Synthesis and Biological Activity of Natural Aminocyclopentitol Glycosidase Inhibitors: Mannostatins, Trehazolin, Allosamidins, and Their Analogues.

Starting from the very simple molecule sulfamic acid, O-substituted-, N-substituted-, or di-/tri-substituted sulfamates may be obtained, which show specific biological activities which were or started to be exploited for the design of many types of therapeutic agents. Among them, sulfamate inhibitors of aminoacyl-tRNA synthetases (aaRSs) were recently reported, constituting completely new classes of antibiotics, useful in the fight of drug-resistant infections. Anti-viral agents incorporating sulfamate moieties have also been obtained, with at least two types of such derivatives investigated: the nucleoside/nucleotide human immunodeficiency virus (HIV) reverse transcriptase inhibitors, and the HIV protease inhibitors (PIs). In the increasing armamentarium of anti-cancer drugs, the sulfamates occupy a special position, with at least two important targets evidenced so far: the steroid sulfatases (STSs) and the carbonic anhydrases (CAs). An impressing number of inhibitors of STSs of the sulfamate type have been reported in the last years, with several compounds, such as 667COUMATE among others, progressing to clinical trials for the treatment of hormone-dependent tumors (breast and prostate cancers). This field is rapidly evolving, with many types of new inhibitors being constantly reported and designed in such a way as to increase their anti-tumor properties, and decrease undesired features (for example, estrogenicity, a problem encountered with the first generation such inhibitors, such as EMATE). Among the many isozymes of CAs, at least two, CA IX and CA XII, are highly overexpressed in tumors, being generally absent in the normal tissues. Inhibition of tumor-associated CAs was hypothesized to lead to novel therapeutic approaches for the treatment of cancer. Many sulfamates act as very potent (low nanomolar) CA inhibitors. The X-ray crystal structure of the best-studied isozyme, CA II, with three sulfamates (sulfamic acid, topiramate, and EMATE) has recently been reported, which allowed for a rationale drug design of new inhibitors. Indeed, low nanomolar CA IX inhibitors of the sulfamate type have been reported, although such compounds also act as efficient inhibitors of isozymes CA I and II, which are not associated with tumors. A large number of anti-convulsant sulfamates have been described, with one such compound, topiramate, being widely used clinically as anti-epileptic drug. By taking into consideration a side effect of topiramate, an anti-epileptic drug leading to weight loss in some patients, it has recently been proposed to use this drug and related sulfamates for the treatment of obesity. The rationale of this use is based on the inhibition of the mitochondrial CA isozyme, CA V, involved in lipogenesis. Some sulfamates were also shown to possess potent inhibitory activity against acyl coenzyme A:cholesterol acyltransferase, an enzyme involved in cholesterol metabolism. One such agent, avasimibe, is in advanced clinical trials for the treatment of hyperlipidemia and atherosclerosis. Thus, the sulfamate moiety offers very attractive possibilities for the drug design of various pharmacological agents, which are on one hand due to the relative ease with which such compounds are synthesized, and on the other one, due to the fact that biological activity of most of them is impressive.

Sulfamates and their therapeutic potential

Publisher Summary This chapter reviews recent advances in the chemistry and biochemistry of C-nucleosides, the literature concerning C-arylglycoside (i.e., nonnitrogen heterocyclic C-nucleoside) antibiotics, and recent significant advances in the synthesis of C-nucleosides and C-glycosides. It also discusses biological test data and data that are relevant to structure–activity relationships. Modification of readily available natural C-nucleosides is an attractive route to new C-nucleoside analogs and derivatives, because one starting material often possesses much of the desired functionality and chiral properties. The chapter illustrates this approach with examples. The most frequently used strategy for C-nucleoside synthesis involves the construction of a heterocyclic aglycone from the C-1 substituent of a functionalized sugar intermediate.

The chemistry and biochemistry of C-nucleosides and C-arylglycosides.

Publisher Summary This chapter reviews progress in the use of bioisosterism in drug design. The broadest definition of bioisosteres is, “groups or molecules those have chemical and physical similarities producing broadly similar biological properties”. A major trend in this area is the increasing prevalence of “nonclassical isosteres” moieties those do not have the same number of atoms, but produce a similarity in a key parameter. Similar effects in two functional groups does not imply atom upon atom overlap. Bioisosterism is part of the spectrum of QSAR. In theory, bioisosterism lends itself to computer substructure searching especially as a means of developing new leads or new series. In practice, examples of new lead generation using bioisosteric principles are few. The chapter describes peptide and dipeptide bioisosteres, amide carbonyl group bioisosteres, ketone carbonyl bioisosteres, ester carbonyl bioisosteres, ester ether oxygen bioisosteres, phosphate bioisosteres, catechol bioisosteres, urea, thiourea bioisosteres, carboxylic acid bioisosteres, ring equivalents, and some basic groups. Bioisosteric substitution of the ammonium group by a sulfonium group finds application in studies on dopamine agonists such as and the isolevorphanol opiate analog . The bioisosteric relationship between aminoalkyl, 2-imidazolidine and 4-imidazole moieties in histamine H1 receptor antagonists and the similarity between amidines and 2-amino pyridines led to bioisosteric design of the histamine H2-receptor antagonist.

Chapter 27. Bioisosterism in Drug Design

A bisubstrate analog inhibitor for alpha(1----2)-fucosyltransferase.

A new procedure for the synthesis of glycosyl isothiocyanates

A facile regioselective 1-O-deacylation of peracylated glycopyranoses

A series of analogues of uridine 5'-diphosphate glucose and uridine 5'-diphosphate glucosamine have been synthesized by reaction of 2,3,4,6-tetra-O-benzyl-, 2,3,4,6-tetra-O-benzoyl-, 2,3,4,6-tetra-O-acetyl-, and 2,3,4,6-tetra-O-palmitoyl-alpha-D-glucopyranose and 2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-alpha-D-glucopyranose with chlorosulfonyl isocyanate and 2',3'-O-isopropylideneuridine. Isopropylidene and acetyl groups of the resulting 5'-O-[[[[(alpha-D-glucopyranosyl)oxy]carbonyl]amino]sulfonyl] -2',3'-O-isopropylideneuridine derivatives were removed by reaction with a TFA/water (5:1) mixture and methanolic ammonia, respectively. The 5'-O-[[[[(2",3",4",6"-tetra-O-benzyl-and 2",3",4",6"-tetra-O-benzoyl-alpha-D-glucopyranosyl)oxy]carbonyl] amino]sulfonyl]-2',3'-O-isopropylideneuridine (13 and 19) and the corresponding deisopropylidenated derivatives showed antiviral activity as determined by the inhibition of the cytopathic effect induced by HSV-1 replication and by the plaque assay method. Compound 13 inhibited glycosylation of proteins in HSV-1 infected HeLa cells.

Paloma P. Méndez-Castrillón

Papers

A new procedure for the synthesis of glycosyl isothiocyanates

A facile regioselective 1-O-deacylation of peracylated glycopyranoses

Uridine 5'-diphosphate glucose analogues. Inhibitors of protein glycosylation that show antiviral activity.

Hexose-modified anti-viral analogues of uridine 5′-disphosphate glucose derivatives

Synthesis of Modified Polyoxins by Reaction of Uridine-5′-aldehyde with Trimethylsilyl Cyanide and Amino Acids