PDF《pure heterocycles》

1 H NMR. The crude product was then purified by flash column chromatography eluted by Hexane/EtOAc with gradation mode changing from 9/1 to 3/7. The desired product was obtained at Hexane/EtOAc=7:3. Reaction of glycolide (1b) with isocyanate catalyzed by Bu2Sn(OMe)2 (Table 2, entry 4). A

5 mL of vial was dried by flame under reduced pressure. After nitrogen was filled, Bu2Sn(OMe)2 (0.0295 g, 0.1 mmol), MeCN (1.0 mL), glycolide (1b) (0.058g, 0.5 mmol) and the isocyanate (1.0 mmol) were added. The vial was sealed with a septum and was set in microwave reactor. The mixture was stirred under microwave irradiation at 100W for

20 min. The reaction temperature was measured by an IR sensor (120 o C). After the reaction, the mixture was quenched by H2O (0.5 mL), and the layers were quickly separated. The aqueous phase was further extracted with ether, and the combined extracts were dried over sodium sulfate and concentrated. The yield was determined by

1 H NMR. The crude product was then purified by flash column chromatography eluted by Hexane/EtOAc with gradation mode changing from 9/1 to 3/7. The desired product was obtained at Hexane/EtOAc=7:3. Reaction of lactide (1c) with isocyanate catalyzed by Sn(OCOC7H17)2 system (Table 4). A

5 mL of vial was dried by flame under reduced pressure. After nitrogen was filled, Tin catalyst Sn(OCOC7H17)2 (0.0405 g, 0.1 mmol), MeOH (0.0064 g, 0.2 mmol), MeCN (1.0 mL), lactide (1c) (0.072g, 0.5 mmol) and isocyanate (1.0 mmol) were added. The vial was sealed with a septum and was set in microwave reactor. The mixture was stirred under microwave irradiation at 150W for

30 min. The reaction temperature was measured by an IR sensor (155-160 o C). After the reaction, the mixture was quenched by H2O (0.5 mL), and the layers were quickly separated. The aqueous phase was further extracted with ether, and the combined extracts were dried over sodium sulfate and concentrated. The yield was determined by

1 H NMR. The crude product was then purified by flash column chromatography eluted by Hexane/EtOAc with gradation mode changing from 9/1 to 3/7. The desired product was obtained at Hexane/EtOAc=7:3. S4 MW Profiles Table 2, entry

1 Table 2, entry

2 Table 2, entry

3 Table 2, entry

4 Table 2, entry

5 Table 2, entry

6 Other profiles corresponding to give novel products, 2a-2d, 3a-3d, 4a-4f are listed after spectral charts. S5 Enantiomeric purity (Scheme 4) Enantio-excess value of product 4a was measured by HPLC. (TOSOH CCPS-UV8020 system using Daicel CHIRALPAK IA (0.46 cmD x 25cmL) detected at

254 nm eluted by 1.0 mL/min Hexane/CHCl3=50/50). Products obtained using Sn(OCOC7H17)2 catalyst indicated high ee values which HPLC charts are shown in this SI. Other HPLC corresponding to novel products, 4a-4f, with high ee are listed after spectral charts. On the other hand, product obtained using Bu2Sn(OMe)2 catalyst (Scheme 4, eq. 1) indicated low ee. value as shown in the following chart. S6 Analytical data for Products 3-Butyloxazolidine-2,4-dione (2a) O N O O a b c d e f g Colorless liquid. Rf= 0.52 (in hexane : ethyl acetate =

7 : 3). IR (neat)

1743 (C=O) cm-1 ,

1736 (C=O) cm-1 .

1 H NMR (CDCl3,

400 MHz) ?4.70 (s, 2H, a), 3.56 (t, J= 7.3 Hz, 2H, d), 1.64 (m, 2H, e), 1.36 (m, 2H, f), 0.95 (t, J= 7.3 Hz, 3H, g).

13 C NMR (CDCl3,

100 MHz) ??170.4 (b), 155.9 (c), 67.7 (a), 39.8 (d), 29.4 (e), 19.7 (f), 13.4 (g) MS (EI,

70 eV) m/z

157 (M+ , 6),

115 (35),

102 (100). HRMS calcd for C7H11NO3: 157.0739, found: m/z 157.0744 (EI, (M+ ), +0.5 mmu). Butylcarbamoyloxy-acetic acid methyl ester (2a'