Synthesis of -Heteroaryl -Glycosides and Polyhydroxylated Alkanes with Diaryl Groups from Unprotected Sugars.

HCl-catalyzed -glycosylation was described herein for the convenient preparation of -heteroaryl -glycosides and polyhydroxylated alkanes with diaryl groups using hetereoaryl amines and unprotected sugars as starting materials. The reaction temperature and the amounts of aryl amines and HCl had significant effects on reactions. The method provided a highly efficient and environmentally friendly route for constructing -glycosides at low cost.

One-Pot Synthesis of Hydroxylated Alkaloids from Sugars via a Pictet-Spengler-Type Reaction.

An efficient and convenient strategy has been successfully developed for the preparation of novel hydroxylated alkaloid derivatives (also called fused multicyclic iminosugars) from -toluenesulfonylated sugars through a Pictet-Spengler-type mechanism. This method is highly stereoselective, does not require metal catalysts, and capable of conducting gram level reactions (with a 53% yield). Some of such iminosugars had an intermediate antiproliferative effect on HCT116 tumor cells.

One-Pot Stereoselective Synthesis of the Naphthofurano-Iminosugars via a [3 + 2] Cycloaddition Reaction.

This study presents the synthesis of novel naphthofurano-iminosugars () using 2,3--isopropylidene D-ribose tosylate (), anilines (), and 1,4-benzoquinone () as starting materials through key iminium ion/enamine intermediates via [3 + 2] cyclization reactions at room temperature. The reaction has unique regioselectivity and stereoselectivity with moderate to excellent yields. The adaptability of this method has been demonstrated using various substituted anilines, on which both electron-donating and electron-withdrawing groups were well employed in the reactions.

Lewis Acid-Promoted Oxidative Cleavage of Carbon-Carbon Bonds: Synthesis of -Arylated Lactam-Type Iminosugars.

In this paper, a mild strategy for the oxidative cleavage of carbon-carbon bonds catalyzed by Lewis acid was developed in air condition at room temperature. Under such conditions, the bis-carbonyl compounds were directly afforded from the reaction of D-ribose tosylate and aniline in excellent yields through the oxidative cleavage of the key intermediate iminium-ion and its tautomer enamine . A series of -arylated lactam-type iminosugars were then successfully obtained by removing the isopropylidene group from with the aid of the condensation agent DCC.

An alternative route for tricyclic quinazolinone-iminosugars and their glucosidase inhibitory activities.

A series of novel tricyclic quinazolinone-iminosugars 5 and their derivatives 7 were obtained from the tosylated sugars by three steps. Firstly, the reaction of the isopropylidene protected sugar tosylate 1 and o-aminobenzylamine 2 generated the precursor tricyclic quinazolin-iminosuar 3, which was then oxidized by KMnO to produce the corresponding quinazolinone 4. Finally, removal of the isopropylidene group yielded the target tricyclic quinazolinone iminosugars 5.

One-Pot Stereoselective Synthesis of Furantetrahydroquinoline Derivatives Using d/l-Ribose with a 2,3--Isopropylidene Group.

An efficient and convenient strategy has been successfully developed for the preparation of novel furantetrahydroquinoline derivatives using d/l-ribose with a 2,3--isopropylidene group through the aza-Diels-Alder mechanism. This method has high atom and step economy, high stereoselectivity, and gram-scale synthesis (yield 67%).

Design, synthesis, and anti-tumor activities of novel triphenylethylene-coumarin hybrids, and their interactions with Ct-DNA.

Novel triphenylethylene-coumarin hybrid derivatives containing different amounts of amino side chains were designed and synthesized in good yields under microwave radiation. The derivatives 5b-d which possessed two amino side chains (except morpholinyl) showed a broad-spectrum and good anti-proliferative activity against five tumor cells and low cytotoxicity in osteoblast. UV-vis, fluorescence, and circular dichroism (CD) spectroscopies and thermal denaturation exhibited that compounds 10 c, 5c, and 13c bearing amino side chain (except morpholinyl) on 4-phenyl had significant interactions with Ct-DNA by the intercalative mode of binding.

[Response of N transformation related soil enzyme activities to inhibitor applications].

With an aerobic incubation test, this paper studied the response of soil urease, nitrate reductase, nitrite reductase, and hydroxylamine reductase to urease inhibitor hydroquinone (HQ) applied in combination with nitrification inhibitor encapsulated calcium carbide (HQ + ECC) or dicyandiamide (HQ + DCD). The results showed that HQ + DCD could inhibit urease activity and increase activities of nitrate reductase, nitrite reductase, and hydroxylamine reductase significantly in comparison with CK, HQ and HQ + ECC. Under the condition of our test, there existed a significant relationship between soil urease, nitrate reductase, nitrite reductase, and hydroxylamine reductase activities and soil NH4+ and NO3- contents, NH3 volatilization and N2O emission rate, and regression analysis indicated that there were significantly positive relationships between soil urease, nitrite reductase and hydroxylamine reductase activities.

[Effect of elevated atmospheric CO2 on soil urease and phosphatase activities].

The response of soil urease and phosphatase activities at different rice growth stages to free air CO2 enrichment (FACE) was studied. The results showed that comparing with the ambient atmospheric CO2 concentration (370 mumol.mol-1), FACE (570 mumol.