JPH0713071B2 - Synthesis of adenine nucleoside derivative - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel method for synthesizing an adenine nucleoside derivative, particularly a 3′-deoxy-2′-ketoadenosine derivative.

(Background of the Invention and Prior Art) Among the branched sugar analogs of adenosine, those which are resistant to adenosine deaminase and show inhibitory activity against cancer cells, certain bacteria and filamentous fungi are known [E . Walton (E.Walton) such as journal of the American Chemical Soaeti (J.Am.Chem.Soc.), 88, 4524 (196
See 6)].

On the other hand, recently, keto nucleosides have been increasingly used as intermediates for various chemical conversions including the synthesis of branched sugar nucleosides.

Therefore, it is considered that the synthesis of adenosine ketonucleosides is useful for the synthesis of novel analogs which can be expected to have physiological activity.

Among the adenosine ketonucleosides, 2'-ketonucleosides are conventionally 3'-deoxy-5'-
There is a method in which 0-trityladenosine is oxidized with CrO ₃ / pyridine / Ac ₂ O to obtain a corresponding 2'-ketonucleoside [Hansske, F. et al. (1984) Tetrahedron 40] , 125].

This method gives the corresponding 2'-ketonucleosides in relatively good yield (about 67%), but with the 3'starting material.
There is a problem that the preparation of -deoxy-5'-0-trityladenosine is complicated, and a method for obtaining it in a higher yield is desired.

(Object of the invention) Therefore, an object of the present invention is to provide a method for synthesizing a 3'-deoxy-2'-ketoadenosine derivative in an extremely high yield.

(Structure of the Invention) The present invention has the formula [I] (In the formula, R ¹ and R ² represent a trityl group or a dimethoxytrityl group, and R ³ represents a methanesulfonyl group or a toluenesulfonyl group.) The compound represented by the formula [II ] (In the formula, R ¹ and R ² are the same as above) The present invention relates to a method for synthesizing an adenine nucleoside derivative, which is characterized in that

The present invention also provides a compound of formula [III] by treating the compound of formula [II] with silica gel. The present invention relates to a method for synthesizing an adenine nucleoside derivative characterized by obtaining a compound represented by

The starting material of the present invention can be obtained, for example, by the following steps.

(In the formula, R ₁ , DMT or Tr is shown, R ₂ is DMT or Tr, and R ₃ is Ts or Ms.) The desired compound [II] of the present invention is obtained from the obtained starting material [I] as follows. First, as the solvent, methanol, ethanol, propanol, tetrahydrofuran, ether, dimethylsulfoxide, dimethylformamide, ethyl acetate, benzene, hexane, dichloromethane, or a combination thereof can be used.

Examples of the metal alkoxide of the reagent used include magnesium methoxide, magnesium ethoxide, magnesium propoxide, magnesium t-butoxide and other magnesium methoxides, lithium alkoxides,
Sodium lower alkoxide, potassium lower alkoxide, aluminum lower alkoxide and the like can be used.

The amount of metal alkoxide used is 1 to 20 with respect to the starting material.
Molar equivalents are suitable.

Reaction temperature, reaction time, −70 to 100 ° C., 5 minutes to 12 hours are suitable.

The reaction is preferably carried out in an inert gas atmosphere. The protecting group can be eliminated by treating the obtained compound with the zinc bromide method or 80% acetic acid.

Further, in the present invention, the obtained β-adenine nucleoside derivative [II] can be anomerized by treating with silica gel to synthesize an α-adenine nucleoside derivative [III].

Hereinafter, the present invention will be described with reference to examples and examples.

Reference Example 1 3'-0-tosyl-adenosine-p-toluenesulfonate (Compound 1) The method of Wagner et al. And Uesugi et al. [Wagner, D., Verhayden, JPH and Moffat, JG ( Wagner, D., Verheyden, JPHand Moffatt, J.
G.) (1974) Journal of Organic Chemistry (J.Org.Chem)., 39 , 24: and Wesugi, S., Kaneyes,
T., Matsugi, J. and Ikehara, M. (Uesugi, S., Kaneyasu,
T., Matsugi, J.and Ikehara, M.) (1983) Nucleosides an Nucleosides
d Nucleotides), 2 , 373] was partially improved.

