HETEROCYCLES

Short Paper | Regular issue | Vol. 92, No. 3, 2016, pp. 528-543
Received, 18th November, 2015, Accepted, 18th January, 2016, Published online, 5th February, 2016.
DOI: 10.3987/COM-15-13372

■ Ring-Opening Reactions of Aziridines with Carboxylic Acids Catalyzed by DBU

Yanqin Guo, Yepeng Xie, Qin Yang, Songsong Xu, Zhihong Deng, Xuechun Mao, and Yiyuan Peng*

College of Chemistry & Chemical Engineering, Jiangxi Normal University, Nanchang, Jiangxi 330022, China

Abstract

An efficient ring-opening of aziridines with various carboxylic acids catalyzed by an organocatalyst—DBU afforded the corresponding products in good to excellent yield under mild reaction conditions.

Aziridines have attracted increasing attention as versatile building blocks for the synthesis of many nitrogen-containing biologically interesting molecules,1 such as amino acids,1b,1h heterocycles,2 and alkaloids.3 Considerable progress has been achieved in the nucleophilic ring-opening reactions of aziridines.4-6 They are known to react with various nucleophiles such as thiols, amines, and anhydrides. However, most of these reactions require a strong base or Lewis acid.5 Recently, organocatalysts have been successfully employed in such transformation. For instance, phosphine,4a,b tertiary amine,4c-4e DABCO,4f DMSO,4g N-heterocyclic carbene6a and pyridine-N-oxide6b had been used as a catalyst or promoter to facilitate the ring-opening reactions of aziridines. Among the nucleophiles, only four references regarded the carboxylic acid used as the nucleophile for the ring-opening reactions of aziridines. Yadav reported that aziridines could react smoothly with carboxylic acids in the presence of indium triflate to afford the corresponding aminoacetates and benzoates in high yields (Scheme 1a).7 Wu reported DABCO as an efficient organocatalyst in the ring-opening reactions of aziridines with amines or thiols and adding one example of p-methoxybenzoic acid that could react with aziridine under reflux condition.4f Recently, Wei described ring opening reactions of N-tosylaziridines with carboxylic acids in DMF catalyzed by TBAB or by KOH in DMSO (Scheme 1b).8
Inspired by the recent advance of organocatalysts, we envisioned that the strong σ-donating property of DBU may catalyze the reactions between aziridines and carboxylic acids. In this paper, as part of our ongoing study on green and metal-free ring-opening processes,4e,6b we would like to disclose our preliminary results for the ring-opening reactions of aziridines with carboxylic acids catalyzed by DBU (Scheme 1c).

First, the reaction of aziridine 1a and 3-phenylacrylic acid 2a were selected as the model for condition optimizing. The results are listed in Table 1. Initially, the reaction was promoted by 40 mol% DBU in THF at 25 ºC, and no product was obtained even after 48 h (entry 1). To our delight, when the temperature rising up to 50 ºC, the DBU catalytic reaction gave an excellent yield of 93% (entry 2). The anti-stereochemistry of the product 3aa was confirmed by the coupling constant for two cyclic methine hydrogens at the trans-positions.9 Wu reported that DABCO could catalyze the reaction of p-methoxybenzoic acid with aziridine 1a giving the corresponding product 3al in a yield of 73%.4f However, when DBU was replaced by DABCO in our reaction model, the reaction afforded low yields (entries 3 and 4). Other base catalysts such as DABCO, pyridine (Py), Et3N, i-PrNH2, t-BuOK and K2CO3 were then screened for this reaction, however, none of them was more efficient than DBU (entries 5-11). Various solvents, such as DMSO, toluene, MeOH, and CH2Cl2, were also investigated, only low yields were obtained (entries 12–15). In addition, a significant drop in yield was observed when 30 mol% of DBU was used (entry 16). And control experiment indicated that the reaction could not take place without adding DBU (entry 17).

With this promising result in hand, we started to explore the generality of this DBU catalyzed ring opening reaction of aziridines with carboxylic acids under the conditions highlighted above (40 mol% of DBU, in THF, at 50 ºC). To assess the impact of the structural and functional motifs on the reaction of 1a, a range of acids 2 was tested, and the results are summarized in Table 2. The results in Table 2 indicated that aromatic acids and aromatic substituted olefinic acids reacted with 1a leading to the corresponding products 3 in good to excellent yields (entries 1-21). Moreover, it was found that substrates with strong electron-withdrawing groups on the phenyl ring were less reactive to some extent than those with the electron-donating groups. For example, the reaction of 4-NO2 substituted cinnamic or benzoic acid 2i or 2q with 1a gave rise to the desired product 3ai and 3aq in 79% and 77% yield, respectively (entries 9 and 17). While for the Me-, MeO-, -NMe2, or halo-substituted substrates 2, the corresponding yields were all higher than 85% (entries 2-7 and 11-16). It is noteworthy that the heterocyclic substrate 2r-2t could also be well tolerated in the reaction, leading to the desired product 3ar-3at in high yields (entries 18-20). However, alkynyl acid such as 3-phenylpropiolic acid reacted with 1a only gave 40% yield (entry 22). Not only aryl- but also alkylcarboxylic acids gave good yields (entries 23 and 24). Unfortunately, when propenoic or propiolic acid was used, only trace amount of product was detected even the reaction was performed at reflux condition (entries 25 and 26).

In a second set of experiments, the scope with respect to aziridines was investigated. As shown in Table 3, moderate to excellent yields were obtained for all aziridines. All the expected products were generated under our standard experimental conditions, whatever the nature of the substrate was. In the case of unsymmetrically substituted aziridine 1g, completely regioselectivity with the attack of nucleophile on the less substituted aziridine carbon was observed (entries 11 and 12). When electronic effect participates, such as substrates 1c-f, the regioselective attack of the acid on the benzyl substituted aziridine carbon was also observed (entries 3-10). But, it was reasonable that regioselectivity was not as specific as the alkyl aziridine when aryl aziridine was employed as the substrate.
In conclusion, an organocatalytic approach for the synthesis of β-amino esters with excellent yields has been described, which DBU is an efficient organocatalyst for the reactions of aziridines with carboxylic acids. The advantages of this method include high yield, good substrate generality, metal-free conditions, and experimentally operational ease.

EXPERIMENTAL
General procedure for ring-opening reactions of aziridines with various carboxylic acids
A mixture of aziridine 1 (0.20 mmol), carboxylic acid 2 (0.24 mmol), and DBU (0.08 mmol, 40 mol%) in THF (2.0 mL) were added subsequently. The mixture was stirred at 50 C for 24-36 h. After completion of the reaction as indicated by TLC, evaporation of the solvent followed by purification on silica gel provided the corresponding product 3.
2-((4-Methylphenyl)sulfonamido)cyclohexyl cinnamate (3aa) This compound was obtained as a white solid; Yield: 74.2 mg (93%); mp 93–94 ºC; 1H NMR (400 MHz, CDCl3): δ 7.71 (d, J = 8.0 Hz, 2H), 7.49–7.39 (m, 6H), 7.12 (d, J = 7.6 Hz, 2H), 5.99 (d, J = 16.0 Hz, 1H), 5.41 (d, J = 7.6 Hz, 1H), 4.71 (td, J = 10.0, 4.0 Hz, 1H), 3.33–3.25 (m, 1H), 2.17–2.15 (m, 4H), 2.00 (d, J = 11.6 Hz, 1H), 1.71–1.69 (m, 2H), 1.40–1.26 (m, 4H); 13C NMR (100 MHz, CDCl3): δ 167.1, 144.9, 142.7, 138.4, 134.1, 130.4, 129.5, 128.9, 128.0, 126.8, 117.4, 74.1, 57.3, 34.1, 31.2, 24.2, 23.7, 21.1; IR (KBr) (cm-1) v 3430, 3309, 3061, 2944, 2863, 1723, 1636, 1598, 1448, 1366, 1329, 1163, 1025; HRMS (ESI): m/z [M+Na]+ calcd for C22H25NO4SNa: 422.1402, found: 422.1423.
