JPH02290894A - Synthetic intermediate for glycolipid and its production - Google Patents

Abstract

NEW MATERIAL:The compound of formula I [R<2> to R<4> are (protected) OH; R<5> is (protected) OH or ether bonded to a ring of a sugar which may have substituent; R<6> is H or OH-protecting group; R<7> is alkyl or alkenyl]. USE:A synthetic intermediate for glycolipid. PREPARATION:A compound of formula II (R<1> is lower alkyl) is made to react with a compound of formula III in the presence of a thiol-activation reagent.

Description

[Detailed Description of the Invention] (Prior Art) Gangliosides exist in cell membranes, and are involved in a wide variety of physiological functions such as cell differentiation, carcinogenesis, and immunity. In order to elucidate these functions, there has been a strong desire to establish chemical synthesis of gangliosides.

High-yield and stereoselective glycosylation of oligosaccharide monomers and lipid ceramides has been one of the important issues. The conventionally used imidate method (R, R. Schmid
t, R. Kager, Angew. Chemie,
, IntEd, Engl, vol. 24, p. 65. 1
985), fluorinated sugar method (T. Mukaiyama)
et al. Chem, Lett, p. 431, 19
(1981) had problems such as low reaction yield and many reaction steps, and there was a desire to develop a reaction with high yield and high stereoselectivity.

(Problems to be Solved by the Invention) Therefore, an object of the present invention is to provide a glycosylation reaction that can easily produce glycolipids from saccharides and lipid ceramides with high yield and high stereoselectivity.

(Means for Solving the Problems) The present inventor has proposed that when activation is not performed, acidic,
When thioglycosides, which are relatively stable under both basic conditions, are used as glycoside donors, the alkylthiol group acts as a very suitable leaving group upon appropriate activation, allowing glycosylation to occur in high yields and with high selectivity. They discovered that the reaction progresses and completed the present invention.

That is, the present invention provides a compound represented by the following formula (I) that is reacted with a compound represented by the following formula (I) in the presence of a thiol activating reagent to form the following formula (I[I) R' and the following formula (I[)]. A method for producing a compound represented by a compound (in the formula, R1 represents a lower alkyl group that may have a fraction, and Rt, R3, and R4 each represent a hydroxyl group protected with a protecting group or a free hydroxyl group) RS represents a hydroxyl group protected with a protecting group, a tx-free hydroxyl group, or an ether group bonded to the ring of a saccharide which may have a substituent, R6 represents hydrogen or a protecting group for the hydroxyl group, R
7 represents an alkyl group or an alkenyl group).

Rl is a methyl group, an ethyl group, an n-probyl group,
Isoprobyl group, n-butyl group, sec-butyl group, t
Examples include ert-butyl group.

Examples of RS include a hydroxyl group protected with a hydroxyl protecting group described below, a free hydroxyl group, and an ether group bonded to the ring of a saccharide, such as, for example.

R7 is 01-C. alkyl group, C, ~Cal
The alkenyl group of is preferred, and the alkyl group of CZ3 is particularly preferred. The alkyl group and alkenyl group may be linear or branched.

Examples of synthesis using the method of the present invention are shown below. α/β=5
7/4 3 α/β=65/35 The compound obtained above can be easily led to ganglioside GM 3 by deprotection. The rainbow is a report by Okamoto and Kondo (Bull. Chem. Soc. J
pn. , 60 volumes. 631, 1987).

In the above scheme, Bn is a benzyl group, and TBDPS is 3
class butyldiphenylsilyl group, Piv is pivaloyl group,
H11 represents a tertiary butyl group, Bz represents a benzoyl group, Ac represents an acetyl group, and Ph represents a phenyl group.

The method of the present invention involves glycosylating a thioglycoside substituted with an alkylthio group by reacting a ceramide of a lipid, in which a thioglycoside serving as a glycosyl donor is activated using a thiol activating reagent to perform a condensation reaction. There are characteristics in what you do. As the thioglycoside serving as a glycosyl donor, ethylthio (Et-S-) derivatives are preferred, but other examples include tertiary butylthio (+S-), methylthio (CH.-S-),
Alkylthio derivatives such as isobrobylthio()-S-) can also be suitably used. As the thioglycosyl derivative, compound 2 in the above scheme and saccharides such as ethylthio derivatives of galactose can also be used. Although the hydroxyl groups of these thioglycosyl derivatives may be used as free hydroxyl groups in the glycosylation reaction of the method of the present invention, it is preferable to use a protecting group that is usually used for protecting hydroxyl groups,
For example, it is desirable to protect with a protecting group such as a benzyl group, benzoyl group, acetyl group, silyl group, or acetonide allyl carbonate group. After completion of the glycosylation reaction, these binders 15 are easily removed by conventional methods such as catalytic reduction and acid treatment to yield the desired glycosyl compound.

