Lignan glycosides from the Rhizomes of Smilax trinervula and their Biological activities

Phytochemical investigation of the rhizomes of Smilax trinervula led to isolation and structure elucidation of eight lignan glycosides, including five new lignans, namely, (7S, 8R, 8′R)-4, 4′, 9-trihydroxy-3, 3′, 5, 5′-tetramethoxy-7, 9′-epoxylignan-7′-one 4′-O-β-d-glucopyranoside (1), (7S, 8R, 8′R)-4, 4′, 9-trihydroxy-3, 3′, 5, 5′-tetramethoxy-7, 9′-epoxylignan-7′-one 4-O-β-d- glucopyranoside (2) (7S, 8R)-4, 9, 9′-trihydroxy-3, 3′, 5-trimethoxy-4′, 7-epoxy-8, 5′-neolignan 9′-O-β-d-glucopyranoside (3), (7R, 8R)-4, 9, 9′-trihydroxy-3, 5-dimethoxy-7.O.4′, 8.O.3′- neolignan 9′-O-β-d-glucopyranoside (4), and (7S, 8R)-4, 9, 9′-trihydroxy-3, 3′, 5-trimethoxy-8, 4′-oxy-neolignan 4-O-β-d-glucopyranoside (5), along with three known compounds (6-8). Their structures were established mainly on the basis of 1D and 2D NMR spectral data, ESI–MS and comparison with the literature. Compounds 1-8 were tested in vitro for their cytotoxic activity against four human tumor cell lines (SH-SY5Y, SGC-7901, HCT-116, Lovo). Compounds 3 and 5 exhibited cytotoxic activity against Lovo cells, with IC₅₀ value of 10.4 μM and 8.5 μM, respectively.     

Phytochemical and chemotaxonomic study on Berchemiella wilsonii (Schneid.) Nakai

Phytochemical investigation of the aerial parts of Berchemiella wilsonii (Schneid.) Nakai (Rhamnaceae) led to the isolation of four flavonoids (1–4), three phenolic acids (5–7), two megastigmane derivatives (8–9) and one triterpene (10). The structures of these compounds were elucidated as taxifolin (1), (−)-epicatechin (2), quercetin 3-O-a-l-arabinopyranoside (3), vitexin (4), methyl p-hydroxycinnamat (5), 3,4-dihydroxybenzoic acid (6), 2-hydroxy-4-methoxy-3,6-dimethyl benzoic acid (7), (3S,5R,6R,7E,9S)-3,5,6,9-tetrahydroxy-7-en-megastigmane (8), (6S,9R)-roseoside (9) and lupeol (10) on the basis of NMR spectral data and comparison with literature values. These results are the first chemical constituent data of the genus Berchemiella, and the chemotaxonomic significance of these compounds is discussed.     

Two new dihydrobenzofuran-type neolignans from Breynia fruticosa

(7S,8R,7′S)-9,7′,9′-Trihydroxy-3,4-methylenedioxy-3′-methoxy [7-O-4′,8-5′] neolignan (1) and (7S,8R,7′S)-9,9′-dihydroxy-3,4-methylenedioxy-3′,7′-dimethoxy [7-O-4′,8-5′] neolignan (2), two new natural dihydrobenzofuran-type neolignans, along with 9,9′-dihydroxy-3,4-methylenedioxy-3′-methoxy [7-O-4′,8-5′] neolignan (3) and (-)-machicendiol (4), were isolated from the whole plants of Breynia fruticosa. The structures of 1 and 2, including the absolute configurations, were determined by spectroscopic methods and circular dichroism (CD) techniques. The absolute configuration of 4 was confirmed by calculations of the OR spectrum, together with OR and ECD spectra of its p-bromobenzoate ester (4a).     

Phytochemical and chemotaxonomic studies on the stems and leaves of Schisandra chinensis (Turcz.) Baill