Amorphous 2 ', 3'-0-stanylene adenosine synthesized according to the literature from adenosine (10.68 g, 40 mmol) and dibutyltin oxide (9.96 g, 40 mmol) was added with methanol (20 ml) and heated to a large volume. Melted part. Dioxane (180 ml), triethylamine (18 ml) and tosyl chloride (22.87 g, 120 mmol) were sequentially added to this with vigorous stirring and stirring was continued overnight at room temperature. The precipitated crystals were separated, the liquid was concentrated under reduced pressure, and boiling methanol (60 ml) was added to the residue to dissolve the amorphous solid, and the mixture was allowed to stand at room temperature overnight. The precipitated crystals (2'-tosyl adenosine) were collected, washed with cold methanol, and the washings were combined and concentrated under reduced pressure. Boiling water (60 ml) was added to the residue, the mixture was stirred well and left at about 5 ° C. overnight. The insoluble matter was removed, washed with cold water (100 ml) and then with ether (100 ml), and the residue was dried and crystallized from methanol. 3'-0-tosyladenosine-p-toluenesulfonate (Compound 1) 3.12 g (yield 13%).

Physical properties of Compound 1 Melting point 195-196 ° C (dec) Elemental analysis CHN S Calculated value 48.56 4.59 11.80 10.80 (as C ₂₄ H ₂₇ N ₅ O ₉ S ₂ ) Measured value 48.55 4.57 11.70 10.71 Specific optical rotation ▲ [ α] ²⁷ _D ▼ = −23.0 ° (C = 0.94, DMSO) UV spectrum (MeOH) λmax 258 nm (ε16,200) IR spectrum (KBr) 3461 1686 1363 (S = O) 1039 891 630 3341 1586 1178 (S = O) 1013 818 560 3176 1511 1126 934 723 495cm -1 2951 1430 1101 913 691 NMR spectrum _{(DMSO-d 6) δ 2.29} (3H, S, CH 3) 5.95 (1H, d, H-1 ') 2.43 ( 3H, S, CH ₃ ) 7.12 (2H, d, Ar) 3.42 (1H, dd, H-5 ') 7.50 (4H, m, Ar) 3.58 (1H, dd, H-5 ") 7.88 (2H, m , Ar) 4.12 (1H, m, H-4 ') 8.47 (1H, S, H-2) 4.83 (1H, dd, H-2') 8.66 (1H, S, H-8) 5.03 (1H, dd , H-3 ') reference example 2 N ^6, 5'-0- di - (4,4'-dimethoxytrityl) -
3'-0-Tosyladenosine (Compound 2) 3'-0-Tosyladenosine-p-toluenesulfonate (Compound 1) (3.27 g, 5.5 mmol) was dissolved in anhydrous pyridine (30 ml) and added to it. ′ -Dimethoxytrityl chloride (3,72 g, 11 mmol) was added and the mixture was stirred at room temperature for 24 hours. Pyridine-methanol (1: 1, 3 ml) was added, the mixture was extracted with chloroform, and the chloroform layer was washed with water, sodium bicarbonate water and water in this order, and then dried over magnesium sulfate. The organic solvent was removed under reduced pressure, and the residue was subjected to silica gel column chromatography (developing solvent: toluene-ethyl acetate-triethylamine (9: 1: 0.1) → toluene-ethyl acetate-triethylamine-methanol (9: 1: 0.1: 0.1). It was purified and recrystallized in benzene-ether to obtain 3.65 g (yield 65%) of dimethoxytrityl-protected nucleoside (Compound 2).

