Synthesis of 6-(4-Chlorophenyl)-2,2-dimethyl-7-phenyl-2,3-dihydro-1H-pyrrolizine
1019
(E)-N-(2,2-Dimethyl-5-phenylpent-4-yn-1-ylidene)benzylamine (19a). Colorless oil. 1H NMR
(CDCl3): 1.26 (s, 6 H, 2 × CH3), 2.57 (s, 2 H, CH2), 4.62 (s, 2 H, CH2), 7.19–7.38 (m , 10 H,
Ar), 7.75–7.79 (m , 1 H, Ar). 13C NMR (CDCl3): 21.5, 24.9, 30.9, 39.8, 64.7, 82.8, 87.5, 124.0,
126.9, 127.7, 127.8, 128.3, 128.5, 131.7, 139.6, 171.5. ATR-IR: ν(CH) 3029, ν(CH) 2964,
ν(CH) 2826, ν(C≡C) 2225, ν(C=N) 1666, ν(C=C) 1490, δ(CH)Ar 755. FT-Ram an : ν(CH) 3061,
ν(CH) 2904, ν(C≡C) 2221, ν(C=N) 1667, ν(C=C) 1598, δ(CH) 1258, δ(CH)Ar 1002. UV (EtOH),
λm ax (log ε): 204 (4.60), 240 (4.35), 250 (4.30). HRMS, m/z: calculated for C20H22N (M + H)
276.1752, foun d 276.1746. EI MS (m/z, %): 276.1 (M+, 95), 234.2 (25), 161.4 (20), 91.2 (100).
(E)-N-(2,2-Dimethyl-5-phenylpent-4-ynylidene)-4-chlorobenzylamine (19b ). Yellowish oil.
1H NMR (CDCl3): 1.28 (s, 6 H, 2 × CH3), 2.57 (s, 2 H, CH2), 4.58 (s, 2 H, CH2), 7.21 (s, 4 H,
Ar), 7.26–7.39 (m , 5 H, Ar), 7.75–7.78 (m , 1 H, Ar). 13C NMR (CDCl3): 24.9, 30.8, 39.8, 63.9,
82.9, 87.39, 123.9, 127.8, 128.3, 128.6, 129.1, 131.7, 132.6, 138.1, 171.8. ATR-IR: ν(CH)
2961, ν(CH) 2826, ν(C≡C) 2223, ν(C=N) 1665, ν(C=C) 1189, ν(CCl) 1088, ν(CCl) 1014,
δ(CC)Ar 755. FT-Ram an : ν(CH) 3060, 2907, ν(C≡C) 2221, ν(C=N) 1666, ν(C=C) 1596, δ(CH)
1061, ν(CCl) 1089, δ(CH)Ar 1001. UV (EtOH), λm ax (log ε): 204 (4.48), 224 (4.24), 240 (4.27).
HRMS, m/z: calculated for C20H21ClN (M + H) 310.1363, foun d 310.1356. EI MS (m/z, %):
310.4 (M + H+, 65), 268.3 (15), 184.1 (10), 124.9 (100).
(E)-N-(2,2-Dimethyl-5-phenylpent-4-ynylidene)-4-methoxybenzylamine (19c). Yellowish oil.
1H NMR (CDCl3): 1.24 (s, 6 H, 2 × CH3), 2.56 (s, 2 H, CH2), 3.74 (s, 3 H, CH3), 4.55 (s, 2 H,
CH2), 6.75–6.78 (m , 2 H, Ar), 7.14–7.17 (m , 2 H, Ar), 7.24–7.38 (m , 5 H, Ar), 7.73–7.75 (m ,
1 H, Ar). 13C NMR (CDCl3): 24.9, 30.9, 39.7, 55.4, 64.2, 82.8, 87.6, 113.9, 124.0, 127.7,
128.0, 128.9, 131.7, 131.8, 158.6, 171.1. ATR-IR: ν(CH) 3009, 2985, 2820, ν(C≡N) 2231,
ν(C=N) 1662, ν(C=C) 1511, ν(CO) 1241, ν(CC)Ar 757. FT-Ram an : ν(CH) 3066, 2918, 2895,
ν(C≡C) 2236, 2220, ν(C=N) 1662, ν(C=C) 1597, ν(CO) 1257, δ(CH)Ar 1001. UV (EtOH), λm ax
(log ε): 204 (4.55), 230 (4.36), 240 (4.35). HRMS, m/z: calculated for C21H24NO (M + H)
306.1858, foun d 306.1852. EI MS (m/z, %): 306.4 (M + H+, 100), 121.1 (85).
2,2-Dim eth yl-5-ph en ylpen t-4-yn -1-am in e Oxalate (22)
A solution of potassium 3,7-dim eth yloctan -3-olate (50 wt.% solution in h eptan e; 3.6 m l,
7.3 m m ol) was added dropwise to a stirred solution of th e Sch iff base (19a; 1 g, 3.6 m m ol)
in tetrah ydrofuran (40 m l) at –50 °C an d th e solution was stirred at th is tem perature for
20 h . Water (10 m l) was added an d th e stirred solution was allowed to warm up to room
tem perature an d th en extracted with dieth yl eth er (3 × 20 m l). Th e com bin ed extracts were
dried with an h ydrous MgSO4 an d evaporated un der reduced pressure. Th e residue was dis-
solved in toluen e an d added to a stirred solution of oxalic acid dih ydrate (0.45 g, 3.6 m m ol)
in water (25 m l). Th is solution was refluxed for 1 h an d th e h ot aqueous layer was separated
an d cooled (10 °C). Th e form ed crystals were isolated by filtration an d dried at 40 °C to give
0.6 g (70%) of wh ite crystals of oxalate 22; m .p. 168–170 °C. For C15H19NO4 (277.32) calcu-
lated: 64.97% C, 6.91% H, 5.05% N; foun d: 65.35% C, 7.09% H, 5.23% N. 1H NMR
(DMSO-d6): 1.09 (s, 6 H, 2 × CH3), 2.49 (s, 2 H, CH2), 2.83 (s, 2 H, CH2), 6.99–7.61 (m , 8 H,
Ar + NH3). 13C NMR (DMSO-d6): 24.2, 29.7, 33.4, 47.7, 82.8, 87.2, 122.9, 128.1, 128.6,
131.3, 164.2. ATR-IR: ν(NH) 3361, ν(CH) 3054, ν(CH) 2966, ν(C=O) 1721, ν(C=0) 1699,
ν(CC)Ar + δ(NH+) 1602, ν(CH) + δ(NH+) 1211. FT-Ram an : ν(CH) 3061, 2969. ν(C≡C) 2251,
2222, ν(C=O) 1718, ν(C=C) 1598, δ(CH) 1429, δ(CH) 1029, 1001. UV (EtOH), λm ax (log ε):
204 (4.57), 240 (4.34), 250 (4.32). HRMS, m/z: calculated for C13H18N (M + H) 188.1439,
Collect. Czech. Chem. Commun. 2009, Vol. 74, No. 6, pp. 1011–1022