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RSC Advances
3024, 2941, 1728 (CLO), 1611, 1531, 1495, 1218, 1024, 828, 753,
686; 1H NMR (400 MHz, DMSO-d6): d = 1.96 (ddd, J = 11.2, 8.6,
3.2 Hz, 1 H, H-39), 2.17 (ddd, J = 12.8, 8.8, 3.2 Hz, 1 H, H-3),
2.64 (m, 1 H, H-3a), 3.61 (dd, J = 9.0, 3.2 Hz, 1 H, H-2), 3.68 (s, 3
H, OCH3), 3.86 (d, J = 13.2 Hz, 1 H, one of NCH2Ph), 4.02 (dd, J
= 10.4, 4.2 Hz, 1 H, one of H-4), 4.11 (dd, J = 9.2, 3.2 Hz, 1 H,
the other of H-4), 4.34 (d, J = 13.2 Hz, 1 H, the other of
NCH2Ph), 4.41 (d, J = 5.6 Hz, 1 H, H-9b), 4.64 (s, 2 H, NH2),
6.48–7.28 (m, 8 H, Ar–H); 13C NMR (100 MHz, DMSO-d6): d =
29.86 (C-3), 33.94 (C-3a), 51.04 (NCH2Ph), 57.16 (C-2), 58.96 (C-
9b), 63.24 (OCH3), 67.31 (C-4), 116.12, 117.32, 117.51, 122.27,
127.32, 128.13, 128.54, 140.28, 142.61, 146.81 (arom.), 173.72
(CLO); MS (ESI): m/z: 339.2 [M + H]+, Anal. calcd for
C20H22N2O3: C, 70.99; H, 6.55; N, 8.28; Found: C, 71.15; H,
6.73; N, 8.41.
(2R,3aS,9bR)-ethyl-8-amino-1-benzyl-1,2,3,3a,4,9b-hexahy-
drochromeno[4,3-b]pyrrole-2-carboxylate (9b). Brown Solid,
yield 67%, 0.570 g, mp = 88–90 uC IR (KBr): n = 3432, 3305,
3018, 2946, 1732 (CLO), 1608, 1535, 1491, 1214, 1020, 822, 761,
749, 689; 1H NMR (400 MHz, DMSO-d6): d = 1.16 (t, J = 7.2 Hz, 3
H, OCH2CH3), 1.87 (ddd, J = 7.2, 5.0, 4.0 Hz, 1 H, H-39), 2.00
(ddd, J = 11.6, 9.2, 3.2 Hz, 1 H, H-3), 2.70 (m, 1 H, H-3a), 3.40
(dd, J = 8.8, 3.2 Hz, 1 H, H-2), 3.69 (d, J = 13.6 Hz, 1 H, one of
NCH2Ph), 3.81 (dd, J = 18.2, 10.4 Hz, 1 H, one of H-4), 3.86 (dd,
J = 10.8, 4.8 Hz, 1 H, the other of H-4), 4.06 (m, 1 H, H-9b and 2
H of OCH2CH3), 4.19 (d, J = 13.6 Hz, 1 H, the other of
NCH2Ph), 4.65 (s, 2 H, NH2), 6.45–7.27 (m, 8 H, Ar–H); 13C
NMR (100 MHz, DMSO-d6): d = 14.63 (OCH2CH3), 30.21 (C-3),
35.25 (C-3a), 51.22 (NCH2Ph), 58.21 (C-2), 59.55 (C-9b), 60.18
(OCH2CH3), 67.70 (C-4), 115.57, 117.19, 117.29, 122.61, 127.32,
128.45, 128.64, 139.39, 142.10, 146.93, (arom.), 173.85 (CLO);
MS (ESI): m/z: 352.8 [M + H]+, Anal. calcd C21H24N2O3: C, 71.57;
H, 6.86; N, 7.95; Found: C, 71.46; H, 6.98; N, 8.02.