Physical properties of Compound 2 Melting point 130 (semi-melting) -142 ° C Elemental analysis CHN S Calculated value 69.48 5.44 6.72 3.08 (as C ₅₉ H ₅₅ N ₅ O ₁₀ S ・ 0.2C ₆ H ₆ ) Measured value 69.64 5.50 6.77 2.95 Specific rotation ▲ [α] ²² _D ▼ ＝ ＋ 4.8 ° (C = 0.57, CHCl ₃ ) UV spectrum (MeOH) λmax 274nm (ε24,200) IR spectrum (KBr) 3350 1599 1290 899 564 3040 1504 1242 820 549 2940 1453 1169 698 cm ^-1 2850 1363 1024 660 NMR spectrum CDCl ₃ , δ 2.40 (3H, S, C-CH ₃ ) 5.02 (1H, q, H-2 ') 3.07 (1H, dd, H-5 ') 5.08 (1H, dd, H-3') 3.39 (1H, dd, H-5 ") 5.88 (1H, d, H-1 ') 3.76 3.77 (12H, S, O-CH 3) 7.97 (2H , S, H−2, H−
8) 4.42 (1H, m, H-4 ¹ ) Reference Example 3 2 ′, 5′-di-0-t-butyldimethylsilyl-N ⁶ −
(4,4'-Dimethoxytrityl) adenosine (Compound 3) 2 ', 5'-di-0-t-butyldimethylsilyladenosine [GH Hakimaki, Zubaignew, A. Prova and KK
Ogilvie (GHHakimelaki, ZZbigniew, A.Proba, and
KkOgilvie), Canadian Journal of Chemistry (Can.J.Chem)., 60 , 1106 (1982)], (2.94g, 5.9
Mmol) was dissolved in dry pyridine (30 ml), dimethoxytrityl chloride (2.61 g, 7.7 mmol) was added, and the mixture was stirred at room temperature for 17 hours. The reaction was stopped by adding a 50% aqueous pyridine solution, the mixture was extracted with ether, the organic layer was washed with water, dried over anhydrous magnesium sulfate, and then the organic solvent was removed. The residue was applied to silica gel column chromatography (developing agent, toluene-ethyl acetate-triethylamine (9: 1: 0.1), and DMT was applied.
4.21 g (89%) of the protected adenosine derivative (Compound 3) was obtained.

Physical properties of Compound 3 Powder (amorphous) elemental analysis C H N Si Calculated value 64.71 7.45 8.77 7.04 (as C ₄₉ H ₅₉ N ₅ O ₆ Si ₂ ) Measured value 64.62 7.41 8.66 6.84 Specific rotation ▲ [α] ²² _D ▼ = −29.7 ° (C = 0.52, CHCl ₃ ) UV spectrum (MeOH) λmax 274nm (ε24,700) IR spectrum (KBr) 3340 1598 1247 1031 741 3130 1507 1173 905 694 3040 1459 1148 823 578cm ^-1 2940 1288 1051 775 NMR spectrum CDCl ₃ , δ −0.17 (3H, S, C−CH ₃ ) 4.00 (1H, dd, H−5 ″) −0.07 (3H, S, C−CH ₃ ) 4.19 (1H, m, H-4 ') 0.12 (3H , S, C-CH 3) 4.26 (1H, q, H-3') 0.14 (3H, S, C-CH 3) 4.65 (1H, t, H-2 ') 0.80 (9H, S, t-Bu) 6.05 (1H, d, H-1 ') 0.95 (9H, S, T-Bu) 8.04 (1H, S, H-2) 3.78 (6H, S, O-CH ₃ × 2) 8.11 (1H, S, H-8) 3.84 (1H, dd, H-5 ′) Reference Example 4 N ^6- (4,4′-dimethoxytrityl) -3′-0-tosyladenosine (Compound 4 ) 2 ', 5'-di -0-t-butyldimethylsilyl -N ⁶ -
(4,4'-Dimethoxytrityl) adenosine (Compound 3) (1.78 g, 2.2 mmol) was dissolved in dry pyridine (20 ml), tosyl chloride (2.46 g, 8.8 mmol) was added, and the mixture was stirred at room temperature for 5 days. The reaction was stopped by adding a 50% aqueous pyridine solution, the mixture was extracted with ether containing a small amount of chloroform, the organic layer was washed with water, sodium bicarbonate water, and water in this order, and then dried over anhydrous magnesium sulfate. The organic solvent was removed.
The residue was dissolved in tetrahydrofuran (18 ml), tetrabutylammonium fluororad (4.4 mmol) in tetrahydrofuran (4.4 ml) was added, and the mixture was stirred at room temperature for 30 min. It was extracted with ether containing a small amount of chloroform, washed with water, and dried over anhydrous magnesium sulfate. The organic solvent was removed, and the residue was subjected to silica gel column chromatography (developing agent, chloroform-ethyl acetate (93: 7)) to give 3 '.
-Tosyl compound (Compound 4) 1.37 g (yield 85%) was obtained.

