J. Org. Chem. 1987,52,2617-2619
2617
Lithium-Selective, Lipophilic, Small-Ring 8 (1.665g, 95%) as a colorless oil: 'H NMR (270MHz, CDC13, Bis(crown ethers) Me,Si) 6 1.23 (3 H, t, J = 7.45 Hz), 2.50 (2H, br s), 3.35 (2 H, d, J = 5.43 Hz), 3.70 (2H, m), 3.82 (3H, s), 4.13 (3H, m), 6.92 (2 H,m), 7.28 (2H, m); IR (NaCl, neat) 3310,2910,1735,1595, Michael J. Pugia, Brian E. Knudsen, and 1485,1455,1230,1180,1020,740cm-'; mass spectrum, CI (NH,) Richard A. Bartsch* m / z 254 ( M', 1.9), 236 (1,8),208 (18.9),168 (2.5),150 (6.7),130 (61.1),104 (11.3),72 (7.2),55 (100). Department of Chemistry and Biochemistry, Texas Tech Cyclic Urethane 9. To a stirred solution of 8 (1.665g, 6.59 University, Lubbock, Texas 79402-4260 mmol, 1.0 equiv) in dry THF (60 mL) was added N,N'carbonyldiiidazole (1.60 g, 9.87mmol, 1.5 equiv). The resulting Received December 23, 1986 solution was stirred at room temperature for 2 h and evaporated to a white residue. The residue was taken up in CHzCl2(100mL), Bis(crown ethers) may exhibit highly selective alkali washed with 1 M HCl(3 X 25 mL), H,O (2 X 25 mL), and brine metal cation complexation by formation of intramolecular (Ix 25 mL), dried over MgSO,, filtered, and evaporated, yielding complexes in which the cation is sandwiched between the 9 as a colorless oil (1.41g, 77%): 'H NMR (270MHz, CDCl,, Me,Si) 6 1.25 (3H, t, J = 7.03 Hz), 3.43 (1H, d, J = 17.96Hz), two adjacent crown ether rings.l Ion-selective, bidcrown 3.82 (3H, s), 4.16 (3H, m), 4.34 (1 H, d, J = 17.98 Hz), 4.72 (1 ether) esters derived from dodecylmethylmalonic acid and H, t, J = 8.67 Hz), 5.35 (1H, m), 6.97 (2H, m), 7.27 (2H, m); hydroxymethyl-substituted crown ethers have been found IR (NaCl, neat) 2960,2920,2820,1750,1600,1580,1485,1460, to be selective for the alkali metal cation that is slightly 1415,1240,1195,1080,1115,745 cm-I. Mass spectrum,CI (NH,) larger than the crown ether cavity. Thus, for bis(crown m/z 280 (M', 54.9%), 250 (3.1),235 (1.2),220 (1.4),162 (1.8),148 ether) esters 1 in which CE corresponds to 12-crown-4, (1.7),133 (2.0),104 (1.7),35 (100). 15-crown-5, and 18-crown-6 rings, selectivity for Na+, K+, Carboxylic Acid 10. To a stirred solution of 9 (1.41g, 5.059 and Cs+, respectively, has been reported.24 Similarly, the mm01,l.O equiv) in 16 mL of absolute ethanol at -10 OC was added complex stability constants for interactions of Na+ and K+ 6.7 mL of 1 M LiOH (6.7mmol, 1.32 equiv). The reaction was allowed to stir for 1.5h at -10 OC and was then neutralized with with 1 where CE = 12-crown-4 in MeOH gave a Na+/K+ 6 M HC1 (1.11mL, 6.7 mmol, 1.32 equiv). The ethanol was selectivity of 34.5 Also, in extractions of aqueous Na+, K+, evaporated, and the resulting residue was partitioned between Rb+, and Cs+ picrate solutions with dichloromethane so1 M HCl and CH2CI,. The organic layer was separated, washed lutions of the malonate bis(l2-crown-4) compound 2, the with HzO (1X 10 mL) and brine (1 X 10 mL), dried over MgS04, distribution ratios for Na+ picrate were the highest by a filtered, and evaporated to a white solid. Recrystallization from considerable margin.6 EtOAc/hexanes afforded 957 mg of pure 10 (75%): mp 165-166 OC; 'H NMR (270MHz, CDC13,Me,Si) 6 3.48 (1H, d, J = 18.25 Hz), 3.83 (3 H, s), 4.19 (1 H, t, J = 8.02 Hz), 4.39 (1 H, d, J = 18.438 Hz), 4.73 (1H, t, J = 9.174Hz), 5.36 (1H, m), 6.95(2H, 8 0 m), 7.36 (2 H, m), 8.52 (1 H, br s); IR (NaCl, neat) 2900,2810, 2700,2585,2500,1750,1675,1595,1580,1450,1240,1200,1190, 1110,940,850,750,735,700,630 cm-'; mass spectrum, CI (NH,) m / z 251 ( M', 13.8%), 236 (3.5),208 (7.9),194 (6.6),164 (2.5),150 ( 5 3 , 135 (4.1), 102 (3.7),76 (3.2),44 (8.1),35 (100). Anal. 1 2 (CizHi&"& C, H, N. Acid Chloride 11. To a suspension of 10 (408mg, 1.626 mmol, By analogy, malonate-type bis(crown ethers) with very 1.0 equiv) in dry benzene (8mL) was added SOClz (0.36mL, 4.91 mmol. 3.02 eauiv). The susDension was then heated to mild reflux small crown ether rings might be expected to exhibit sefor 3 h, and t i e benzene and SWlZwere evaporated under reduced lectivity for complexation of Li+. We now report the pressure. The resulting light amber residue (438mg, 100%) was synthesis of new lipophilic bidcrown ethers) 3-5, which used directly for the next step without purification: 'H NMR have 9-crown-3, 12-crown-4, and 14-crown-4 ring sizes, (270MHz, CDCl,, Me4Si) S 3.78 ( l / * H, s), 3.84 (3.5H, s), 4.25 respectively, and comparison of their efficiencies for ex(1H, dd, J = 8.63 Hz), 4.73 (2H, m), 5.32(1H, dd, J = 9.02Hz), traction of Li+, Na+, K+, and Rb+ picrates into deuterio6.97 (2H, m), 7.27 (2H, m); IR (NaCl, neat) 3060,3020,2940, 2830,1800,1760,1600,1590,1490,1460,1420,1250,1180,1110,chloroform. For 3 and 4, the crown ether rings are too small to accommodate even Li', whereas for 5, the crown 1090,1020,950,920,850,750,670 cm-l. ether ring size is appropriate for Li+ c o m p l e ~ a t i o n . ~ - ' ~ Isoquinolone 12. To a stirred solution of 11 (438mg, 1.626 mmol, 1.0 equiv) in 16 mL of dry 1,1,2,2-tetrachloroethane was Previously unreported (hydroxymethyl)-9-crown-3 (6) added A1C13 (867mg, 6.5 mmol, 4.0 equiv). The reaction was was prepared in high yield by an Okahara cyclization" of stirred at room temperature for 24 h, when it was poured into 40 mL of ice water and acidified to pH
