Helvetica Chimica Acta – Vol. 93 (2010)
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0.77 (t, J ¼ 6.7, 3 H); 0.58 (d, J ¼ 7.6, 3 H). 13C-NMR (75 MHz): 173.5; 138.7; 128.5; 126.6; 126.4; 76.6;
73.1; 47.1; 40.7; 34.1; 31.4; 26.4; 25.4; 23.5; 22.0; 20.7; 16.4. FAB-MS: 318 (24, Mþ), 300 (100, [M ꢀ
H2O]þ). Anal. calc. for C20H30O3 (318.45): C 75.43, H 9.50; found: C 75.49, H 9.66.
3.2. Menthyl (R)-2-Hydroxy-2-(4-methylphenyl)butanoate (¼(1R,2S,5R)-5-Methyl-2-(1-methyl-
ethyl)cyclohexyl (2R)-2-Hydroxy-2-(4-methylphenyl)butanoate; 3b). White solid. Yield 82%. M.p.
103.2 – 106.38. de 95%. [a]2D0 ¼ ꢀ64.3 (c ¼ 0.13, acetone). IR: 3460 (OH); 2954, 1730 (C¼O), 1612, 1513,
1458, 1388, 1262, 825, 794. 1H-NMR (300 MHz): 7.12 – 7.29 (m, 4 arom. H); 4.63 – 4.76 (m, CHꢀO); 2.33
(s, 3 H); 2.17 (s, OH); 1.75 – 1.90 (m, 1 H); 1.56 – 1.67 (m, 2 H); 1.38 – 1.55 (m, 3 H); 1.04 – 1.10 (m, 2 H);
0.91 (d, J ¼ 6.7, 6 H); 0.85 (s, 3 H); 0.79 (t, J ¼ 6.0, 3 H); 0.59 (d, J ¼ 7.6, 3 H). 13C-NMR (75 MHz): 173.5;
143.0; 138.1; 129.2; 126.6; 76.6; 73.0; 47.1; 40.7; 34.1; 31.4; 26.4; 25.3; 23.5; 22.0; 21.2; 20.7; 16.4. FAB-MS:
332 (19, Mþ), 314 (100, [M – H2O]þ). Anal. calc. for C21H32O3 (332.48): C 75.86, H 9.70; found: C 75.88,
H 9.76.
3.3. Menthyl (R)-2-(4-Ethylphenyl)-2-hydroxybutanoate (¼(1R,2S,5R)-5-Methyl-2-(1-methylethyl)-
cyclohexyl (2R)-2-(4-Ethylphenyl)-2-hydroxybutanoate; 3c). White solid. Yield 80%. M.p. 58.8 – 61.18. de
94%. [a]2D0 ¼ ꢀ67.3 (c ¼ 0.26, acetone). IR: 3461 (OH), 2955, 1732 (C¼O), 1512, 1458, 1388, 1263, 833,
784. 1H-NMR (300 MHz): 7.15 – 7.36 (m, 4 arom. H); 4.62 – 4.80 (m, CHꢀO); 3.30 (s, OH); 2.62 (q, J ¼
7.1, 2 H); 1.76 – 1.88 (m, 1 H); 1.55 – 1.67 (m, 2 H); 1.39 – 1.43 (m, 3 H); 1.22 (t, J ¼ 7.1, 3 H); 0.97 – 1.04
(m, 2 H); 0.91 (d, J ¼ 4.8, 6 H); 0.85 (s, 3 H); 0.79 (t, J ¼ 6.8, 3 H); 0.58 (d, J ¼ 6.8, 3 H). 13C-NMR
(75 MHz): 173.5; 142.8; 136.1; 128.0; 126.6; 76.5; 73.0; 47.1; 40.7; 34.1; 31.4; 28.6; 26.3; 25.3; 23.4; 21.9;
20.7; 16.4; 15.8. FAB-MS: 346 (18, Mþ), 328 (100, [M ꢀ H2O]þ). Anal. calc. for C22H34O3 (346.50): C
76.26, H 9.89; found: C 76.32, H 9.91.
3.4. Menthyl (R)-2-Hydroxy-2-[4-(1-methylethyl)phenyl]butanoate (¼(1R,2S,5R)-5-Methyl-2-(1-
methylethyl)cyclohexyl (2R)-2-Hydroxy-2-[4-(1-methylethyl)phenyl]butanoate; 3d). White solid. Yield
80%. M.p. 64.9 – 65.78. de 91%. [a]2D0 ¼ ꢀ55.7 (c ¼ 0.17, acetone). IR: 3454 (OH), 2957, 1725 (C¼O),
1
1513, 1462, 1388, 1372, 1260, 832, 785. H-NMR (300 MHz): 7.17 – 7.34 (m, 4 arom. H); 4.65 – 4.78 (m,
CHꢀO); 3.41 (s, OH); 2.89 (m, 1 H); 1.86 – 1.90 (m, 1 H); 1.63 – 1.77 (m, 2 H); 1.43 – 1.55 (m, 3 H); 1.24
(d, J ¼ 5.1, 6 H); 0.96 – 1.10 (m, 2 H); 0.91 (d, J ¼ 5.3, 6 H); 0.85 (s, 3 H); 0.79 (t, J ¼ 7.2, 3 H); 0.56 (d, J ¼
6.8, 3 H). 13C-NMR (75 MHz): 173.6; 149.2; 136.3; 126.7; 126.4; 76.3; 72.9; 47.1; 40.8; 34.1; 31.4; 26.3;
25.3; 24.0; 23.4; 22.9; 21.9; 20.7; 16.3. FAB-MS: 360 (17, Mþ), 342 (100, [M ꢀ H2O]þ). Anal. calc. for
C23H36O3 (360.53): C 76.62, H 10.06; found: C 76.69, H 10.10.
