Three New Kaempferol Glycosides from Cardamine leucantha

Three new kaempferol glycosides, kaempferol 3‐O‐β‐D ‐glucopyranosyl‐(1→6)‐β‐D ‐galactopyranosyl‐7‐O‐α‐L ‐rhamnopyranoside ( 1 ), kaempferol 3‐O‐β‐D ‐galactopyranosyl‐7‐O‐β‐D ‐glucopyranosyl‐(1→3)‐α‐L ‐rhamnopyranoside ( 2 ), and kaempferol 3‐O‐β‐D ‐glucopyranosyl‐(1→6)‐β‐D ‐galactopyranosyl‐7‐O‐β‐D ‐glucopyranosyl‐(1→3)‐α‐L ‐rhamnopyranoside ( 3 ), were isolated from the whole herbs of Cardamine leucantha, along with three known kaempferol glycosides, kaempferol 7‐O‐α‐L ‐rhamnopyranoside, kaempferitrin, and kaempferol 3‐O‐β‐D ‐galactopyranosyl‐7‐O‐α‐L ‐rhamnopyranoside. Their structures were elucidated on the basis of spectroscopic methods.     

Synthesis of a New C(1→2)‐Linked Iminodisaccharide Starting from Levoglucosenone

Methyl 2‐deoxy‐2‐[(1S)‐2,5‐dideoxy‐2,5‐imino‐L ‐ribitol‐1‐C‐yl)‐α‐D ‐glucopyranoside ((+)‐ 6 ) was obtained from the product of Nozaki‐Kishi coupling of 2,5‐{[(tert‐butoxy)carbonyl]imino}‐2,5‐dideoxy‐3,4‐O‐isopropylidene‐L ‐ribose ((−)‐ 9 ) and 4‐O‐benzyl‐6‐O‐[(benzyloxy)methyl]‐3‐deoxy‐2‐O‐[(trifluoromethyl)sulfonyl]‐α‐D ‐erythro‐hex‐2‐enopyranoside ((+)‐ 12 ). The alkenyl triflate (+)‐ 12 was derived from levoglucosenone ( 1 ).     

Design and Synthesis of Aminoglycoside Antibiotics to Selectively Target 16S Ribosomal RNA Position 1408

The glucopyranosyl moiety (ring I) of paromomycin was modified in a search for novel aminoglycoside antibiotics. The key intermediates were the 4′,6′‐O‐benzylidenated N‐Boc derivative 3 and the azido analogue 18 . The bromobenzoates 4 and 19 were prepared by treating the benzylidene acetals 3 and 18 , respectively, with N‐bromosuccinimide (NBS), and the diol 8 was obtained by hydrogenolysis of 3. The C(6′)‐deoxy derivative 5 was obtained from 4 by treatment with Bu₃SnH. Selective fluorodehydroxylation of 8 gave the fluoro derivative 9. The pseudotrisaccharide 13 was obtained by reductive fragmentaion of the iodo compound 12 obtained from the bromobenzoate 4 . The 3′,6′‐anhydro derivative 20 was obtained upon deacetylation of 19. Standard deprotection gave the C(6′)‐deoxy compound 7 , the fluoro compound 11 , the pseudotrisaccharide 15 , and the 3′,6′‐anhydro‐paromomycin 22 . As compared to paromomycin, the C(6′)‐deoxy and fluorodeoxy derivatives 7 and 11 showed a lower activity against both wild type 1408A and 1408G mutant ribosomes. A lower activity was also found for the 3′,6′‐anhydro derivative 22 and for the pseudotrisaccharide 15 .     

