Total synthesis of chondroitin sulfate E oligosaccharides and biological study.

A total synthesis approach of CS-E oligosaccharides was established and a series of derivatives were synthesized. These oligosaccharides were evaluated for a glycosaminoglycan (GAG)-binding protein interaction against cytokines, midkine, and pleiotrophin, by surface-plasmon resonance (SPR) assay. The binding epitopes of oligosaccharides to midkine were mapped using a saturation transfer difference (STD) NMR technique.

Synthesis and Antibacterial Activity of Novel 4″--desosaminyl clarithromycin derivatives with 11, 12-arylalkyl side chains.

A series of novel 4″--desosaminyl clarithromycin derivatives with 11, 12-arylalkyl side chains was synthesized by coupling 6-deoxy-desosamine donors (, ) with 4″-OH of compounds -. The activities of the target compounds were tested against a series of macrolide-sensitive and macrolide-resistant pathogens. Some of them showed activities against macrolide sensitive and resistant pathogens, and compounds and displayed significant improvement of activities against resistant pathogens.

Antibacterial activities of a series of novel 5-O-(4', 6'-O-dimodified)-mycaminose 14-membered ketolides.

A series of novel 5-O-(4',6'-O-dimodified)-mycaminose 14-membered ketolides were assessed for their in vitro antibacterial activities against a panel of sensitive and resistant pathogens. Compound 1 and compound 2, two ester analogs, showed the best antibacterial activities against several macrolide-sensitive and macrolide-resistant strains. These results indicated that introducing ester to 6-OH and a small volume ether substituent to the 4-OH of mycaminose could improve the antibacterial activities of ketolides.

Synthesis and cytotoxic activity of two steroids: icogenin aglycone analogs.

During the process of icogenin analog research, we obtained two cytotoxic steroids: compound 4 and compound 6 casually. Their in vitro antitumor activities were tested by the standard MTT assay. The results disclosed that compound 4 (IC = 3.

Synthesis and antibacterial activities of some novel 17, 18-unsaturated carbonyl compounds derivated from josamycin.

Some novel josamycin derivatives bearing an arylalkyl-type side chain were designed and synthesized. By HWE or Wittig reaction, 16-aldehyde group of josamycin analogs were converted into unsaturated carbonyl compounds. They were evaluated for their in vitro antibacterial activities against a panel of respiratory pathogens.

Synthesis of three OSW-1 analogs with maltose side chains bearing different protection groups.

In order to simplify the synthesis of OSW-1's disaccharide side chain and explore the structure-activity relationship of OSW-1, three 16α-O-maltose OSW-1 analogs carrying three maltose side chains bearing different protections were designed and synthesized.

Synthesis and antitumor activity of 5,6-dihydro-17-hydroxy icogenin analogs.

Four 5,6-dihydro-17-hydroxy icogenin analogs were designed and synthesized. Their in vitro antitumor activities were tested by the standard MTT assay. Compound 22 (IC(50) = 3.

Synthesis and antibacterial activity of novel ketolides with 11,12-sulfur contained aryl alkyl side chains.

A novel series of ketolides with 11,12-sulfur contained aryl alkyl side chains were synthesized and evaluated for their antibacterial activity. These ketolides exhibited potent activity against key macrolide sensitive and resistant respiratory pathogens. The newly synthesized 9a, 9e, 9k and 9n showed a similar antimicrobial spectrum and comparable activity to telithromycin, the commercial ketolide antibacterial.

Synthesis and antibacterial activity of 11,12-carbamate-3-O-acyl erythromycin derivatives.

A novel series of acylide derivatives have been synthesized which exhibit in vitro potency against key respiratory pathogens. Modification of position 3 was accomplished by replacing different 3-O-substituted acyl groups in the macrolide core via a facile procedure. Compounds 7a-7i were eventually yielded by the conjunction of diverse hetero-aryl side chains with the 11-N,12-O-carbamate sub-structure.

[Effect of icogenin on and its mechanism in anti-metastasis of pancreatic cancer BxPC3 cells].

This study is to investigate the effect of Icogenin on and its mechanism in anti-metastasis of pancreatic cancer BxPC3 cells in vitro. Using transwell assay, the effects of Icogenin on the invasion of BxPC3 cells were measured. The abilities of cell motility and adhesion in BxPC3 cells were detected by MTT assay and wound healing assay, respectively.

Synthesis of novel macrolide derivatives with imidazo[4,5-b]pyridinyl sulfur contained alkyl side chains and their antibacterial activity.

In an effort to find new antibiotics, a novel series of 14-membered macrolides with imidazo[4,5-b]pyridinyl sulfur contained alkyl side chains has been synthesized based on commercially available clarithromycin. Chemical transformation of hydroxy group at position C-3 afforded range of ketolides and acylides. Compared to telithromycin, compound 15a demonstrated improved in vitro activity against erythromycin-susceptible and -resistant strains.

Synthesis and antibacterial activity of 4''-O-heteroarylcarbamoyl derivatives of macrolide.

A series of novel 4''-position modified macrolide derivatives has been synthesized via a facile procedure. Their in vitro antibacterial activities against constitutively erythromycin-resistant strains were evaluated. Among the derivatives tested, compound 8a which has 11,12-carbamate and 4''-O-heteroarylcarbamoyl groups was found to have potent activity against most resistant bacteria.

[Synthesis of derivatives of (9S) -9-hydroxyl-12-methylene erythromycin A and their antibacterial activity in vitro].

The derivatives of (9S)-9-hydroxyl-12-methylene erythromycin A were synthesized by using erythromycin A as a starting material. An intermediate (9S)-9,11-O-isopropylidene-6-O-allyl-2' ,4"-O-bis(benzoyl)-12,21-anhydro erythromycin A 12 was obtained. The antibacterial activity in vitro of two compounds, 6 and 11, was tested.

[Synthesis of derivatives of (9S)-12-methylene erythromycin and their antibacterial activity in vitro].

Aim: To synthesizs of derivatives of (9S)-12-methylene erythromycin possessed potent antibacterial activity.

Methods: Using erythromycin A as a starting material, via two intermediate compounds protected 12,21-dehydroerythromycin A and 6,7: 12,21-didehydro erythromycin A, several 9-O, 11-O-ethylidene compounds were obtained. During this process, benzyl and isopropyl have been selected as the protecting group.

[Advance in synthesis of ketolides, a new class of erythromycin derivatives].

Drug-resistance has become a challenging clinical problem. Ketolides, a new class of erythromycin derivatives, have shown promising effectiveness in killing drug-resistant bacteria. This article reviews recent development in synthesis of ketolides, with focus on the modification and synthesis of some important positions on erythromycin A cycles.

The synthesis of gracillin and dioscin: two typical representatives of spirostanol glycosides.

Two representative spirostanol saponins that have the typical structure for the sugar moiety, diosgenyl alpha-L-rhamnopyranosyl-(1-->2)-[beta-D-glucopyranosyl-(1-->3)]-beta-D-glucopyranoside (gracillin) and diosgenyl alpha-L-rhamnopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1-->4)]-beta-D-glucopyranoside (dioscin), were easily synthesized by a general approach. A procedure using guanidine for the selective deblocking of acetyl while retaining benzoyl protecting groups is described.