652 Kanoh et al.
Macromolecules, Vol. 35, No. 3, 2002
as well as a 337-nm nitrogen laser (pulse width, 3 ns). The
experiment was done using no salt additive at an accelerating
potential of 20 kV. A mixture of angiotensin I (human; MW )
1296.5; Sigma) and adrenocorticotropic hormone (fragment
7-38; MW ) 3659.2; Sigma) was used for the calibration of
the mass scale. Sample solutions were prepared by dissolving
a polymer (2.6 mg mL-1) and dithranol (5.6 mg mL-1; Aldrich)
in THF. Immediately after 1.0 mL of the polymer solution and
2.0 mL of the matrix solution were mixed together in a glass
vial, 2.0 µL portions of the mixed solution were deposited with
a calibrated pipet (Eppendorf) onto the dimples of a sample
plate and gently dried under air at room temperature. The
plate was inserted into the apparatus under high vacuum (ca.
10-6 Pa).
supernatant solution was determined to be 19%, and the
soluble part was obtained in 78 wt % after evaporation. From
these data, the total conversion of 1 was deduced to be 41%.
The Mn SEC values of soluble and insoluble 3 were 1.72 × 103
(Mw/Mn ) 1.13) and 1.78 × 103 (Mw/Mn ) 1.12), respectively.
The precipitates were used for the second-stage polymerization
before complete removal of the slightly remaining solvent. A
toluene solution of 1 (0.25 g in 3.14 mL) was added to the tube
containing the toluene-wet precipitates immediately after
centrifugal separation. The second-stage polymerization was
continued for additional 5 h at 25 °C, to give homoblock 3
having Mn SEC ) 2.58 × 103 (Mw/Mn ) 1.10) in 30% yield based
on the first feed of 1 (0.25 g).
Similarly, two polymerizations of 1 with 2.5 mol % of MAD
at 25 °C were carried out in toluene for 5 h and in toluene-
CH2Cl2 (4:1 v/v) for 24 h, and the resulting precipitate parts
were separated by centrifugation under nitrogen at 25 °C:
Mn SEC ) 2.26 × 103 (Mw/Mn ) 1.12) for toluene-soluble 3 and
3.64 × 103 (Mw/Mn ) 1.18) for toluene-CH2Cl2-soluble 3. About
half of a solution of 1 (0.25 g) in toluene-CH2Cl2 (4:1 v/v, 3.14
mL) was added to each precipitate part immediately after
centrifugal separation, and then the resulting suspensions
were mixed together. The second-stage polymerization was
continued for additional 24 h at 25 °C, to give 3 showing a
unimodal SEC curve: Mn SEC ) 3.68 × 103 (Mw/Mn ) 1.21).
P r ep a r a t ion of 2-Oxir a n ylm et h ylisoin d ole-1,3-d ion e
(1). The oxirane phthalimide (1) was prepared from epichlo-
rohydrin (45.0 mL, 0.574 mol) and potassium phthalimide
(13.9 g, 75.1 mmol) under refluxing for 5 h, according to a
literature method:5 yield 92%; colorless needles; mp 98-99 °C
1
(acetone-Et2O); H NMR δ 7.87, 7.74 (each dd, J 1 ) 5.4 Hz,
J 2 ) 2.9 Hz, each 2H, carbonyl m- and o-HAr), 3.97, 3.87 (each
dd, J 1 ) 14.7 Hz, J 2 ) 4.9 Hz, each 1H, NCH2), 3.24 (m, 1H,
OCH), 2.81 (t-like, J ) 4.5 Hz, 1H, trans-OCH2 to CH2N), 2.69
ppm (dd, J 1 ) 4.9 Hz, J 2 ) 2.4 Hz, 1H, cis-OCH2 to CH2N);
13C NMR δ 167.9 (CdO), 134.1 (carbonyl m-CAr), 131.9 (car-
bonyl ipso-CAr), 123.4 (carbonyl o-CAr), 49.0 (OCH), 46.1
(OCH2), 39.6 ppm (NCH2); IR (KBr) 1770, 1723, 1706 (νCd
O imide), 1399 (νC-N), 963, 790 cm-1 (νC-O); HRMS found, m/e
203.0594 (calcd for C11H9NO3, m/e 203.0583). Anal. Calcd for
C11H9NO3: C, 65.02; H, 4.46; N, 6.89. Found: C, 65.10; H, 4.34;
N, 6.87.
