OXAZOLIDIN-2-ONES ISOCYANATES AND EPOXIDES MgI2
3657
The Representative Procedure for the Synthesis of Oxazolidin-2-ones
To a stirred solution of freshly prepared MgI2 etherate (2.5 mmol) in
THF (10 mL) was added dropwise epichlorohydrin (552 mg, 6 mmol) followed by
cycloaddition of phenyl isocyanate (595 mg, 5 mmol) at room temperature. After
addition, the reaction mixture was allowed to warm to 65 ꢀC and continued to be
stirred for 2 hours. The resulting homogeneous reaction mixture was quenched
with saturated Na2SO3 aqueous solution. Extractive workup with CH2Cl2 and
flash chromatographic purification of the crude product on silica gel gave the
5-chloromethyl-3-phenyloxazolidin-2-one 1a (970 mg) in 92% yield.
Spectroscopic Data for Selected Products (Table 1)
Compound 1a. Mp 104.3–105.4 (lit.[5] 103 ꢀC). tmax (KBr)=cmꢂ1 ¼ 1739
(C O). 1H NMR (500 MHz, CDCl3) d 3.73–3.81 (m, 2H), 3.96 (dd, J ¼ 6.0,
=
9.0 Hz, 1H), 4.17 (t, J ¼ 9.0 Hz, 1H), 4.85–4.88 (m, 1H), 7.14–7.18 (m, 1H),
7.37–7.40 (m, 2H), 7.54 (dd, J ¼ 1.0, 8.5 Hz, 2H).
1
Compound 1b. Mp 76.7–77.9 ꢀC. tmax (KBr)=cmꢂ1 ¼ 1748 (C O). H NMR
=
(500 MHz, CDCl3) d 2.25 (s, 3H), 3.72 (dd, J ¼ 3.5, 12.0 Hz, 1H), 3.77 (dd, J ¼ 6.0,
9.0 Hz, 1H), 3.82 (dd, J ¼ 5.0, 12.0 Hz, 1H), 4.00 (t, J ¼ 9.0 Hz, 1H), 4.89–4.94 (m,
1H), 7.19 (dd, J ¼ 8.5, 9.5 Hz, 2H), 7.23 (s, 1H). 13C NMR (125 MHz; CDCl3): d
17.4, 45.0, 50.0, 71.7, 126.6, 128.4, 131.8, 132.4, 134.6, 136.5, 155.1. M=z: (relative
intensity): 259 (12) [M]þ, 224 (35), 180 (78), 145 (55), 117 (100), 77 (10). Found
(HRMS): m=z 259.0187 (C11H11Cl2NO2), Calc. 259.0167.
1
Compound 1c. Mp 56.8–57.8 ꢀC. tmax (KBr)=cmꢂ1 ¼ 1731 (C O). H NMR
=
(500 MHz, CDCl3) d 2.32 (s, 3H), 3.77 (dd, J ¼ 3.5, 11.5 Hz, 1H), 3.81–3.86 (m, 2H),
4.06 (t, J ¼ 9.0 Hz, 1H), 4.89–4.94 (m, 1H), 7.22–7.29 (m, 4H). 13C NMR (125 MHz,
CDCl3): d 17.7, 45.1, 50.2, 71.6, 126.6, 126.9, 128.3, 131.3, 135.5, 135.9, 155.4. M=z:
(relative intensity): 227 (20) [M þ 2]þ, 225 (62) [M]þ, 190 (88), 146 (100), 118 (96).
Found (HRMS): m=z 225.0562 (C11H12ClNO2), Calc. 225.0557.
1
Compound 1d.[11] Mp. 131.8–132.5 ꢀC. tmax (KBr)=cmꢂ1 ¼ 1743 (C O). H
=
NMR (500 MHz, CDCl3) d 3.74–3.81 (m, 2H), 3.94 (dd, J ¼ 6.0, 9.0 Hz, 1H), 4.15 (t,
J ¼ 9.0 Hz, 1H), 4.86–4.91 (m, 1H), 7.33–7.36 (m, 2H), 7.48–7.51 (m, 2H).
1
Compound 1e.[12] Mp. 150.4–152.4 ꢀC. tmax (KBr)=cmꢂ1 ¼ 1759 (C O). H
=
NMR (500 MHz, CDCl3) d 3.82–3.84 (m, 2H), 4.05 (dd, J ¼ 6.0, 9.0 Hz, 1H), 4.26
(t, J ¼ 9.0 Hz, 1H), 4.96–5.01 (m, 1H), 7.75 (dd, J ¼ 2.0, 7.0 Hz, 2H), 8.28 (dd,
J ¼ 2.0, 7.0 Hz, 2H).
Compound 1f.[11] Mp. 104.5–106.3 ꢀC. tmax (KBr)=cmꢂ1 ¼ 1741 (C O). H
1
=
NMR (500 MHz, CDCl3) d 1.54 (d, J ¼ 6.5 Hz, 3H), 3.60 (dd, J ¼ 7.5, 8.5 Hz, 1H),
4.09 (t, J ¼ 8.5 Hz, 1H), 4.77–4.82 (m, 1H), 7.32 (dd, J ¼ 2.0, 7.0 Hz, 2H), 7.48 (dd,
J ¼ 2.0, 7.0 Hz, 2H).
Compound 1g. Mp 70.9–71.9 ꢀC. tmax (KBr)=cmꢂ1 ¼ 1739 cmꢂ1 (C O). H
1
=
NMR (500 MHz, CDCl3) d 1.54 (d, J ¼ 6.5 Hz, 3H), 2.19 (s, 3H), 2.30 (s, 3H),
3.49 (dd, J ¼ 7.0, 9.0 Hz, 1H), 3.98 (t, J ¼ 8.0 Hz, 1H), 4.81–4.85 (m, 1H),