7‐Iodo‐5‐aza‐7‐deazaguanine: Syntheses of Anomeric D‐ and L‐Configured 2‐Deoxyribonucleosides

Iodination of N²‐isobutyryl‐5‐aza‐7‐deazaguanine ( 7 ) with N‐iodosuccinimide (NIS) gave 7‐iodo‐N²‐isobutyryl‐5‐aza‐7‐deazaguanine ( 8 ) in a regioselective reaction (Scheme 1). Nucleobase‐anion glycosylation of 8 with 2‐deoxy‐3,5‐di‐O‐toluoyl‐α‐D ‐ or α‐L ‐erythro‐pentofuranosyl chloride furnished anomeric mixtures of D ‐ and L ‐nucleosides. The anomeric D ‐nucleosides were separated by crystallization to give the α‐D ‐anomer and β‐D ‐anomer with excellent optical purity. Deprotection gave the 7‐iodo‐5‐aza‐7‐deazaguanine 2′‐deoxyribonucleosides 3 (β‐D ; ≥99% de) and 4 (α‐D ; ≥99% de). The reaction sequence performed with the D ‐series was also applied to L ‐nucleosides to furnish compounds 5 (β‐L ; ≥99% de) and 6 (α‐L ; ≥95% de).     

New Acylated Presenegenin Saponins from Two Species of Muraltia

Six new acylated bisdesmosidic triterpene glycosides 1 – 6 were isolated from the roots of Muraltia heisteria (L.) DC., as three inseparable mixtures 1 / 2, 3 / 4 , and 5 / 6 of the (E)‐ and (Z)‐3,4,5‐trimethoxycinnamoyl derivatives. The compound pair 1 / 2 along with four known saponins were also isolated from the roots of Muraltia satureioides DC. Their structures were elucidated mainly by spectroscopic experiments including 2D‐NMR techniques as 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐{O‐β‐D ‐apiofuranosyl‐(1→3)‐O‐[β‐D ‐xylopyranosyl‐(1→4)]‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐O‐[6‐O‐acetyl‐β‐D ‐galactopyranosyl‐(1→3)]‐4‐O‐[(E)‐3,4,5‐trimethoxycinnamoyl]‐β‐D ‐fucopyranosyl} ester ( 1 ) and its (Z)‐isomer 2 , 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐{O‐6‐O‐acetyl‐β‐D ‐galactopyranosyl‐(1→3)‐O‐[3‐O‐acetyl‐α‐L ‐rhamnopyranosyl‐(1→2)]‐4‐O‐[(E)‐3,4,5‐trimethoxycinnamoyl]‐β‐D ‐fucopyranosyl} ester ( 3 ) and its (Z)‐isomer 4 , and 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐{O‐3‐O‐acetyl‐α‐L ‐rhamnopyranosyl‐(1→2)‐O‐[β‐D ‐xylopyranosyl‐(1→3)]‐4‐O‐[(E)‐3,4,5‐trimethoxycinnamoyl]‐β‐D ‐fucopyranosyl} ester ( 5 ) and its (Z)‐isomer 6 , respectively.     

Two New Triterpene Saponins from Acanthophyllum laxiusculum

Two new triterpene glycosides, 1 and 2 , together with three known ones, were isolated from roots of Acanthophyllum laxiusculum Schiman ‐Czeika . The structures of the new compounds were established by extensive 1D‐ and 2D‐NMR spectroscopic experiments and MS analyses as 23‐O‐β‐D ‐galactopyranosylgypsogenic acid 28‐O‐{β‐D ‐glucopyranosyl‐(1→2)‐6‐O‐[4‐carboxy‐3‐hydroxy‐3‐methyl‐1‐oxobutyl]‐β‐D ‐glucopyranosyl‐(1→6)}‐[β‐D ‐glucopyranosyl‐(1→3)]‐β‐D ‐galactopyranosyl ester ( 1 ) and gypsogenic acid 28‐O‐{β‐D ‐glucopyranosyl‐(1→2)‐6‐O‐[4‐carboxy‐3‐hydroxy‐3‐methyl‐1‐oxobutyl]‐β‐D ‐glucopyranosyl‐(1→6)}‐[β‐D ‐glucopyranosyl‐(1→3)]‐β‐D ‐galactopyranosyl ester ( 2 ).     