p-ter t-Bu tylp h en oxyl En d -Ca p p ed 3. A polymer sample
of 3 for the end capping6 was prepared in the polymerization
of 1 (0.25 g, 1.2 mmol) with MAD (5 mol %) in toluene (3.0
mL) at 25 °C for 4 h. SEC analysis of an aliquot of the
polymerization mixture showed Mn SEC ) 1.84 × 103 (Mw/Mn
) 1.11). The Mn calc was presumed to be certainly 1.90 × 103
based on the 46% conversion of 1 in another polymerization
under the same conditions. Immediately after the polymeri-
zation, a solution of sodium p-tert-butylphenoxide (ca. 0.1 mol
L-1, 2.5 mL, 0.25 mmol) in anhydrous THF distilled from Na-
benzophenone was added to the remaining polymerization
mixture, and the homogeneous mixture was stirred at 25 °C
for 12 h under a nitrogen atmosphere. The residue obtained
by evaporation was dissolved in CHCl3, and repeated precipi-
tation with Et2O gave p-tert-butylphenoxyl end-capped 3. The
IR spectrum of the resulting polymer (cast film) showed two
P olym er iza tion of 1 w ith MAD. Typically, a 10-mL tube,
equipped with a three-way stopcock, containing 1 (0.25 g, 1.2
mmol) was repeatedly evacuated and filled with dry nitrogen.
Anhydrous toluene (3.0 mL) was added to the tube, and the
monomer was dissolved at 25 °C. A toluene solution of MAD
(0.43 mol L-1, 0.14 mL, 0.061 mmol) was charged by a syringe
in a nitrogen stream, and then the resulting solution was
allowed to stand at this temperature. After the polymerization
was quenched with anhydrous Et3N (0.1 mL), volatile materi-
als were evaporated to dryness. A small amount of the residue
was subjected to 1H NMR and SEC analyses to determine the
product ratio and average molecular weights (Mn and Mw) of
the produced polymer, respectively. For instance, the polym-
erization at 25 °C for 70 h resulted in 73% conversion of 1,
and Mn SEC of 3 ) 2.87 × 103 (Mw/Mn ) 1.13): the theoretical
number-average molecular weight (Mn calc) of 3 was estimated
to be 2.98 × 103 according to Mn calc ) [1]0/[MAD]0 × MW of 1
(203) × % conversion/100 + FW of H and HO ends (18). The
crude polymer, if necessary, was purified by reprecipitation
from a concentrated CHCl3 solution with diethyl ether.
P oly{oxy[1-(iso in d ole -1,3-d io n e -2-y lm e t h y l)e t h yl-
weak absorption bands at 3400 (νOH) and 1770 (νCdO imide
)
cm-1, suggesting that the initiating end is a hydroxyl group
and the terminating end is a ring-opened ether unit carrying
a phthalimide group and a phenoxyl cap, as shown in Scheme
3 (vide infra). The number-average degree of polymerization
(DPNMR) was estimated to be 9.07 from the peak area ratio of
the total aromatic protons in the lactam and imide units
(7.9-7.4 ppm) to the tert-butyl protons (1.24 ppm). Thus,
Mn NMR of 3 before end capping, i.e., 3 having a hydroxyl end
in place of a p-tert-butylphenoxyl one, was estimated to be 1.86
1
× 103 according to Mn NMR ) DPNMR × MW of 1 (203) + FW of
en e]} (2). H NMR: δ 7.71 (s-like, 2H, carbonyl o-HAr), 7.60
H and OH ends (18).
