Coordination polymerization of renewable β-ocimene has been investigated using asymmetric diiminophosphinate lutetium complex1, β-diketiminate yttrium complex 2, bis(phosphino)carbazolide yttrium complex 3, half-san...Coordination polymerization of renewable β-ocimene has been investigated using asymmetric diiminophosphinate lutetium complex1, β-diketiminate yttrium complex 2, bis(phosphino)carbazolide yttrium complex 3, half-sandwich benzyl fluorenyl scandium complex 4 and pyridyl-methylene-fluorenyl rare-metal complexes 5a–5c. Complexes 1, 4 and 5a–5c show trans-1,2-regioselectivities and high activities, of which 5c exhibits excellent isoselectivity(mmmm>99%). Conversely, complexes 2 and 3 promote β-ocimene polymerization to produce isotactic cis-1,4-polyocimenes(cis-1,4>99%, mm>95%). Diblock copolymers cis-1,4-PIP-block-cis-1,4-POc and cis-1,4-PBD-block-cis-1,4-POc are obtained in one-pot reactions of β-ocimene with isoprene and butadiene using complex 3. Epoxidation and hydroxylation of polyocimene afford functionalized polyolefins with enhanced T_(g)(from-20 ℃ to 79 ℃ and 74 ℃) and hydrophilicity.展开更多
b-D-Glcp-(13)-[b-D-Glcp-(16)-]a-D-Manp-(13)-b-D-Glcp-(13)-[b-D-Glcp-(16)-]D-Glcp (18) and b-D-Glcp-(13)-[b-D-Glcp-(16)-]a-D-Manp-(13)-b-D-Glcp-(13)-[b-D-Glcp-(16)-]b-D-Glcp-D-(13)-Glcp-1OMe (29) were synthesized as th...b-D-Glcp-(13)-[b-D-Glcp-(16)-]a-D-Manp-(13)-b-D-Glcp-(13)-[b-D-Glcp-(16)-]D-Glcp (18) and b-D-Glcp-(13)-[b-D-Glcp-(16)-]a-D-Manp-(13)-b-D-Glcp-(13)-[b-D-Glcp-(16)-]b-D-Glcp-D-(13)-Glcp-1OMe (29) were synthesized as the analogues of the immunomodulator b-D-Glcp-(13)-[b-D-Glcp- (16)-]a-D-Glcp-(13)-b-D-Glcp-(13)-[b-D-Glcp-(16)-]D-Glcp through coupling of trisaccharide donors 9 with trisaccharide acceptor 16 and tetrasaccharide acceptor 27 followed by deprotection, respectively.展开更多
The phytoalexin elicitor β-(1→3)-branched β-(1→6)-linked glucohexatose has been regie- and stereospeciflcally synthesized by coupling of the 3, 6-branched gluco-trisaccharide Schmidt reagent 10 with a mixture of m...The phytoalexin elicitor β-(1→3)-branched β-(1→6)-linked glucohexatose has been regie- and stereospeciflcally synthesized by coupling of the 3, 6-branched gluco-trisaccharide Schmidt reagent 10 with a mixture of multiol 3,6-branched gluco-trisac-charides 13 which consists of free 5,6'-OH trisaccharide, free 5,2' ,6'-OH trisaccharide, free 5,3' ,6'-OH trisaccharide and so on. The compounds 10 and 13 were prepared from 1,2:5,6-di-O-isopropylidene-α-D-glucofuranose, 2, 3, 4, 6-tetra-O-ben-zoyl-α-D-glucopyranosyl trichloroacetimidate, and 2,3,4,6-te-tra-O-acetyl-α-D-glucopyranosyl trichloroacetimidate through re-gio- and stereoselective manners.展开更多
A β-（1→）6）-branched β-（1→）3）-linked glucohexaose （1） and its lauryl glycoside （2）, present in many biologically active polysaccharides from traditional herbal medicines such as Ganoderma lucidum, Schizop...A β-（1→）6）-branched β-（1→）3）-linked glucohexaose （1） and its lauryl glycoside （2）, present in many biologically active polysaccharides from traditional herbal medicines such as Ganoderma lucidum, Schizophyllum commune and Lentinus edodes, were highly efficiently synthesized. Coupling of 2,3,4,6-tetra-O-benzoyl-β-D-glucopyranosyl- （1--）3）-2-O-benzoyl-4,6-O-benzylidene-a-D-glucopyranosyl trichloroacetimidate （7） with 3,6-branched acceptors 8 and 12 gave β-（1→）3）-linked pentasaccharides （9） and （13）, then via simple chemical transformation 4＇,6＇-OH pentasaccharide acceptors 10 and 14 were obtained. Regio- and stereoselective coupling of 3 with 10 and 14 gave β-（1→）3）-linked hexasaccharides （11） and （15） as the major products. Deprotection of 11 and 15 provided the target sugar 1 and 2. Thus, a new method for the preparation of this kind of compounds was developed.展开更多
