DE2527568A1 - PROCESS FOR THE PRODUCTION OF ALKYLTE TRACYCLINES AND NEW TETRACYCLIN DERIVATIVES - Google Patents

Description

The present invention relates to a new process for the preparation of biologically active tetracycline derivatives. In particular the present invention relates to a new method for introducing a lower alkyl group of 1 to Carbon atoms in the 2-, 7- or 9-position of the tetracycline nucleus, and the new derivatives obtained in this way.

Applicant's Belgian patent specification 804 913 describes and claims a method for producing in 7-position substituted tetracycline derivatives. It consists in the

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essential in a selective alkylation of tetracycline derivatives of the following structure:

OH O

N (CH) _ 3 2

OH O

CONH,

wherein R ^ is hydrogen, hydroxy, acyloxy having 1 to 4 carbon atoms and R _{2 is} hydrogen or methyl, the corresponding derivatives monosubstituted in the 9-position being obtained, which are then subjected to an electrophilic substitution reaction in the 7-position; these 7- and 9-position disubstituted compounds are then appropriately treated to remove the 9-position substituent and the 7-derivatives are isolated and purified according to known procedures for such class of compounds.

According to the invention it was found that in the Belgian 7-Alky1tetracyclinderivate described in patent 804,913

2 with 1 to 4 carbon atoms and the new N- and 9-alkyl derivatives of tetracyclines, which are stable in acidic medium, such as sancycline (6-desmethyl-6-deoxy-tetracycline), minocycline (7-dimethylamino-6-desmethyl-6-deoxy-tetracycline), doxycycline (oi -ö-Deoxy-S-hydroxy-tetracycline) and their in the Belgian Patent 804 913 described and claimed 9-alkyl

derivatives,

in the case of those substituted in the 7-position

Derivatives are more advantageous or in the case of those in the N- or 9-position

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* 3.

substituted derivatives in an original way by electrophiles Reaction of a vX-Ch1 oralkylmethyIsulfids of the formula ClCH (R) -S-CHo, where R is hydrogen or lower alkyl of 1 to 4 carbon atoms, under anhydrous conditions and in the presence of an acidic condensing agent and then treating the alkyl sulfide intermediate with an excess of Raney-Niekel.

The chloroalkylmethyl sulfide reacts quickly, with the 7- and 9-positions of the tetracycline nucleus are attacked if they are free and no deactivating substituent is present, or the 2-carboxamido group can be attacked if the positions mentioned are occupied or if deactivating substituents are present.

The condensing agent can be strong organic or inorganic Be acid. It acts both as a condensing agent and as a solvent for the tetracycline and the sulfide and can be selected, for example, from sulfuric acid, methanesulfonic acid, hydrofluoric acid, THf 1 uoroacetic acid and its homologues.

The CX-ChI oralkylmethylsulfid can be used in the same amount as the tetracycline or in excess and it is added either immediately at the beginning of the reaction or in successive proportions. The reaction temperature can vary between ⁰ ° C. and 60 ^° C., but the process is usually carried out at room temperature. The time required for the reaction varies from a few hours to a few days. To convert the compounds thus obtained into the alkyl derivatives, the products are subjected to desulfurization with Raney nickel in a suitable solvent and under reflux.

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The suitable solvent is a lower alcohol such as Methanol or ethanol, which is preferably diluted with water, and the mixture is for a period of 1 refluxed to 18 hours, then the catalyst by centrifugation or filtration over Celite is removed. The nickel traces are acidic Removed washes of the tetracycline derivative in butanol solution

If you take, for example, the chloromethyl methyl sulfide and the simplest tetracycline, that is, the sancycline (I), gives the reaction when carried out with an excess on chloromethyl methyl sulfide for a longer period of time, the compound II

OH O

CONII

OH O

CONHR.

II

wherein

= CH ₂ SCH ₃ . However, if an equi-

equivalent amount of chloromethylmethyl sulfide is used, an equimolar mixture is obtained which consists of the 7-methylthiomethyl (formula II: R ₁ = R ₃ = H and R ₂ = CH ₂ SCH ₃ )

(Formula II: R ₁ = R ₃ = and the 9-methylthiomethyl derivatives (Formula II: and R ₂ = R ₃ = H).