To activate the alkylthio group, a thiol activating reagent such as DMTST (dimethylmethylthiosulfonium triflate) or phenylselenyl triflate can be used. These reagents activate the thiol group, producing a sulfonium ion that acts as an active leaving group. The reaction is usually carried out at a temperature in the range of -20°C to 50°C, preferably in an inert gas stream such as N2 or argon.

The solvent is preferably an anhydrous solvent, such as anhydrous methylene chloride, anhydrous ethylene dichloride, anhydrous acetonitrile, dimethyl sulfoxide, dimethylformamide, ditromethane, and the like. The reaction time is usually 1 to 24 hours under these conditions. Dehydration may be carried out using a method using molecular sieves.

Note that it is preferable to carry out the above reaction in the presence of molecular sieves. Molecular sieves act as a dehydrating agent in the reaction system and are useful for improving reaction yield and selectivity. For example, Molecular Thieves AW-3'0
0, 4A, 3A, etc. may be used. In carrying out the above reaction, the thioglycosyl form as a glycosyl donor is added at 1 mol to 3 mol based on the ceramide form.
When using an activation reagent such as DMTST, the amount is usually 1 to 3 moles per ceramide body. You can use Moreover, it is preferable to use the molecular sieves in an amount 10 times the weight of the ceramide body. Furthermore, it is preferable to use the solvent in an amount 30 times the weight of the solute.

In the reaction step, for example, a thioglycosyl compound and a ceramide compound are dissolved in a solvent such as anhydrous methylene chloride (anhydrous treated with Catlz), and molecular sieves (for example, molecular sieves AW-300) are added thereto and the mixture is heated at room temperature for 30 minutes under an argon atmosphere. Stir for ~100 minutes. After this operation, the reaction mixture is cooled to 0°C and the DMTST is normally
After dropwise addition of LtJ solution and reaction for about 30 minutes to 24 hours, preferably after stopping the reaction with an amine such as triethylamine, after usual post-treatment, for example, filtration using Celite, 5% Nal{COi aqueous solution Wash with anhydrous N
The solvent may be distilled off after dehydration using atS04 or the like.

The yield of the reaction is usually 25% or more, and the stereoselectivity is, for example, α/β=1 to 0, as shown in the scheme. (Effects of the Invention) The method of the present invention enables high-yield and highly stereoselective glycosylation of lipid ceramide.

This method has the characteristics of providing the desired glycolipid in high yield with an extremely simple operation.

(Example) The synthesis of glycolipids using the method of the present invention will be shown as an example below, but the present invention is not limited to these examples.

The reagents, measuring instruments, etc. used in the examples are shown below.

NMR: JEOL GX-5 0 0C
DC j! * was used as a solvent, and chemical shifts were expressed as δ values using tetramethylsilane as an internal standard.

Silica gel: Fuji Davison Chemical B W-20
0 Silica gel plate: Merck Kieselgel 60 F
254S Solvent: CIIzCI! ．． z and CH2CN were distilled using Callz and then evacuated. For the rest, first-class products from Hani Chemicals and Wako Pure Chemical Industries were used as they were.

In addition, the compound numbers in the examples correspond to the compound numbers in the above scheme.

Example 1 1 20■ and 2 14■ were treated with CI. C/! 20.4-
Dissolved in molecular sieves AW-300 13
0 ■ was added, and the mixture was stirred at room temperature for 100 minutes under an Ar flow.
There 0. 2 3 M DMTST (CH.C ff
i! Solution) 0.2d was added dropwise while stirring at 0°C,
After 30 minutes, the reaction solution was filtered through Celite. Add 5% Na to the filtrate.
H.C.O. Wash with anhydrous NazSO. After dehydration, the mixture was concentrated to dryness under reduced pressure. The residue was separated by silica gel column chromatography (hexane/ethyl acetate = 7/1) and was a mixture of α/β = 5 7/4 3. NMR measurements were performed on the mixture as it was.

Properties: Pale yellow oily NMR (signal derived from alpha form) 5.61 (ppm) d lll Nil
J=8.5 (Hz)5.37
dd ill Cer-4 J=7.5.
15.25.18 td III
Cer-5 J=6.8, 15.24.77
d IH Glu-1' J=4
．． 03.52 dd Ill Glu
-2' J=4.0, 9.3 (signal derived from β body) 5.54 (ppm) d IH Nl{
J・8.5 (lh) 5.30 dd
1}I Cer-4 J=7.5. 15.05
．． 03 td IH Cer-5 J=6
．． 8, 15.04.32 dltl
Glu-1' J=7.8 Example 2? Then, Molecular Sieves AW-300130■ was added, and the mixture was stirred at room temperature for 30 minutes under an Ar flow. There 0
．． 2 3 M DMTST (CH■C2.} solution) 0
．． 2d was added dropwise while stirring at -23°C, and -23
The reaction was carried out at °C. After 40 minutes, add 10μ of Et and N! and stopped the reaction. The reaction solution was filtered through Celite, and the filtrate was concentrated to dryness under reduced pressure. Transfer the residue to a silica gel plate (hexane/
(Developed 3 times with ethyl acetate = 5/3). Separate and target object 8
．． 2■ was obtained (yield 25%). This compound is α/β=
It was a 65/35 mixture. Various measurements were performed on the mixture. Properties: Pale yellow oil. Same as NMR 3 signals.

However, the intensity ratios of the α and β signals were different.

Example 3 6 15.0mgS1 23.8mg as CIItC
l z 0. Molecular Sieves AW-300130■ was added to the solution, and the mixture was stirred at room temperature for 30 minutes under an Ar stream. There 0. 2 3 M DM
TST CLC l t solution 0. 21 was added with stirring, and after 4 hours, Et3N was added to stop the reaction. The reaction solution was filtered through Celite, and the filtrate was concentrated to dryness under reduced pressure. The residue was purified by silica gel column chromatography (hexane/ethyl acetate = 8/
1), the target object lO. 7■ was obtained (yield 29%)
.

Properties: Pale yellow oil NMR 7.7-7.3 (ppn+) cm 10N Aromatic hydrogen 5.44 5.32-5.26 5.16-5.08 4.97 4.46 4.23 4.19 4.16-4.03 3.61 3.58 2.19-1.84 1.69 1.3-1.2 d III tn 2H m 2H dd ill d IH dd 1}1 dd IH m 3H m IH m IH m21st br 28 br 6411 1.01 s 911 0.90-0.86 br 6H Example 4? H J=8.5 (II ■) Glu
-3' Cer-4 Glu-4' Cer-5 Glu-2' J=7.6.9.4Glu-
1' J=7.6 Cer-I J=9.4.3.7Cer-
3 J=7.2, 7.2Glu-6'
Cer-2 Glu-5' Cer-1 COCI1■ Cer-6 COCL-Cz+IIn■, C It = C II C II■-C+ lHz■
Si4CJ* Cz+lLz-Clli, C+ +lI■z-CH
Dissolved in molecular sieves AW-300120
Add ■, and stir at room temperature under a stream of air for 1 hour. . There 0
．． 2 5 M DMTST (Cll■C2■ solution)
After 3 hours, Et3N was added to stop the reaction. The reaction solution was filtered through Celite, and the filtrate was concentrated to dryness under reduced pressure. The residue was separated on a silica gel plate (developed with benzene/diethyl ether=lO/1 4 times) to obtain 4.5 μl of the desired product (yield: 15%).

Properties: Pale yellow oil NMR 8.10-7.30 (ppm) m 3585.72
dd IH 5.40 dd il+5.21
dll1 5.17-5. 12 rth 2H4.87
ta lo 4.59 d l}I 4.57 d lI1 4.47-4.44 br 2H4.31
dd IH 4.26-4.20 m 3114. 10-
4.01 m 3H aromatic hydrogen Glu-3' J=9.0. 9.0Glu-2'
J=7.0. 7.8N Dan J・8.5 Gal-2', Cer-4 Cer-5 J=6.8, 15.0Glu-1'
J=7.8 Gal-1' J=7.8 Gal-6' Cer-I J=3.0. 9.0Glu-4'
．． Gal-3', Gal-4''Glu-6', Ce
r-2+Cer-3? ．． 76 m
lit Glu-5'3.73-3.68
rn2HGlu-6'. Gat-
5”3.47 dd Ill
Cer-I J=3.0. 9.751.5
7 s 3}1 acetonide 1.34
-1.12 br 67H Acetonide, CH
=CI-CTo-C+ 1822, COC}l. -C
■114■ 0.90-0.86 br 15H C++H
iz-CHz, CzJaz-Cth, SitcJ* Reference Example 1 A stirrer bar and Na2HPO. (5
0 mg), Molecular Sieves 4A (80■) was added, and after heating and drying, the top 0 (50 mg, 0.0 8 1
mmof), upper (55 mg, 0.089 mm
CII.offi) was added and replaced with argon. C.N.
(0.3 d) was added and stirred at room temperature, and after 30 minutes,
AgOTf (42mg, 0.1 6 1IIta
ol) in toluene (0.3ae) was added, the mixture was stirred at room temperature, and after 8 hours it was heated to 40°C (oil bat
After 2 days, the mixture was stirred at 60°C, and after 1 day it was diluted with ethyl acetate, filtered through Celite 545, and thoroughly washed with ethyl acetate. Transfer the filtrate and washing liquid to a separatory funnel, and add Na
gS. 0. Aqueous solution, Na}ICO, aqueous solution, washed with water, washed with saturated saline, dried with an anhydrous NazS04 column, and concentrated to dryness. The obtained residue (103 mg) was subjected to column chromatography (CH.C/!2:acetone=4:
1) and removed 11. The remaining residue was subjected to ram chromatography (acetone:hexane=1:2) again to obtain 12 (68 mg, 69%) as a white powder.

The hydrogens in the structure shown are H, H-0, H, respectively.
Shown in one.

IH NMR (δ, J in Hz, CDCj!z
)1.14-1.27 (30H, m, aPiv
& -SCH2CHl)1.93. 2.02. 2.
06. 2.09, 2.12 (3}1,5.-CH
3) 3.21 (Ill, d, 3.44 (Ill. t, 3.47 (ill, d, 3.51 (ill. dt, 3.60 (1B, ddd, 3.70 (E. t, 3.72 (IL ddd, 3.91 (311, s, 4.02 (IH, dd, 4.07 (ill. t, 4.10 (ill, dd, 4.11 (IH, dd, 4.18) (1}1, dd, 4.21 (Ill, td, 4.27 (LH, dd, 4.29 (IH, s, 4.30 (IH, d, 4.32 (Ill, dd, 4.41) (ill. dd, 4.42 (LH, dd, J・1.0, ■-OH) .r=9.5+ I+-4) J=11.0.n-tg) J=1.0&7.5 .11-■) J=1.5. 7.0 & 9.5, II-5
') J・9,5, H-3) J=3.0, 4.0 & 8.0, H-■
0-CH3) J・7.0 & 12.5, H-(9)) J=3.
0, If-■) J・3.0&7.5, H-■) J=7.0&12.5, I1-6) J・8.0 & 12.5, H-■) J=10.0
&11. O, I1-(5)) J= 2.5 &l2.
5, u-[m)10H) J=7.5. 1+-■) J・4.0 &12. O. lI-■) J・1.5
&10. O. H-(6)) J・9.5, I+-1
) 4.66 (IH, dd, J=2.0
&12. O, H-6) 4.87 (lft,
t, J=9.5}1-2)5.23 (
LH, dd, J=1.5 & 9.0. ll glance) 5.33 (IH, ddd, J=2.5,
7.0 & 9.0 H-1) 5.36 (IH.
t, , J=11. O, H one stop) 5.39 (
11{, d, , J=10.0. compensation) 7.
13-7. 25 (5H, m, Ph) Reference Example 2 12, 62 mg was dissolved in pyridine-acetic anhydride solution (2/1)
The solution was dissolved in 3rnl and stirred at 50°C overnight. After concentrating the reaction solution to dryness, the residue was subjected to silica gel column chromatography (
Separate with acetone/n-hexane = 1/1) to obtain the target product 6.
5 mg was obtained (yield, 96%).

