The present invention relates to aldimines of the formula (I), said aldimines having at least one aldimino group and at least one grouping comprising an active hydrogen in the form of a hydroxyl, mercapto, or secondary amino group. Said aldimines may be converted in a simple fashion with compounds that are reactive to active hydrogen to obtain a wide variety of reaction products. Thus, for example, reaction products may be obtained that comprise isocyanate groups and aldimino groups. Such reaction products are primarily suitable for polyurethane compositions, which are particularly used as adhesives, sealing compounds, and coatings.