Chemo‐Enzymatic Synthesis of 3‐Deoxy‐β‐D‐ribofuranosyl Purines

9‐(3‐Deoxy‐β‐D ‐erythro‐pentofuranosyl)‐2,6‐diaminopurine ( 6 ) was synthesized by an enzymatic transglycosylation of 2,6‐diaminopurine ( 2 ) with 3′‐deoxycytidine ( 1 ) as a donor of 3‐deoxy‐D ‐erythro‐pentofuranose moiety. This transformation comprises i) deamination of 1 to 3′‐deoxyuridine ( 3 ) under the action of whole cell (E. coli BM‐11) cytidine deaminase (CDase), ii) the phosphorolytic cleavage of 3 by uridine phosphorylase (UPase) giving rise to the formation of uracil ( 4 ) and 3‐deoxy‐α‐D ‐erythro‐pentofuranose‐1‐O‐phosphate ( 5 ), and iii) coupling of the latter with 2 catalyzed by whole cell (E. coli BMT‐4D/1A) purine nucleoside phosphorylase (PNPase). Deamination of 6 by adenosine deaminase (ADase) gave 3′‐deoxyguanosine ( 7 ). Treatment of 6 with NaNO₂ afforded 9‐(3‐deoxy‐β‐D ‐erythro‐pentofuranosyl)‐2‐amino‐6‐oxopurine (3′‐deoxyisoguanosine; 8 ). Schiemann reaction of 6 (HF/HBF₄+NaNO₂) gave 9‐(3‐deoxy‐β‐D ‐erythro‐pentofuranosyl)‐2‐fluoroadenine ( 9 ).     

New Triterpenoid Saponins from Achyrantes aspera Linn.

Two new bisdesmosidic triterpenoid saponins, i.e. 1 and 2 , were isolated, besides the three known saponins 3 – 5 , from the MeOH extract of the aerial parts of Achyranthes aspera Linn. (Amaranthaceae). Their structures were elucidated as β‐D ‐glucopyranosyl 3β‐[O‐α‐L ‐rhamnopyranosyl‐(1→3)‐O‐β‐D ‐glucopyranuronosyloxy]machaerinate ( 1 ) and β‐D ‐glucopyranosyl 3β‐[O‐β‐D ‐galactopyranosyl‐(1→2)‐O‐α‐D ‐glucopyranuronosyloxy]machaerinate ( 2 ) by NMR spectroscopy, including 2D‐NMR experiments (machaerinic acid=3β,21β‐dihydroxyolean‐12‐en‐28‐oic acid). The other saponins were identified as β‐D ‐glucopyranosyl 3β[O‐α‐L ‐rhamnopyranosyl‐(1→3)‐O‐β‐D ‐glucopyranuronosyloxy]oleanolate ( 3 ), β‐D ‐glucopyranosyl 3‐β‐[O‐β‐D ‐galactopyranosyl‐(1→2)‐O‐β‐D ‐glucopyranuronosyloxy]oleanolate ( 4 ), and β‐D ‐glucopyranosyl 3β‐[O‐β‐D ‐glucopyranuronosyloxy]oleanolate ( 5 ) (oleanolic acid=3β‐hydroxyolean‐12‐en‐28‐oic acid).     

Presenegenin Glycosides from Securidaca welwitschii

The five new presenegenin glycosides 1 – 5 were isolated from Securidaca welwitschii, together with one known sucrose diester. Compounds 1 – 4 were obtained as pairs of inseparable (E)/(Z)‐isomers of a 3,4‐dimethoxycinnamoyl derivative, i.e., 1 / 2 and 3 / 4 . Their structures were elucidated mainly by 2D‐NMR techniques and mass spectrometry as 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐{O‐β‐D ‐xylopyranosyl‐(1→4)‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐O‐[β‐D ‐glucopyranosyl‐(1→3)]‐4‐O‐[(E)‐3,4‐dimethoxycinnamoyl]‐β‐D ‐fucopyranosyl} ester ( 1 ) and its (Z)‐isomer 2 , 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐{O‐β‐D ‐galactopyranosyl‐(1→4)‐O‐β‐D ‐xylopyranosyl‐(1→4)‐O‐3‐O‐acetyl‐α‐L ‐rhamnopyranosyl‐(1→2)‐O‐[β‐D ‐glucopyranosyl‐(1→3)]‐4‐O‐[(E)‐3,4‐dimethoxycinnamoyl]‐β‐D ‐fucopyranosyl} ester ( 3 ) and its (Z)‐isomer 4 , and 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐[O‐β‐D ‐galactopyranosyl‐(1→3)‐O‐β‐D ‐xylopyranosyl‐(1→4)‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐β‐D ‐fucopyranosyl] ester ( 5 ) (presenegenin=(2β,3β,4α)‐2,3,27‐trihydroxyolean‐12‐ene‐23,28‐dioic acid).     

