Phthalaldehyde → 1-Methoxy-3-(1-nitrocyclopentyl)-1,3-dihydroisobenzofuran

Beteiligte Stoffe

Reaktionsschritte

Condensation of nitrocyclopentane (5.00 g, 40.0 mmol) with o-phthalaldehyde (3.76 g, 28.0 mmol) in the presence of freshly prepared sodium methoxide (10 mmol) in MeOH is carried out as described above for compound a. The resulting pale green oil (7.21 g, 98%) is pure enough for use in the next step. The following data were obtained on a ca. 1:1 mixture of the cis and trans diastereoisomers. 1H NMR (CDCl3) 7.50-7.25 (m, 3), 7.10-7.00 (m, 1), 6.16 and 5.91 (isomer I, 2 d, 1 total, J=2.3), 5.93 and 5.80 (isomer II, s and d, respectively, 1 total, J=0.7 Hz), 3.49 and 3.30 (isomers I and II, respectively, 2 s, 3 total), 2.50-2.35 (m, 1), 2.30-1.90 (m, 3), 1.75-1.50 (m, 4); IR (film) 1543, 1464, 1398, 1373, 1348, 1113, 1094, 1026, 974, 756; MS (CI/CH4, eE=120 eV), m/z 236 (M-H)+, 219, 206, 191, 175, 159, 149 (base peak), 131, 118, 91, 73; Anal. Calcd for C12H15NO2 (MW=237.3): C, 60.75; H, 6.37; N, 5.90. Found: C, 60.48; H, 6.28; N, 6.00.

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