3.5. Menthyl (R)-2-(4-Fluorophenyl)-2-hydroxybutanoate (¼(1R,2S,5R)-5-Methyl-2-(1-methyl-
ethyl)cyclohexyl (2R)-2-(4-Fluorophenyl)-2-hydroxybutanoate; 3e). White solid. Yield 92%. M.p.
103.5 – 104.68. de 80%. [a]2D0 ¼ ꢀ64.1 (c ¼ 0.12, acetone). IR: 3450 (OH), 2957, 1719 (C¼O), 1603,
1
1512, 1461, 1389, 1234, 1201, 840, 810. H-NMR (300 MHz): 7.02 – 7.36 (m, 4 arom. H); 4.63 – 4.79 (m,
CHꢀO); 3.56 (s, OH); 1.82 – 1.90 (m, 1 H); 1.55 – 1.74 (m, 2 H); 1.37 – 1.41 (m, 3 H); 0.96 – 1.04 (m, 2 H);
0.90 (d, J ¼ 7.0, 6 H); 0.84 (s, 3 H); 0.78 (t, J ¼ 6.7, 3 H); 0.61 (d, J ¼ 7.7, 3 H ) . 13C-NMR (75 MHz): 173.3;
161.4; 134.6; 128.4; 115.4; 76.7; 72.4; 46.8; 40.7; 34.0; 31.4; 26.4; 25.5; 23.4; 21.9; 20.6; 16.4. FAB-MS: 336
(19, Mþ), 318 (100, [M ꢀ H2O]þ). Anal. calc. for C20H29FO3 (336.44): C 71.40, H 8.69; found: C 71.48,
H 8.76.
3.6. Menthyl (R)-2-(4-Chlorophenyl)-2-hydroxybutanoate (¼(1R,2S,5R)-5-Methyl-2-(1-methyl-
ethyl)cyclohexyl (2R)-2-(4-Chlorophenyl)-2-hydroxybutanoate; 3f). Light yellow solid. Yield 91%.
M.p. 82.5 – 83.48. de 81%. [a]2D0 ¼ ꢀ53.2 (c ¼ 0.22, acetone). IR: 3454 (OH), 2954, 1720 (C¼O), 1598,
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1501, 1458, 1386, 1201, 1189, 830, 795. H-NMR (300 MHz): 7.12 – 7.45 (m, 4 arom. H); 4.62 – 4.77 (m,
CHꢀO); 3.60 (s, OH); 1.80 – 1.97 (m, 1 H); 1.56 – 1.71 (m, 2 H); 1.30 – 1.41 (m, 3 H); 0.95 – 1.04 (m, 2 H);
0.90 (d, J ¼ 6.2, 6 H); 0.84 (s, 3 H); 0.77 (t, J ¼ 7.1, 3 H); 0.63 (d, J ¼ 7.7, 3 H ) . 13C-NMR (75 MHz): 170.2;
139.1; 134.6; 130.5; 129.6; 77.9; 73.6; 47.1; 41.2; 34.0; 31.5; 26.4; 25.6; 23.4; 22.1; 20.6; 16.4. FAB-MS: 352
(15, Mþ), 334 (100, [M ꢀ H2O]þ). Anal. calc. for C20H29ClO3 (352.90): C 68.07, H 8.28; found: C 68.00, H
8.21.
3.7. Menthyl (R)-2-(4-Bromophenyl)-2-hydroxybutanoate (¼(1R,2S,5R)-5-Methyl-2-(1-methyl-
ethyl)cyclohexyl (2R)-2-(4-Bromophenyl)-2-hydroxybutanoate; 3g). Light yellow solid. Yield 93%.
M.p. 78.8 – 79.68. de 83%. [a]2D0 ¼ ꢀ47.6 (c ¼ 0.23, acetone). IR: 3455 (OH), 2955, 1737 (C¼O), 1591,
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1487, 1457, 1388, 1201, 1180, 828, 780. H-NMR (300 MHz): 7.15 – 7.51 (m, 4 arom. H); 4.61 – 4.76 (m,
CHꢀO); 3.78 (s, OH); 1.80 – 2.00 (m, 1 H); 1.56 – 1.66 (m, 2 H); 1.23 – 1.41 (m, 3 H); 0.96 – 1.03 (m, 2 H);