= CH ₂ SCH ₃

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However, if an excess of reagent and short reaction times are used, the bis-derivative is mainly obtained (formula II: R ₁ = R ₂ = CH ₂ SCH ₃ and R ₃ = H). In the case of the 9-substituted sancycline analogs (Belgian patent 804 913), the 9-tert-butyl derivatives (II: R ₁ = C (CH ₃ ) ₃ , R ₂ = R ₃ = H), 7-methyl, are easily obtained thiotethyl derivative (II: R ₁ = C (CH ₃ J ₃ , R ₂ = CH ₂ SCH ₃ , R ₃ = H) and the corresponding bis-derivative (II: R ₁ = C (CH ₃ J ₃ , R ₂ = R ₃ = CH ₂ SCH ₃ )

In the case of doxycycline (III), in which the 7-position is through a methyl group in the 6-position is hindered, only two compounds are obtained, according to the reaction conditions,

CiI OH N (CH)

Jl t J *

OH

III

CONH.

CH OH N (CH)

OH O OH ⁰ "O IV

CONHR.

that is, the 9-methylthiomethyl derivative (IV: R ₁ = CH ₂ SCH ₃ , R ₃ = H) or the N ² , 9-methylthiomethyl derivative (IV: R ₁ = R ₂ = CH ₂ SCH ₃ ).

In the case of minocycline (V) one finally obtains due to the presence of a substituent in the 7-position only that N derivative:

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♦ 6.

OH O OH

(V)

CONH.

N (CH) J

OH 0 OH 0
(VI)

CONHR.

where Rg = CH ^ SCHg. As previously stated, the CH (R) SCHg radicals then into the corresponding alkyl radicals CH «R transferred by desulfurization with Raney-Niekel In the special case in which R stands for H, the CHg group is obtained by desulfurization.

The following examples serve to illustrate the invention without, however, restricting it.

example

7-Methylthiomethyl -6-desmethyl- 6-deoxy-tetracyciiη and 9-M ethylthiomethyl -6-desmethyl-6-desoxy-tetracyc el in

1.658 g (4 mmol) of e-desmethyl-δ-deoxy-tetracycline (I) are dissolved in 18 ml of trifluoroacetic acid, the mixture is ^{cooled to 0} ° C. and 0.332 ml (4 mmol) of chloromethylmethyl sulfide are added. After 24 hours at +4 ⁰ C the solvent is evaporated under reduced pressure and the residue

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Λ.

is converted into the hydrochloride by treatment with a solution of gaseous HCl in anhydrous methanol (HCl / MeOH). 1.8 g of a mixture consisting of 7- and 9-thiomethoxymethyl derivatives and from the starting material 6-desmethyl-6-deoxy-tetracycline are caused by precipitation from N-butanol / ethyl ether / petroleum ether obtain.

The 6-desmethyi-6-deoxy-tetracycline is easily purified by countercurrent purification in the mixture consisting of methyl isobutyl ketone / stylacetate / n-butanol / McElvain buffer pH 4.6 (480: 480: 210: 1100), and 0.9 g of a mixture consisting of the 7- and 9-methylthiomethyl derivatives is obtained in an approximate ratio of 1: 1.

Further countercurrent purification and partition chromatography over Celite yields 7-methylthiomethyl-ö-desmethyl-ö-deoxytetracycline; NMR spectrum (CDCl ₃ ) for the amphoteric form: 2.01cf (s, -S-CH ₃ ); 2.49 <f (s, -N (CH ₃ J ₂ ); 3.62 <f (s, -CH ₂ -S-); 6.78c ^r and 7.3IcT (two d, J = 9.0 Hz, C _g -H_ and C ₉ -HJ.