2-((4-Methylphenyl)sulfonamido)cyclohexyl (E)-3-(p-tolyl)acrylate (3ab) This compound was obtained as a white solid; Yield: 75.2 mg (91%); mp 134–136 ºC; 1H NMR (400 MHz, CDCl3): δ 7.70 (d, J = 8.0 Hz, 2H), 7.44 (d, J = 15.6 Hz, 1H), 7.34 (d, J = 8.0 Hz, 2H), 7.20 (d, J = 8.0 Hz, 2H), 7.12 (d, J = 8.4 Hz, 2H), 5.93 (d, J = 15.6 Hz, 1H), 5.27–5.24 (m, 1H), 4.69 (td, J = 10.0, 4.4 Hz, 1H), 3.31–3.23 (m, 1H), 2.38 (s, 3H), 2.18 (d, J = 13.2 Hz, 1H), 2.13 (s, 3H), 2.00–1.96 (m, 1H), 1.71–1.68 (m, 2H), 1.42–1.25 (m, 4H); 13C NMR (100 MHz, CDCl3): δ 167.3, 145.0, 142.8, 140.9, 138.5, 131.5, 129.6, 129.6, 128.1, 126.9, 116.5, 74.0, 57.4, 34.1, 31.3, 24.3, 23.8, 21.5, 21.2; IR (KBr) (cm-1) v 3451, 3299, 3031, 2949, 2920, 2856, 1684, 1631, 1605, 1511, 1426, 1358, 1334, 1182, 1020; HRMS (ESI): m/z [M+Na]+ calcd for C23H27NO4SNa: 436.1558, found: 436.1543.
2-((4-Methylphenyl)sulfonamido)cyclohexyl (E)-3-(4-methoxyphenyl)acrylate (3ac) This compound was obtained as a white solid; Yield: 84.9 mg (99%); mp 133–134 ºC; 1H NMR (400 MHz, CDCl3): δ 7.69 (d, J = 8.4 Hz, 2H), 7.44–7.38 (m, 3H), 7.12 (d, J = 8.0 Hz, 2H), 6.91 (d, J = 8.8 Hz, 2H), 5.85 (d, J = 15.6 Hz, 1H), 5.28–5.22 (m, 1H), 4.69 (td, J = 10.4, 4.4 Hz, 1H), 3.85 (s, 3H), 3.30–3.22 (m, 1H), 2.20–2.14 (m, 4H), 1.99–1.96 (m, 1H), 1.72–1.69 (m, 2H), 1.43–1.27 (m, 4H); 13C NMR (100 MHz, CDCl3): δ 167.4, 161.6, 144.6, 142.7, 138.7, 129.8, 129.5, 127.1, 126.9, 115.2, 114.4, 74.0, 57.3, 55.4, 34.0, 31.3, 24.3, 23.8, 21.2; IR (KBr) (cm-1) v 3442, 3293, 2929, 2856, 1703, 1514, 1457, 1325, 1170, 1159, 1028; HRMS (ESI): m/z [M+Na]+ calcd for C23H27NO5SNa: 452.1508, found: 452.1478.
2-((4-Methylphenyl)sulfonamido)cyclohexyl (E)-3-(4-(dimethylamino)phenyl)acrylate (3ad) This compound was obtained as a brown solid; Yield: 87.5 mg (99%); mp 146–148 ºC; 1H NMR (400 MHz, CDCl3): δ 7.69 (d, J = 8.0 Hz, 2H), 7.39 (d, J = 16.0 Hz, 1H), 7.33 (d, J = 8.8 Hz, 2H), 7.12 (d, J = 8.0 Hz, 2H), 6.66 (d, J = 8.8 Hz, 2H), 5.74 (d, J = 15.6 Hz, 1H), 5.36–5.30 (m, 1H), 4.68 (td, J = 10.0, 4.0 Hz, 1H), 3.26–3.18 (m, 1H), 3.02 (s, 6H), 2.21 (d, J = 13.6 Hz, 1H), 2.16 (s, 3H), 1.96 (d, J = 12.8 Hz, 1H), 1.75–1.60 (m, 2H), 1.40–1.26 (m, 4H); 13C NMR (100 MHz, CDCl3): δ = 168.3, 151.9, 145.7, 142.8, 138.2, 129.9, 129.5, 126.9, 121.9, 111.7, 111.6, 73.6, 57.6, 40.2, 34.3, 31.4, 24.3, 23.9, 21.4; IR (KBr) (cm-1) v 3431, 3322, 3046, 2926, 2859, 2810, 1698, 1627, 1601, 1527, 1446, 1364, 1326, 1159, 1036; HRMS (ESI): m/z [M+Na]+ calcd for C24H30N2O4SNa: 465.1824; found: 465.1836.
2-((4-Methylphenyl)sulfonamido)cyclohexyl (E)-3-(4-chlorophenyl)acrylate (3ae) This compound was obtained as a white solid; Yield: 81.4 mg (94%); mp 124–125 ºC; 1H NMR (400 MHz, CDCl3): δ 7.71 (d, J = 8.0 Hz, 2H), 7.46–7.34 (m, 5H), 7.14 (d, J = 7.6 Hz, 2H), 6.00 (d, J = 16.0 Hz, 1H), 5.37 (d, J = 8.0 Hz, 1H), 4.71 (td, J = 10.0, 4.0 Hz, 1H), 3.34–3.26 (m, 1H), 2.16 (s, 3H), 2.11 (d, J = 12.8 Hz, 1H), 2.00 (d, J = 10.8 Hz, 1H), 1.72–1.67 (m, 2H), 1.38–1.27 (m, 4H); 13C NMR (100 MHz, CDCl3): δ 166.8, 143.4, 142.7, 138.7, 136.3, 132.8, 129.5, 129.3, 129.2, 126.9, 118.3, 74.4, 57.1, 33.8, 31.2, 24.3, 23.7, 21.3; IR (KBr) (cm-1) v 3427, 3278, 3065, 2940, 2862, 1688, 1636, 1592, 1491, 1325, 1160, 1092, 1024, 1011; HRMS (ESI): m/z [M+Na]+ calcd for C22H24NO4SClNa: 456.1012; found: 456.0994.
2-((4-Methylphenyl)sulfonamido)cyclohexyl (E)-3-(2-chlorophenyl)acrylate (3af) This compound was obtained as a white solid; Yield: 85.7 mg (99%); mp 146–148 ºC; 1H NMR (400 MHz, CDCl3): δ 7.82 (d, J = 16.0 Hz, 1H), 7.70 (d, J = 8.4 Hz, 2H), 7.51 (dd, J = 7.2, 1.6 Hz, 1H), 7.44 (dd, J = 8.0, 1.6 Hz, 1H), 7.36–7.27 (m, 2H), 7.13 (d, J = 8.0 Hz, 2H), 5.97 (d, J = 16.0 Hz, 1H), 4.99–4.96 (m, 1H), 4.71 (td, J = 10.4, 4.4 Hz, 1H), 3.34–3.26 (m, 1H), 2.20 (d, J = 13.6 Hz, 1H), 2.07 (s, 3H), 1.99 (d, J = 12.8 Hz, 1H), 1.74–1.66 (m, 2H), 1.47–1.27 (m, 4H); 13C NMR (100 MHz, CDCl3): δ 166.5, 142.7, 140.5, 138.7, 135.0, 132.6, 131.1, 130.3, 129.5, 127.6, 127.1, 126.9, 120.2, 74.3, 57.4, 34.1, 31.2, 24.2, 23.8, 21.0; IR (KBr) (cm-1) v 3450, 3271, 3067, 2943, 2864, 1706, 1630, 1590, 1450, 1325, 1188, 1086, 1027; HRMS (ESI): m/z [M+Na]+calcd for C22H24NO4SClNa: 456.1012; found: 456.1031.