A comprehensive phytochemical investigation of the stems and leaves of Schisandra chinensis (Turcz.) Baill. resulted in isolation of seventeen compounds, including five lignans: meso-dihydroguaiaretic acid (1), licarin-A (2), pregomisin (3), gomisin A (4), acutissimanide (5), three phenylpropanoids: 2-[4-(3-hydroxypropyl)-2-methoxyphenoxy]-propane-1,3-diol (6), 2-methoxy-4-(2-propenyl) phenyl β-D-glucopyranoside (7), erigeside 2 (8), six sesquiterpenoids: 7′-hydroxy-abscisic acid (9), burmannic acid (10), (3S,5R,6R,7E)-3,5,6-trihydroxy-7-megastigmen-9-one (11), 3-Cyclohexene-1,2-diol, 4-(3-hydroxybutyl)- 3, 5, 5-trimethyl- (12), (−)-loliolide (13), (3Z,5R,8R,11R)-Caryophyll-3-ene-5,8,15-triol (14), one monoterpenoid: (6R,3Z)-6,7-dihydroxy-3,7-dimethyl-2-octenoic acid (15) and two other compounds: methyl shikimate (16), 4-Hydroxydodec-2-enedioic acid (17). Their chemical structures were confirmed through NMR, HRESIMS and comparison with the data in the literature. This is the first report of compounds 5, 6, 8–15, 17 from the family Schisandraceae and compounds 2, 16 from the genus Schisandra. Furthermore, we performed a chemotaxonomic study of the separated compounds.     

Dolabellane diterpenoids from Aglaia odorata

Dolabellane diterpenoids, (1R,3E,7E,10S,11S,12R)-dolabella-3,7-dien-10,18-diol (1), (1R,3S,7E,11S,12R)-dolabella-4(16),7-dien-3,18-diol (2), (1R,7E,11S,12R)-18-hydroxydolabella-4(16),7-dien-3-one (3), (1R,3S,4S,7E,11S,12R)-3,4-epoxydolabella-7-en-18-ol (4), and (1R,3R,7E,11S,12R)-dolabella-4(16),7,18-trien-3-ol (5), were obtained from the ornamental plant Aglaia odorata. Their structures were characterized on the basis of spectroscopic analyses and further confirmed by X-ray diffraction. Compounds 1 and 5 showed weak cytotoxicity against the human myeloid leukemia HL-60, hepatocellular carcinoma SMMC-7721, and lung cancer A-549 cells.     

Phytochemical and chemotaxonomic study on Piper pleiocarpum Chang ex Tseng

The phytochemical study of Piper pleiocarpum Chang ex Tseng led to the isolation of eighteen compounds (1–18), including ten lignanoids, galbelgin (1), (+) sesamin (2), denudatin A (3), hancinone (4), (7S,8S, 3′R)-Δ^8'-3,3′,4-trimethoxy-3′,6′-dihydro-6′-oxo-7.0.4′,8.3′-lignan[(2S,3S,3aR)-2-(3,4-dimethoxyphenyl)-3,3a-dihydro-3a-methoxy-3-methyl-5-(2-propenyl)-6(2H))-benzofuranone] (5), (−)-(7R,8R)-machilin D (6), (1R,2R)-2-[2-methoxy-4-((E)-prop-1-enyl)phenoxy]-1-(3,4-dimethoxyphenyl)propyl acetate (7), piperbonin A (8), machilin D (9), 4-methoxymachilin D (10), one amide alkaloid, Δ^α,β-dihydropiperine (11), six polyoxygenated cyclohexenes, ent-curcuminol F (12), uvaribonol E (13), ellipeiopsol A (14), 1S,2R,3R,4S-1-ethoxy-2-[(benzoyloxy)methyl]cyclohex-5-ene-2,3,4-triol, 3-acetate (15), (+)-crotepoxide (16), (+)-senediol (17), and one benzoate derivative, 2-acetoxybenzyl benzoate (18). Their structures were established by spectroscopic data and by comparison with the literature. All the compounds were firstly isolated from P. pleiocarpum, while ten compounds 6–7, 9–10, 12–15, 17–18 were isolated from the genus Piper and the family Piperaceae for the first time. The chemotaxonomic significance of these compounds was also discussed. The isolation of compounds 6–7, 9–10 may be used as chemotaxonomic markers for the genus of Piper.     

Two new nonacosanetriols from Ginkgo biloba sarcotesta

Two new fatty alcohols named as (7S,8R,11S)-nonacosanetriol (1) and (10R,12R,15S)-nonacosanetriol (2), along with eight known compounds including ginkgolic acid (3), hydroginkgolic acid (4), sciadopitysin (5), ginkgetin (6), isoginkgetin (7), ginkgolide A (8), ginkgolide B (9) and ginkgolide C (10) have been isolated from the petroleum ether extract of Ginkgo biloba sarcotesta. Their structures were elucidated by means of chemical and extensive spectroscopic analysis. The absolute stereochemistry of compounds 1 and 2 was elucidated on the spectroscopic analysis of the R- and S-MTPA esters. Compounds 1 and 2 exhibited slight activity of antithrombin and moderate activity of antiplatelet aggregation in vitro. This was the first report regarding the anticoagulative activities of biflavonoids in G. biloba, and isoginkgetin (7) showed significant antithrombin and antiplatelet aggregation activity.     

