Efficient synthesis of medium-sized cyclic ether diamines

Phenylboronic-acid-based carbohydrate binders as antiviral therapeutics: bisphenylboronic acids

BACKGROUND

carbohydrate-binding agents are considered as potential therapeutic agents for the inhibition of highly glycosylated enveloped viruses such as HIV type-1. Phenylboronic acids are well-known to bind the cis-diol functionality of carbohydrate structures, thereby identifying themselves as potential lead structures.

METHODS

bisphenylboronic acids connected via a functionalized linker at variable length (1-13 atoms) bearing the binding boronic acid functionality at the three possible ring geometries relative to the linker have been investigated as probes for selective and non-selective saccharide sensors. Herein, we describe the compilation of a 'linker-diverse' compound library of bisphenylboronic acids and the determination of the structure-activity relationship versus a variety of enveloped viruses. Molecular modelling of the gp120 glycans of simian immunodeficiency virus was undertaken to ascertain a theoretical minimum length of the linker unit.

RESULTS

the compounds demonstrated no pronounced antiviral activity. The general low toxicity of the boronic acids became evident in this study, thereby justifying further studies.

CONCLUSIONS

a higher concentration of phenylboronate functional groups per molecule, resulting in multivalency, might be necessary to bind with sufficient potency to HIV type-1 gp120 and to elicit an antiviral action.

7-N,7'-N'-(1",2"-Dithianyl-3",6"-dimethylenyl)bismitomycin C: synthesis and nucleophilic activation of a dimeric mitomycin

Dimeric alkylating agents that modify complementary DNA strands have engendered significant interest. We have prepared the novel dimeric mitomycin, 7-N,7'-N'-(1",2"-dithianyl-3",6"-dimethylenyl)bismitomycin C (9), in which the mitomycins are bridged by a dithiane unit. Dimer 9, like the clinically tested acyclic disulfides KW-2149 (3) and BMS-181174 (4), was designed to activate under nucleophilic and reductive conditions. Successive nucleophile-mediated disulfide cleavage transformations of 9 are expected to generate thiol species ideally positioned to render the two mitomycin systems vulnerable to nucleophilic attack and permit DNA interstrand cross-link formation. The dithiane linker, strategically positioned between the two mitomycins, distinguished 9 from 3 and 4. Nucleophilic activation of this cyclic disulfide permitted both activated mitomycins to remain tethered to one another. We report the synthesis of 9, and show that the nucleophile Et(3)P markedly enhances the activation and consumption of 9, compared with the reference compound 7-N, 7"-N'-(cyclohexanyl-trans-1",4"-dimethylenyl)bismitomycin C (27). We further demonstrated that provides higher levels of DNA interstrand cross-links than either the dimeric reference compounds, and 7-N,7-N'-(2",5"-dihydroxy-1",6"-hexanediyl)bismitomycin C (28), or the monomeric mitomycins, 1 and 3, when Et(3)P is added to solutions containing EcoRI-linearized pBR322 DNA.