UV spectrum (CHoOH - HCl 0.01 η): λ _mav = 222, 268 and

ο m Q x

341 nm; and 9-methylthiomethyl -6-desmethy1-6-deoxytetracycl i η;

NMR spectrum (CDCl ₃ ) of the amphoteric form: 2.08cf (s, -S-CH ₃ ); 2.49 <f (s, -N (CH ₃ J ₂ ); 3.74 ({(s, - £ H_ ₂ -S-); 6.64cf and 7.3 * 8 ^ (two d, J = 8 , 0 Hz, C ₇ -H ^ and Cg-H ^);

UV spectrum (CH.OH - HCl 0.01 n):> _mav = 222, 271 and 345 nm.

w IH el X

Example 2

7, 9-Di-methylthiomethyl-6-desmethy1-6-des oxy-tetracycline

Dissolve 1 g of δ-desmethyl-e-deoxy-tetracycline (I) in 9 ml of trifluoroacetic acid and add 3 ml of chlorine

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methyl sulfide too.

After 15 hours at room temperature, the reaction mixture is as described in Example 1, treated.

1.3 g of crude product are obtained, which is obtained by dissolving in water and extracting the amphoteric form with chloroform after adjusting the pH is purified to 5.5 with 2N NaOH.

The chloroform extracts are obtained by concentrating and diluting 1.2 g of the 7,9-di-thiomethoxymethyl derivative with petroleum ether.

UV spectrum (CHoOH - HCl 0.01η): λ _av = 229, 270 and 345 nm.

O IEiQ X

NMR Spectrum (CDCl ₃ ): 2.01cf (s, -S-CjH ₃ in 7); 2.07 </ (s, -S- £ H ₃ in 9); 2.53cf (s, -N (£ H_ ₃ ) ₂ ); 3.62 <f (s, C ₇ -O ^ -S-); 3,73cf (s, C ₉ -CH ₂ -S); 7.32 cT (s, C ₈ -Ji).

example

7-Methy 1-6-desmethy1-6-des oxy-tetracycline

A solution of 5 g of 7-methylthiomethyl -6-desmethy1-6-deoxytetracycline hydrochloride (as obtained in Example 1) in 150 ml of methanol containing 2 ml of water is 16 hours refluxed with stirring in the presence of 50 g of Raney nickel. The catalyst is removed by centrifugation and washed with methanol acidified with HCl. The methanolic solution is evaporated under reduced pressure and the residue is dissolved in butanol.

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«T ♦

The butanol solution is several times with a saturated solution washed by NaCl acidified with HCl (pH 1.2) and then concentrated under reduced pressure. After removing a small amount of NaCl, the butanol solution, about 50 ml, diluted with ethyl ether. 2.5 g of 7-methyl-6-desmethyl-6-deoxy-tetracycline hydrochloride are obtained The sample is distributed by countercurrent distribution, as in Example 1 described, further cleaned.

UV spectrum (CHoOH - HCl 0.01η); λ _mav = 270 and 343 nm.

«J m Q x

NMR spectrum (CDC ^ -DMSO-dg, 1: 1) carried out for the amphoteric form: 2.17ο "(s, C ₇ -C ^ ₃ ); 2.45 cT (s, -N (CH ^) ₂ ) ; 6.71 / and 7.26cf (two d, J = 90 Hz, Cg-H and C ₉ -U).

example

g-Methyl-e-desmethyl-ö-deoxy-tetracycline

If you work as described in Example 3 and you start from 9-Methylthiomethy1 -6-desmethy 1-6-des oxy-tetracy eliη off, 9-methyl-6-desmethy1-6-deoxy-tetracycline is obtained

UV spectrum (CH-, ΟΗ - HCl 0.0In) 2 = 272 and 345 nm ^.:

O TTl α Χ

NMR spectrum (CDCIo) carried out for the amphoteric form: 2.2OcT (S ₁ C ₉ -CH ₃ ); 2.47 / (s, -N (CH ₃ ) ₂ ); 6, 53 J "and 7, 22 / (two d, ΰ = 7.0 Hz, C ₇ -H and Cg-H).

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example

7,9-dimethyl-6-desmethyl-6-deoxy-tetracycline

If you work as described in Example 3 and you start from 7,9-dimethylthiomethyl-o-desmethyl-ö-deoxy-tetracycline (as obtained in Example 2), 7,9-dimethyl-e-desmethyl-ö-deoxy-tetracycline is obtained.