2-((4-Methylphenyl)sulfonamido)cyclohexyl (E)-3-(3-chlorophenyl)acrylate (3ag) This compound was obtained as a pale yellow solid; Yield: 82.3 mg (95%); mp 55–56 ºC; 1H NMR (400 MHz, CDCl3): δ 7.71 (d, J = 7.6 Hz, 2H), 7.42–7.33 (m, 5H), 7.15 (d, J = 7.6 Hz, 2H), 6.00 (d, J = 16.0 Hz, 1H), 5.36 (d, J = 7.6 Hz, 1H), 4.73–4.68 (m, 1H), 3.23–3.23 (m, 1H), 2.17–2.12 (m, 4H), 2.00 (d, J = 11.2 Hz, 1H), 1.71–1.67 (m, 2H), 1.40–1.28 (m, 4H); 13C NMR (100 MHz, CDCl3): δ 166.6, 143.2, 142.8, 138.6, 136.1, 134.9, 130.2, 130.2, 129.5, 127.6, 126.9, 126.4, 119.2, 74.4, 57.1, 33.9, 31.2, 24.3, 23.7, 21.3; IR (KBr) (cm-1) v 3500, 3274, 3064, 2940, 2861, 1707, 1639, 1597, 1565, 1452, 1325, 1160, 1093, 1030; HRMS (ESI): m/z [M+Na]+ calcd for C22H24NO4SClNa: 456.1012; found: 456.1027.
2-((4-Methylphenyl)sulfonamido)cyclohexyl (E)-3-(4-fluorophenyl)acrylate (3ah) This compound was obtained as a pale yellow solid; Yield: 70.9 mg (85%); mp 82–84 ºC; 1H NMR (400 MHz, CDCl3): δ 7.77–7.70 (m, 2H), 7.48–7.43 (m, 3H), 7.15–7.00 (m, 4H), 6.04–5.93 (m, 1H), 5.44–5.36 (m, 1H), 4.78–4.68 (m, 1H), 3.35–3.26 (m, 1H), 2.21–2.10 (m, 4H), 2.03–1.99 (m, 1H), 1.78–1.68 (m, 2H), 1.39–1.28 (m, 4H); 13C NMR (100 MHz, CDCl3): δ 166.9, 165.2, 162.7, 143.6, 142.6, 138.8, 130.6, 130.0, 129.9, 129.5, 126.9, 117.6, 116.1, 115.9, 74.3, 57.1, 33.8, 31.2, 24.3, 23.7, 21.2; IR (KBr) (cm-1) v 3450, 3324, 3070, 2948, 2862, 1687, 1635, 1600, 1509, 1415, 1331, 1239, 1179, 1093, 1019, 1002; HRMS (ESI): m/z [M+Na]+ calcd for C22H24NO4SFNa: 440.1308; found: 440.1331.
2-((4-Methylphenyl)sulfonamido)cyclohexyl (E)-3-(4-nitrophenyl)acrylate (3ai) This compound was obtained as a pale yellow solid; Yield: 70.2 mg (79%); mp 160–161 ºC; 1H NMR (400 MHz, CDCl3): δ 8.25 (d, J = 7.6 Hz, 2H), 7.73 (d, J = 8.0 Hz, 2H), 7.63–7.56 (m, 3H), 7.18 (d, J = 7.6 Hz, 2H), 6.22 (d, J = 16.0 Hz, 1H), 5.16–5.14 (m, 1H), 4.77–4.68 (m, 1H), 3.37–3.28 (m, 1H), 2.21 (s, 3H), 2.04–2.02 (m, 2H), 1.76–1.67 (m, 2H), 1.44–1.29 (m, 4H); 13C NMR (100 MHz, CDCl3): δ 166.1, 148.5, 142.8, 141.9, 140.5, 138.7, 129.5, 128.7, 126.9, 124.1, 122.0, 74.8, 57.0, 33.5, 31.2, 24.3, 23.7, 21.3; IR (KBr) (cm-1) v 3441, 3284, 2939, 2862, 1712, 1640, 1599, 1520, 1344, 1061, 1091, 1032; HRMS (ESI): m/z [M+Na]+ calcd for C22H24N2O6SNa: 467.1253; found: 467.1268.
2-((4-Methylphenyl)sulfonamido)cyclohexyl benzoate (3aj)10 This compound was obtained as a white solid; Yield: 62.7 mg (84%); mp 170–172 ºC; 1H NMR (400 MHz, CDCl3): δ 7.77 (d, J = 8.0 Hz, 2H), 7.59 (d, J = 8.0 Hz, 2H), 7.54 (t, J = 6.8 Hz, 1H), 7.36 (t, J = 7.6 Hz, 2H), 6.91 (d, J = 8.0 Hz, 2H), 5.20 (d, J = 7.2 Hz, 1H), 4.82 (td, J = 10.4, 4.4 Hz, 1H), 3.36–3.28 (m, 1H), 2.18 (s, 4H), 2.04–2.01 (m, 1H), 1.73–1.70 (m, 2H), 1.51–1.30 (m, 4H); 13C NMR (100 MHz, CDCl3): δ 166.8, 142.7, 138.1, 133.0, 129.7, 129.4, 128.1, 126.6, 74.6, 57.2, 34.0, 31.2, 24.2, 23.8, 21.4; IR (KBr) (cm-1) v 3440, 3329, 2927, 2862, 1707, 1599, 1450, 1323, 1158, 1015; HRMS (ESI): m/z [M+Na]+ calcd for C20H23NO4SNa: 396.1245; found: 396.1259.
2-((4-Methylphenyl)sulfonamido)cyclohexyl 4-methylbenzoate (3ak)7 This compound was obtained as a white solid; Yield: 76.6 mg (99%); mp 147–149 ºC; 1H NMR (400 MHz, CDCl3): δ 7.64 (d, J = 8.4 Hz, 2H), 7.58 (d, J = 8.0 Hz, 2H), 7.15 (d, J = 8.0 Hz, 2H), 6.91 (d, J = 8.0 Hz, 2H), 5.13 (d, J = 6.4 Hz, 1H), 4.80 (td, J = 10.4, 4.4 Hz, 1H), 3.33–3.25 (m, 1H), 2.42 (s, 3H), 2.23–2.18 (m, 4H), 2.00 (d, J = 13.6 Hz, 1H), 1.76–1.69 (m, 2H), 1.51–1.30 (m, 4H); 13C NMR (100 MHz, CDCl3): δ 166.9, 143.7, 142.6, 138.0, 129.8, 129.4, 128.8, 126.9, 126.5, 74.4, 57.4, 34.2, 31.3, 24.2, 23.8, 21.7, 21.4; IR (KBr) (cm-1) v 3410, 3323, 3052, 3035, 2930, 2919, 2855, 1708, 1613, 1443, 1324, 1272, 1157, 1087, 1027, 1020; HRMS (ESI): m/z [M+Na]+ calcd for C21H25NO4SNa: 410.1402; found: 410.1413.
2-((4-Methylphenyl)sulfonamido)cyclohexyl 4-methoxybenzoate (3al)10 This compound was obtained as a white solid; Yield: 74.2 mg (92%); mp 132–134 ºC; 1H NMR (400 MHz, CDCl3): δ 7.71 (d, J = 8.8 Hz, 2H), 7.59 (d, J = 8.0 Hz, 2H), 6.94 (d, J = 8.0 Hz, 2H), 6.83 (d, J = 8.8 Hz, 2H), 5.29 (d, J = 6.8 Hz, 1H), 4.78 (td, J = 10.4, 4.4 Hz, 1H), 3.87 (s, 3H), 3.33–3.25 (m, 1H), 2.20–2.17 (m, 4H), 2.01 (d, J = 13.2 Hz, 1H), 1.74–1.68 (m, 2H), 1.49–1.26 (m, 4H); 13C NMR (100 MHz, CDCl3): δ 166.6, 163.4, 142.6, 138.1, 131.8, 129.4, 126.6, 122.1, 113.3, 74.3, 57.3, 55.5, 34.0, 31.3, 24.2, 23.8, 21.4; IR (KBr) (cm-1) v 3399, 3331, 3083, 2932, 2863, 1706, 1607, 1441, 1326, 1261, 1158, 1080, 1033, 1016; HRMS (ESI): m/z [M+Na]+ calcd for C21H25NO5SNa: 426.1351; found: 426.1355.
