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S. Kanoh et al. / Tetrahedron 58 (2002) 7065–7074
dd, J¼11.2, 2.9 Hz, 1H, H4a, H6a), 6.97–7.27 (m, 10H,
ArH of Ph), 7.73–7.80 (m, 8H, ArH of NPI ); 13C NMR d
33.5, 37.9, 39.6, 42.2, 44.5, 73.5, 102.0, 123.0, 123.2, 125.2,
125.8, 127.5, 128.2, 128.6, 128.8, 132.0, 132.1, 133.6,
133.7, 139.2, 139.3, 168.2, 168.4. EI HRMS calcd for
C36H30N2O6: found 586.2101. Anal. calcd for C36H30N2O6:
C, 73.70; H, 5.15; N, 4.78. Found: C, 73.76; H, 5.26; N,
4.67. Crystal data: monoclinic, space group C2/c, Z¼8
4.3. Preparation and reaction of oxetane benzamide
4.3.1. N-(3-Phenyloxetan-3-ylmethyl)benzamide (2a).
Hydrazine hydrate (2.58 g, 51.6 mmol) was added dropwise
to an EtOH (200 mL) solution of 1a (2.52 g, 8.60 mmol)
with stirring. The mixture was refluxed for 3 h, and the
resulting precipitates were filtered off. Small portions of
Raney Ni (W-2)20 were added to the filtrate under vigorous
refluxing in order to decompose unreacted hydrazine.21 The
inorganic materials were filtered off, and the filtrate was
concentrated by distillation at atmospheric pressure. The
residue was distilled in vacuo to give 3-phenyl-3-amino-
methyloxetane in 54% yield: bp 110–1308C (10 mmHg).
Benzoic anhydride (1.16 g, 5.11 mmol) was added to a
CHCl3 solution of the above amine (0.757 g, 4.64 mmol)
and Et3N (0.516 g, 5.11 mmol) at 58C, and then the mixture
was stirred at rt for 4 h. The organic layer was washed with
5% aq NaOH and brine, dried over Na2SO4, and evaporated
in vacuo. The residue was recrystallized from CHCl3–Et2O
to give 2a (0.786 g, 63%). Colorless powder; mp 125–
˚
˚
˚
with a¼32.598(9) A, b¼11.517(2) A, c¼19.118(4) A;
3
V¼5958(2) A , and Dcalc¼1.308 g/cm3, 9558 measured,
˚
4683 independent reflections, of which 6153 were
considered as observed (I.3.00s(I )]. R¼0.048,
Rw¼0.056.
cis-Ph-1d. Colorless needles; mp 192–1938C (MeOH–
CH2Cl2–hexane); IR (KBr) 1780, 1710, 1140, 1095–
1025 cm21
;
1H NMR d 2.40, 2.72 (both dd, J¼13.9,
6.9 Hz, 1H, H38a, b), 2.50–2.61 (m, 1H, H25), 3.58 (d,
J¼7.3 Hz, 1H, H26a, b), 3.65 (s, 2H, H13a, b), 3.81 (d,
J¼11.6 Hz, 2H, H4b, H6b), 4.51 (d, J¼2.3 Hz, 1H, H2),
4.67 (d, J¼11.6 Hz, 2H, H4a, H6a), 6.90–7.37 (m, 10H,
ArH of Ph), 7.56–7.84 (m, 8H, ArH of NPI ); 13C NMR d
33.5, 37.8, 42.4, 42.9, 43.2, 72.8, 101.5, 122.9, 123.5, 125.6,
126.8, 127.9, 128.1, 128.3, 128.7, 131.7, 132.0, 133.6,
134.2, 139.6, 139.9, 168.4. EI HRMS calcd for
C36H30N2O6: 586.2105. Found: 586.2104. Anal. calcd for
C36H30N2O6: C, 73.70; H, 5.15; N, 4.78. Found: C, 73.75;
H, 5.19; N, 4.72.
1278C; IR (KBr) 3300, 1640, 1310, 1180, 980, 830 cm21
;
1H NMR d 4.04 (d, J¼5.9 Hz, 2H, NCH2), 4.84, 5.03 (both
d, J¼6.1 Hz, 2H, OCH2 trans and cis to 3-CH2NH), 6.22 (br
s, 1H, NH ), 7.04–7.69 (m, 10H, ArH ); 13C NMR d 47.9,
48.1, 79.7, 125.6, 126.7, 127.1, 128.5, 128.9, 131.5, 134.2,
142.5, 167.8. EI HRMS calcd for C17H17NO2: 267.1260.
Found: 267.1263.
4.3.2. (2,5-Diphenyl-5,6-dihydro-4H-1,3oxazin-5-yl)-
methanol (2b). A hexane solution of Me3Al (0.02 mL,
0.98 mol/L, 0.02 mmol) was added to a PhCl (1.0 mL)
solution of 2a (100 mg, 0.374 mmol). The resulting solution
was allowed to react at 1208C for 30 h and quenched by
adding Et3N (0.1 mL) followed by MeOH (3.0 mL). The
mixture was evaporated in vacuo and purified by alumina
chromatography with AcOEt, to give 2b (63 mg, 63%).