(s-like, 2H, carbonyl m-HAr), 4.0-3.2 ppm (m, 5H, OCH, OCH2,
and NCH2). 13C NMR: δ 168.0 (CdO), 133.6 (carbonyl m-CAr),
132.3 (carbonyl ipso-CAr), 123.1 (carbonyl o-CAr), 73-69 (OCH2
and OCH), 42-38 ppm (NCH2). IR (KBr): 3450 (m; νOH), 1770,
1721 (νCdO imide), 1395 (νC-N), 1118-1046 cm-1 (νC-O).
Hyd r olysis of 3. Hydrolysis of 3 (0.1 g) was carried out in
THF (5 mL) containing a few drops of 1 mol L-1 hydrochloric
acid for 12 h at room temperature, and evaporation almost
quantitatively gave crude 2-(2,3-dihydroxypropyl)isoindole-1,3-
dione (4), which was recrystallized from CH2Cl2-hexane to
P oly[oxy(2,3-dih ydr o-9bH-oxazolo[2,3-a ]isoin dol-5-on e-
1
1
afford pure 4: colorless needles; mp 106-107 °C; H NMR δ
9b,2-d iyl)m eth ylen e] (3). H NMR: δ 7.9-7.4 (m, 4H, HAr),
7.87, 7.74 (each dd, J 1 ) 5.4 Hz, J 2 ) 3.2 Hz, each 2H, carbonyl
o- and m-HAr), 3.99 (sept-like, J ) 5.0 Hz, 1H, OCH), 3.88 (dd,
J 1 ) 14.4 Hz, J 2 ) 5.9 Hz, 2H, NCH2), 3.64 (ddd, J 1 ) 12.7
Hz, J 2 ) 6.4 Hz, J 3 ) 4.6 Hz, 2H, OCH2), 2.91 (d, J ) 5.9 Hz,
1H, CHOH), 2.62 ppm (t, J ) 6.4 Hz, 1H, CH2OH); 13C NMR
δ 169.0 (CdO), 134.3 (carbonyl m-CAr), 131.8 (carbonyl ipso-
4.6-3.9 (m, 2H, NCH2), 3.9-3.0 ppm (m, 3H, OCH2 and OCH).
13C NMR: δ 164.8 (CdO), 141.0 (carbonyl ipso-CAr), 134.0
(acetal ipso-CAr), 133.3 (carbonyl p-CAr), 131.3 (acetal o-CAr),
124.1 (acetal p-CAr), 121.9 (carbonyl o-CAr), 105.7 (acetal-C),
64.3 (OCH), 63.9 (OCH2), 40.3 ppm (NCH2). IR (KBr): 3450
(w; νOH), 1770 (vw; νCdO imide), 1720 (νCdO lactam), 1397 (νC-N),
1115-978 cm-1 (νC-O).
Mon om er -Ad d ition P olym er iza tion . The monomer-ad-
dition polymerization was similarly carried out in a centrifuge
tube equipped with a glass stopcock at 25 °C. The heteroge-
neous reaction mixture obtained in 2.5 h was separated into
the supernatant solution and the precipitate by centrifugation
under nitrogen at 25 °C. An aliquot of each part was taken
out and treated with anhydrous Et3N, and then each part was
analyzed by 1H NMR and SEC. The conversion of 1 in the
C
Ar), 123.6 (carbonyl o-CAr), 70.3 (OCH), 63.8 (OCH2), 40.5 ppm
(NCH2); IR (KBr) 3340 (νOH), 1772, 1723, 1716 (νCdO imide), 1394
(νC-N), 1087 cm-1 (νC-O); HRMS found, m/e 222.0757 (MH+)
(calcd for C11H11NO4 + H+, m/e 222.0767). Anal. Calcd for
C
11H11NO4: C, 59.73; H, 5.01; N, 6.33. Found: C, 59.75; H,
4.91; N, 6.32.
Isom er ization of N-Oxir an ylm eth ylben zam ide (6). Ben-
zoyl chloride (10.0 mL, 86.5 mmol) was slowly added to a
solution of allylamine (5.19 g, 90.8 mmol) and Et3N (24.0 mL,