2-((4-Methylphenyl)sulfonamido)cyclohexyl 4-(dimethylamino)benzoate (3am) This compound was obtained as a pale yellow solid; Yield: 78.2 mg (94%); mp 148–150 ºC; 1H NMR (400 MHz, CDCl3): δ 7.61–7.57 (m, 4H), 6.92 (d, J = 8.0 Hz, 2H), 6.56 (d, J = 9.2 Hz, 2H), 5.33 (d, J = 6.4 Hz, 1H), 4.75 (td, J = 10.4, 4.4 Hz, 1H), 3.26–3.05 (m, 1H), 3.05 (s, 6H), 2.26–2.19 (m, 4H), 1.98 (d, J = 13.6 Hz, 1H), 1.77–1.63 (m, 2H), 1.46– 1.28 (m, 4H); 13C NMR (100 MHz, CDCl3): δ 167.5, 153.4, 142.4, 137.8, 131.5, 129.4, 126.6, 116.3, 110.4, 73.7, 57.7, 40.1, 34.3, 31.4, 24.2, 23.9, 21.4; IR (KBr) (cm-1) v 3422, 3303, 3066, 2935, 2863, 1679, 1609, 1534, 1443, 1374, 1330, 1284, 1181, 1088, 1026; HRMS (ESI): m/z [M+Na]+ calcd for C22H28N2O4SNa: 439.1667; found: 439.1647.
2-((4-Methylphenyl)sulfonamido)cyclohexyl 4-chlorobenzoate (3an)10 This compound was obtained as a white solid; Yield: 74.9 mg (92%); mp 145–146 ºC; 1H NMR (400 MHz, CDCl3): δ 7.70 (d, J = 8.4 Hz, 2H), 7.59 (d, J = 8.0 Hz, 2H), 7.32 (d, J = 8.4 Hz, 2H), 6.95 (d, J = 8.0 Hz, 2H), 5.18–5.15 (m, 1H), 4.81 (td, J = 10.4, 4.0 Hz, 1H), 3.38–3.30 (m, 1H), 2.22 (s, 3H), 2.13 (d, J = 12.8 Hz, 1H), 2.02 (d, J = 14.0 Hz, 1H), 1.75–1.68 (m, 2H), 1.50–1.29 (m, 4H); 13C NMR (100 MHz, CDCl3): δ 165.8, 142.8, 139.4, 138.2, 131.1, 129.4, 128.4, 128.2, 126.5, 74.9, 57.2, 34.0, 31.3, 24.3, 23.8, 21.4; IR (KBr) (cm-1) v 3435, 3271, 2940, 1712, 1595, 1467, 1400, 1327, 1280, 1154, 1093, 1014; HRMS (ESI): m/z [M+Na]+ calcd for C20H22NO4SClNa: 430.0856; found: 430.0864.
2-((4-Methylphenyl)sulfonamido)cyclohexyl 2-chlorobenzoate (3ao)10 This compound was obtained as a white solid; Yield: 75.7 mg (93%); mp 138–140 ºC; 1H NMR (400 MHz, CDCl3): δ 7.68 (dd, J = 16.0, 8.0 Hz, 3H), 7.40 (d, J = 3.6 Hz, 2H), 7.28–7.23 (m, 1H), 7.01 (d, J = 8.0 Hz, 2H), 5.28 (d, J = 7.6 Hz, 1H), 4.85 (td, J = 10.0, 4.4 Hz, 1H), 3.39–3.31 (m, 1H), 2.23 (s, 3H), 2.10–2.03 (m, 2H), 1.74–1.64 (m, 2H), 1.52–1.29 (m, 4H); 13C NMR (100 MHz, CDCl3): δ 165.3, 142.8, 138.2, 134.0, 132.7, 131.9, 131.0, 129.4, 129.3, 126.6, 126.5, 75.3, 56.8, 33.4, 31.0, 24.2, 23.7, 21.5; IR (KBr) (cm-1) v 3442, 3261, 2942, 2862, 1733, 1590, 1472, 1440, 1324, 1254, 1158, 1117, 1084, 1052, 1013; HRMS (ESI): m/z [M+Na]+ calcd for C20H22NO4SClNa: 430.0856; found: 430.0833.
2-((4-Methylphenyl)sulfonamido)cyclohexyl 2-iodobenzoate (3ap) This compound was obtained as a white solid; Yield: 88.8 mg (89%); mp 165–167 ºC; 1H NMR (400 MHz, CDCl3): δ 7.97 (d, J = 8.0 Hz, 1H), 7.67–7.64 (m, 3H), 7.33 (t, J = 7.6 Hz, 1H), 7.14 (td, J = 7.6, 1.2 Hz, 1H), 7.00 (d, J = 8.0 Hz, 2H), 5.12 (d, J = 7.2 Hz, 1H), 4.84 (td, J = 10.0, 4.4 Hz, 1H), 3.40–3.32 (m, 1H), 2.23 (s, 3H), 2.12–2.09 (m, 2H), 1.76–1.66 (m, 2H), 1.54–1.27 (m, 4H); 13C NMR (100 MHz, CDCl3): δ 166.0, 142.8, 141.3, 138.2, 133.8, 132.8, 131.5, 129.5, 127.8, 126.6, 94.7, 75.6, 56.8, 33.6, 31.2, 24.3, 23.7, 21.6; IR (KBr) (cm-1) v 3435, 3264, 2938, 2861, 1728, 1582, 1452, 1323, 1254, 1160, 1086, 1045, 1016; HRMS (ESI): m/z [M+Na]+ calcd for C20H22NO4SINa: 522.0212; found: 522.0177.
2-((4-Methylphenyl)sulfonamido)cyclohexyl 4-nitrobenzoate (3aq)8a This compound was obtained as a white solid; Yield: 64.4 mg (77%); mp 151–153 ºC; 1H NMR (400 MHz, CDCl3): δ 8.20 (d, J = 8.4 Hz, 2H), 8.01 (d, J = 8.8 Hz, 2H), 7.63 (d, J = 8.0 Hz, 2H), 7.03 (d, J = 7.6 Hz, 2H), 5.17–5.06 (m, 1H), 4.85 (td, J = 10.0, 4.4 Hz, 1H), 3.46–3.37 (m, 1H), 2.24 (s, 3H), 2.10–2.00 (m, 2H), 1.77–1.68 (m, 2H), 1.54–1.29 (m, 4H); 13C NMR (100 MHz, CDCl3): δ 164.6, 150.4, 143.0, 138.4, 135.3, 130.9, 129.5, 126.6, 123.2, 75.9, 56.7, 33.3, 31.1, 24.3, 23.7, 21.4; IR (KBr) (cm-1) v 3429, 3305, 2952, 2860, 1724, 1608, 1600, 1527, 1436, 1328, 1272, 1163, 1088, 1011; HRMS (ESI): m/z [M+Na]+ calcd for C20H22N2O6SNa: 441.1096; found: 441.1116.
2-((4-Methylphenyl)sulfonamido)cyclohexyl nicotinate (3ar) This compound was obtained as a white solid; Yield: 65.8 mg (88%); mp 151–153 ºC; 1H NMR (400 MHz, CDCl3): δ 8.94 (s, 1H), 8.75 (d, J = 3.6 Hz, 1H), 8.10 (d, J = 8.0 Hz, 1H), 7.62 (d, J = 8.4 Hz, 2H), 7.35–7.30 (m, 1H), 6.99 (d, J = 8.0 Hz, 2H), 5.57–5.54 (m, 1H), 4.87 (td, J = 10.4, 4.4 Hz, 1H), 3.42–3.34 (m, 1H), 2.22 (s, 3H), 2.07 (t, J = 16.4 Hz, 2H), 1.77–1.69 (m, 2H), 1.50–1.29 (m, 4H); 13C NMR (100 MHz, CDCl3): δ 165.1, 153.1, 150.7, 142.9, 138.4, 137.3, 129.4, 126.5, 125.7, 123.2, 75.3, 56.8, 33.6, 31.1, 24.3, 23.7, 21.5; IR (KBr) (cm-1) v 3431, 3095, 2942, 2868, 1730, 1595, 1474, 1430, 1315, 1276, 1157, 1093, 1027, 1014; HRMS (ESI): m/z [M+Na]+ calcd for C19H22N2O4SNa: 397.1198; found: 397.1222.