Physical properties of Compound 4 Amorphous powder Elemental analysis CHN S Calculated value 63.06 5.15 9.68 4.43 (as C ₃₈ H ₃₇ N ₅ O ₈ S) Measured value 62.92 5.14 9.57 4.33 Specific optical rotation ▲ [α] ²¹ _D ▼ = −29.6 ° (C = 0.64, CHCl ₃ ) UV spectrum (MeOH) λmax 273 nm (ε21,100) IR spectrum (KBr) 3425 3140 2850 1466 1246 900 701 3324 3050 1600 1366 1171 822 681 3220 2950 1506 1291 1031 786 551 cm ^-1 NMR spectrum _{CDCl 3, δ 2.46 (3H,} S, C-CH 3) 5.76 (1H, d, H-1 ') 3.55 (1H, t, H-5') 7.39 (2H, d , Ts) 3.76 3.77 (6H, S, O-CH ₃ ) 7.76 (1H, S, H-2) 3.82 (1H, d, H-5 ″) 7.85 (2H, d, Ts) 4.37 (1H, S, H-4 ') 7.95 (1H , d, H-8) 5.11 (2H, m, H-2', H-3 ') example 5 N ^6, 5'-0- di - (4,4' Dimethoxytrityl)-
3'-0-tosyl adenosine (Compound 2) (alternative method) N ⁶ - (4,4'-dimethoxytrityl) -3'-O-tosyl adenosine (Compound 4) (490 mg, 0.68 mmol) in anhydrous pyridine (4ml ), 4,4'-dimethoxytrityl chloride (230 g, 0.68 mmol) was added, and the mixture was stirred at room temperature for 80 minutes. The reaction was stopped by adding a 50% aqueous pyridine solution, the mixture was extracted with ether containing a small amount of chloroform, washed with water, and dried over anhydrous magnesium sulfate. The organic solvent was removed, and the residue was treated in the same manner as in the other method (from 3'-0-tosyladenosine-p-tosylate) to give 618 mg of the title compound (Compound 2).
(Yield 89%) was obtained.

EXAMPLE 1 N ^6, 5'-0- di - (4,4'-dimethoxytrityl) -9
-(3-Deoxy-β-D-glycero-pentofuranosyl-2-ulose) adenine (Compound 5) Magnesium methoxide in methanol solution prepared from edible metal magnesium (48.6 mg, 2 mmol) (5 m
l) to DMT-protected 3'-tosyl compound (Compound 2) (513 mg, 0.5
(5 mmol) of benzene) in a dry nitrogen stream was added dropwise with stirring at room temperature under stirring at room temperature for 15 minutes, and immediately cooled with ice water. The reaction was stopped by adding an aqueous solution of ammonium chloride, the mixture was extracted with ether containing a small amount of chloroform, the organic phase was washed several times with water, dried over magnesium sulfate and concentrated.

The residue was dissolved in dichloromethane (4 ml) and pentane (40 m
l) was dripped into the mixture under vigorous stirring, the resulting white precipitate was collected, and dried to give β-form (compound 5) 396 mg (yield 93%).
Got This product was easily anomerized and contained 10% or less of α-form, but it can be used as it is as a raw material for synthesis without purification. The analytical sample was purified by column chromatography (developing agent, benzene-ethyl acetate (85:15)) using neutral silica gel (Silica AR) manufactured by Mallinckrodt.

Physical properties of compound 5 Powder (amorphous) Elemental analysis C H N Calculated value 72.37 5.61 8.12 (as C ₅₂ H ₄₇ N ₅ O ₇・ 0.5H ₂ O) Measured value 72.16 5.66 7.81 Specific rotation ▲ [α] ²⁴ _D ▼ = -14.9 ° (C = 0.50, CHCl ₃ ) TLC Rf = 0.52 [Silica gel: benzene-ethyl acetate (7: 3)] UV spectrum (MeOH) λmax 273 nm (ε23,200) λsh 234 nm (ε35, 100) IR spectrum (KBr) 3420 1604 1297 828 2950 1507 1252 703 2850 1467 1180 584 cm ^-1 1774 (C = O) 1034 NMR spectrum CDCl ₃ , δ 2.76 (1H, dd, H-3 ') 3.76,3.77 ( 12H, S, OCH ₃ ) 3.13 (1H, dd, H-3 ″) 4.61 (1H, m, H-4 ′) 3.49 (1H, dd, H-5 ′) 5.85 (1H, S, H-1 ′) ) 3.42 (1H, dd, H -5 ") 7.78 (1H, S, H-2) 7.97 (1H, S, H-8) example 2 N ^6, 5'-0- di - (4,4 ' -Dimethoxytrityl) -9
-(3-Deoxy-α-D-glycero-pentofuranosyl-2-ulose) adenine (compound 6) 3'-tosyladenosine (compound 2) (1.03 g, 1 mmol) was prepared in the same manner as the corresponding β-form. The crude product (β-form) obtained by treating
Column chromatography using 160 g of Merck silica gel (Kieselgel 60) (developing agent, benzene-ethyl acetate-
Triethylamine (9: 1: 0.1)) was carried out to carry out anomerization to obtain a β-form excess mixture (α: β≈9: 1). This was again subjected to column chromatography (developing agent, benzene-ethyl acetate (95: 5)) using Mallinckrodt's (neutral) silica gel (100 g), and the eluate was combined and concentrated. Dichloromethane-pentane treatment was carried out in the same manner as in, to give 567 mg (yield 66
%) Was obtained.

