Library components of general structure 7 formed in the presence (red bars) and in the absence (blue bars, where applicable) of neuraminidase from the reactions of 2 with aldehydes containing (A) aliphatic (A4-A11, A14-A19, A23-A26, A28, A29) and (B) aromatic groups (A13, A20-A22, A30-A32, A34, A37, A39, A41, A44-A49). See Fig. 2A for experimental conditions.