基金financially supported by the open research fund program of Science and Technology on Aerospace Chemical Power Laboratory (No. STACPL120221B03)the National Natural Science Foundation of China (Nos. s22175059,52073275 and U21A20279)。
文摘Coordination polymerization of renewable β-ocimene has been investigated using asymmetric diiminophosphinate lutetium complex1, β-diketiminate yttrium complex 2, bis(phosphino)carbazolide yttrium complex 3, half-sandwich benzyl fluorenyl scandium complex 4 and pyridyl-methylene-fluorenyl rare-metal complexes 5a–5c. Complexes 1, 4 and 5a–5c show trans-1,2-regioselectivities and high activities, of which 5c exhibits excellent isoselectivity(mmmm>99%). Conversely, complexes 2 and 3 promote β-ocimene polymerization to produce isotactic cis-1,4-polyocimenes(cis-1,4>99%, mm>95%). Diblock copolymers cis-1,4-PIP-block-cis-1,4-POc and cis-1,4-PBD-block-cis-1,4-POc are obtained in one-pot reactions of β-ocimene with isoprene and butadiene using complex 3. Epoxidation and hydroxylation of polyocimene afford functionalized polyolefins with enhanced T_(g)(from-20 ℃ to 79 ℃ and 74 ℃) and hydrophilicity.
基金Project supported by Chinese Academy of Sciences (No. KZCX3-J-08) and the National Science Foundation of China (Nos. 30070185 and 39970964).
文摘b-D-Glcp-(13)-[b-D-Glcp-(16)-]a-D-Manp-(13)-b-D-Glcp-(13)-[b-D-Glcp-(16)-]D-Glcp (18) and b-D-Glcp-(13)-[b-D-Glcp-(16)-]a-D-Manp-(13)-b-D-Glcp-(13)-[b-D-Glcp-(16)-]b-D-Glcp-D-(13)-Glcp-1OMe (29) were synthesized as the analogues of the immunomodulator b-D-Glcp-(13)-[b-D-Glcp- (16)-]a-D-Glcp-(13)-b-D-Glcp-(13)-[b-D-Glcp-(16)-]D-Glcp through coupling of trisaccharide donors 9 with trisaccharide acceptor 16 and tetrasaccharide acceptor 27 followed by deprotection, respectively.
基金Project supported by the Beijing Natural Science Foundation(No.6021004)and the Ministry of Science and Technology(No.2001AA246014).
文摘The phytoalexin elicitor β-(1→3)-branched β-(1→6)-linked glucohexatose has been regie- and stereospeciflcally synthesized by coupling of the 3, 6-branched gluco-trisaccharide Schmidt reagent 10 with a mixture of multiol 3,6-branched gluco-trisac-charides 13 which consists of free 5,6'-OH trisaccharide, free 5,2' ,6'-OH trisaccharide, free 5,3' ,6'-OH trisaccharide and so on. The compounds 10 and 13 were prepared from 1,2:5,6-di-O-isopropylidene-α-D-glucofuranose, 2, 3, 4, 6-tetra-O-ben-zoyl-α-D-glucopyranosyl trichloroacetimidate, and 2,3,4,6-te-tra-O-acetyl-α-D-glucopyranosyl trichloroacetimidate through re-gio- and stereoselective manners.
文摘A β-（1→）6）-branched β-（1→）3）-linked glucohexaose （1） and its lauryl glycoside （2）, present in many biologically active polysaccharides from traditional herbal medicines such as Ganoderma lucidum, Schizophyllum commune and Lentinus edodes, were highly efficiently synthesized. Coupling of 2,3,4,6-tetra-O-benzoyl-β-D-glucopyranosyl- （1--）3）-2-O-benzoyl-4,6-O-benzylidene-a-D-glucopyranosyl trichloroacetimidate （7） with 3,6-branched acceptors 8 and 12 gave β-（1→）3）-linked pentasaccharides （9） and （13）, then via simple chemical transformation 4＇,6＇-OH pentasaccharide acceptors 10 and 14 were obtained. Regio- and stereoselective coupling of 3 with 10 and 14 gave β-（1→）3）-linked hexasaccharides （11） and （15） as the major products. Deprotection of 11 and 15 provided the target sugar 1 and 2. Thus, a new method for the preparation of this kind of compounds was developed.