UV spectrum (CH.OH - HCl Ό, ΟΙη): X _mav = 273 and 345 nm.

O FM el X

NMR spectrum (CDCIg) carried out on the amphoteric form: 2.17cf (s, C ₇ -C] I ₃ ); 2.20 / (S, C ₉ -CJi ₃ ); 2.46cT (s, -N (CH ₃ J ₂ ); 6.80 c ^r (s, C ₈ -Jl).

B is ρ ie 1

7-Methylthi omethyl -9-tert-butyl-6-desmethy1-6-deoxytetracyel in

3.6 ml of chloromethylmethyl sulfide are added dropwise at 0.degree to a solution of 6 g of 9-tert-butyl-ö-desmethyl-e-deoxytetracycline (Belgian patent 804 913) was added in 54 ml of trifluoroacetic acid. The reaction mixture is treated then as described in Example 2. 4.5 g of 7-methylthiomethyl-9-tert-butyl-e-desmethyl-δ-deoxytetracycline are obtained .

UV spectrum (CH.OH - HCl 0.01η): λ _mav = 234, 271 and 345 nm.

ο m et x

NMR spectrum (CDCl ₃ ) carried out for the amphoteric form: _{1.40 / (s, -C (CH 3} J ₃ ); 2.01cT (s, -S-CH_ ₃ ); 3.6l / (s, - CH ₂ -S-); 7.26 cf (s, C ₈ -H).

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example

7-methyl-9-tert-butyl-G-desmethyl-S-deoxy-tetracycline

If you work as described in Example 3 and use 6 g of 7-methylthiomethyl -9-tert-butyl-e-desmethyl-G-deoxytetracycline, 5.2 g of 7-methyl-9-tert-butyl-6-desmethyl-δ-deoxy-tetracycline hydrochloride are obtained in this way.

UV spectrum (CH, OH - HCl 0.0In): Λ. _mav = 229, 275 and 345 nm.

O m ο χ

NMR spectrum (DMSO-d,) carried out for the hydrochloride:

1.31 of (s, -C (CHg) ₃ ); 2.13 d "(s, C _{7 -Oi 3} ); 2.85 f (s ,? NH (CHg) ₂ );

7.28 _c ^r (s, C ₈ -H).

example

9-methyl thiomethyl-ex -S-deoxy-S-hydroxy-tetracycl in

30 g cx-e-deoxy-ö-hydroxy-tetracycline hydrochloride (III) are dissolved in 240 ml of trifluoroacetic acid, the mixture is cooled to -1O ⁰ C and 15 ml · chloromethyl methyl sulfide is added dropwise.

After 15 hours at room temperature, the trifluoroacetic acid becomes removed under reduced pressure and the residue is converted into the hydrochloride by treatment with HCl / MeOH. Crystallization from isopropanol / ethyl ether results 23.6 g of the hydrochloride of the 9-methylthiomethyl derivative. A sample is made by dissolving it in water and precipitating it amphoteric form further purified with 2N NaOH at pH 5.4. The precipitate is separated off by centrifugation and recrystallized from dimethylformamide-acetone-ethyl ether.

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• Λ.

UV spectrum (CH-, ΟΗ - HCl 0.01η): λ _mnv = 270 and 347 nm.

ö FTl α Χ

NMR spectrum (DMSO-dg) carried out for the amphoteric form:

1. 42cf (d, J = 5.0 Hz, C ₅ -CH ^ ₃ ); 1. 96cf (s, -S-JCH ₃ ); 2.49cT (s, -N (CH ₃ J ₂ ); 3.81cT (s, -CJl ₂ -S-); 6.87cT and 7.45 <T (two d, J =. 8.0 Hz, C ₇ -H and Cg-H).

example

g-methyl-c ^ -S-deoxy-S-hydroxy-tetracycline

Working as described in Example 3 and starting from 19.75 g of 9-methylthiomethyl -o ( -ö-deoxy-ö-hydroxy-tetracycline hydrochloride, 11.84 g of the crude hydrochloride of the 9-methyl derivative are obtained The product is purified by dissolving it in the minimum amount of boiling water and reprecipitating it by saturating the solution with gaseous HCl and then cooling it. Crystallization from isopropanol / ethyl ether gives 5.92 g of 9-methyl-c ^ -6-deoxy-5- hydroxy-tetracyeline hydrochloride.

