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.

New catenane (cf 3) and rotaxane (cf 26) types have been obtained in remarkable yields via supramolecular template syntheses. The amide-based mechanically bonded structures can be designed by appropriate choice of building units. The selective formation of stable outlout, idin and idout [2]catenane isomers (cf Scheme 2), which were separated, allowed conclusions concerning their mechanism of formation. It was demonstrated that one of the two macromonocycles of the catenane molecule forms initially and acts as a host cavity for a building block of the second, interlocking macrocycle. This knowledge made a simple synthesis of amide-linked rotaxanes possible. The first X-ray structural analysis of a hano-catenane revealed a self-assembled, interlocked system held together by networks of inter-and intramolecular hydrogen bonds, including the amide groups and the h a n oxygen atoms. There is no doubt that these new intertwined amide systems will be extendable to higher catenanes and rotaxanes.Catenanes, rotaxanes and knots have become "Highlights" in supramolecular chemistry (1) thanks to more recent high yield syntheses via the use of supramolecular template effects (2). Amide-based catenanesDuring work on the syntheses of basket-shaped host molecules (3) we unexpectedly found an extremely simple catenane synthesis in 1992 (4). Catenane 3 could be prepared from the Simple components 1 and 2 in one step (Scheme 1) (5). As byproducts, the dimethoxy-substituted macromonocycle 4 was isolated along with the 72-membered "tetramer"

Abstract:Two new rotaxane types, the [2]rotaxanes 12a,b and the [3]rotaxane 13, have been synthesised by treating the "axle" 7 with the stopper component 9 in the presence of the "wheel" 8. A nonionic template intermediate of type 10 is proposed. The [3]rotaxane 13 was only obtained when the chain of the "axle" had a certain length: with n = 1 only [2]rotaxane 12a was isolated, whereas with n = 2 the [3]rotaxane 13 was formed besides the [2]rotaxane 12b. This suggests that more extended rotaxanes and polyrotaxanes can be synthesised by the template strategy.

COMMUNICATIONS out in the same way. but without the addition of enzyme. Oxidation of amines: 2-, 3-, or 4-chloroaniline (78 FM), H,O, (44.4 p~) , and 1 M sodium acetate buffer (pH 4.5) The reaction was started by the addition of 0.5 u (determined by the monochlorodimedone assay) CPO-P or CPO-T to 1 mL of the mixture. The reaction was carried out at 30 C (3-chloroaniline: 30 min; 2.. 4-chloroaniiine. 50 min). The products were identified by HPLC-coinjection. O.Yidrriion.s wirh peruci'iii' u c i d Under identical experimental conditions, peracetic acid was used instead of H, O, enzyme. (200 pnol CH,CO,H instead of 150 Fmol H,O,). In the monochlorodimedone assay, peracetic acid was used in a concentration of 72 p~ (instead of 7200 p~ H,O,).'iiiutii irm~forinutioii ofperacetic acid hy mass spectrometry: sectorfield mass spectrometer Jeol JMS-700 MS, high-resolution CI-MS with isobutane as reactant gas. positile ion mode, resolution R = 8000. accumulation of 5-10 scans of the accelerating voltage (m/r 56-90,s s per cycle), quasi-molecular ion [ M + HIi (calcd. for C,H,O, 77.0239, found: 77.0261), internal mass calibration with ions derived from isobutane and the solvent. Aliquots (2.5 mL) of a 37 mM solution of peracetic acid in 1 M \odium acetate buffer (pH 5.5) were a) incubated with 5.5 mg (ca. 50 u) CPO-T for 10 min at room temperature (RT). b) incubated with 5.5 mg trypsin for 1 h at RT. or c) kept at RT without the addition of enzyme. The solutions were then acidified with H,SO, to pH 1 and extracted with ether (1 mL). The extracts were concentrated to approximately 50 pL in a stream of N, and introduced into the mass spectrometer through the reference inlet. Whereas peracetic acid was clearly present in approximately the same concentration in experiments (b) and ( c ) , no peracetic acid could be detected by MS in the extract from (a). Furthermore. whereas the pungent smell of peracetic acid persisted in the experiments (h) and (c). this typical odor vanished immediately after the addition of enzyme in experiment (a) Hydrolow uriiviti f t~~~~i c u l~. i p e r~~n e n / .~~.The enzymes were added to a solution of 0.1 pmol p-nitrophenylacetate in 2.0 mL 1 M sodium acetate buffer (pH 5.5) and 10 pL trri-but$ alcohol. The reaction was followed by the decrease of extinction at i = 317 nm. Inliihifion rrperinimr.\' In a typical experiment, 0.04 u CPO-T (determined by the rnonochlorodimedone assay) in 500 pL of water or sodium acetate buffer (pH 5.5, various concentrations) were incubated with a solution of PMSF (4 pmol) in tertbutyl alcohol (20 wL) at 50 C. The remaining enzymatic activity was determined at various incubation times as described above.

The direct introduction of sulfonamide units (cf. 9) into CO-NH and then be substituted by treatment with suitable carboxamide-based rotaxanes allows us to intramolecularly iodo compounds. This leads intramolecularly to 11 (7 1 % bridge the "wheel" and the "axle" of such species for the yield) and intermolecularly to bis[2]rotaxane 16 (76% yield). first time as is shown by the bridged bissulfonamide rotaxane The iodo-substituted rotaxane 15 isolated as a remarkably 11. Due to its stronger acidity the S02-NH proton can be se-stable byproduct offers a new synthetic potential demonlectively abstracted by mild bases even in the presence of strated by the preparation of 16.While early statistical ['] and multistep[*] syntheses yielded rotaxanes"] only in analytical quantities, the application of supramolecular template effectd4] for several years allows their preparation on a laboratory However, the use of rotaxanes as structural entities for further reactions, in other words a preparative "chemistry with rotaxanes", has remained a dream so far.Directed incorporation of sulfonamide units['0] into the "wheel" and "axle" parts" of amide-based rotaxanes[12] as described below offers rather simple approaches to realize this goal: Due to their stronger acidity sulfonamide protons in such rotaxanes can be removed selectively by mild bases even in the presence of carboxylic acid amide protons. The sulfonamide units thus allow the selective alkylation by suitable iodo compounds in this position. Reaction with diiodo compounds results in intramolecular covalent bridging between "axle" and "wheel" sulfonamide groups and likewise intermolecular covalent connection leads to bis[2]rotaxanes[l31. Intramolecular Covalent LinkageInvestigating whether intramolecular covalent bridging in suitable rotaxanes was feasible, we first attempted to alkylate rotaxane 1 (prepared in 41 '% yield["]), which possesses a single sulfonamide unit in the "axle". Since the "wheel" could sterically hinder a substitution reaction on the "axle" site we chose the methyl group as a substituent of low steric demand. Therefore, an equimolar amount of K2C03 was DMF K2C0363 Yo