound 23) (3 mg, 17%) as a dark red sol id. Compounds in accordance with this invention which have al kyl groups as such or as part of another radical such as al karyl, al koxy, aral koxy, al karyl , aralyl, acyloxy, al kylamino, al koxycarbonyl, mono- or poly-hydroxyal kyl include those wherein the al kyl groups are saturated or unsaturated, have from 1-20 carbon atoms, preferably 1-6 carbon atoms, and may bear such substituents as are common in the art incl uding halogen, hydroxy, am i no, im ino, nitroso, carbonyl , carboxy together with such other substituents as may be desired and as are listed as radicals in IUPAC nomenclature rules. Compounds in accordance with this invention which have aryl groups as such or as part of another radical such as al karyl, aral kyl, aryloxy, aryloxycarbonyl include those wherein the aryl moiety is a single or multi-ring aromatic system which may bear similar substituents as discussed above in respect of alkyl groups and which may contain hetero atoms such as nitrogen, oxygen or sulfur. The claims form part of the disclosure of this specification. Modifications and adaptations may be made to the above described without departing from the spirit and scope of this invention which includes every novel feature and combination of features disclosed herein.

Claims (20)

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A compound of formula II and tautomeric forms thereof wherein:-

R₁ - R₄ are H, al kyl, aryl, alkaryl, halogen, hydroxy, alkoxy, aryloxy, aralkoxy, acyloxy, amino or alkylamino;

R₈ has the same meaning as given to R₁ - R₄ or may be glycosyloxy;

R₉ and R₁₂ have the same meaning as given to R₁ - R₄ and alternatively may be al koxycarbonyl, aryloxycarbonyl or carboxy; one of R_x or R_b i s hydroxy and the other is H, hal, alkoxy, aryloxy or acyloxy;

R₁₀ and R_{1 1} taken together are oxo or ethylenedioxy

(provided that if R₁₀ and R₁₁ taken together are ethylenedioxy then if R₄ is hydrogen or methoxy, R_b is not hydrogen or acetoxy); or

R₁₀ is hydroxy; and

R₁₁ is hydroxyalkyl or dihydroxyalkyl or - CO - R₁₅ where

R₁₅ is H, alkyl, aryl, aralkyl, hydroxyalkyl.

2. A compound in accordance with claim 1, wherein R₁₀ and R₁₁ taken together are oxo.

3. A compound in accordance with claim 1 or cl aim 2, wherein:

(a) not al l of R₁ - R₄ is H;

(b) R₄ is hydroxy, alkoxy, aralkoxy or acyloxy;

(c) R_x i s hydroxy; R_b is H, Br,Cl, methoxy;

(i) R₈, R₉ and R₁₂ are H and R₁₀ and R _{1 1} taken together are oxo; or

(i i) R₈ is hydroxy or glycosyloxy; and R₉ and R ₁₂ are H; and R _{1 0} i s hydroxy; and R _{1 1} i s hydroxya l kyl , dihydroxyalkyl or R_{1 1} is -CO-R₁₅ where R_{1 5} is H, alkyl, aryl, aralkyl, hydroxyalkyl.

4. A compound in accordance with claim 1 or claim 2, wherei n:

(a) not all of R₁ - R₄ is H;

(b) R₄ is hydroxy, alkoxy, aralkoxy or acyloxy;

(c) R_x i s H; R_b is hydroxy; R₈ is H, hydroxy, glycosyloxy; R₉ and R₁₂ are H and R₁₀ is hydroxy; and R_{1 1} is -CO-R₁₅ where R_{1 5} is H, al kyl, aryl, aralkyl, hydroxyal kyl; or R_{1 1} is hydroxyalkyl, dihydroxyalkyl. 5. A compound in accordance with claim 1, or claim 2 wherein R₁ - R₄ are H; R₈ is alkyl, aryl, al karyl, halogen, hydroxy, al koxy, aryloxy, aral koxy, acyloxy, am i no, al kyl am i no or glycosyloxy; R₉ and R_{1 2} have the same meaning as given to R₁ - R₄ and alternatively may be al koxycarbonyl, aryloxycarbonyl or carboxy; one of R_x or R_b is hydroxy and the other is H, hal, alkoxy, aryloxy or acyloxy; R₁₀ and R-J-J taken together are oxo or ethylenedioxy; or R₁₀ is hydroxy; and R_{1 1} is hydroxyalkyl or di hydroxyal kyl or -CO-R₁₅ where R₁₅ is H, alkyl, aryl, aralkyl, hydroxyalkyl. 6. Novel compounds 3, 4,

5,

6, 7, 9, 10, 11, 12, 13, 14, 15, 19, 20, 21, 22, 23, 24 and 25 of the Reaction Schemes I, II, III or V substituted, if desired and where possible, with any one or more of R₁ - R₁₅, R_x, R_a or R_b as defined in claim 1.