UV spectrum (CH.OH - HCl 0.01η): λ _av = 272 and 345 nm.

NMR spectrum (DMSO-dg) carried out for the hydrochloride: 1.42cf (d, J = 5.0 Hz, C ₆ -C H ₃ ); 2.13cT (s, C ₉ -C ^ ₃ ); 2.83α ^Γ (s, ®NH (CH ₃ ) ₂ ); 6.18cT and 7.40 / (two d, J = 8.0Hz, C ₇ -U and C ₈ -H).

Example 10

N -Methylthiomethyl -7-dimethylamino-6-desmethyl-6-desoxytetracycline

8 g of 7-dimethylamino-6-desmethyl-6-deoxy-tetracycline dihydrochloride (V) are dissolved in 100 ml of trifluoroacetic acid

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and with external cooling with ice, 8 ml of chloromethylmethyl sulfide are added dropwise. After 5 days at room temperature the solution is filtered, diluted with isopropanol and concentrated to a small volume, then the Product by adding HCl / MeOH to the dihydrochloride convicted. Further concentration and dilution with ethyl ether give 8.79 g of crude product. This is going through Dissolve in water, adjust the pH to 6.5 with 2N NaOH and extraction with chloroform converted into the amphoteric form.

Countercurrent purification in the mixture described in Example 1 gives 4.36 g of the N ² -methyl thiomethyl derivative.

UV spectrum (CHoOH - HCl 0.01η): 3 _mav = 268 and 355 nm.

NMR spectrum (CDCl ₃ ) carried out on the amphoteric form: 2.22cf (s, -S-Oi ₃ ); 2.47 <f (s, C ₄ -N (CH ₃ J ₂ ); 2.59 <Γ ( _δ , C ₇ -N (CH ^) ₂ ); 4.47cf (d, J = 6 Hz, - CH ₂ -S-); 6.82 / and 7.32cT (two d, J = 9 Hz, Cg-H and C _g -H).

Example 11 N -Methyl-7-dimethyl amino-6-desmethyl-6-deoxy-tetracyel in

2
A solution of 7.26 g of N-methylthiomethyl-7-dimethylaminoe-desmethyl-δ-deoxy-tetracycline in 200 ml of _# methanol containing 2 equivalents of HCl is refluxed with stirring for 4 hours in the presence of 73 g of Raney nickel . The reaction mixture is filtered through Celite and this is washed with methanol. The methanol solution is then treated as described in Example 3. The thus obtained

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Crude dihydrochloride turns into the amphoteric form at pH 6.5 and by countercurrent distribution as in the example described cleaned.

2
2.40 g of the N -methyl derivative, which is isolated in the form of the dihydrochloride, are obtained.

UV spectrum (ChUOH - HCl 0.01n): 2 _mov = 265 and 355 nm.

O Iu el X

NMR spectrum (CDCl ₃ ) carried out for the amphoteric form: 2.47 / (S, C ₄ -N (£ H ₃ ) ₂ ); 2.59 / (S, C ₇ -N (CU ₃ ) ₂ ); 3.00 ₆ Γ (α, J = 5.2 Hz, CO-NH-CH ₃ ); 6.84c and 7.34 / (two d, J = 9.0 Hz, C ₈ -H and C ₉ -H _- ).