Physical properties of Compound 6 Powder (amorphous) Elemental analysis C H N Calculated value 73.55 6.00 7.87 (as C ₅₂ H ₄₇ N ₅ O ₇・ 0.5C ₅ H ₁₂ ) Measured value 73.34 6.11 7.85 Specific rotation ▲ [α] ²⁴ _D ▼ = + 3.8 ° (C = 0.54, CHCl ₃ ) TLC Rf = 0.71 [silica gel: benzene-ethyl acetate (7: 3)] UV spectrum (MeOH) λmax 273 nm (ε 28,700) λsh 234 nm ( ε39,800) IR spectrum (KBr) 3425 1774 (C = 0) 1460 1175 702 2950 1606 1329 1034 582 2850 1506 1250 825 cm ^-1 NMR spectrum CDCl ₃ , δ 2.73 (1H, dd, H-3 ') 5.00 ( 1H, m, H-4 ') 3.2 (2H, m, H-3 ¹ "H-5') 5.92 (1H, S, H-
1 ') 3.57 (1H, dd, H-5 ") 7.81 (1H, S, H-2) 3.78 3.79 (12H, S, OCH ₃ ) 7.92 (1H, S, H-8) Reference Example 6 9- ( 3-Deoxy-α-D-glycero-pentofuranosyl-2-ulose) adenine (Compound 7) DMT-protected α-form (Compound 6) (427 mg, 0.5 mmol) in chloroform (1 ml) was brominated. A mixed solution of zinc (900 mg, 4 mmol) in methanol (1,1 ml) -chloroform (4 ml) was added, the mixture was stirred at room temperature for 4 hours, diluted with chloroform (40 ml) and the desired product was extracted with water (20 ml). Azeotropically with ethanol at about 45 ° C or below
The precipitate was concentrated under reduced pressure to 5 ml, and the resulting precipitate was separated using Celite and washed with water. Approximately 3m as before with the combined liquid and wash
The solution was concentrated to l, the insoluble portion was separated again, and the liquid was directly adsorbed on an activated carbon column (1.3 × 6 cm). After washing with water (50 ml), the mixture was extracted with 80% aqueous methanol solution and the eluate containing nucleoside was concentrated to obtain 63 mg of α-form (yield about 50%).

The product was easily anomerized and was a mixture of α: β = 93: 7.

Physical properties of compound 7 TLC Rf = 0.43 [silica gel: chloroform methanol (8: 2)] Reference Example 7 9- (3-deoxy-β-D-glycero-pentofuranosyl-2-ulose) adenine (Compound 8) β-compound with DMT protecting group (Compound 5) (427 mg, 0.5 mmol) was α-compound Free β-form (8) 76mg
(Yield about 61%) was obtained. The product was a mixture of α: β = 18: 82.

Physical properties of compound 8 TLC Rf = 0.43 (silica gel: chloroform-methanol (8: 2))

Claims (2)

[Claims] 1. A formula [I] (In the formula, R ¹ and R ² represent a trityl group or a dimethoxytrityl group, and R ³ represents a methanesulfonyl group or a toluenesulfonyl group.) The compound represented by the formula [II ] (Wherein R ¹ and R ² are the same as above). A method for synthesizing an adenine nucleoside derivative, which comprises: 2. A formula [I] (In the formula, R ¹ and R ² represent a trityl group or a dimethoxytrityl group, and R ³ represents a methanesulfonyl group or a toluenesulfonyl group.) The compound represented by the formula [II ] (Wherein R ¹ and R ² are the same as above), and the compound of the formula [II] is treated with silica gel to obtain the compound of the formula [III] (Wherein R ¹ and R ² are the same as above). A method for synthesizing an adenine nucleoside derivative, which comprises: