Reaction mechanism and quantum-chemical computation of hydrosilylation reaction of allyl glycosides Текст научной статьи по специальности «Химические науки»

UDC 544.18:544.43

N. Sidamonidze, R. Vardiashvili, M. Nutsubidze, G. E. Zaikov

REACTION MECHANISM AND QUANTUM-CHEMICAL COMPUTATION OF HYDROSILYLATION REACTION OF ALLYL GLYCOSIDES

Keywords: hydrosilylation, allyl glycoside, dicobalt octacarbonyl, reactions, mechanism, quantum chemistry.

By hydrosilylation of 1-O-allyl-2,3,4,6-tetra-O-acetyl-e-D-glucopyranose and 1-O-allyl-2,3,4,6-tetra-O-acetyl-e-D-galactopyranose with 1,3-bis(dimethylsilyl)-2,2,4,4-tetramethylcyclodisilazane and 1,3-bis(diphenylsilyl)-2,2,4,4-tetraphenylcyclodisilazane in the presence of the catalyst Co2(CO)8, we obtained 1,3-di[3-(2,3,4,6-tetra-O-acetyl-fi-D-glucopyranosyloxy)propyldimethylsilyl]-2,2,4,4-tetramethylcyclodisilazane, 1,3-di[3-(2,3,4,6-tetra-O-acetyl-fi-D-galactopyranosyloxy)-propyldimethylsilyl]-2,2,4,4-tetramethylcyclodisilazane, 1,3-di[3-(2,3,4,6-tetra-O-acetyl-@-D-glucopyranosyloxy)propyldiphenylsilyl]-2,2,4,4-tetraphenylcyclodisilazane and 1,3-di[3-(2,3,4,6-tetra-O-acetyl-fi-D-galactopyranosyloxy)propyldiphenylsilyl]-2,2,4,4-tetraphenylcyclodisilazane. By deacetylation, we obtained 1,3-di[3-(e-D-glucopyranosyloxy)propyldimethylsilyl]-2,2,4,4-tetramethylcyclodisilazane and 1,3-di[3-(ft-D-

glucopyranosyloxy)propyldiphenylsilyl]-2,2,4,4-tetra-phenylcyclodisilazane.

Ключевые слова: гидросилилирование, аллилгликозиды, дикобальта октакарбонил, реакции, механизм, квантовая химия.

Гидросилилированием 1-O-аллил-2,3,4,6-тетра-О-ацетил-в-D-глюкопиранозы и Ю-аллил-2,3,4,6-тетра-О-ацетил-в^-галактопиранозы с 1,3-бис(диметилсилил)-2,2,4,4-тетраметилциклодисилазаном и 1,3-бис(дифенилсилил)-2,2,4,4-тетрафенилциклодисилазаном в присутствии катализатора CO2(CO)8 получен 1,3-ди[3-(2,3,4,6-тетра-O-ацетил-в-D-глюкопираносилокси)пропилдиметилсилил]-2,2,4,4-

тетраметилциклодисилазан, 1,3-ди[3-(2,3,4,6-тетра-O-ацетил-в-D-галактопираносилокси)-

пропилдиметилсилил]-2,2,4,4-тетраметилциклодисилазан, 1,3-ди[З-^^^^-тетра^-ацетил-в^-

глюкопираносилокси)пропилдифенилсилил]-2,2,4,4-тетрафенилциклодисилазан и 1,3-ди[3-(2,3,4,6-тетра-O-ацетил-в^-галактопираносилокси)пропилдифенилсилил]-2,2,4,4-тетрафенилциклодисилазан. Деацетилированием получены 1,3-ди[3-(в^-глюкопираносилокси)пропилдиметилсилил]-2,2,4,4-

тетраметилциклодисилазан и 1,3-ди[3-(в^-глюкопираносилокси)пропилдифенилсилил]-2,2,4,4-тетра-фенилциклодисилазан.

Introduction

Synthesis of low-toxicity compound has become important in biological and pharmacological studies, and so there is interest in using carbohydrates to modify linear and cyclolinear siloxanes, which may lead to a substantial change in the nature of the drug action [1-4].

Experimental

The IR spectra were obtained on a UR-20 in KBr disks. The :H NMR spectrum was taken on a Bruker WM-250 spectrometer (250 MHz); the 13C NMR spectrum was taken on Bruker AM-300 spectrometer (75 MHz) in CDCI3. The purity of the compounds obtained and the Rf values were determined on Silufol UV-254. The optical rotation was measured on an SU-3 general-purpose saccharimeter at 20±20C.

1,3-di[3-(2,3,4,6-tetra-O-acetyl-P-D-glucopyranosyloxy)propyldimethylsilyl]-2,2,4,4-tetra-methylcyclodisilazane (5). 1.15 g (5 mmol) 1,3-bis(dimethylsilyl)-2,2,4,4-tetramethylcyclodisi-lazane (3) in dry chloroform (20 ml) and Co2(CO)8 (0.15 g) were added dropwise to a solution of 4.85 g (12.5 mmol) compound (1) in dry chloroform (25 ml). The reaction was carried out under a nitrogen atmosphere with constant stirring for 1.5 h (60-65°C). After cooling and separating on a column (2:1 benzene-chloroform system, silicagel L (50/100), a chromatographically pure product was obtained in a yield of 5.91 g (61.7%); m.p. 152-153°C. Rf 0.61 (2:1 benzene-chloroform

system). [a]D18 +98° (c 0.52, chloroform). IR spectrum, v, cm-1: 690 (Si-C); 1120, 1030 (C-O-C); 1715 (C=O); 920 (Si-N); 1460 (CH3). 1H NMR spectrum, 5, ppm (J, Hz): 4.35 (1H, d, J1,2=8, H-1); 5.55 (1H, d, J12=4, H-1'); 4.38 (1H, dd, J2,'i=8.1; J2,3=9.4, H-2); 4.78 (1H, dd, J2,i=4; J2,3=10.6, H-2'); 5.67 (1H, dd, J3,2=9.4; J3,4=10, H-3); 5.60 (1H, dd, J32=10.6; J34=9.8, H-3'); 4.22-4.28 (dd, J4,3=10; J4,5=12.3, H-4); 5.29-5.30 (dd, J4,3=9.8; J4,5=9.9, H-4'); 3.62-3.68 (1H, m, H-5); 3.90-4.00 (1H, m, H-5'); 4.80-4.10 and 4.11-4.14 (2H, d, H-6 and H-6' CH^OCOCH3); 3.55-3.60 and 3.78-3.84 (2H, 2m, ROCH - CH2 - CH2 -SiR3); 1.85-1.90 and 1.92-1.98 (2H, 2m, RO-CH2 - CHg - CH2 -SiR3); 1.62-1.70 and 1.73-1.82 (2H, 2m, RO-CH2 - CH2 - CHg -SiR3); 1.05-1.10 (24H, m, 8 Si- CH3); 2.13-2.18 (21H, m, 7 CO-CH3). Found,1/: C 48.73; H 7.02; N 2.41; Si 10.33. C42H74N2O2oSi4. Calculated,0/«: C 48.55; H 7.12; N 2.72; Si 10.79.

1,3-di[3-(2,3,4,6-tetra-O-acetyl-ß-D-galactopyranosyloxy)propyldimethylsilyl]-2,2,4,4-tetra-methylcyclodisilazane (6) were obtained similarly from compound (2) (4.85 g, 12.5 mmol) and 1,3-bis(dimethylsilyl)-2,2,4,4-

tetramethylcyclodisilazane (3) (1.31 g, 5 mmol) with a yield of 4.92 g (51%); m.p. 160-161.5°C. Rf 0.73 (2:1 benzene-chloroform system). [a]D17 +102° (c 0.81, chloro-form). IR spectrum, v, cm-1: 710 (Si-C); 1020, 1050, 1110 (C-O-C); 1700 (C=O); 899 (Si-N); 1445 (CH3). 13C NMR spectrum, 5, ppm. CDCI3: 170.00175.88 (RO-CO-CH3); 20.62 (RO-CO-CH3); 70.8271.05 (RO-CH2-CH2-CH2-SiR3); 29.38-29.73 (RO-CH2-CH2-CH2-SiR3); 20.78-22.72 (RO-CH2-CH2-

CH2-SiR3); 8.05-13.40 (Si-CH3); 91.90 and 100.88 (C(1) and C(1')); 60.98 and 61.80 (C(6) and CCT); 66.8077.51 (C(2-5) and Cg^)). Found,"/: C 48.94; H 7.53; N 2.43; Si 10.02. C42H74N2C>2oSi4. Calculated,0/«: C 48.55; H 7.12; N 2.72; Si 10.79.

1,3-di[3-(2,3,4,6-tetra-O-acetyl-P-D-glucopyranosyloxy)propyldiphenylsilyl]-2,2,4,4-tetra-phenylcyclodisilazane (7). 3.79 g (5 mmol) 1,3-bis(diphenylsilyl)-2,2,4,4-tetraphenylcyclodisi-lazane (4) in dry chloroform (25 ml) and Co2(CC)8 (0.15 g) were added dropwise to a solution of 3.88 g (12.5 mmol) compound (1) in dry chloroform (30 ml). The reaction was carried out under a nitrogen atmosphere with constant stirring for 3-3.5 h (60-65°C). After cooling and separating on a column (2:1 benzene-chloroform system, silicagel L 50/100), a chromatographically pure product was obtained in a yield of 4.37 g (57.0%); m.p. 146-147°C. Rf 0.44 (3:1 benzene-chloroform system). [a]D17 +115° (c 0.64, chloroform). IR spectrum, v, cm-1: 702 (Si-C); 1100, 1040, 1030

(C-C-C); 1720 (C=O); 940 (Si-N); 1460 (1743 (C=Carom)3 732, 839 (C-Harom).

C NMR spectrum, 5, ppm. CDCI3: 170.00175.88 (RC-CC-CH3); 91.4 and 89.9 (C-1 and C-1'); 72.5 and 72.46 (RC-CH2-CH2-CH2-SiR3); 77.31; 76.99; 76.677; 70.5; 70.1; 70.631; 69.242; 67.535 (C2-5 and C2'-5'); 61.29 and 60.97 (C-6 and C-6'); 20.680 and 20.566 (RO-CH2-CH2-CH2-SiR3); 20.452-20.422 (RC-CC-CH3); 20.543-20.490 (RO-CH2-CH2-CH2-SiR3); 124-130 (Si-C6H5). Found,/: C 64.71; H 6.32; N 1.54; Si 6.97. C82HgoN2O2oSi4. Calculated,/: C 64.14; H 5.86; N 1.82; Si 7.23.

1,3-di[3-(2,3,4,6-tetra-O-acetyl-P-D-galactopyranosyloxy)propyldiphenylsilyl]-2,2,4,4-tetra-phenylcyclodisilazane (8) were obtained similarly from compound (2) (3.88 g, 12.5 mmol) and 1,3-bis(diphenylsilyl)-2,2,4,4-

tetraphenylcyclodisilazane (4) (3.79 g, 5 mmol) with a yield of 3.05 g (40.0%); m.p. 98-99°C. Rf 0.33 (3:1 benzene-chloroform system). [a]D18 +68° (c 1.5, chloroform). IR spectrum, v, cm-1: 680 (Si-C); 1080, 1050, 1100 (C-C-C); 932 (Si-N); 820, 710 (C-Harom); 1695 (C=O); Found,/: C 64.45; H 6.01; N 2.03; Si 7.63. C82HgoN2O2oSi4. Calculated,/: C 64.14; H 5.86; N 1.82; Si 7.23.

Deacetylation 1,3-di[3-(P-D-

glucopyranosyloxy)propyldimethylsilyl]-2,2,4,4-tetramethylcyclodisilazane(9). A suspension of compound (5) (1.038 g, 12.5 mmol) in absolute methanol (20 ml) was heated for 10 min in a water bath with a 0.1 N sodium methoxide (1.5 ml) and the solution obtained was allowed to stand overnight. The mixture was filtered and the filtrate was concentrated using a water-jet aspirator, and ether was added to the residual mass until crystals separated out. The crystals were filtered out and recrystallized from hexane. Yield of compound (9) 0.23 g (34/); m.p. 170-171°C. Rf 0.51 (2:1 chloroform-methanol system). [a]D17 +62° (c 0.47, water). IR spectrum, v, cm-1: 1220-1248 (Si-CH3); 1080, 100, 1150 (C-C-C); 915 (Si-N); 3580-3650 (OH);

1390-1410 (-CH2-); Found,/: C 44.12; H 8.53; N 3.81; Si 15.29. C26H58N2C12Si4. Calculated,/: C 44.44; H 8.2; N 4.0; Si 15.9.

1,3-di[3-(P-D-glucopyranosyloxy)propyldiphenylsilyl]-2,2,4,4-tetraphenylcyclodisilazane(10). A suspension of compound (7) (1.534 g, 12.5 mmol) in absolute methanol (45 ml) was heated for 25 min in a water bath with a 0.1 N sodium methoxide (1.5 ml) and the solution obtained was allowed to stand overnight. The mixture was filtered and the filtrate was concentrated using a water-jet aspirator, and ether was added to the residual mass until crystals separated out. The crystals were filtered out and recrystallized from hexane. Yield of compound (10) 0.5 g (42.0/); m.p. 157-158.5°C. Rf 0.42 (ethylacetat). [a]D17 +87° (c 0.52, water). IR spectrum, v, cm-1: 1220-1248 (Si-CH3); 1080, 100, 1150 (C-C-C); 915 (Si-N); 3580-3650 (OH); 1390-1410 (-CH2-); Found,/: C 66.27; H 6.02; N 2.02; Si 8.94 . C66H74N2C12Si4. Calculated,/: C 66.11; H 6.17; N 2.33; Si 9.3.

13C NMR spectrum, 5, ppm. TGF: 91.106 and 89.722 (C-1 and C-1'); 69.293 and 67.794 (RC-CH2-CH2-CH2-SiR3); 20.697 and 20.661 (RC-CH2-CH2-CH2-SiR3); 20.600-20.570 (RC-CH2-CH2-CH2-SiR3); 60.990 and 76.673-77.310 (C2-5 and Cz-50; 67.041 and 67.151 (C-6 and C-6'); 126-137 (Si-C6H5).

We have studied the reaction of hydrosilylation of 1-O-allyl-2,3,4,6-tetra-O-acetyl-p-D-glucopyranoses (1) and 1-O-allyl-2,3,4,6-tetra-O-acetyl-p-D-

galactopyranoses (2) with 1,3-bis-(dimethylsilyl)-2,2,4,4-tetramethylcyclodisilazane (3) and 1,3-bis(diphenylsilyl)-2,2,4,4-tetraphenyl-cyclodisilazane (4). The reaction was carried out in dry chloroform with a mole ratio of the reacting components equal to 2.5:1 at a temperature of 60-650 in the presence of the catalyst Co2(CC)8.

Results and Discussion

We obtained the corresponding 1,3-di[3-(2,3,4,6-tetra-O-acetyl-P-D-glucopyranosyloxy)propyl-dimethylsilyl]-2,2,4,4-tetramethylcyclodisilazane (5), 1,3-di[3-(2,3,4,6-tetra-O-acetyl-P-D-galactopyranosyloxy)propyldimethylsilyl]-2,2,4,4-tetramethylcyclodisilazane (6), 1,3-di[3-(2,3,4,6-tetra-O-acetyl-p-D-glucopyranosyloxy)propyldiphenylsilyl]-2,2,4,4-tetraphenylcyclodisilazane (7) and 1,3-di[3-(2,3,4,6-tetra-O-acetyl-p-D-galactopyranosyloxy)propyldiphenylsilyl]-2,2,4,4-tetraphenylcyclodisilazane (8).

The reaction mainly occurs according to Farmers rule, although a small amount of Markovnikov addition product is also formed.

CH2OAc

R O O-CH2-CH=CH2 +

OAc

1, 2

2

R".

R1

R 1 1

I А I

H Si N^ ^N—Si—H ■и S' ./ \

R

R

3, 4 R1

R

\ /

CH2OAc R" ^Si R11 OAc

-O O-CHrCH-CHrSi—N \-S^CH2-CH2-CH2 -OA-1 R

, , Si I ^OAc \

^OAc / R" / \ r" ' '

VcOH,« n-

OAc

H group is completely removed, which is supported by the IR spectrum.

By deacetylation of compounds 5 and 7 in absolute methanol in the presence of sodium methoxide, 1,3-di[3 -(P-D-glucopyranosyloxy)propyldimethylsilyl]-2,2,4,4-tetramethylcyclodisilazane (9) and 1,3-di[3-(P-D-glucopyranosyloxy)propyldiphenylsilyl]-2,2,4,4-tetraphenylcyclodisilazane (10) were obtained.

CH2OH

R1

OH

R II R1

R, ,R \/

R 'Sis I

"O O-CH2-CH-CHTSi~N^ sn—Si- CH2-CH2-CH2 -O

Ri, /( Ri, M

R11 R"

O—^OH

OH 9, 10

5, 8

R , = CH3 (9); R' , = Ph (10).

(2); R=OAc, RI=H, R" =Me (3,6), Ph (4,8).

Physical-chemical characteristics of synthesized compounds are presented in the Table 1.

The course of the reaction was monitored from the decrease in active hydrogen on the silicon over time. We have established that in 1.5 h, the hydrogen in

Table 1 - Physical-chemical characteristics of synthesized compounds

R

(1); R=H, R=OAc, R ^Me (3,5), Ph (4,7).

Com pound Reaction Duration hr m.p. °C [a]D, CHCI3 Rf

5 1.5 152-153°C +98° (c 0.52; t=18°) 0.61*

6 1.5 160-161.5°C +102° (c 0.81; t=17°) 0.73*

7 3.0 146-147°C +115° (c 0.64; t=17°) 0.44**

8 3.5 98-99°C +60° (c 1.5; t=17°) 0.33**

9 10 min 170-171°C +62° (c 0.47; t=17°, water 0.51***

10 25 min 157-158°C +87 ° (c 0.52; t=17°, water) 0 42****

Com pound Elemental analysis Found,% / Calculated,0/ Yield,%

C H N Si

5 48.73 / 48.55 7.02 / 7.12 2.41 / 2.72 10.33 / 10.79 61.7

6 48.94 / 48.55 7.53 / 7.12 2.43 / 2.72 10.02 / 10.79 51.0

7 64.45 /64.14 6.01 /5.86 2.03 /1.82 7.63 /7.23 57.0

8 64.71 /64.14 6.32 /5.86 1.54 /1.82 6.97 /7.23 40.0

9 44.12 /44.44 8.53 /8.2 3.81 /4.0 15.29 /15.9 34.0

10 66.27 /66.11 6.02 /6.17 2.02 /2.33 8.94 /9.3 42.0

* benzene-chloroform 2:1, ** benzene-chloroform 3:1, *** chloroform-methanol 2:1, **** ethylacetat

Addition of 1,3-bis-(dimethylsilyl)-2,2,4,4-tetramethylcyclodisilazane (3) to allyl glucoside (1) was selected to study the pathway and mechanism of the

model reaction. Quantum-chemical computation was performed using CS MOPAC (Chem 3D Ultra version 8.03). Each computation by the AM1 method was

preceded by optimization of the compounds, i.e. minimization of the energy by molecular (MM) and quantum-chemical method. This reaction was examined in two directions, according to the Farmer and Markovnikov rules. The calculated heats formations of products and reactions showed that production of compound 5 was highly probable.

The reactions in the presence of Co2(CO)8 probable occurred according to the following mechanism. The Co2(CO)8 itself cannot catalyze a hydrosilylation process of allyl glucosides, the first step in the formation of the active catalyst species, HCo(CO)4, is important and results from the reactions of Co2(CO)8 with compound 3:

Me Me Me V

„ I /ч I

2Co2(CO)8 + H-Si-N N—Si-H

I V I / \

Me I

Me

Me /\ Me Me Me

3

Me Me

Me V I Si

I \ I

2 HCo(CO)4 + (CO)4Co~Si—Ns ^N—Si-Co(CO)4

M Si" I

Me / \ Me Me Me

It is known that HCo(CO)4 adds readily to olefins to form intermediate 11, that is unstable because of the excess of electron density on the metal and tends to convert into the saturated Co complex 11a by loss of the most labile ligand, in this instance hydride. The last step of the mechanism is formation of the final product and regeneration of the catalysts:

HCo(CO)4 + r-ch2-ch=ch2

R-CH2-CH=CH2

xo<

CO 11

r-ch2-ch2-ch2

OC

CO CO

CO

OC—Co

\

r-ch2-ch2-ch2 + I /CO OC—Co"T

I NCO CO

CO

11a

Me Me

Me У Me

I ' \ I

H-Si-N N—Si—H

M « 1

Me / \ Me

Me Me

CO

Me Me

Me У Me

R-CH2-CH2-CH~Si-N4 ^N—Si-CH2-CH2-CH2-R +

1 Si' I

Me

m/ Me

Me

+ 2 HCo(CO)4

The proposed mechanism of cyclodisilazane addition to allylglycosides agrees well with the experimental results.

References

1. Kochetkov N.K., Bochkov A.F., Dmitriev B.A., Usov A.I., Chizhov O.S., and Shibaev V.N.. Carbohydrate Chemistry. Moscow, 1967.

2. Lonas G. and Stadler R.. Acta Polymer, 45, 14, 1994.

3. Sidamonidze N.N., Gakhokidze R.A., Chan Van Tan, and Khidzsheli Z.G. Zashchita Rastenii, 7, 41, 1987.

4. Sidamonidze N.N., Janiashvili .K., Isakadze M.O. and Vardiashvili R.O. Ceorg. Eng. News, 2, 153, 2005.

© N. Sidamonidze - Doctor of Chemistry, Full Professor, Iv. Javakhishvili Tbilisi State University, Department of Chemistry, Tbilisi, Georgia, E-mail: [email protected], R. Vardiashvili - Ph.D., Iv. Javakhishvili Tbilisi State University, Department of Chemistry, Tbilisi, Georgia, M. Nutsubidze - Iv. Javakhishvili Tbilisi State University, Department of Chemistry, Tbilisi, Georgia, G. E. Zaikov - Doctor of Chemistry, Full Professor, Plastics Technology Department, Kazan National Research Technological University, Kazan, Russia.

© Н. Сидамонидзе - доктор химических наук, профессор, кафедра Химии, Тбилисский государственный университет им. И. Джавахишвили, Тбилиси, Грузия, E-mail: [email protected], Р. Вардиашвили - кандидат химических наук, кафедра Химии, Тбилисский государственный университет им. И. Джавахишвили, Тбилиси, Грузия, М. Нуцубидзе - кафедра Химии, Тбилисский государственный университет им. И. Джавахишвили, Тбилиси, Грузия, Г. Е. Заиков - доктор химических наук, профессор, кафедра Технологии пластических масс, Казанский национальный исследовательский технологический университет, Казань, Россия.