2.18 (ddd, J = 11.8, 7.9, 2.8 Hz, 1 H, H-3), 2.69 (m, 1 H, H-3a),
3.61 (dd, J = 9.0, 3.6 Hz, 1 H, H-2), 3.88 (d, J = 13.2 Hz, 1 H, one
of NCH2Ph), 4.12 (m, 2 H of H-4 and 2 H of OCH2 (CH2)2CH3),
*
4.32 (d, J = 13.2 Hz, 1 H, the other of NCH2Ph), 4.42 (d, J = 5.6
Hz, 1 H, H-9b), 4.63 (s, 2 H, NH2), 6.47–7.24 (m, 8 H, Ar–H); 13
C
NMR (100 MHz, DMSO-d6): d = 13.09 (O(CH2)3CH3), 18.74
*
(O(CH2)2CH2CH3), 30.18 (OCH2CH2 CH2CH3), 30.81 (C-3),
33.89 (C-3a), 50.41 (NCH2Ph), 57.24 (C-2), 59.12 (C-9b), 65.17
*
(C-4), 67.68 (OCH2 (CH2)2CH3), 116.72, 117.26, 117.68, 122.51,
127.43, 128.74, 129.12, 139.15, 142.31, 146.72, (arom.), 173.46
(CLO); MS (ESI): m/z: 381.2 [M + H]+, Anal. calcd for
C23H28N2O3: C, 72.60; H, 7.42; N, 7.36; Found: C, 72.78; H,
7.26; N, 7.19.
(2R,3aS,9bR)-methyl-8-amino-1-methyl-1,2,3,3a,4,9b-hexahy-
drochromeno[4,3-b]pyrrole-2-carboxylate (11a). Brown Solid;
yield 66%, 0.418 g; mp 92–94 uC; IR (KBr): n = 3435, 3309, 3036,
2961, 1731 (CLO), 1614, 1530, 1491, 1218, 1029, 830, 763, 764,
694; 1H NMR (400 MHz, DMSO-d6): d = 1.98 (ddd, J = 11.6, 9.2,
3.2 Hz, 1 H, H-39), 2.26 (ddd, J = 11.6, 9.0, 3.2 Hz, 1 H, H-3),
2.55 (s, 3 H, NCH3) 2.70 (m, 1 H, H-3a), 3.77 (s, 3 H, OCH3),
3.81 (dd, J = 8.8, 3.2 Hz, 1 H, H-2), 4.03(m, 2 H, H-4), 4.11 (d, J =
6.0 Hz, 1 H, H-9b), 4.64 (s, 2 H, NH2), 6.51–6.97 (m, 3 H, Ar–H);
13C NMR (100 MHz, DMSO-d6): d = 30.13 (C-3), 34.32 (C-3a),
34.76 (NCH3), 51.15 (C-2), 58.57 (C-9b), 63.45 (OCH3), 68.14 (C-
4), 115.76, 117.53, 122.35, 139.27, 142.21, 145.97 (arom.),
173.38 (CLO); MS (ESI): m/z: 263.1 [M + H]+, Anal. calcd for
C14H18N2O3: C, 64.10; H, 6.92; N, 10.68; Found: C, 64.29; H,
7.12; N, 10.79.
(2R,3aS,9bR)-ethyl-8-amino-1-methyl-1,2,3,3a,4,9b-hexahy-
drochromeno[4,3-b]pyrrole-2-carboxylate (11b). Brown Solid;
yield 62%, 0.413 g; mp 101–103 uC; IR (KBr): n = 3429, 3313,
3028, 2951, 1728 (CLO), 1614, 1534, 1493, 1224, 1025, 819,756,
690; 1H NMR (400 MHz, DMSO-d6): d = 1.35 (t, J = 7.6 Hz, 3 H,
OCH2CH3), 2.03 (ddd, J = 11.8, 9.4, 3.2 Hz, 1 H, H-39), 2.28
(ddd, J = 11.2, 9.0, 3.2 Hz, 1 H, H-3), 2.60 (s, 3 H, NCH3), 2.74
(m, 1 H, H-3a), 3.82 (d, J = 8.4, 3.0 Hz, 1 H, H-2), 4.07 (m, 2 H,
H-4), 4.18 (d, J = 4.8 Hz, 1 H, H-9b), 4.26 (dq, J = 7.6, 2.0 Hz, 2H,
OCH2CH3), 4.65 (s, 2 H, NH2), 6.59–6.88 (m, 3 H, Ar–H); 13C
NMR (100 MHz, DMSO-d6): d = 14.34 (OCH2CH3), 30.71 (C-3),
34.42 (C-3a), 34.68 (NCH3), 58.56 (C-2), 60.65 (C-9b), 63.69
(OCH2CH3), 67.81 (C-4), 116.15, 117.74 123.61, 138.92, 142.41,
145.65 (arom.), 173.58 (CLO); MS (ESI): m/z: 277.2 [M + H]+,
Anal. calcd for C15H20N2O3: C, 65.20; H, 7.30; N, 10.14; Found:
C, 65.01; H, 7.52; N, 10.32.
