Abstract: An injection mould for manufacturing disc-shaped plastic articles with a central hole comprises a first mould part and a second mould part displaceable relative to the first mould part by a first displacing mechanism. The two mould parts are displaceable between a closed first position, in which they together partially bound a mould cavity corresponding to the shape of an article for manufacture, and an open second position in which a formed article can be removed. A third mould part is provided which, in the closed position of the first and second mould parts, extends through the mould cavity and has a shape in the region of the mould cavity which corresponds to the shape of the central hole. The third mould part is axially displaceable by a guide sleeve forming part of the first mould part between a first position, in which it partially forms a bounding of the mould cavity, and a second retracted position.

Abstract: Heterocyclic compounds of the formula ##STR1## wherein Het denotes optionally substituted pyridazinyl, pyrimidinyl, pyrazinyl or substituted pyridyl, R.sub.1 is hydrogen or methyl and R.sub.2 is lower alkyl, optionally substituted phenyl-lower alkyl, carboxy-lower alkyl or functionally modified carboxy-lower alkyl, their condensation products with aldehydes, ketones or carbonic acid and their N-oxides, which are valuable (cardioselective) .beta.-rezeptor blocking agents, and/or (cardioselective) .beta.-rezeptor-stimulants.