Properties: White powder OAc The hydrogen in the structure shown is H, H10, and H, respectively.
Indicated by one. Ill NMR (δ , J in llz,
CDCls) 1.17-1.29 (30H, m
, aPiv & -SC82CH3) 2.574.7
6 (211, va, -SCICH3)3.
05 (IH, d, J.l2. I+-(3)
) 3.57 (IH, dd, J・3.0 & 10.
5, o-[] )3.67 (IH, dd
d, J・2.0. 6.5 & 10.0.
11-5) 3.78 (18.t,
J=10.0, II-4 )3.90 (III,
dd, J・6.5&? ．． 5, I1-■)3.
91 (3}1, 3.97 (lH. 4.00 (1}1. 4.05 (IH. 4.09 (IH. 4.16 (l}I, 4.40 (LH, 4.52 ( IH. 4.63 (IH, 4.66 (l}l, 4.84 (IH. 4.93 (III, 5.10 (IH. 5.22 (IH. 5.23 (IH, 5.26) 1}1. 5.27 (l}l, 5.39 (1}1, 5.48 (l}l, 7.2-7.5 s, 0-CH3) dd, J=7.5&lO.5 .H-■)td,
J・10.0 &10.5, H-mouth》dd,
J=4.5&l2.5. H one so called) dd, J=6.
5&l2.0. }I-6) dd, J= 6.5
&10.5. H-■)dd, J=3.0&12
．． 5.8 1) d, J=10.0, }l-1
)dd, J=2.0&l2.0, H-6>
d. J=7.5. 8-■) dd, J=3.5&lO. 5, H-■)t,
J=10.0 H-2)dd, J=7.5
&10.5. 81■》dd, J=10.0 &
12.0] sip) d, J=10.0, Inl
)d, J=3.5. 8-■) t, J=lO, O, H-3) dd, J=
3.0 & 9.0. 8-mouth》ddd, J.a.
o 4.5 & 9.0. 8-El) (5H,
m, Ph) 3.69 3.59 3.57 3.53 3.05 1.32 1.01 0.88? Example 5 13 12.0 mg of CIhCj2 Z-ClhCN
(1:1) 0. Add Molecular Sieves AW-300100■ to
Stir for a minute. There, 0.13M DMTST
Cll■C! ■Add 0.14ml of the solution, and then add 1ml at room temperature.
Stir for 5 minutes. Further, convert 19.5■ to CHHz (lz
o. A solution dissolved in 14d was added with stirring to carry out the reaction at room temperature, and after 4 hours, EtsN was added to stop the reaction. The reaction solution was filtered through Celite, the filtrate was washed with 11.0, and the organic layer was washed with Na, So. After dehydration, the residue was concentrated to dryness under reduced pressure. The residue was collected on a silica gel plate (hexane/acetone = 3:2), and then purified again on a silica gel plate (benzene/ethyl acetate = 1:1) to obtain 2.5 μl of almost pure 13 (yield: rate 13χ).

Properties: Pale yellow oil NMR 7.69-7.29 (ppm) m 358 ar
omatic (Hz)5.81 td
01 Cer-5 J=7.0, 15.15
．． 62dd IH Cer-4
J=15.1, 8.5Gal-5 Glu-5 Neu-6 Cer-1' Neu-3 J=IO. 8. 2.8 J=9.8, 3.7 J=11.3 1.18? II = C II- C II■-CllflL
lCOCHz-Ci+flj. ? it CaiL CIIHz■-Ci! ．． ．． COCHHz-Cz1■4z-
CLIJ=6.3 5.50 5.4l 5.39 5.27 5.23 5.22 5.17 5. 10 4.94 4.87 4.84 4.65 4.56 4.45 4,39 4.21 4.06 4.05 4.00 3.78 Neu-8 Cer-Nil Neu-7 Gal-4 Glu -3 Neu-4 Neu-Ntl Gal-2 Cer-3 Glu-2 Gal-3 Gal-I Glu-6 Glu-I Neu-9 Cer-I Glu-6'Neu-9' Neu-5 Glu-4 J・9.0. 5.1, 2.8 J・8.3 J・9.0, 2.8 J・3.8 J=9.5. 9.0 J・11.3, 10. O J=9.8 J・9.9. 8.0 J・9.3, 8.5 J・9.5. 7.6 J=9.9.3.8 J=8.0 J=11.5, 2.3 J・7.6 J・12.8. 2.8 J・9.8. 4.0 J・11.5. 6.5 J=12.8. 5.1 J・9.0, 9.0

Claims (2)

[Claims] (1) A compound represented by the following formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼……(I) and a compound represented by the following formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ ...(I) in the presence of a thiol activating reagent to produce a compound represented by the following formula (III) ▲Mathematical formula, chemical formula, table, etc.▼...(III) In the formula, R^1 represents a lower alkyl group that may have a branch, R^2, R^3 and R^4 each represent a hydroxyl group protected with a protecting group or a free hydroxyl group, and R
^5 represents a hydroxyl group protected by a protecting group, a free hydroxyl group, or an ether group bonded to the ring of a sugar that may have a substituent; R^6 represents hydrogen or a hydroxyl protecting group; R^7 represents an alkyl group or an alkenyl group). (2) Glycolipid synthesis intermediate represented by the following formula (III) ▲Mathematical formulas, chemical formulas, tables, etc.▼...(III) (wherein R^1 is a lower alkyl group that may have a branch) , R^2, R^3 and R^4 each represent a hydroxyl group protected with a protecting group or a free hydroxyl group, and R
^5 represents a hydroxyl group protected by a protecting group, a free hydroxyl group, or an ether group bonded to the ring of a sugar that may have a substituent; R^6 represents hydrogen or a hydroxyl protecting group; R^7 represents an alkyl group or an alkenyl group).