A pair of new sesquiterpene isomers containing spiro heterocyclic skeleton from plant-derived fungus Botryosphaeria dothidea

A pair of new sesquiterpene isomers containing a spiro heterocyclic skeleton, dothimes A (1) and B (2), together with six known compounds, quindoline (3), (S)-3-(3-indolyl)lactic acid methyl ester (4), dankasterone B (5), dibutyl phthalate (6), (1S,3R,4R,7S)-3,4-dihydroxy-α-bisabolol (7), and p-hydroxybenzaldehyde (8), were isolated from the plant-derived fungus Botryosphaeria dothidea. The structures of all isolated compounds were determined based on extensive spectroscopic analyses, including 1D/2D nuclear magnetic resonance (NMR), and high resolution electrospray ionization mass spectrometry (HRESIMS) data, as well as by comparison with literature reports. Compounds 1 and 2 exhibited inhibitory effects on lipopolysaccharide (LPS)-induced nitric oxide (NO) production with IC₅₀ values of 63.66 and 58.29 μM, respectively.     

Renoprotective chemical constituents from an edible mushroom,Pleurotus cornucopiae in cisplatin-induced nephrotoxicity

Pleurotus cornucopiae (Pleurotaceae) is an edible and medicinal mushroom widely distributed in Korea, China, and Japan. The MeOH extract of the fruiting bodies of P. cornucopiae showed renoprotective effects against cisplatin-induced kidney cell damage. Chemical investigation of the MeOH extract led to the isolation and identification of 12 compounds including noransine (1), uridine (2), uracil (3), (3β, 5α, 6β, 22E, 24S) -ergosta-7, 22-diene-3, 5, 6, 9-tetrol (4), (22E,24S)-ergosta-7,22-diene-3β,5α,6β-triol (5), (22E,24R)-ergosta-8(14),22-diene-3β,5α,6β,7α-tetrol (6), cerebroside B (7), (2R) -N- [(1S, 2R, 3E, 7E) -1- [(β-d-glucopyranosyloxy) methyl] -2-hydroxy-8-methyl-3, 7-heptadecadien-1-yl] -2-hydroxy-heptadecanamide (8), cerebroside D (9), nicotinamide (10), 1,2-bis(hydroxymethyl)-4,5-dimethoxybenzene (11), and benzoic acid (12). Among them, compounds 1 and 11 were isolated as naturally occurring products for the first time, though they were reported as synthetic products in previous papers. All of the compounds (except 8 and 11) abrogated cisplatin-induced LLC-PK1 cell damage in a dose-dependent manner. Of special note, compounds 2, 5, 6, and 12 ameliorated cisplatin-induced nephrotoxicity to 80% of the control value at 10 μM. The protective effects of compounds 2, 5, 6, and 12 were mediated via the deactivation of JNK-caspase 3 apoptotic cascade. This study is the first to demonstrate that the chemical constituents of P. cornucopiae display renoprotective effects against anticancer drug-induced damage in kidney cells.     

New eudesmane sesquiterpenes from Alpinia oxyphylla and determination of their inhibitory effects on microglia

The fruits of Alpinia oxyphylla are used as healthcare products for the protection on neurons and prevention of dementia. Two new noreudesmane sesquiterpenoids, (5R,7S,10S)-5-hydroxy-13-noreudesma-3-en-2,11-dione (1) and (10R)-13-noreudesma-4,6-dien-3,11-dione (2), and a new eudesmane sesquiterpenoid, (5S,8R,10R)-2-oxoeudesma-3,7(11)-dien-12,8-olide (3), as well as 12 known sesquiterpenoids, were isolated from the fruits of A. oxyphylla. The structures of the new compounds (1–3) were elucidated on the basis of spectroscopic data and circular dichroism experiments. All isolates were evaluated their neuroprotective potential by inhibitory assay on nitric oxide (NO) and tumor necrosis factor-α (TNF-α) production in lipopolysaccharide (LPS)-induced mouse microglia BV-2 cells.     