(2R,3aS,9bR)-propyl-8-amino-1-benzyl-1,2,3,3a,4,9b-hexahy-
drochromeno[4,3-b]pyrrole-2-carboxylate (9c). Brown Solid,
yield 62%, 0.548 g; mp 85–87 uC; IR (KBr): n = 3438, 3312,
3027, 2951, 1729 (CLO), 1612, 1529, 1494, 1209, 1028, 816, 763,
753, 691; 1H NMR (400 MHz, DMSO-d6): d = 0.94 (t, J = 7.6 Hz, 3
*
H, O(CH2)2CH3), 1.63 (m, 2 H, OCH2CH2 CH3), 1.95 (ddd, J =
11.8, 9.2, 3.2 Hz, 1 H, H-39), 2.16 (ddd, J = 11.2, 8.6, 3.2 Hz, 1 H,
H-3), 2.71 (m, 1 H, H-3a), 3.62 (dd, J = 8.8, 3.2 Hz, 1 H, H-2),
3.90 (d, J = 13.2 Hz, 1 H, one of NCH2Ph), 4.10 (m, 2 H of H-4
*
and 2 H of OCH2 CH2CH3), 4.31 (d, J = 13.2 Hz, 1 H, the other
of NCH2Ph), 4.42 (d, J = 5.6 Hz, 1 H, H-9b), 4.65 (s, 2 H, NH2),
6.51–7.26 (m, 8 H, Ar–H); 13C NMR (100 MHz, DMSO-d6): d =
(2R,3aS,9bR)-propyl-8-amino-1-methyl-1,2,3,3a,4,9b-hexahy-
drochromeno[4,3-b]pyrrole-2-carboxylate (11c). Brown Solid;
yield 68%, 0.477 g; mp 89–91 uC; IR (KBr): n = 3434, 3317, 3022,
2958, 1730 (CLO), 1614, 1559, 1495, 1221, 1023, 824, 763, 679;
1H NMR (400 MHz, DMSO-d6): d = 0.99 (t, J = 7.6 Hz, 3 H,
*
10.16 (O(CH2)2CH3), 21.42 (OCH2CH2 CH3), 29.36 (C-3), 33.83
(C-3a), 50.21 (NCH2Ph), 57.43 (C-2), 58.65 (C-9b), 65.26 (C-4),
*
67.14 (OCH2 CH2CH3), 116.23, 117.41, 117.62, 122.53, 127.61,
128.42, 128.67, 139.11, 142.26, 146.58, (arom.), 172.97 (CLO);
MS (ESI): m/z: 367.2 [M + H]+, Anal. calcd for C22H26N2O3: C,
72.11; H, 7.15; N, 7.64; Found: C, 72.27; H, 7.31; N, 7.81.
(2R,3aS,9bR)-butyl-8-amino-1-benzyl-1,2,3,3a,4,9b-hexahy-
drochromeno[4,3-b]pyrrole-2-carboxylate (9d). Brown Solid,
yield 64%, 0.588 g; mp 78–80 uC; IR (KBr): n = 3431, 3315,
3024, 2948, 1735 (CLO), 1610, 1526, 1496, 1213, 1032, 823, 761,
748, 685; 1H NMR (400 MHz, DMSO-d6): d = 1.03 (t, J = 7.6 Hz, 3
H, O(CH2)3CH3), 1.39 (m, 2 H, O(CH2)2CH2CH3), 1.64 (m, 2 H,
*
O(CH2)2CH3), 1.72 (m, 2 H, OCH2CH2 CH3), 2.00 (ddd, J = 11.6,
9.2, 3.2 Hz, 1 H, H-39), 2.24 (ddd, J = 11.2, 8.8, 3.2 Hz, 1 H, H-3),
2.62 (s, 3 H, NCH3), 2.78 (m, 1 H, H-3a), 3.96 (dd, J = 8.4, 2.8
*
Hz, 1 H, H-2), 4.12 (m, 2 H of H-4 and 2 H of OCH2 CH2CH3),
4.25 (d, J = 5.6 Hz, 1 H, H-9b), 4.66 (s, 2 H, NH2), 6.56–6.89 (m,
3 H, Ar–H); 13C NMR (100 MHz, DMSO-d6): d = 10.23
*
(O(CH2)2CH3), 22.26 (OCH2CH2 CH3), 29.72 (C-3), 34.71 (C-
3a), 35.07 (NCH3), 57.92 (C-2), 59.46 (C-9b), 65.75 (C-4), 68.03
*
*
OCH2CH2 CH2CH3), 1.93 (ddd, J = 12.8, 8.6, 3.2 Hz, 1 H, H-39),
(OCH2 CH2CH3), 115.87, 118.14, 122.64, 138.56, 142.28, 145.37
RSC Adv.
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