The first rotaxanes 6a, 6b and 11 with a n amide structure are described. Their (supramolecular template) syntheses are strikingly simple. The central part of the "axle" is added to the "wheel" and subsequently capped. The macromonocycle ("wheel") provides the receptor cavity for the "axle" and the triphenylmethane stoppers confirm the mechanical bond between "wheel" and "axle".While in the synthesis of the first rotaxanes Schill et al. connected "wheel" and "axle" through covalent bonds to form prerotaxanes['l, mechanical bonds have recently been tied more easily by the use of supramolecular template effectsl21. Particularly, complexing metal and donoracceptor interaction~ [~] have been employed successfully also with cyclodextrin building elementsL5]. A mechanism recently suggested by us [6] for the template-directed formation of carboxylic amide catenanesL7I may also be used for the preparation of rotaxanesL'1. We could show that in the formation of the catenane, a macromonocycle of the type 3 is generated initially. The isophthaloylic moiety like 1, which according to molecular models shows a good fit, is incorporated as host almost orthogonally before reacting with a diamine 2 to form the second catenane ring. We assume that the incorporation of 1 in 3 is due to several effects: steric fit, n-.n interactions, and NH...O=C hydrogen bonds between host and guestL61. On this basis, we herein describe the synthesis of rotaxanes with an amide structure.In conformity with the synthesis of catenanes, we first charged the host, i.e. the macromonocycle 3a (or 3b), into the cavity of which the dicarboxylic acid dichloride l a (or a corresponding monochloride monoamide 7) can be nested. The resulting supramolecular intermediate 4a (or 4b) should then be treated with bulky stoppers to form the desired rotaxane 6a (or 6b).The stopper component 5 must be selected such that the rotaxane "axle" is of a certain minimum length to prevent steric hindrance of the reaction [']. Initially, we employed as stopper reagent the diamine 8 which has proven successful in the synthesis of the corresponding catenanes. In order to reduce the competing formation of a catenane, it was added in a large excess to a 1 : 1 mixture of l a and 3a. The formation of a rotaxane, however, could not be detected. For this reason, we then replaced the diamine 8 by the monofunctionalized (4-aminopheny1)triphenylmethane (Ctritylaniline) (5) which prevents the competing reaction to afford the catenane due to the absence of a second amino group.

To unambiguously identify their structures and to evaluate their organoleptic properties, several constitutional und configurational isomers of dialkyl-tetrathianes and dialkyl-pentathiepanes were synthesized by two different synthetic protocols, and separated by preparative gas chromatography. Raman and NMR spectroscopy were used to differentiate between the constitutional 3,6-dialkyl-1,2,4,5-tetrathiane and the 4,6-dialkyl-1,2,3,5-tetrathiane isomers. Furthermore, cis- and trans-isomers of 3,6-dialkyl-1,2,4,5-tetrathianes were distinguished by temperature-dependent NMR experiments. Static, quantum-chemical simulations of the NMR spectra for these cis- and trans-isomers were calculated in the gas layer in order to confirm our experimental assignments. In addition, the assignment of 4,7-alkyl-1,2,3,5,6-pentathiepanes were deducted from their Raman spectra. Dialkyl-tetrathianes and dialkyl-pentathiepanes are interesting components to be used in flavor applications due to their unique olfactory impact and facets.

No abstract

Ring formation with p‐toluenesulfonylmethyl isocyanide (TosMIC), and successive CO loss, leads preparatively to hitherto unobtainable or not easily obtained polycyclic hydrocarbons. From the triketone 1, the ketone intermediates 2 and 3 and the hydrocarbon 4 can be isolated.