Two new guaiane sesquiterpenes from Datura metel L. with anti-inflammatory activity

Chemical investigation of an acidic methanol extract of the whole plants of Datura metel resulted in the isolation of two new guainane sesquiterpenes, 1β,5α,7β-guaiane-4β,10α,11-triol (1) and 1α,5α,7α-11-guaiene-2α,3β,4α,10α,13-pentaol (2), along with eight known compounds: pterodontriol B (3), disciferitriol (4), scopolamine (5), kaempferol 3-O-β-d-glucosyl(1 → 2)-β-d-galactoside 7-O-β-d-glucoside (6), kaempferol 3-O-β-glucopyranosyl(1 → 2)-β-glucopyranoside-7-O-α-rhamnopyranoside (7), pinoresinol 4′′-O-β-d-glucopyranoside (8), (7R,8S,7′S,8′R)-4,9,4′,7′-tetrahydroxy-3,3′-dimethoxy-7,9′-epoxy-lignan-4-O-β-d-glucopyranoside (9), and (7S,8R,7′S,8′S)-4,9,4′,7′-tetrahydroxy-3,3′-dimethoxy-7,9′-epoxylignan-4-O-β-d-glucopyranoside (10). Their structures were elucidated by extensive spectroscopic methods, including 1D and 2D NMR and MS spectra. Compounds 2-4 and 6-10 were shown to have modest anti-inflammatory effects through inhibition of NO production in LPS-stimulated BV cells.     

Phenolic compounds and their anti-oxidative properties and protein kinase inhibition from the Chinese mangrove plant Laguncularia racemosa

Phenolic compounds, named integracin D (1), (7′R, 8′S, 8S)-8-hydroxyisoguaiacin (3), (2R, 3R) pinobanksin-3-caffeoylate (5) and threo-8S-7-methoxysyringylglycerol (6), respectively, were isolated from the Chinese mangrove plant Laguncularia racemosa (L) Gaertn. f. (Combretaceae), together with 23 known phenolic metabolites. Their structures were elucidated on the basis of extensive spectroscopic analyses including that of IR, UV, MS, CD, 1D and 2D NMR spectra as well as by comparison with literature data. Compound 5 showed significant anti-oxidative activity in the DPPH and TEAC free-radical-scavenging assays, while several of the phenolic compounds were tested for protein kinase inhibitory activity in an assay involving 24 different human tumor related protein kinases. Compounds 5, 7, and 23 showed potential inhibition with IC₅₀ values between 2.2 and 3.6 μg/mL toward individual kinases. The ellagic acid derivatives were tested for insecticidal activity.     

Neolignans from Aniba lancifolia

The branches of the shrub Aniba lancifolia Kubitzki et Rodrigues (Lauraceae) contain besides 2-hydroxy-4,5- dimethoxyallylbenzene and its dimer cyclohexan-2-allyl- 5-en-4,5-dimethoxy-4-O-(2′-allyl-4′,5′-dimethoxyphenyl)-1-one (lancilin, 2) 6 further novel neolignans: (4S,2′R)- and (4R,2′E)-cyclohexan-2-allyl-2,5-dien-4,5-dimethoxy-4-[2′-(1′-guaiacyl)-propyl]-1-one (lancifolins A and B, 3a and 3b), (4S,2′R)- and (4R,2′R)-cyclohexan- 2-allyl-2,5-dien-4,5-dimethoxy-4-[2′-(1′-veratryl)-propyl]-1-one (lancifolins C and D, 3c and 3d), (4S,2′R)-and (4R,2′R)-cyclohexan-2-allyl-2,5-dien-4,5-dimethoxy-4-[2′-(1′-piperonyl)-propyl]-1-one (lancifolins E and F, 3e and 3f).     

Terpenoids from Russula lepida and R. amarissima (Basidiomycota,Russulaceae)

Four aristolane sesquiterpenes were isolated from the fruiting bodies of Russula lepida and R. amarissima, namely (1R,2S)-1,2-dihydroxyaristolone (6), (2S,11S)-2,12-dihydroxy-aristolone (7), (1R,2S,11S)-1,2,12-trihydroxyaristolone (8), (1S,2S,11S)-1,2,12-trihydroxy-aristolone (9). In addition, a seco-cucurbitane triterpene, i.e. 3,4-secocucurbita-4,24E-diene-3-hydroxy-26-carboxylic acid (14) was isolated from both species. The configuration at C-2 of the already known rulepidol (2-hydroxyaristolone, 5) was corrected as S instead of R. Several more aristolane and nardosinane sesquiterpenes, as well as cucurbitane triterpenes, already reported both from European and Chinese samples of R. lepida, were also isolated. Compound 14 showed moderate cell growth inhibitory activity.     