2-((4-Methylphenyl)sulfonamido)cyclohexyl furan-2-carboxylate (3as)10 This compound was obtained as a white solid; Yield: 66.1 mg (91%); mp 124–127 ºC; 1H NMR (400 MHz, CDCl3): δ 7.65 (d, J = 8.0 Hz, 2H), 7.53 (s, 1H), 7.06 (d, J = 8.0 Hz, 2H), 6.92 (d, J = 3.2 Hz, 1H), 6.47–6.46 (m, 1H), 5.25 (d, J = 7.6 Hz, 1H), 4.78 (td, J = 10.8, 4.4 Hz, 1H), 3.35–3.27 (m, 1H), 2.29 (s, 3H), 2.13 (d, J = 12.8 Hz, 1H), 2.01 (d, J = 13.2 Hz, 1H), 1.72–1.67 (m, 2H), 1.50–1.26 (m, 4H); 13C NMR (100 MHz, CDCl3): δ 158.8, 146.4, 144.1, 142.7, 138.1, 129.3, 126.7, 118.4, 111.8, 74.7, 57.1, 33.9, 31.2, 24.2, 23.7, 21.5; IR (KBr) (cm-1) v 3424, 3318, 2936, 2859, 1716, 1472, 1398, 1321, 1296, 1235, 1158, 1085, 1012; HRMS (ESI): m/z [M+Na]+ calcd for C18H21NO5SNa: 386.1038; found: 386.1012.
2-((4-Methylphenyl)sulfonamido)cyclohexyl thiophene-2-carboxylate (3at) This compound was obtained as a white solid; Yield: 70.5 mg (93%); mp 179–181 ºC; 1H NMR (400 MHz, CDCl3): δ 7.62 (d, J = 8.0 Hz, 2H), 7.54–7.52 (m, 2H), 7.05–7.02 (m, 1H), 6.99 (d, J = 8.0 Hz, 2H), 5.25 (d, J = 7.2 Hz, 1H), 4.77 (td, J = 10.0, 4.8 Hz, 1H), 3.34–3.25 (m, 1H), 2.24 (s, 3H), 2.19–2.15 (m, 1H), 2.03–1.99 (m, 1H), 1.75–1.67 (m, 2H), 1.52–1.29 (m, 4H); 13C NMR (100MHz, CDCl3): δ 162.5, 142.7, 138.0, 133.8, 133.5, 132.7, 129.4, 127.6, 126.6, 74.9, 57.1, 33.9, 31.2, 24.1, 23.7, 21.5; IR (KBr) (cm-1) v 3434, 3272, 3096, 3059, 2924, 2854, 1685, 1597, 1523, 1455, 1416, 1364, 1287, 1267, 1163, 1107, 1094, 1039, 1006; HRMS (ESI): m/z [M+Na]+ calcd for C18H21NO4S2Na: 402.0810; found: 402.0790.
2-((4-Methylphenyl)sulfonamido)cyclohexyl 1-naphthoate (3au)10 This compound was obtained as a white solid; Yield: 82.1 mg (97%); mp 125–126 ºC; 1H NMR (400 MHz, CDCl3): δ 8.85 (d, J = 8.4 Hz, 1H), 7.96 (dd, J = 18.0, 8.0 Hz, 2H), 7.86 (d, J = 8.0 Hz, 1H), 7.59–7.50 (m, 4H), 7.37 (t, J = 7.6 Hz, 1H), 6.67 (d, J = 8.0 Hz, 2H), 5.45 (d, J = 7.2 Hz, 1H), 4.93 (td, J = 10.4, 4.8 Hz, 1H), 3.44–3.36 (m, 1H), 2.12–2.09 (m, 2H), 1.97 (s, 3H), 1.73–1.64 (m, 2H), 1.55–1.29 (m, 4H); 13C NMR (100 MHz, CDCl3): δ 167.4, 142.5, 138.2, 133.7, 133.5, 131.5, 130.7, 129.2, 128.5, 127.8, 126.5, 126.3, 126.2, 125.9, 124.4, 74.6, 57.2, 33.9, 31.3, 24.3, 23.8, 21.2; IR (KBr) (cm-1) v 3422, 3303, 3066, 2935, 2863, 1679, 1609, 1534, 1443, 1374, 1330, 1284, 1181, 1088, 1026; HRMS (ESI): m/z [M+Na]+ calcd for C24H25NO4SNa: 446,1402; found: 446.1413.
2-((4-Methylphenyl)sulfonamido)cyclohexyl 3-phenylpropiolate (3av) This compound was obtained as a white solid; Yield: 31.8 mg (40%); mp 149–150 ºC; 1H NMR (400 MHz, CDCl3): δ 7.77 (d, J = 8.4 Hz, 2H), 7.57 (d, J = 7.2 Hz, 2H), 7.48 (t, J = 7.2 Hz, 1H), 7.40 (t, J = 7.6 Hz, 2H), 7.21 (d, J = 8.4 Hz, 2H), 4.89 (d, J = 6.8 Hz, 1H), 4.73 (td, J = 10.0, 4.4 Hz, 1H), 3.33–3.25 (m, 1H), 2.20–2.17 (m, 4H), 2.02–1.99 (m, 1H), 1.73–1.68 (m, 2H), 1.46–1.27 (m, 4H); 13C NMR (100 MHz, CDCl3): δ 153.9, 143.0, 138.3, 133.0, 130.8, 129.6, 128.6, 127.0, 119.6, 87.0, 80.5, 75.8, 56.6, 33.6, 30.8, 24.0, 23.6, 21.2; IR (KBr) (cm-1) v 3386, 3251, 3064, 2939, 2859, 2224, 1706, 1596, 1468, 1360, 1325, 1161, 1023; HRMS (ESI): m/z [M+K]+ calcd for C22H23NO4SK: 436.0985, found: 436.1009.
2-((4-Methylphenyl)sulfonamido)cyclohexyl acetate (3aw)10 This compound was obtained as a white solid; Yield: 37.9 mg (61%); mp 123–125 ºC; 1H NMR (400 MHz, CDCl3): δ 7.75 (d, J = 8.0 Hz, 2H), 7.29 (d, J = 8.0 Hz, 2H), 5.08 (d, J = 7.6 Hz, 1H), 4.56 (td, J = 10.0, 4.4 Hz, 1H), 3.22–3.15 (m, 1H), 2.42 (s, 3H), 2.05–1.90 (m, 2H), 1.78 (s, 3H), 1.70–1.63 (m, 2H), 1.37–1.24 (m, 4H); 13C NMR (100 MHz, CDCl3): δ 171.5, 143.1, 138.6, 129.6, 126.9, 74.1, 56.9, 33.4, 31.1, 24.2, 23.7, 21.5, 21.0; IR (KBr) (cm-1) v 3406, 3245, 2942, 2865, 1715, 1597, 1494, 1454, 1373, 1336, 1259, 1160, 1090, 1039; HRMS (ESI): m/z [M+Na]+ calcd for C15H21NO4SNa: 334.1089; found: 334.1055.
2-((4-Methylphenyl)sulfonamido)cyclohexyl dodecanoate (3ax) This compound was obtained as a white solid; Yield: 67.7 mg (75%); mp 38–39 ºC; 1H NMR (400 MHz, CDCl3): δ 7.75 (d, J = 8.0 Hz, 2H), 7.28 (d, J = 7.2 Hz, 2H), 5.22 (d, J = 7.6 Hz, 1H), 4.60–4.55 (m, 1H), 3.26–3.27 (m, 1H), 2.41 (s, 3H), 2.04–1.91 (m, 5H), 1.69–1.61 (m, 2H), 1.49–1.46 (m, 3H), 1.26 (s, 21H); 13C NMR (100 MHz, CDCl3): δ 174.1, 142.8, 138.9, 129.5, 126.9, 73.8, 56.8, 34.2, 33.2, 31.9, 31.0, 29.6, 29.5, 29.3, 29.3, 29.1, 24.7, 24.2, 23.6, 22.6, 21.4, 14.1; IR (KBr) (cm-1) v 3305, 2923, 2853, 1731, 1455, 1383, 1326, 1304, 1206, 1161, 1090, 1020; HRMS (ESI): m/z [M+Na]+ calcd for C25H41NO4SNa: 474.2654; found: 474.2650.
