Abstract: A plug-in connection for the connection of tube and hose lines, in particr for use in tube-line systems of motor vehicles, consists of a male part (S), on which is provided a clip receiving locking groove, a female part (A), into which the male part can be sealingly inserted and on which female-part cavities are provided, with which the locking groove can be axially aligned. The locking of the male part (S) and the female part (A) is obtained by means of a locking clip.To achieve a long lifetime for the plug-in connection even under changing loads and to achieve a simple handling and inexpensive manufacture, the legs (28, 29) of the locking clip (St.sub.1) can be spread apart by an elastic deformation and can be maintained in the spread-apart position disengaged from the male part locking mechanism. Between the female part (A) and the male part there is arranged a spring (F) which guyes these parts in an axial direction with respect to one another. A seal ring (D.sub.

Abstract: A process for the preparation of racemic or optically active isomers of alkyl esters of cis chrysanthemic of the formula ##STR1## wherein R is alkyl of 1 to 6 carbon atoms comprising reacting a racemic or optically active cis compound of the formula ##STR2## wherein R has the above definition with an aryl halothioformate of the formula ##STR3## wherein Hal is a halogen and Ar is aryl of 6 to 12 carbon atoms optionally substituted with at least one alkyl of 1 to 3 carbon atoms to obtain a compound of the formula ##STR4## of cis configuration and heating the latter optionally in an organic solvent to obtain the compound of formula I and novel intermediates.

Abstract: A process for the preparation of racemic or optically active isomers of alkyl esters of cis chrysanthemic of the formula ##STR1## wherein R is alkyl of 1 to 6 carbon atoms comprising reacting a racemic or optically active cis compound of the formula ##STR2## wherein R has the above definition with an aryl halothioformate of the formula ##STR3## wherein Hal is a halogen and Ar is aryl of 6 to 12 carbon atoms optionally substituted with at least one alkyl of 1 to 3 carbon atoms to obtain a compound of the formula ##STR4## of cis configuration and heating the latter optionally in an organic solvent to obtain the compound of formula I and novel intermediates.

Abstract: A coupling includes a receiving part having an external thread which can be crewed into a threaded bore and includes a plug-in part, which can be plugged into and coupled to the receiving part. A retaining ring is secured to the front end of the receiving part, for example through engagement with a groove in the receiving part, and during plugging in of the plug-in part engages a groove provided in the plug-in part. Widening of the retaining ring is limited by the wall of the threaded bore. By unscrewing the receiving part from the threaded bore, the retaining ring can be released by widening it at an interrupting slot, after which the plug-in part can be removed from the receiving part. The coupling is short, which is achieved in such a manner that, due to the arrangement of the retaining ring at the front end of the receiving part, the entire length of the receiving part can be used as a guide for the plug-in part.