Steroidal Saponins from Disporopsis pernyi

Four new steroidal saponins, named disporosides A–D ( 1 – 4 ), corresponding to (3β,25R)‐3‐[(β‐D ‐glucopyranosyl‐(1→2)‐[β‐D ‐glucopyranosyl‐(1→6)]‐β‐D ‐glucopyranosyl)oxy]‐5β‐spirostan ( 1 ), (3β,25R)‐3‐[(β‐D ‐glucopyranosyl‐(1→2)‐[6‐O‐hexadecanoyl‐β‐D ‐glucopyranosyl‐(1→6)]‐β‐D ‐glucopyranosyl)oxy]‐5β‐spirostan ( 2 ), (3β,22R,25R)‐26‐[(β‐D ‐glucopyranosyl)oxy]‐3‐[(β‐D ‐glucopyranosyl‐(1→2)‐β‐D ‐glucopyranosyl)oxy]‐5β‐furostan ( 3 ), and (3β,22R,25R)‐26‐[(β‐D ‐glucopyranosyl)oxy]‐3‐[(β‐D ‐glucopyranosyl‐(1→2)‐[β‐D ‐glucopyranosyl‐(1→6)]‐β‐D ‐glucopyranosyl)oxy]‐5β‐furostan ( 4 ), have been isolated from the fresh rhizomes of Disporopsis pernyi, together with the three known compounds Ys‐I, agavoside B, and (3β,25R)‐3‐[(β‐D ‐xylopyranosyl‐(1→3)‐β‐D ‐glucopyranosyl‐(1→4)‐β‐D ‐galactopyranosyl)oxy]‐5α‐spirostan‐12‐one. Their structures were elucidated by spectroscopic analyses, chemical transformations (acid hydrolysis), and comparison with literature data.     

Two New Cytotoxic Nonsulfated Pentasaccharide Holostane (=20‐Hydroxylanostan‐18‐oic Acid γ‐Lactone) Glycosides from the Sea Cucumber Holothuria grisea

Two new lanostane‐type nonsulfated pentasaccharide triterpene glycosides, 17‐dehydroxyholothurinoside A ( 1 ) and griseaside A ( 2 ), were isolated from the sea cucumber Holothuria grisea. Their structures were elucidated by spectroscopic methods, including 2D‐NMR and MS experiments, as well as chemical evidence. Compounds 1 and 2 possess the same pentasaccharide moieties but differ slightly in their side chains of the holostane‐type triterpene aglycone. The structures of the two new glycosides were established as (3β,12α)‐22,25‐epoxy‐3‐{(O‐β‐D ‐glucopyranosyl‐(1→4)‐O‐[O‐3‐O‐methyl‐β‐D ‐glucopyranosyl‐(1→3)‐O‐β‐D ‐glucopyranosyl‐(1→4)‐6‐deoxy‐β‐D ‐glucopyranosyl‐(1→2)]‐β‐D ‐xylopyranosyl)oxy}‐12,20‐dihydroxylanost‐9(11)‐en‐18‐oic acid γ‐lactone ( 1 ) and (3β,12α)‐3‐{(O‐β‐D ‐glucopyranosyl‐(1→4)‐O‐[O‐3‐O‐methyl‐β‐D ‐glucopyranosyl‐(1→3)‐O‐β‐D ‐glucopyranosyl‐(1→4)‐6‐deoxy‐β‐D ‐glucopyranosyl‐(1→2)]‐β‐D ‐xylopyranosyl)oxy}‐12,20,22‐trihydroxylanost‐9(11)‐en‐18‐oic acid γ‐lactone ( 2 ). The 17‐dehydroxyholothurinoside A ( 1 ) and griseaside A ( 2 ) exhibited significant cytotoxicity against HL‐60, BEL‐7402, Molt‐4, and A‐549 cancer cell lines.     

New Furostanol Glycosides from the Roots of Digitalis ciliata Trautv.