Thiophenes,polyacetylenes and terpenes from the aerial parts of Eclipata prostrata

One new bithiophenes, 5-(but-3-yne-1,2-diol)-5′-hydroxy-methyl-2,2′-bithiophene (2), two new polyacetylenic glucosides, 3-O-β-d-glucopyranosyloxy-1-hydroxy-4E,6E-tetradecene-8,10,12-triyne (8), (5E)-trideca-1,5-dien-7,9,11-triyne-3,4-diol-4-O-β-d-glucopyranoside (9), six new terpenoid glycosides, rel-(1S,2S,3S,4R,6R)-1,6-epoxy-menthane-2,3-diol-3-O-β-d-glucopyranoside (10), rel-(1S,2S,3S,4R,6R)-3-O-(6-O-caffeoyl-β-d-glucopyranosyl)-1,6-epoxy menthane-2,3-diol (11), (2E,6E)-2,6,10-trimethyl-2,6,11-dodecatriene-1,10-diol-1-O-β-d-glucopyranoside (12), 3β,16β,29-trihydroxy oleanane-12-ene-3-O-β-d-glucopyranoside (13), 3,28-di-O-β-d-glucopyranosyl-3β,16β-dihydroxy oleanane-12-ene-28-oleanlic acid (14), 3-O-β-d-glucopyranosyl-(1→2)-β-d-glucopyranosyl oleanlic-18-ene acid-28-O-β-d-glucopyranoside (15), along with fifteen known compounds (1, 3–7, and 16–24), were isolated from the aerial parts of Eclipta prostrata. Their structures were established by analysis of the spectroscopic data. The isolated compounds 1–9 were tested for activities against dipeptidyl peptidase IV (DPP-IV), compound 7 showed significant antihyperglycemic activities by inhibitory effects on DPP-IV in human plasma in vitro, with IC₅₀ value of 0.51 μM. Compounds 10–24 were tested in vitro against NF-κB-luc 293 cell line induced by LPS. Compounds 12, 15, 16, 19, 21, and 23 exhibited moderate anti-inflammatory activities.     

Sulfur-containing constituents and one 1H-pyrrole-2-carboxylic acid derivative from pineapple [Ananas comosus (L.) Merr.] fruit

Two sulfur-containing compounds, (S)-2-amino-5-((R)-1-carboxy-2-((E)-3-(4-hydroxy-3-methoxyphenyl)allylthio)ethyl-amino)-5-oxopentanoic acid (1) and (S)-2-amino-5-((R)-1-(carboxymethylamino)-3-((E)-3-(4-hydroxyphenyl)allylthio)-1-oxopropan-2-ylamino)-5-oxopentanoic acid (2), and one 1H-pyrrole-2-carboxylic acid derivative, 6-(3-(1H-pyrrole-2-carbonyloxy)-2-hydroxypropoxy)-3,4,5-trihydroxy-tetrahydro-2H-pyran-2-carboxylic acid (3), together with eighteen known phenolic compounds, were isolated from the fruits of pineapple. Their structures were elucidated by a combination of spectroscopic analyses. Some of these compounds showed inhibitory activities against tyrosinase. The half maximal inhibitory concentration values of compounds 1, 4, 5, 6, 7 are lower than 1 mM. These compounds may contribute to the well-known anti-browning effect of pineapple juice and be potential skin whitening agents in cosmetic applications.     

Diterpenoids from the needles and twigs of the cultivated endangered pine Pinus kwangtungensis and their PTP1B inhibitory effects

Pinus kwangtungensis is an endangered pine species native to China. In the present study, 15 diterpenoids including three new labdane-type analogs were isolated and characterized during a pioneer phytochemical investigation on a mass-limited sample of the needles and twigs of this plant, which is growing in a Cantonese garden. The new structures, (4S,5R,9S,10R)-6-oxo-labd-7,13-dien-16,15- olid-19-oic acid (1), 15(S)-n-butoxypinusolidic acid (2), and β-d-glucopyranosyl- (4S,5R,9S,10R)-labda-8(17),13-dien-15,16-olid-19-oate (3), were established by extensive spectroscopic methods and some chemical transformations. Among the isolates, lambertianic acid (10) and cassipourol (15) showed inhibitory activities against human protein tyrosine phosphatase 1 B (PTP1B), a target for the treatment of type-II diabetes and obesity, with IC₅₀ values of 25.5 and 11.2 μM, respectively.     

