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Flosser and Olofson
Similar reaction of 2 (5.94 g, 0.0600 mol), Et2NH (3.29 g, 0.0450 mol),
and Et2NH.HCl (0.55 g, 0.0050 mol, 10 mol%) (Aldrich) at 70ꢀC for 24 h,
then neutralization with 21% NaOEt/EtOH (0.41 g, 0.006 mol) yielded
5.90 g (84%) of pure 5, b.p.: 98–101ꢀC at 25 mm (lit.[5]: 98–101ꢀC at
25 mm). 1H NMR (CDCl3): ꢀ 3.67 (t, 2H, J ¼ 7.2 Hz), 3.32 (q, 4H,
J ¼ 6.9 Hz), 2.51 (t, 2H, J ¼ 8.3 Hz), 2.0–1.9 (m, 2H), 1.13 (t, 6H,
J ¼ 7.2 Hz).
N-Alkylpyrrolinium Halides 6, 7
A mixture of 3 (2.5 g, 0.013 mol) and 1-bromooctadecane (5.3 g,
0.016 mol) in CH3CN (20 mL) was stirred at 90ꢀC (18 h) and then con-
centrated. A solution of the residue in CH2Cl2 (65 mL) was extracted with
water (2 ꢁ 65 mL), dried (Na2SO4), concentrated, and the remaining resi-
due dried in vacuo (60ꢀC); then trituated in hexane and dried in vacuo for
18 h to obtain 3.7 g (54% yield) of pure 6, m.p.: 75–78ꢀC. 1H NMR
(CDCl3): ꢀ 3.97 (t, 2H, J ¼ 7.2 Hz), 3.6–3.3 (m, 8H), 2.3–2.1 (m, 2H),
1.9–1.7 (m, 6H), 1.5–1.2 (m, 34H), 1.1–0.8 (m, 9H). IR (NaCl): 2368
(sh, w), 1669 cmÀ1 (s). Thermogravimetric analysis (PPG): stable above
200ꢀC.
A solution of 3 (8.9 g, 0.045 mol) and benzyl chloride (7.5 g,
0.059 mol) in CH3CN (30 mL) was stirred at 90ꢀC overnight. After con-
centration, the remaining orange gum was dried in vacuo at 60ꢀC for 2 h,
then dissolved in CH2Cl2 (50 mL), extracted with water (2 ꢁ 15 mL), and
back extracted with CH2Cl2 (2 ꢁ 15 mL). The combined organic layers
were dried (Na2SO4) and concentrated, and the orange gum was trituated
in ether and dried in vacuo at 80ꢀC overnight to obtain 13.3 g (92% yield)
of pure 7. 1H NMR (CDCl3): ꢀ 7.6–7.2 (m, 6H), 4.98 (s, 2H), 4.00 (t, 2H,
J ¼ 7.2 Hz), 3.6–3.3 (m, 6H), 2.4–2.3 (m, 2H), 2.0–1.6 (m, 4H), 1.5–1.1 (m,
4H), 1.1–0.7 (m, 6H). When the water wash was skipped, 7 was contami-
nated with the HCl salt of 3.
Catalyst Evaluations
A 60% solution of 7 (0.020 g, 0.062 mmol, 0.25 mol%) in o-dichloro-
benzene was added to stirred, cooled (0ꢀC, ice bath) triphosgene (3.0 g,
0.010 mol) under a –70ꢀC condenser. After 5 min, octanethiol (3.7 g,
0.025 mol) (Aldrich) was injected into the yellow liquid and the mixture
stirred for 8 h under the À70ꢀC condenser. The excess phosgene was
flushed awaywith N (20–30 s) followed byshort vacuum evaporation
2