Three new furostanol glycosides, named ciliatasides A, B, and C ( 1 – 3 , resp.), have been isolated from the roots of Digitalis ciliata, along with two known furostanol glycosides. The structures of the new compounds were identified as (2α,3β,5α,14β,25R)‐26‐(β‐D ‐glucopyranosyloxy)‐2‐hydroxyfurost‐20(22)‐en‐3‐yl β‐D ‐glucopyranosyl‐(1→2)‐[β‐D ‐glucopyranosyl‐(1→3)]‐β‐D ‐galactopyranoside ( 1 ), (2α,3β,5α,14β,22R)‐26‐(β‐D ‐glucopyranosyloxy)‐2‐hydroxy‐22‐methoxyfurost‐25(27)‐en‐3‐yl β‐D ‐galactopyranosyl‐(1→2)‐[β‐D ‐xylopyranosyl‐(1→3)]‐β‐D ‐glucopyranosyl‐(1→4)‐β‐D ‐galactopyranoside ( 2 ), and (2α,3β,5α,14β,22R,25R)‐26‐(β‐D ‐glucopyranosyloxy)‐2,22‐dihydroxyfurostan‐3‐yl β‐D ‐glucopyranosyl‐(1→2)‐[β‐D ‐glucopyranosyl‐(1→3)]‐β‐D ‐galactopyranoside ( 3 ).     

New Acylated Triterpene Saponins from Polygala arenaria

Eight new acylated triterpene saponins 1 – 8 were isolated from the roots of Polygala arenaria as four inseparable (E)/(Z) mixtures of the 4‐methoxycinnamoyl and 3,4‐dimethoxycinnamoyl derivatives by repeated MPLC over silica gel. Their structures were established mainly by 600‐MHz 2D‐NMR techniques (¹H,¹H‐COSY, TOCSY, NOESY, HSQC, HMBC) as 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐(O‐β‐D ‐galactopyranosyl‐(1→4)‐O‐[β‐D ‐glucopyranosyl‐(1→3)]‐O‐β‐D ‐xylopyranosyl‐(1→4)‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐{4‐O‐[(E)‐4‐methoxycinnamoyl]}‐β‐D ‐fucopyranosyl) ester and its (Z)‐isomer ( 1 / 2 ), 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐(O‐β‐D ‐galactopyranosyl‐(1→4)‐O‐[β‐D ‐glucopyranosyl‐(1→3)]‐O‐β‐D ‐xylopyranosyl‐(1→4)‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐{4‐O‐[(E)‐3,4‐dimethoxycinnamoyl]}‐β‐D ‐fucopyranosyl) ester and its (Z)‐isomer ( 3 / 4 ), 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐(O‐β‐D ‐glucopyranosyl‐(1→3)‐O‐α‐L ‐arabinopyranosyl‐(1→4)‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐{4‐O‐[(E)‐4‐methoxycinnamoyl]}‐β‐D ‐fucopyranosyl) ester and its (Z)‐isomer ( 5 / 6 ), and 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐(O‐β‐D ‐glucopyranosyl‐(1→3)‐O‐α‐L ‐arabinopyranosyl‐(1→4)‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐{4‐O‐[(E)‐3,4‐dimethoxycinnamoyl]}‐β‐D ‐fucopyranosyl) ester and its (Z)‐isomer ( 7 / 8 ) (presenegenin=(2β,3β)‐2,3,27‐trihydroxyolean‐12‐ene‐23,28‐dioic acid). In our in vitro lymphocyte proliferation assay (Jurkat T‐leukemia cells), a fraction containing 1 – 4 showed a concentration‐dependent immunomodulatory effect. This effect was not found for the prosapogenin (tenuifolin=3‐O‐(β‐D ‐glucopyranosyl)presenegenin), underlining the importance of the acyl? oligosaccharidic moiety.     