Colorless semi-solid; IR (KBr) 3300, 1650, 1150–
4.2.4. 2-(1H-Inden-2-ylmethyl)isoindole-1,3-dione (1e).
Similarly, the reaction of 1a with TfOH (5 mol%) was
carried out at 1308C for 3 days. The crude products were
separated by preparative TLC on alumina with AcOEt–
hexane¼1:1, to give 1e in 9% (Rf¼0.95). The analytical
sample was further purified by recrystallization from
CH2Cl2–hexane. Colorless needles; mp 192–1938C; IR
1
(KBr) 1770, 1708, 1615 cm21; H NMR d 3.41 (s, 2H,
1
1-CH2), 4.73 (s, 2H, NCH2), 6.77 (s, 1H, 3-CH ), 7.13
(td, J¼7.3, 1.7 Hz, 1H, either 5- or 6-ArH ), 7.21 (t,
J¼6.9 Hz, 1H, either 5- or 6-ArH ), 7.29 (d, J¼6.9 Hz,
1H, either 4- or 7-ArH ), 7.37 (d, J¼7.3 Hz, 1H, either 4-
or 7-ArH ), 7.73, 7.87 (both dd, J¼5.3, 3.0 Hz, 2H,
carbonyl m- and o-ArH of NPI ); 13C NMR d 37.8, 40.1,
121.0, 123.4, 123.6, 124.7, 126.4, 130.0, 132.1, 134.1,
142.9, 143.2, 144.3, 168.0. EI HRMS calcd for C18H13NO2:
275.0946. Found: 275.0947. Anal. calcd for C18H13NO2:
C, 78.53; H, 4.76; N, 5.09. Found: C, 78.48; H, 4.81; N,
5.04.
1020 cm21; H NMR d 1.88 (br s, 1H, OH ), 3.93–3.79
(m, 4H, NCH2 and CH2OH), 4.51, 4.77 (both d, J¼10.9 Hz,
1H, OC6H2), 7.30–7.45 (m, 8H, ArH of 5-Ph and m- and p-
ArH of 2-Ph), 7.95 (d, J¼6.9 Hz, 2H, o-ArH of 2-Ph); 13C
NMR d 40.3, 50.1, 65.8, 68.2, 126.0, 127.0, 127.3, 128.0,
128.9, 130.5, 132.9, 140.2, 155.1. FAB HRMS calcd for
C17H18NO2 (MþþH): 268.1338. Found: 268.1336.
On the other hand, the reaction with TfOH (5 mol%) in PhCl
at 1308C for 48 h gave oligomeric products (Mn GPC¼522),
which showed an ester carbonyl stretching band
(1720 cm21).
4.2.5. Poly(2-phthalimidomethyl-1,2-indanylene) (1f).
The above reaction was continued for 11 days to give 1f.
The crude oligomer was dissolved in THF, and precipitated
by adding Et2O, to separate it into lower- and higher-
molecular-weight fractions: Mn (polydispersity)¼916 (1.14)
and 1730 (1.18), isolated yield¼28 and 41%, respectively.
The latter part was used for analytical purposes. IR (KBr)
1780, 1710 cm21; 1H NMR d 2.0–3.4 (m, 3H, CH2 and CH
in indane moiety), 3.4–4.8 (m, 2H, NCH2), 6.0–7.3 (m, 4H,
ArH of indane moiety), 7.3–8.1 (m, 4H, ArH of NPI ); 13C
NMR d 36.2, 41.4, 47.7, 55.6, 122.9, 124.0, 126.6, 128.3,
141.7, 131.8, 133.8, 147.1, 168.2. Anal. calcd for
C18H13NO2: C, 78.53; H, 4.76; N, 5.09. Found: C, 78.93;
H, 4.60; N, 4.50.
4.4. Preparation and reaction of oxetane benzoate
4.4.1. 3-Phenyloxetan-3-ylmethyl benzoate (3a). Benzoic
anhydride (7.00 g, 31.0 mmol) was added to a CH2Cl2
(20 mL) solution of 6 (1.00 g, 6.10 mmol) and Et3N (4.00 g,
40.0 mmol) at 58C, and then the mixture was stirred at rt for
5 h. Ordinary extractive work-up, followed by distillation in
vacuo, gave the crude ester, which was purified by
recrystallization from Et2O–hexane to give 1a (1.12 g,
69%). Colorless needles; mp 76–778C; bp 130–1408C
(1 mmHg); IR (KBr) 1720, 1270, 1120, 990, 850 cm21; 1H
NMR d 4.70 (s, 2H, 3-CH2O), 4.92, 5.07 (both d, J¼6.4 Hz,
2H, cis- and trans-OCH2 to 3-Ph), 7.17 (dd, J¼8.3, 1.0 Hz,