2-((4-Methylphenyl)sulfonamido)cyclopentyl cinnamate (3ba)7 This compound was obtained as a white solid; Yield: 67.0 mg (87%); mp 125–126 ºC; 1H NMR (400 MHz, CDCl3): δ 7.77 (d, J = 8.0 Hz, 2H), 7.55–7.39 (m, 6H), 7.21 (d, J = 7.6 Hz, 2H), 6.21 (d, J = 16.0 Hz, 1H), 5.70 (d, J = 5.2 Hz, 1H), 5.03–4.98 (m, 1H), 3.62–3.56 (m, 1H), 2.24 (s, 3H), 2.10–2.03 (m, 2H), 1.74–1.52 (m, 4H); 13C NMR (100 MHz, CDCl3): δ 166.9, 145.1, 143.2, 137.5, 134.2, 130.5, 129.6, 129.0, 128.1, 127.2, 117.6, 79.6, 59.9, 31.3, 29.5, 21.4, 20.8; IR (KBr) (cm-1) v 3270, 3059, 2866, 1702, 1630, 1576, 1493, 1449, 1326, 1152, 1088, 1074, 1018, 991; HRMS (ESI): m/z [M+Na]+ calcd for C21H23NO4SNa: 408.1245; found: 408.1248.
2-((4-Methylphenyl)sulfonamido)cyclopentyl benzoate (3bj) This compound was obtained as a white solid; Yield: 61.0 mg (85%); mp 147–148 ºC; 1H NMR (400 MHz, CDCl3): δ 7.85 (d, J = 8.4 Hz, 2H), 7.70 (d, J = 8.0 Hz, 2H), 7.56 (t, J = 7.6 Hz, 1H), 7.41 (t, J = 8.0 Hz, 2H), 7.08 (d, J = 8.0 Hz, 2H), 5.32–5.28 (m, 1H), 5.11–5.06 (m, 1H), 3.63–3.57 (m, 1H), 2.23–2.08 (m, 5H), 1.74–1.59 (m, 4H); 13C NMR (100 MHz, CDCl3): δ 166.6, 143.2, 137.0, 133.2, 129.6, 128.3, 127.1, 80.0, 77.4, 77.1, 76.7, 60.1, 31.6, 29.5, 21.4, 20; IR (KBr) (cm-1) v 3321, 2961, 2927, 2870, 1712, 1599, 1450, 1358, 1322, 1274, 1151, 1113, 1091, 1070, 1029; HRMS (ESI): m/z [M+Na]+ calcd for C19H21NO4SNa: 382.1089; found: 382.1074.
2-((4-Methylphenyl)sulfonamido)-2-phenylethyl cinnamate (3ca) / 2-((4-methylphenyl)- sulfonamido)-1-phenylethyl cinnamate (3ca') These compounds were obtained as mixture white solid; Yield: 74.9 mg (89%, 3ca/3ca' = 80/20); mp 106–108 ºC; 1H NMR (400 MHz, CDCl3): δ 7.73 (d, J = 8.0 Hz, 0.4H), 7.64–7.21 (m, 13H), 7.06 (d, J = 7.6 Hz, 1.6H), 6.36 (d, J = 16.0 Hz, 0.2H), 6.21 (d, J = 16.0 Hz, 0.8H), 6.09–6.08 (m, 0.8H), 5.88–5.85 (m, 0.2H), 5.55–5.52 (m, 0.2H), 4.74–4.69 (m, 0.8H), 4.36–4.24 (m, 1.6H), 3.43–3.38 (m, 0.4H), 2.33 (s, 0.6H), 2.20 (s, 2.4H); 13C NMR (100 MHz, CDCl3): δ 166.6, 165.9, 145.7, 145.6, 143.4, 143.1, 137.8, 137.5, 137.3, 134.2, 130.5, 129.7, 129.4, 128.9, 128.7, 128.6, 128.2, 128.0, 127.1, 126.9, 126.4, 117.5, 117.2, 74.3, 66.6, 57.2, 47.9, 21.4, 21.3; IR (KBr) (cm-1) v 3446, 3258, 3063, 3030, 2922, 1719, 1698, 1638, 1495, 1450, 1331, 1283, 1205, 1161, 1091, 1021; HRMS (ESI): m/z [M+Na]+ calcd for C24H23NO4SNa: 444.1245; found: 444.1256.
2-((4-Methylphenyl)sulfonamido)-2-phenylethyl benzoate (3cj) / 2-((4-methylphenyl)- sulfonamido)-1-phenylethyl benzoate (3cj') These compounds were obtained as mixture white solid; Yield: 52.9 mg (67%, 3cj/3cj' = 70/30); mp 160–162 ºC; 1H NMR (400 MHz, CDCl3): δ 8.00 (d, J = 7.2 Hz, 0.6H), 7.87 (d, J = 7.2 Hz, 1.4H), 7.70 (d, J = 8.4 Hz, 0.6H), 7.59–7.22 (m, 10H), 7.02 (d, J = 8.0 Hz, 1.4H), 5.97–5.94 (m, 0.3H), 5.47–5.44 (m, 0.7H), 4.91–4.86 (m, 0.3H), 4.77–4.73 (m, 0.7H), 4.49–4.35 (m, 1.4H), 3.54–3.47 (m, 0.6H), 2.38 (s, 0.9H), 2.27 (s, 2.1H); 13C NMR (100 MHz, CDCl3): δ 166.4, 165.6, 143.6, 143.2, 137.3, 137.2, 133.4, 133.4, 129.8, 129.8, 129.7, 129.5, 129.2, 128.9, 128.7, 128.5, 128.4, 128.2, 127.0, 127.0, 126.9, 126.4, 74.6, 67.0, 57.2, 47.9, 21.6, 21.5; IR (KBr) (cm-1) v 3437, 3343, 3062, 2924, 1709, 1600, 1495, 1434, 1322, 1278, 1157, 1128, 1090, 1026; HRMS (ESI): m/z [M+Na]+ calcd for C22H21NO4SNa: 418.1089; found: 418.1070.
2-((4-Methylphenyl)sulfonamido)-2-(p-tolyl)ethyl cinnamate (3da) / 2-((4-methylphenyl)- sulfonamido)-1-(p-tolyl)ethyl cinnamate (3da')7 These compounds were obtained as mixture white solid; Yield: 78.3 mg (90%, 3da/3da' = 70/30); mp 128–130 ºC; 1H NMR (400 MHz, CDCl3): δ 7.73 (d, J = 8.0 Hz, 0.6H), 7.63–7.08 (m, 12H), 7.02 (d, J = 8.0 Hz, 1.4H), 6.34 (d, J = 16.0 Hz, 0.3H), 6.21 (d, J = 16.0 Hz, 0.7H), 5.88–5.80 (m, 1H), 5.39–5.31 (m, 0.3H), 4.68–4.64 (m, 0.7H), 4.36–4.23 (m, 1.4H), 3.46–3.33 (m, 0.6H), 2.34 (s, 0.9H), 2.30 (s, 0.9H), 2.27 (s, 2.1H), 2.22 (s, 2.1H); 13C NMR (100 MHz, CDCl3): δ 166.8, 166.1, 145.7, 145.6, 143.5, 143.1, 138.5, 137.8, 137.6, 137.0, 134.4, 134.2, 134.2, 134.1, 130.6, 130.5, 129.8, 129.4, 129.3, 128.9, 128.9, 128.2, 127.1, 127.1, 126.9, 126.4, 117.4, 117.1, 74.3, 66.7, 56.9, 47.9, 21.5, 21.4, 21.2, 21.1; IR (KBr) (cm-1) v 3312, 3061, 3027, 2955, 2922, 1698, 1634, 1598, 1578, 1516, 1496, 1450, 1384, 1330, 1285, 1156, 1118, 1089, 1017, 982; HRMS (ESI): m/z [M+Na]+ calcd for C25H25NO4SNa: 458.1402; found: 458.1411.