New Triterpene Saponins from Acanthophyllum pachystegium

Four new triterpenoid saponins, pachystegiosides A ( 1 ), B ( 2 ), C ( 3 ), and D ( 4 ), were isolated from the roots of Acanthophyllum pachystegium K. H. Their structures were elucidated by means of a combination of homo‐ and heteronuclear 2D‐NMR techniques (COSY, TOCSY, NOESY, HSQC, and HMBC) and by FAB‐MS. The new compounds were characterized as 3‐O‐{O‐β‐D ‐galactopyranosyl‐(1→2)‐O‐[β‐D ‐xylopyranosyl‐(1→3)]‐β‐D ‐glucuronopyranosyl}quillaic acid 28‐{O‐β‐D ‐xylopyranosyl‐(1→3)‐O‐β‐D ‐xylopyranosyl‐(1→4)‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐O‐[3,4‐di‐O‐acetyl‐β‐D ‐quinovopyranosyl‐(1→4)]‐β‐D ‐fucopyranosyl}ester ( 1 ), 3‐O‐{O‐β‐D ‐galactopyranosyl‐(1→2)‐O‐[β‐D ‐xylopyranosyl‐(1→3)]‐β‐D ‐glucuronopyranosyl}quillaic acid 28‐{O‐β‐D ‐xylopyranosyl‐(1→3)‐O‐β‐D ‐xylopyranosyl‐(1→4)‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐O‐[4‐O‐acetyl‐β‐D ‐quinovopyranosyl‐(1→4)]‐β‐D ‐fucopyranosyl} ester ( 2 ), 3‐O‐{O‐β‐D ‐galactopyranosyl‐(1→2)‐O‐[β‐D ‐xylopyranosyl‐(1→3)]‐β‐D ‐glucuronopyranosyl}quillaic acid 28‐{O‐β‐D ‐xylopyranosyl‐(1→4)‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐O‐[4‐O‐acetyl‐β‐D ‐quinovopyranosyl‐(1→4)]‐β‐D ‐fucopyranosyl} ester ( 3 ), and gypsogenic acid 28‐[O‐β‐D ‐glucopyranosyl‐(1→2)‐O‐β‐D ‐glucopyranosyl‐(1→6)‐O‐β‐D ‐glucopyranosyl‐(1→3)‐β‐D ‐galactopyranosyl] ester ( 4 ).     

Three New Medicagenic Acid Saponins from Polygala micrantha Guill. & Perr.

Three new medicagenic acid saponins, micranthosides A–C ( 1 – 3 ), were isolated from the roots of Polygala micrantha Guill . & Perr ., along with six known presenegenin saponins. Their structures were elucidated on the basis of extensive 1D‐ and 2D‐NMR experiments (¹H, ¹³C, DEPT, COSY, TOCSY, NOESY, HSQC, and HMBC) and mass spectrometry as 3‐O‐β‐D ‐glucopyranosylmedicagenic acid 28‐[O‐β‐D ‐galactopyranosyl‐(1→4)‐O‐β‐D ‐xylopyranosyl‐(1→4)‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐β‐D ‐fucopyranosyl] ester ( 1 ), 3‐O‐β‐D ‐glucopyranosylmedicagenic acid 28‐[O‐6‐O‐acetyl‐β‐D ‐galactopyranosyl‐(1→4)‐O‐β‐D ‐xylopyranosyl‐(1→4)‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐β‐D ‐fucopyranosyl] ester ( 2 ), and 3‐O‐{O‐β‐D ‐glucopyranosyl‐(1→3)‐O‐[β‐D ‐glucopyranosyl‐(1→6)]‐β‐D ‐glucopyranosyl}medicagenic acid 28‐{O‐β‐D ‐apiofuranosyl‐(1→3)‐O‐β‐D ‐xylopyranosyl‐(1→4)‐O‐[β‐D ‐apiofuranosyl‐(1→3)]‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐β‐D ‐fucopyranosyl} ester ( 3 ). Compounds 1 – 3 were evaluated against HCT 116 and HT‐29 human colon cancer cells, but they did not show any cytotoxicity.     

Chemical Constituents from Myrsine africana L.

