Boron complexes antibiotics

Several complexes have been tested for potential pharmaceutical applications and some of them have been introduced into practice.84,126 Isolation of antibiotics of boron complex type (Section 24.3.3.2) and results obtained with carboxyborane complexes that are analogues of amino acids (Section 24.2.2) are likely to stimulate further studies. Quite a few boron complexes have found application in 10B neutron capture therapy based on the 10B(n, a)7Li nuclear reaction.84,126,172... 

Boric acid, fluoro-, 101 Boromycin, 96 Boron, 81-101 as ligand, 99 Boron complexes anionic, 90-97 antibiotics, 101 applications, 101 cationic, 97 chelates, 89... 

Few medicines based on boron are known, in general boric acid or a boronic acid serve to esterify an a-diol or an ortho-diphenol. This is the case for the emetic antimony borotartrates of the ancient pharmacopoieas, for the injectable catecholamine solutions, for tolboxane " , that is close to meprobamate and that was commercially available as a tranquilhzer some decades ago, or also for the phenylbo-ronic esters of chloramphenicol. " Boromycine was the first natural product containing boron isolated. " It is a complex between boric acid and a polyhydroxylated tet-radentate macrocycle. " Another natural product is aplas-momycin with antibiotic properties. " " ... 

The reactions of enolates with aldehydes (aldol reactions) or with imines have been widely developed since the 1970s. Asymmetric aldol-type reactions are very important in the multistep synthesis of complex molecules such as ionophores or p-lactam antibiotics. Chirality has been introduced either on the substituents of boron, on the metal ligands or on the carbon skeleton of the enolate. Aldol reactions are usually run at low temperatures, and when metal enolates are used, the reactions are sometimes easily reversible [160, 209],... 

The novel antibiotic boromycin (162) is the first well-defined boron-containing organic compound to have been found in Nature, and is a Boeseken complex of boric add with a macrolide which consists of two... 

Methylation of Inorganic oxyarsenic anions occurs in organisms ranging from microbial to mammalian methylated and products include arsenocholine, arsenobetaine, dimethylarsinic acid, and methylarsonic acid arsenite methyltransferase and monomethylarsonic acid methyltransferase use S-adenosylmethionine for the methyl donor Boron biochemistry essentially that of boric acid, which forms ester complexes with hydroxyl groups, preferably those adjacent and cis, in organic compounds. Five naturally occurring boron esters (all antibiotics) synthesized by various bacteria have been characterized Exists as Br Ion in vivo, binds to proteins and amino acids... 

---