2-((4-Methylphenyl)sulfonamido)-2-(p-tolyl)ethyl benzoate (3dj) / 2-((4-methylphenyl)- sulfonamido)-1-(p-tolyl)ethyl benzoate (3dj')7 These compounds were obtained as mixture pale yellow solid; Yield: 66.3 mg (81%, 3dj/3dj' = 70/30); mp 151–154 ºC; 1H NMR (400 MHz, CDCl3): δ 7.97 (d, J = 7.2 Hz, 0.6H), 7.88–7.85 (m, 1.4H), 7.70 (d, J = 8.0 Hz, 0.6H), 7.59–6.98 (m, 10.4H), 5.95–5.91 (m, 0.3H), 5.87 (d, J = 6.8 Hz, 0.7H), 5.31 (t, J = 6.8 Hz, 0.3H), 4.73–4.68 (m, 0.7H), 4.45–4.33 (m, 1.4H), 3.53–3.38 (m, 0.6H), 2.35 (s, 0.9H), 2.29 (s, 0.9H), 2.27 (s, 2.1H), 2.25 (s, 2.1H); 13C NMR (100 MHz, CDCl3): δ 166.4, 165.7, 143.4, 143.1, 138.5, 137.8, 137.4, 137.1, 134.4, 134.2, 133.2, 129.8, 129.5, 129.4, 129.3, 128.4, 128.3, 127.0, 126.8, 126.4, 74.7, 67.1, 56.9, 47.9, 21.5, 21.4, 21.2, 21.1; IR (KBr) (cm-1) v 3332, 3030, 2956, 2921, 1712, 1599, 1515, 1494, 1449, 1384, 1321, 1270, 1152, 1122, 1090, 1019, 996; HRMS (ESI): m/z [M+Na]+ calcd for C23H23NO4SNa: 432.1245; found: 432.1264.
2-(4-Chlorophenyl)-2-((4-methylphenyl)sulfonamido)ethyl cinnamate (3ea) / 1-(4-chlorophenyl)-2- ((4-methylphenyl)sulfonamido)ethyl cinnamate (3ea')7 These compounds were obtained as mixture white solid; Yield: 65.5 mg (72%, 3ea/3ea' = 80/20); mp 160–163 ºC; 1H NMR (400 MHz, CDCl3): δ 7.70 (d, J = 8.0 Hz, 0.4H), 7.66–7.14 (m, 12H), 7.11 (d, J = 8.0 Hz, 1.6H), 6.36 (d, J = 16.0 Hz, 0.2H), 6.22 (d, J = 16.0 Hz, 0.8H), 5.95–5.88 (m, 0.8H), 5.82 (t, J = 6.0 Hz, 0.2H), 5.38–5.31 (m, 0.2H), 4.70–4.64 (m, 0.8H), 4.34–4.21 (m, 1.6H), 3.43–3.34 (m, 0.4H), 2.37 (s, 0.6H), 2.25 (s, 2.4H); 13C NMR (100 MHz, CDCl3): δ 166.6, 145.9, 143.4, 137.4, 135.9, 134.1, 134.0, 130.6, 129.8, 129.5, 128.9, 128.8, 128.4, 128.2, 127.8, 127.1, 127.0, 116.8, 66.3, 56.6, 21.3; IR (KBr) (cm-1) v 3442, 3271, 2924, 1717, 1707, 1636, 1599, 1494, 1450, 1319, 1170, 1156, 1091, 1014, 980; HRMS (ESI): m/z [M+Na]+ calcd for C24H22NO4SClNa: 478.0856; found: 478.0861.
2-(4-Chlorophenyl)-2-((4-methylphenyl)sulfonamido)ethyl benzoate (3ej) / 1-(4-chlorophenyl)- 2-((4-methylphenyl)sulfonamido)ethyl benzoate (3ej')7 These compounds were obtained as mixture white solid; Yield: 71.2 mg (83%, 3ej/3ej' = 84/16); mp 155–156 ºC; 1H NMR (400 MHz, CDCl3): δ 7.98 (d, J = 7.2 Hz, 0.32H), 7.86 (d, J = 7.2 Hz, 1.68H), 7.68 (d, J = 8.4 Hz, 0.32H), 7.59–7.18 (m, 9H), 7.02 (d, J = 7.2 Hz, 1.68H), 5.95–5.92 (m, 0.16H), 5.72 (d, J = 6.8 Hz, 0.84H), 5.10 (t, J = 6.4 Hz, 0.16H), 4.74–4.69 (m, 0.84H), 4.44–4.32 (m, 1.68H), 3.49–3.44 (m, 0.32H), 2.39 (s, 0.48H), 2.28 (s, 2.52H); 13C NMR (100 MHz, CDCl3): δ 166.3, 143.5, 137.0, 135.8, 135.6, 134.0, 133.5, 133.4, 129.8, 129.8, 129.7, 129.5, 129.1, 129.0, 128.8, 128.5, 128.4, 128.3, 127.8, 126.9, 74.1, 66.7, 56.6, 47.7, 21.6, 21.5; IR (KBr) (cm-1) v 3429, 3272, 2955, 2923, 1721, 1697, 1599, 1491, 1441, 1385, 1330, 1269, 1156, 1123, 1092, 1071, 1027, 1015, 989; HRMS (ESI): m/z [M+Na]+ calcd for C22H20NO4SClNa: 452.0699; found: 452.0672.
2-((4-Methylphenyl)sulfonamido)-2-(4-nitrophenyl)ethyl cinnamate (3fa) / 2-((4-methylphenyl)- sulfonamido)-1-(4-nitrophenyl)ethyl cinnamate (3fa') These compounds were obtained as mixture pale yellow solid; Yield: 25.2 mg (27%, 3fa/3fa' = 55/45); mp 139–142 ºC; 1H NMR (400 MHz, CDCl3): δ 8.16–8.09 (m, 2.0H), 7.70–7.24 (m, 10.9H), 7.13 (d, J = 8.0 Hz, 1.1H), 6.41 (d, J = 16.0 Hz, 0.45H), 6.21 (d, J = 16.0 Hz, 0.55H), 6.15–6.02 (m, 0.55H), 5.94 (t, J = 5.6 Hz, 0.45H), 5.47–5.34 (m, 0.45H), 4.80–4.77 (m, 0.55H), 4.37–4.22(m, 1.1H), 3.63–3.44 (m, 0.9H), 2.37 (s, 1.35H), 2.24 (s, 1.65H); 13C NMR (100 MHz, CDCl3): δ 166.6, 165.6, 147.8, 147.6, 146.7, 146.4, 144.7, 144.4, 143.9, 136.9, 136.8, 133.8, 130.9, 129.9, 129.7, 129.0, 129.0, 128.3, 128.3, 128.0, 127.3, 127.0, 127.0, 123.9, 123.8, 116.5, 116.3, 73.5, 65.9, 56.8, 47.5, 21.5, 21.4; IR (KBr) (cm-1) v 3447, 3273, 2923, 2853, 1709, 1636, 1600, 1520, 1450, 1347, 1332, 1204, 1164, 1090, 1018, 982; HRMS (ESI): m/z [M+Na]+ calcd for C24H22N2O6SNa: 489.1096; found: 489.1107.
2-((4-Methylphenyl)sulfonamido)-2-(4-nitrophenyl)ethyl benzoate (3fj) / 2-((4-methylphenyl)- sulfonamido)-1-(4-nitrophenyl)ethyl benzoate (3fj') These compounds were obtained as mixture pale yellow solid; Yield: 20.2 mg (23%, 3fj/3fj' = 67/33); mp 139–142 ºC; 1H NMR (400 MHz, CDCl3): δ 8.16–8.10 (m, 2.0H), 8.01 (d, J = 7.6 Hz, 0.66H), 7.84 (d, J = 7.6 Hz, 1.34H), 7.68–7.38 (m, 7.0H), 7.21 (d, J = 8.0 Hz, 0.66H), 7.03 (d, J = 8.0 Hz, 1.34H), 6.11–6.05 (m, 1H), 5.45–5.30 (m, 0.33H), 4.85–4.82 (m, 0.67H), 4.47–4.37 (m, 1.34H), 3.52–3.44 (m, 0.66H), 2.38 (s, 0.99H), 2.27 (s, 2.01H); 13C NMR (100 MHz, CDCl3): δ 166.3, 165.3, 147.9, 147.6, 144.7, 144.3, 143.9, 143.8, 136.7, 133.8, 133.6, 129.8, 129.8, 129.7, 129.6, 128.9, 128.8, 128.6, 128.5, 128.0, 127.3, 126.9, 124.0, 123.9, 73.9, 66.4, 56.8, 47.5, 21.5, 21.5; IR (KBr) (cm-1) v 3436, 3276, 3066, 2924, 2853, 1714, 1600, 1520, 1451, 1439, 1348, 1271, 1158, 1090, 1027; HRMS (ESI): m/z [M+Na]+ calcd for C22H20N2O6SNa: 463.0940; found: 463.0941.