(2S)-Prenylflavanones and taraxerane triterpenoids from Mallotus mollissimus

Three prenylflavanones, (2S)-5,7-dihydroxy-4′-methoxy-8-(3″,3″-dimethylallyl)flavanone (3), (2S)-5,4′-dihydroxy-7-methoxy-6-(3″,3″-dimethylallyl)flavanone (6), 8-prenylnaringenin (11), and a new epimeric pair (2″S/2″R)-(2S)-5,7-dihydroxy-4′-methoxy-6-(2″-hydroxy-3″-methylbut-3″-enyl)flavanones (4a/4b) were isolated together with taraxerone, taraxerol, epitaraxerol, β-sitosterol, oleanolic acid, 1-O-docosanoyl glycerol, apigenin, and apigenin 7-O-β-D-glucopyranoside from the MeOH extract of the leaves of Mallotus mollissimus. The structures of the isolated compounds were determined on the basis of 1D/2D NMR and HR-MS spectroscopic data; the 2S configuration of the prenylflavanones 3, 4, and 6 was deduced from CD spectroscopic data. The presence of three taraxerane triterpenoids reinforces the inclusion of M. mollissimus (syn. Croton mollissimus) in Mallotus genus. Among species of Mallotus the occurrence of the (2S)-prenylflavanones 3, 4, and 6 is confined to M. mollissimus.     

New guaiane sesquiterpenes from Artemisia rupestris and their inhibitory effects on nitric oxide production

Phytochemical investigation of the ethanol extract of the aerial parts of Artemisia rupestris resulted in the isolation of three new guaiane sesquiterpenes, (1R,7R,10S)-1-hydroxy-3-oxoguaia-4,11(13)-dien-12-oic acid (1), (1R,7R,10S)-10-hydroxy-3-oxoguaia-4,11(13)-dien-12-oic acid (2), pechueloic acid 12-O-β-d-glucopyranoside (3), together with 12 known compounds (4–15). The structures of these new compounds were established on the basis of extensive spectroscopic analysis and electronic circular dichroism (ECD) calculation. All isolates were evaluated for their in vitro inhibitory effects on nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages cells, and the structure–activity relationships were also discussed.     

Synthesis of C-glycopyranosylfuran derivatives by reaction of dialdehydes with cyanoacetamide

The reaction of diglycol- and thiodiglycol-aldehyde (1a,b) with cyanoacetamide yields cis-3,5-diacetoxy-4-carbamoyl-4-cyano-tetrahydropyran (2a) and -tetrahydrothiopyran (2b). When this reaction is applied to (2S)-2-(3-ethoxycarbonyl-2-methyl-5-furyl)-3,5-dihydroxy-1,4-dioxane (1c), (2S)-3,5-dihydroxy-2-(3-methoxycarbonyl-2-methyl-5-furyl)-1,4-dioxane (1d), and (2S,3R,5S)-2-(3-acetyl-2-methyl-5-furyl)-3,5-dihydroxy-1,4-dioxane (1e), 5-(3-carbamoyl-3-cyano-3-deoxy-β-d-xylo-pentopyranosyl)-3-ethoxycarbonyl-2-methylfuran (2c), 5-(2,4-di-O-acetyl-3-carbamoyl-3-cyano-3-deoxy-β-d-xylo-pentopyranosyl)-3-methoxycarbonyl-2-methylfuran (2e), and 3-acetyl-5-(2,4-di-O-acetyl-3-carbamoyl-3-cyano-3-deoxy-β-d-xylo-pentopyranosyl)-2-methylfuran (2f), respectively, are formed with (4S,5S)-4-carbamoyl-4-cyano-2-(3-ethoxycarbonyl-2-methyl-5-furyl)-5-hydroxy-5,6-dihydropyran (3a) and (4S,5S)-4-carbamoyl-4-cyano-5-hydroxy-2-(3-methoxycarbonyl-2-methyl-5-furyl)-5,6-dihydropyran (3b) as minor products. The dehydration of 2a,b, 5-(2,4-di-O-acetyl-3-carbamoyl-3-cyano-3-deoxy-β-d-xylo-pentopyranosyl)-3-ethoxycarbonyl-2-methylfuran (2d), 2e, and 2f yields cis-3,5-diacetoxy-4,4-dicyano-tetrahydropyran and -tetrahydrothiopyran (2l,m), and the 5-(2,4-di-O-acetyl-3,3-dicyano-3-deoxy-β-d-erythro-pentopyranosyl) derivatives (2n–p) of 3-ethoxycarbonyl-2-methylfuran, 3-methoxycarbonyl-2-methylfuran, and 3-acetyl-2-methylfuran, respectively.