Enzymic acylation of 506U78 (2-amino-9-beta-D-arabinofuranosyl-6- methoxy-9H-purine), a powerful new anti-leukaemic agent

A practical enzymic approach for acylation of 506U78 (2-amino-9-beta-D-arabinofuranosyl-6-methoxy -9H-purine), a powerful anti-leukaemic agent, is described. Novozyme-435, an immobilized preparation of Candida antarctica lipase, was used to acylate 506U78 regioselectively at the 5'-position. This rendered the compound more soluble and bioavailable. Vinyl acetate was used as the acyl donor and reactions were carried out in anhydrous 1,4-dioxane with up to 100 g/l of substrate input. Bioconversions were optimised to achieve impurity (3'-mono- and di-acetates) levels of less than 0.5%.

2,4-Diamino-5-benzylpyrimidines and analogues as antibacterial agents. 9. Lipophilic trimethoprim analogues as antigonococcal agents

Lipophilic analogues of trimethoprim (1) bearing 3,5-dialkyl-4-hydroxy substituents in the benzene ring are much more active in vitro against Neisseria gonorrhoeae than is 1. The 3,5-diisopropyl-4-hydroxy derivative (2) was selected as a candidate for clinical evaluation as an antigonococcal agent, and as part of the preliminary evaluation it was submitted to extended pharmacokinetic and metabolism studies in dogs. Although the compound was not extensively conjugated by metabolic enzymes, one of the methyl groups was metabolized to produce a 3-isopropyl-4-hydroxy-5-(alpha-carboxyethyl)benzyl derivative (43), which was rapidly excreted. Related analogues were likewise extensively metabolized.