Organic & Biomolecular Chemistry
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DOI: 10.1039/C8OB00768C
5); yield of trans/cis-20p mixture 109 mg (61%), dr 2.8:1; after additional column
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chromatography: yield of trans-20p 50 mg (28%); colorless amorphous solid. H NMR (400
MHz, CDCl3) / 9.99 (br.s, 1H), 8.58 (d, J = 2.2 Hz, 1H), 8.53 (dd, J = 4.9, 1.6 Hz, 1H), 8.01 (dd,
J = 7.8, 1.4 Hz, 1H), 7.79 (dd, J = 8.0, 1.9 Hz, 1H), 7.51 (dd, J = 7.7, 1.3 Hz, 1H), 7.44 (td, J =
7.5, 1.4 Hz, 1H), 7.36 – 7.31 (m, 1H), 7.29 (d, J = 6.1 Hz, 1H), 5.51 (d, J = 1.9 Hz, 1H), 4.47 (d,
J = 2.0 Hz, 1H), 3.56 (dt, J = 14.0, 7.7 Hz, 1H), 2.97 (q, J = 7.3 Hz, 6H), 2.80 (dt, J = 13.6, 6.3
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Hz, 1H), 1.64 – 1.44 (m, 2H), 1.19 (t, J = 7.3 Hz, 9H), 0.95 (t, J = 7.4 Hz, 3H). C NMR (101
MHz, CDCl3) / 169.0, 149.0, 149.0, 144.2, 135.3, 134.0, 133.2, 130.6, 127.6, 127.5, 127.4,
123.7, 62.7, 61.1, 46.0, 42.1, 21.2, 11.6, 8.5. HRMS m/z [M–H]– calcd for C17H17N2O4S
345.0915, found 345.0916.
2-(cis-2-Oxo-1-propyl-4-(pyridin-3-yl)azetidin-3-yl)benzenesulfonic acid triethylammonium
salt (cis-20p). Isolated after additional column chromatography: yield 18 mg (10%); colorless
amorphous solid. 1H NMR (400 MHz, CDCl3) / 10.43 (br.s, 1H), 8.48 (d, J = 2.1 Hz, 1H), 8.26
(dd, J = 4.9, 1.7 Hz, 1H), 7.74 (dd, J = 7.7, 1.4 Hz, 1H), 7.64 (dt, J = 8.0, 1.9 Hz, 1H), 7.29 (dd,
J = 7.8, 1.2 Hz, 1H), 7.18 (td, J = 7.5, 1.4 Hz, 1H), 7.06 (td, J = 7.6, 1.3 Hz, 1H), 7.00 (dd, J =
7.9, 4.8 Hz, 1H), 6.02 (d, J = 5.6 Hz, 1H), 5.30 (d, J = 5.6 Hz, 1H), 3.65 (dt, J = 13.9, 7.8 Hz,
1H), 3.09 (q, J = 7.3 Hz, 6H), 2.94 (ddd, J = 13.7, 7.7, 5.8 Hz, 1H), 1.67 – 1.51 (m, 2H), 1.30 (t,
J = 7.3 Hz, 9H), 0.95 (t, J = 7.4 Hz, 3H). 13C NMR (101 MHz, CDCl3) / 168.8, 149.0, 148.2,
143.9, 136.5, 131.6, 130.4, 130.2, 129.7, 127.1, 126.9, 122.7, 59.2, 59.0, 46.2, 42.6, 21.0, 11.6,
8.6. HRMS m/z [M–H]– calcd for C17H17N2O4S 345.0915, found 345.0903.
2-(trans/cis-1-Cyclohexyl-2-ethyl-4-oxoazetidin-3-yl)benzenesulfonic
acid
triethylammonium salt (trans/cis-20q). Eluent for chromatography EtOAc/MeOH/Et3N (85 :
10 : 5); yield of trans/cis-20q mixture 24 mg (11%), dr 8:1; colorless amorphous solid. 1H NMR
(400 MHz, CDCl3) of major trans-isomer / 8.02 (dd, J = 7.8, 1.3 Hz, 1H), 7.34 (td, J = 7.3, 1.3
Hz, 1H), 7.28 (d, J = 7.1 Hz, 1H), 7.21 (td, J = 7.6, 1.4 Hz, 1H), 6.41 (br.s, 1H), 5.24 (d, J = 2.1
Hz, 1H), 3.58 (ddd, J = 6.8, 3.8, 2.1 Hz, 1H), 3.49 (tt, J = 11.5, 3.7 Hz, 1H), 2.87 (q, J = 7.3 Hz,
6H), 2.09 – 1.91 (m, 2H), 1.89 – 1.61 (m, 5H), 1.60 – 1.45 (m, 2H), 1.38 – 1.20 (m, 3H), 1.17 (t,
J = 7.3 Hz, 9H), 1.03 (t, J = 7.4 Hz, 3H). 13C NMR (101 MHz, CDCl3) of major trans-isomer /
169.0, 144.6, 134.4, 130.2, 127.7, 127.2, 126.6, 63.1, 54.6, 52.2, 46.2, 32.1, 31.1, 26.1, 25.4,
25.4, 25.3, 9.6, 8.9. HRMS m/z [M–H]– calcd for C17H22NO4S 336.1275, found 336.1285.
2-(cis-1-Cyclohexyl-2-ethyl-4-oxoazetidin-3-yl)benzenesulfonic acid triethylammonium salt
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(cis-20q). Next was isolated cis-20q; yield 115 mg (53%); colorless amorphous solid. H NMR
(400 MHz, CDCl3) / 10.18 (br.s, 1H), 8.02 (d, J = 7.6 Hz, 1H), 7.38 (d, J = 4.2 Hz, 2H), 7.32 –
7.21 (m, 1H), 5.58 (d, J = 5.4 Hz, 1H), 4.06 – 3.91 (m, 1H), 3.48 (tt, J = 11.8, 3.8 Hz, 1H), 3.13
– 2.98 (m, 6H), 2.01 – 1.88 (m, 2H), 1.86 – 1.71 (m, 3H), 1.71 – 1.62 (m, 1H), 1.62 – 1.49 (m,
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1H), 1.49 – 1.35 (m, 2H), 1.34 – 1.11 (m, 12H), 0.70 (t, J = 7.5 Hz, 3H). C NMR (101 MHz,
CDCl3) / 168.6, 144.7, 132.0, 130.4, 129.7, 127.4, 126.9, 58.9, 54.6, 52.7, 46.3, 32.2, 30.8, 25.5,
25.4, 25.4, 24.1, 10.8, 8.7. HRMS m/z [M–H]– calcd for C17H22NO4S 336.1275, found
336.1272.
2-(trans/cis-1-Butyl-2-isopropyl-4-oxoazetidin-3-yl)benzenesulfonic acid triethylammonium
salt (trans/cis-20r). Eluent for chromatography EtOAc/MeOH/Et3N (85 : 10 : 5); yield 103 mg
1
(48%), dr 1:1.1; colorless amorphous solid. H NMR (400 MHz, CDCl3) signals of cis-isomer /
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