Three new compounds, myrsinoside A (=2,4‐dihydroxy‐6‐methylphenyl β‐D ‐(6′‐galloyl)glucopyranoside; 1 ), myrsinoside B (2,4‐dihydroxy‐6‐methylphenyl β‐D ‐glucopyranoside; 2 ), and (3β,16α,20α)‐3,16,28‐trihydroxyolean‐12‐en‐29‐oic acid 3‐{O‐β‐D ‐glucopyranosyl‐(1→2)‐O‐[β‐D ‐glucopyranosyl‐(1→4)]‐α‐L ‐arabinopyranoside} ( 3 ), along with four known compounds, were isolated from the stems of Myrsine africana L. The structures of these new compounds were elucidated on the basis of spectroscopic analysis, including 1D‐ and 2D‐NMR and ESI‐MS techniques, and chemical methods.     

Synthesis of 5′‐O‐(2‐Azido‐2‐deoxy‐α‐D‐glycosyl)nucleosides and Their Antitumor Activities

The 1,3,4,6‐tetra‐O‐acetyl‐2‐azido‐2‐deoxy‐β‐D ‐mannopyranose ( 4 ) or the mixture of 1,3,6‐tri‐O‐acetyl‐2‐azido‐2‐deoxy‐4‐O‐(2,3,4,6‐tetra‐O‐acetyl‐β‐D ‐galactopyranosyl)‐β‐D ‐mannopyranose ( 10 ) and the corresponding α‐D ‐glucopyranose‐type glycosyl donor 9 / 10 reacted at room temperature with protected nucleosides 12 – 15 in CH₂Cl₂ solution in the presence of BF₃?OEt₂ as promoter to give 5′‐O‐(2‐azido‐2‐deoxy‐α‐D ‐glycosyl)nucleosides in reasonable yields (Schemes 2 and 3). Only the 5′‐O‐(α‐D ‐mannopyranosyl)nucleosides were obtained. Compounds 21, 28, 30 , and 31 showed growth inhibition of HeLa cells and hepatoma Bel‐7402 cells at a concentration of 10 μM in vitro.     

Three New Triterpenoid Saponins from Ardisia crenata

Three new triterpenoid saponins, ardisicrenoside I ( 1 ), ardisicrenoside J ( 2 ), and ardisicrenoside M ( 3 ), along with eight known compounds, were isolated from the roots of Ardisia crenata Sims . Their structures were elucidated as 16α‐hydroxy‐30,30‐dimethoxy‐3β‐O‐{β‐D ‐xylopyranosyl‐(1→2)‐β‐D ‐glucopyranosyl‐(1→4)‐[β‐D ‐glucopyranosyl‐(1→2)]‐α‐L ‐arabinopyranosyl}‐13β,28‐epoxyoleanane ( 1 ), 16α‐hydroxy‐30,30‐dimethoxy‐3β‐O‐{α‐L ‐rhamnopyranosyl‐(1→2)‐β‐D ‐glucopyranosyl‐(1→4)‐[β‐D ‐glucopyranosyl‐(1→2)]‐α‐L ‐arabinopyranosyl}‐13β,28‐epoxyoleanane ( 2 ), 30,30‐dimethoxy‐16‐oxo‐3β‐O‐{β‐D ‐xylopyranosyl‐(1→2)‐β‐D ‐glucopyranosyl‐(1→4)‐[β‐D ‐glucopyranosyl‐(1→2)]‐α‐L ‐arabinopyranosyl}‐13β,28‐epoxyoleanane ( 3 ), ardisiacrispin A ( 4 ), ardisiacrispin B ( 5 ), ardisicrenoside B ( 6 ), ardisicrenoside A ( 7 ), ardisicrenoside H ( 8 ), ardisicrenoside G ( 9 ), cyclamiretin A‐3β‐O‐β‐D ‐xylopyranosyl‐(1→2)‐β‐D ‐glucopyranosyl‐(1→4)‐α‐L ‐arabinopyranoside ( 10 ), and cyclamiretin A‐3β‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐β‐D ‐glucopyranosyl‐(1→4)‐α‐L ‐arabinopyranoside ( 11 ) by means of chemical and spectral analysis, and their cytotoxicities were evaluated in vitro.     

