The design and syntheses of four new macrocyclic host compounds (1-4, Chart I) are reported which contain three cyclic urea carbonyls and two anisyl-like oxygens alternately arranged to bind alkali metal or alkylammonium ion guests. The macroring systems are completed with a 1,3-xylyl bridging unit containing a methoxy in its 2-and a methyl in its 4-position (1, 2) or a 3,5-dimethylphenyl group in its 2-position (3, 4). Hosts 1-4 are rigidified further with a trimethylene bridge that spans the two aryl oxygens. Hosts 1 and 2 differ only by the absence in 1 and the presence in 2 of methyl groups in the positions para to the two aryl oxygens. Hosts 3 and 4 are diastereomers, whose interconvertibility by ring inversion is blocked by steric limitations imposed on the system by the two bridging units. The configurational identities of 3 and 4 were established from their crystal structures. Hosts 5-7 (Chart I) were also prepared. Macrocycle 5 resembles 4 except the aryl oxygen trimethylene bridge is replaced by hydrogens. In 6 and 7, the trimethylene bridge is in place, but the 1,3-xylyl bridge is replaced by hydrogens.The crystal structures of the more conformationally mobile compounds 5 and 6 show that the dipoles of the carbonyl groups are better arranged to cancel one another than those of the more rigid hosts, 3 and 4. The crystal structure of 2-(CH3)3CNH3+ is exactly what was expected from molecular model examination. Free energies and association constants were determined for 1-4 and 7 binding Li', Na', K ' , Rb', Cs', NH4', CH3NH3', and (CH3)3CNH3' picrates at 25 OC in CDCI, saturated with D20. The resulting -AGO values ranged from 7.3 (7 binding Li') to 16.7 kcal mol-' (3 binding Na'). The -AGO values correlate with the degrees of preorganization of the hosts for binding. Cycle 2 was the strongest binding host. Diastereomer 3, the second strongest complexing host, bound the eight guests 2.25 A 0.75 (extremes) kcal mol-' better than diastereomer 4. The crystal structure of 3 shows its binding sites to be better organized for complexation than those of 4. Host 2, containing methyl groups para to the aryl oxygens, bound the eight guests an average of 3.7 kcal mol-' better than 1 without the two methyl groups. This effect is attributed to greater steric inhibitions of solvation of the binding sites of 2 than of 1. Host 7, containing the trimethylene but lacking the xylyl bridge, bound the eight guests with = 7.5 kcal mol-', which is lower by 4.4-7.1 kcal mol-' than the hosts containing the latter bridge. Host 3 was found to complex 1 mol of (CH3)3C-O-N=0 ('H NMR). The -AGO value of known host 8 was used for comparisons. (5) Cram, D. J.; Dicker, I. B.; Lauer, M.; Knobler, C. B.; Trueblood, K.
General. Reactions were carried out in an inert atmosphere using predried (sodium benzophenone ketyl) and distilled THF. Haloalkanes were obtained commercially. Product mixtures were separated to obtain analytical data by medium-pressure chromatography using an EM Lobar Si 60 column with 10% diethyl ether-gO% ligroin (60-80 "C) as eluent. Quantitative analysis of the reaction mixtures was accomplished on a Waters 6000 HPLC using an IBM silica column with 15% diethyl ether-85% ligroin (60-80 "C). The UV detector was calibrated on known product mixtures. NMR spectra were obtained using a Varian EM-390 spectrometer.General Alkylation Procedure. One millimole each of the sulfone and base were added to 7-15 mL of T H F and allowed to stir for 1 h at 0 "C. One millimole of the alkylating agent was added a t that same temperature, and the mixture was allowed to stir a t room temperature for 5 h. Addition of 5 mL of water, ether extraction, drying with MgS04, and removal of the solvent via a rotary evaporator provided the product mixture.Kinetic Reactions. Six millimoles of the appropriate sulfone in T H F and of butyllithium were mixed a t 0 "C. After 1 h the slurry was brought to room temperature, and then 6 mmol of bromoalkane was added. Alliquots (1 mL) were removed and quenched with water a t specific times. The samples were recovered as above and analyzed by HPLC.Equilibration-Deuterium Quench. An equimolar mixture of butyllithium, sulfone 1, and sulfone 4a were stirred for 1 h at 0 "C in 7 mL of THF. Deuterium oxide was added to the mixture, and the products were recovered as above, separated by medium-pressure chromatography, and analyzed for deuterium content by NMR spectroscopy.Deuterium Quench. An equimolar mixture of 1 and butyllithium were stirred in 7 mL of T H F a t 0 "C for 1 h. Deuteriosulfuric acid (1 M) was added, and the product was recovered as above and analyzed for deuterium content by NMR spectroscopy.Methyl phenyl sulfone (1): via oxidation of methyl phenyl sulfide with 30% hydrogen peroxide in acetic acid;18 91%; mp 87.4-89.6 "C (lit.IEb mp 86-88 "C); 'H NMR (CDCl,) 6 3.0 (9, 3), 7.5-7.8 (m, 5).Butyl phenyl sulfone (4a): 'H NMR (CC14) 6 0.9 (t, 3, J = 6 Hz), 1.1-1.9 (m, 41, 3.0 (t, 2, J = 6 Hz), 7.3-7.9 (m, 5 ) . Anal. Calcd for CI0Hl4O2S: C, 60.58; H, 7.12. Found C, 60.71; H, 7.20. 4-Heptyl phenyl sulfone (5a): 'H NMR (CC14) 6 0.9 (t, 6, J = 6 Hz), 1.1-1.9 (m, a), 2.6-2.9 (m, l), 7.2-7.9 (m, 5). Anal. Calcd for C13H,o0,S: C, 64.96; H, 8.39. Found: C, 64.79; H, 8.07. 4-(4-Propylheptyl) phenyl sulfone (6a): 'H NMR (CDCl,) 6 0.8 (t, 9, J = 6 Hz), 1.2-1.8 (m, 12), 7.3-7.8 (m, 5 ) .
The synthesized hemispherands (VII) and (IX)‐(X) form complexes with alkali picrates or alkylammonium picrates.
ChemInform Abstract The tetrahydroquinoline derivatives (I) are converted to the methoiodides (III) and then subjected to Birch reduction conditions, forming the 2-octalones (IV).
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