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Claims (23)

M / 16 090 Claims Process for the preparation of 7-, 9- or N -alkyl tetracyclines, in which the alkyl group contains 1 to 4 carbon atoms, characterized in that a tetracycline which is stable in an acidic medium is obtained under anhydrous conditions at a temperature in the range from 0 to 6O ⁰ C for one period of several hours to several days in the presence of a strongly acid condensing agent, which also acts as a solvent, with a u -ChIoralkylmethylsulfid of the formula Cl (R) CHSCH _3, wherein R is hydrogen or an alkyl radical having 1 to 4 carbon atoms, treated where a thiomethoxyalkyl derivative is obtained which can be isolated as such or can be subjected to desulphurization with Raney nickel for a period of between 1 and 18 hours, the corresponding alkyl derivative being obtained. 2. The method according to claim 1, characterized in that that the starting tetracycline is sancycline, minocycline, Doxycycline or its 9-alkyl derivatives are used. 3. Process according to Claims 1 and 2, characterized in that the condensing agent used is sulfuric acid, Methanesulfonic acid, hydrofluoric acid, trifluoroacetic acid and analogous compounds are used. 4. Compounds of the formula: - 15 509883/0991 M / 16 090 4u . ? ^(Cn 3 ^} 2 OH O OH CONHR " Oh " ³ wherein R ₁ , R ₂ and R ₃ for hydrogen or the RCHSCH ₃ radical stand, R is hydrogen or an alkyl radical having 1 to 4 carbon atoms and in which at least one of the three substituents is other than hydrogen. 5. Compound of formula OH CONIIR. wherein R 1, R ₂ and R _{3 represent} hydrogen or a lower alkyl radical having 1 to 4 carbon atoms and wherein at least one of the three substituents is different from hydrogen. 6. Compound of the general formula CH ₃ oh N (CH ₃ ) OH O OH 0 509883/0991 M / 16 090 wherein R ₁ and R- stand for hydrogen or the RCHSCH ₃ radical, wherein R represents hydrogen or an alkyl radical having 1 to carbon atoms and wherein at least one of the two substituents is different from hydrogen. 7. Compound of Formula CIl pH N (CH) ? 3 s? OH CONHR. wherein R, and R- are hydrogen or a lower alkyl radical having 1 to 4 carbon atoms and wherein at least one of the two substituents is different from hydrogen. 8. Compound of Formula N (CIl) CONHR OH O OH where R _{3 represents} the radical RCHSCH ₃ and R represents hydrogen or a radical having 1 to 4 carbon atoms. - 17 - 509883/0991 M / 16 090 9. Compound of Formula OH O OH CONHR. wherein R _{3 is} an alkyl radical having 1 to 4 carbon atoms. 10. Compound of Formula OH N (CH) - ο * CONIIR. wherein R ₂ and R _{3 represent} hydrogen or the RCHSCH ₃ radical and R represents hydrogen or an alkyl radical having 1 to 4 carbon atoms and wherein one of the two substituents is different from hydrogen. 11. Compound of Formula < ^C1I 3 ⁾ 3 ^C OH 0 OH - 18 - 509883/0991 M / 16 090 - wherein Ro and R, represent hydrogen or a lower one Alkyl radical with 1 to 4 carbon atoms and in which one of the two substituents of hydrogen is different. 12. 7-Methylthiomethyl-δ-desmethyl-ε-deoxy-tetracycline. 13. 9-Methylthiomethyl-6-desmethyl-G-deoxy-tetracycline. 14. 7,9-Di-methylthiomethyl-δ-desmethyl-δ-deoxy-tetracycline 15. 7-Methy ^ -6-desmethy ^ -6-deoxy-tetracycl ^ n. 16. g-Methyl-e-desmethyl-ö -deoxy-tetracycline. 17. 7,9-Dimethyl 1-6-des-methyl 1-6-deoxy-tetracycline. 18. 7-Methylthiomethyl-g-tert-butyl-e-desmethyl-δ-deoxytetracycline. 19. 7-Methy 1-9-tert-butyl-6-desmethyl 1-6-deoxy-tetracycline. 20. 9-Methylthiomethyl-f * -e-deoxy-B-hydroxy-tetracyclic η 21. 9-methyl- # -6-d es oxy-5-hydroxy-tetracycline. 22. N ² -Methylthiomethyl W-dimethylamino-δ-desmethyl-edesoxy-tetracycline. 23. N ² -Methyl 1-7-dimethyl amino-6-desmethy 1-6-des oxy-tetracyel in. 21 / V. - 19 - S09883 / Q991