Unusual Nortriterpenoid Saponins from Stauntonia chinensis

Four new saponins, yemuosides YM₁₇–YM₂₀ ( 1 – 4 , resp.), were isolated from the rattan of Stauntonia chinensis DC. (Lardizabalaceae) along with a known saponin, nipponoside D ( 5 ). Their structures were elucidated by spectroscopic analysis and chemical evidence as 20,30‐dihydroxy‐29‐noroleanolic acid 28‐O‐α‐L ‐rhamnopyranosyl‐(1→4)‐β‐D ‐glucopyranosyl‐(1→6)‐β‐D ‐glucopyranosyl ester ( 1 ), 20,29‐dihydroxy‐30‐noroleanolic acid 28‐O‐α‐L ‐rhamnopyranosyl‐(1→4)‐β‐D ‐glucopyranosyl‐(1→6)‐β‐D ‐glucopyranosyl ester ( 2 ), 29‐hydroxy‐30‐norolean‐20(21)‐enolic acid 28‐O‐α‐L ‐rhamnopyranosyl‐(1→4)‐β‐D ‐glucopyranosyl‐(1→6)‐β‐D ‐glucopyranosyl ester ( 3 ), 29‐hydroxyoleanolic acid 28‐O‐α‐L ‐rhamnopyranosyl‐(1→4)‐β‐D ‐glucopyranosyl‐(1→6)‐β‐D ‐glucopyranosyl ester ( 4 ), and 23,29‐dihydroxyoleanolic acid 28‐O‐α‐L ‐rhamnopyranosyl‐(1→4)‐β‐D ‐glucopyranosyl‐(1→6)‐β‐D ‐glucopyranosyl ester ( 5 ). Yemuoside YM₁₇–YM₁₉ ( 1 – 3 , resp.) contain novel unusual nortriterpene aglycones.     

New Acylated Saponins from Polygala myrtifolia

The ten new acylated presenegenin (=(2β,3β,4α)‐2,3,27‐trihydroxyolean‐12‐ene‐23,28‐dioic acid) glycosides 1 – 10 have been isolated by successive MPLC from the roots of Polygala myrtifolia L. as five inseparable mixtures of the trans‐ and cis‐4‐methoxycinnamoyl derivatives, i.e., myrtifoliosides A₁/A₂ ( 1 / 2 ), B₁/B₂ ( 3 / 4 ), C₁/C₂ ( 5 / 6 ), D₁/D₂ ( 7 / 8 ), and E₁/E₂ ( 9 / 10 ). Their structures were elucidated mainly by extensive spectroscopic experiments, including 2D NMR techniques, as 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐{O‐β‐D ‐galactopyranosyl‐(1→3)‐O‐β‐D ‐xylopyranosyl‐(1→4)‐O‐[D ‐apio‐β‐D ‐furanosyl‐(1→3)]‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐O‐[α‐L ‐arabinopyranosyl‐(1→3)]‐4‐O‐(trans‐4‐methoxycinnamoyl)‐β‐D ‐fucopyranosyl} ester ( 1 ) and its cis‐isomer 2 , 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐{O‐β‐D ‐galactopyranosyl‐(1→3)‐O‐β‐D ‐xylopyranosyl‐(1→4)‐O‐[D ‐apio‐β‐D ‐furanosyl‐(1→3)]‐α‐L ‐rhamnopyranosyl‐(1→2)‐4‐O‐(trans‐4‐methoxycinnamoyl)‐β‐D ‐fucopyranosyl} ester ( 3 ) and its cis‐isomer 4 , 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐{O‐β‐D ‐galactopyranosyl‐(1→3)‐O‐β‐D ‐xylopyranosyl‐(1→4)‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐4‐O‐(trans‐4‐methoxycinnamoyl)‐β‐D ‐fucopyranosyl} ester ( 5 ) and its cis‐isomer 6 , 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐{O‐D ‐apio‐β‐D ‐furanosyl‐(1→3)‐O‐[β‐D ‐xylopyranosyl‐(1→4)]‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐4‐O‐(trans‐4‐methoxycinnamoyl)‐β‐D ‐fucopyranosyl} ester ( 7 ) and its cis‐isomer 8 , and 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐{O‐α‐L ‐arabinopyranosyl‐(1→3)‐O‐[β‐D ‐xylopyranosyl‐(1→4)]‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐4‐O‐(trans‐4‐ methoxycinnamoyl)‐β‐D ‐fucopyranosyl} ester ( 9 ) and its cis‐isomer 10 .