2-((4-Methylphenyl)sulfonamido)hexyl cinnamate (3ga) This compound was obtained as a white solid; Yield: 56.9 mg (71%); mp 105–106 ºC; 1H NMR (400 MHz, CDCl3): δ 7.78 (d, J = 8.0 Hz, 2H), 7.60 (d, J = 16.0 Hz, 1H), 7.48–7.46 (m, 2H), 7.38–7.37 (m, 3H), 7.23 (d, J = 8.0 Hz, 2H), 6.23 (d, J = 16.0 Hz, 1H), 5.43 (d, J = 8.4 Hz, 1H), 4.15–4.00 (m, 2H), 3.58–3.50 (m, 1H), 2.29 (s, 3H), 1.54–1.47 (m, 2H), 1.26–1.20 (m, 4H), 0.81 (t, J = 6.8 Hz, 3H); 13C NMR (100 MHz, CDCl3): δ 166.7, 145.3, 143.2, 138.4, 134.3, 130.4, 129.6, 128.9, 128.1, 127.0, 117.4, 65.8, 53.2, 32.2, 27.5, 22.3, 21.3, 13.7; IR (KBr) (cm-1) v 3320, 2956, 2853, 1704, 1634, 1579, 1499, 1453, 1430, 1389, 1317, 1286, 1187, 1159, 1142, 1093, 1008, 983; HRMS (ESI): m/z [M+Na]+ calcd for C22H27NO4SNa: 424.1558; found: 424.1580.
2-((4-Methylphenyl)sulfonamido)hexyl benzoate (3gj) This compound was obtained as a white solid; Yield: 49.5 mg (66%); mp 104–106 ºC; 1H NMR (400 MHz, CDCl3): δ 7.91 (d, J = 7.6 Hz, 2H), 7.74 (d, J = 8.0 Hz, 2H), 7.55 (t, J = 7.6 Hz, 1H), 7.40 (t, J = 8.0 Hz, 2H), 7.16 (d, J = 8.0 Hz, 2H), 5.19 (d, J = 8.0, 1H), 4.27–4.11 (m, 2H), 3.64–3.56 (m, 1H), 2.32 (s, 3H), 1.60–1.51 (m, 2H), 1.30–1.20 (m, 4H), 0.80 (t, J = 6.8 Hz, 3H); 13C NMR (100 MHz, CDCl3): δ 166.4, 143.3, 137.9, 133.2, 129.7, 129.6, 129.5, 128.4, 126.9, 66.2, 53.1, 32.3, 27.6, 22.3, 21.5, 13.9; IR (KBr) (cm-1) v 3406, 3299, 2933, 2858, 1709, 1601, 1495, 1452, 1428, 1395, 1325, 1280, 1164, 1114, 1092, 1044, 1028, 971; HRMS (ESI): m/z [M+Na]+ calcd for C20H25NO4SNa: 398.1402; found: 398.1412.

ACKNOWLEDGEMENTS
We are grateful to the National Natural Science Foundation of China (grant no. 21162012 and 21362014), Jiangxi Provincial Department of Science and Technoloy (for Jiangxi’s Key Laboratory of Green Chemistry, and no. 20122BAB203007), and the Science Foundation of Education Department of Jiangxi provice (grant no. GJJ10386 and GJJ12616) for their financial supported.

References

1. For some reviews of syntheses and reactions of activated and unactivated aziridines, see: (a) M. Kasai and M. Kono, Synlett, 1992, 778; CrossRef (b) D. Tanner, Angew. Chem., Int. Ed. Engl., 1994, 33, 599; CrossRef (c) H. M. L. Osborn and J. Sweeney, Tetrahedron: Asymmetry, 1997, 8, 1693; CrossRef (d) C. M. Rayner, Synlett, 1997, 11; CrossRef (e) T. Ibuka, Chem. Soc. Rev., 1998, 27, 145; CrossRef (f) A. H. Li, L. X. Dai, and V. K. Aggarwal, Chem. Rev., 1997, 97, 2341; CrossRef (g) H. J. Stamm, Prakt. Chem., 1999, 319; (h) M. McCoull and F. A. Davis, Synthesis, 2000, 1347. CrossRef
2. (a) A. Dureault, I. Tranchepain, and J. C. Depezay, J. Org. Chem., 1989, 54, 5324; CrossRef (b) D. Tanner and H. M. He, Tetrahedron, 1992, 48, 6079. CrossRef
3. T. Hudlicky, H. Luna, J. D. Price, and F. J. Rulin, J. Org. Chem., 1990, 55, 4683. CrossRef
4. (a) X. L. Hou, R. H. Fan, and L. X. Dai, J. Org. Chem., 2002, 67, 5295; CrossRef (b) X. L. Hou and R. H. Fan, J. Org. Chem., 2003, 68, 726; CrossRef (c) Z. B. Lou, X. L. Hou, and L. X. Dai, Tetrahedron: Asymmetry, 2007, 18, 443; CrossRef (d) R. H. Fan, Y. G. Zhou, W. H. Zhang, X. L. Hou, and L. X. Dai, J. Org. Chem., 2004, 69, 335; CrossRef (e) Y. Y. Peng, M. Yang, and Q. Yang, Chin. J. Chem., 2011, 29, 499; CrossRef (f) J. Wu, X. Y. Sun, and Y. Z. Li, Eur. J. Org. Chem., 2005, 4271; CrossRef (g) J. Wu, X. Y. Sun, and W. Sun, Org. Biomol. Chem., 2006, 4, 4231; CrossRef (h) C. Benoît, N. Satoru, B. D. Danièle, and J. P. Bégué, Synlett, 2001, 679. CrossRef
5. (a) H. Stamm and T. Baumnn, Pharmazie, 1997, 52, 441; (b) P. Muller and P. Nury, Org. Lett., 1999, 1, 439; CrossRef (c) Z. Li, M. Fernandez, and E. N. Jacobsen, Org. Lett., 1999, 1, 1611; CrossRef (d) W. Y. Lee, J. M. Salvador, and K. Bodige, Org. Lett., 2000, 2, 931; CrossRef (e) M. Nakagawa and M. Kawahara, Org. Lett., 2000, 2, 953. CrossRef
6. (a) J. Wu, X. Y. Sun, and S. Q. Ye, Eur. J. Org. Chem., 2006, 4787; (b) Y. Y. Peng, Q. Yang, Z. L. Yin, and M. Yang, Chin. J. Chem., 2011, 29, 79. CrossRef
7. J. S. Yadav, B. V. S. Reddy, K. Sadashiv, and K. Harikishab, Tetrahedron Lett., 2002, 43, 2099. CrossRef
8. (a) X. Li, G. Li, H. Chang, Y. Zhang, and W. We, RSC Adv., 2014, 4, 6490; (b) F. Zhang, H. Chamg, and W. Wei, J. Heterocycl. Chem., 2015, 52, 284. CrossRef
9. (a) J. Wu, X. L. Hou, and L. X. Dai, J. Chem. Soc., Perkin Trans. 1, 2001, 1314; CrossRef (b) G. Sekar and Singh, J. Org. Chem., 1999, 64, 2537. CrossRef
10. Y. K. Liu, R. Li, L. Yue, B. J. Li, Y. C. Chen, Y. Wu, and L. S. Ding, Org. Lett., 2006, 8, 1521. CrossRef