7. A compound of formula II in claim 1, or claim 2 wherein:- (i) R₁ - R₃ are H; R₄ and R_x taken together are -OSO₂O-; R_b is hydroxy, alkoxy, aralkoxy or acyloxy; and R₈ - R₁₅ are as defined in claim 1; or (ii) R₁ and R_b taken together are -OSO₂O-; R₂ - R₄ are H; R_x is hydroxy, alkoxy, aralkoxy or acyloxy; and R₈ - R₁₅ are as defined in claim 1.

8. A compound of formula III and tautomeric forms thereof wherein:- R₁ - R₄ are H, al kyl, aryl, alkaryl, halogen, hydroxy, alkoxy, aryloxy, aral koxy, acyloxy, amino or alkylamino; R_a is H, halogen, alkoxy, aryloxy or acyloxy; and R_b is H, halogen, alkoxy, aryloxy or acyloxy. Provided that if R ₁ - R₄ and R_a ar all H, R_b is not H or chloro and provided that if R1 - R₄ are al l H and R_a i s chloro or bromo R_b is not chloro.

9. A compound in accordance with claim 8, wherein: (a) not all of R₁ - R₄ are H; (b) R₄ is hydroxy, alkoxy, aralkoxy or acyloxy; (c) R_a is H, Br, Cl; and (d) R_b is H, Br, Cl, methoxy, acyloxy.

10. A compound of formula IV and tautomeric forms thereof wherein:- R₁ is H, alkyl, aralkyl or acyl; R₂ is H, halogen, alkoxy, aryloxy or acyloxy; or R₃ is H, halogen, alkoxy, aryloxy or acyloxy.

11. A compound in accordance with claim 10 wherein:- R₁ is H or methyl; R₂ is H, Br or Cl; or R₃ i s H, Br or Cl.

12. A method of obtaining a precursor of carminomycinone or of daunomyci none or thei r analogues or derivatives comprising reacting a compound of formula III as defined in claim 8 or claim 9 with a substituted butadiene under conditions forming the A ring of a compound of formul a II as defined in any one of claims 1 - 7 and converting the group Rtø at position 10 in formula I II to a hydroxy group which taken with the hydroxy group at position 9 i n formul a II I leads to a system tautomeric with the anthracycl inone chromophore.

13. A method of obtaining a precursor of carminomycinone or its analogues or derivatives comprising reacting a compound of formula IV as defined i n cl aim 10 or cl aim 11 with a substituted butadiene under conditions forming the A ring of a compound of formula II and converting the group R₁ i n formula IV to H and hydrolysing the bridging sulfate.

14. A method of obtai ni ng precursors of 4-deoxy carminomycinone, that is of 4-demethoxy daunomycinone, or its analogues or derivatives comprising reacting a compound of formula III as defi ned i n claim 8 or claim 9, where R₄ i s H and R₁-R₃, R_a and R_b are as defined in claim 8 or claim 9 with a substituted butadiene under conditions forming the A ring of a compound of formula II and converti ng the group R_b at position 10 in formul a III to a hydroxy group which ta ken with the hydroxy group at position 9 in formula I II leads to a system tautomeric wi th the anthracycli none chromophore.

15. A method of obtai ni ng precursors of 12-deoxy carminomycinone or of 12-deoxy daunomyci none or their analogues or derivatives comprising reacting a compound of formula I I I as defined i n claim 8 or cl aim 9 w ith a substituted butadiene under conditions forming the A ring of a compound of formula II and, where R_b is not al ready H, converting it to H.

16. A method of obtaining 5-deoxy daunomycin or 5-deoxy adriamycin or their anal ogues or derivatives comprising either reduction of a compound of formula I as defined herein or tautomeric forms thereof, where R₁ i s not H, or reduction of a compound of formul a II as defi ned herein or tautomeric forms thereof, where R₄ is not OH, in either case to give a compound of formula II where R_x i s H.

17. A method as cl aimed i n any one of cl aims 12 - 15, wherei n the butadiene bears one or more of a 1 - R _{1 2}substituent, a 2-tri al kyl si lyloxy- or 2-al koxy- or 2hydroxyalkyl- or 2-oxoalkyl-, or 2 -hydroxyoxoalkyl- or 2dihydroxyalkyl-substituent, a 3-R₉-substituent, and a 4-R₈substituent.

18. A method of preparing organic compounds substantially as hereinbefore descri bed with reference to any one of the Examples.

19. A pharmaceutical composition comprising a compound in accordance with any one of claims 1 - 11 together with a pharmaceutically acceptable diluent.

20. The articles, things, parts, elements, steps, features, methods, processes, compounds and compositions referred to or indicated in the specification and/or claims of the appl ication individual ly or collectively, and any and al l combinations of any two or more of such.