Search

Preliminary enzymatic polymerization studies in the simple stoichiometric adipic acid/butane-1,4-diol system using lipase B from Candida antarctica, immobilized as Novozym 435®, suggest that in solvent-free conditions a step-growth mechanism operates involving the sequential addition of an AB synthon by esterification mode only. Conversely, in toluene as solvent there is a change to the more facile transesterification mode in line with the conventional polyesterification procedure, pointing to a change in specificity of the lipase. Evidence is drawn from qualitative studies using a series of synthetic intermediates, enabling authentication of product mixtures together with an indication of the comparative reactivity of species along the proposed reaction pathway. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2069–2080, 1998

THE exact route for the biological transformation of 3-hydroxyanthranilic acid to nicotinic acid has not been established with certainty.

Starting with the cyclohexenonecarbaldehyde (I), the iodomethylhexahydroisobenzopyrans (VI) are prepared which are alkylated with the cuprate (VII), derived from acetone N,N‐dimethylhydrazone, forming the oxobutyl derivative (VIII).