The solution of diazomethane in diethyl ether was added
dropwise to a cooled solution of 4-hydroxyphthalic anhydride
(0.5 g, 3.0 mmol) in diethyl ether (10 ml). The diethyl ether was
evaporated and the remaining solid was recrystallised from
toluene–petroleum spirit (50:50, v/v) to yield 0.31 g (57%) of
an off-white crystalline solid with mp 95–97 ЊC (lit. mp 98–
99 ЊC23). δH(CDCl3) 3.96 (3 H, s, OCH3), 7.42 (1 H, d of d, Ar),
7.47 (1 H, d, Ar), 7.92 (1 H, d, Ar); δC(CDCl3) 57.5 (OCH3),
110.3, 123.9, 128.2 (Ar, 3 × C), 124.0, 135.3, 167.3 [Ar,
s, OCH3), 3.52–3.67 (32 H, m, OCH2). m/z (HRMS, EI)
found 405.1604; calc. for (C20H44O12Ti)ϩ = 524.2312; calc. for
(C15H33O9Ti)ϩ = 405.1604 (Mϩ Ϫ C5H11O3).
Acknowledgements
We are indebted to the EPSRC and Jotun Polymer (UK) for a
CASE award to N. J. H. and to Jotun Polymer (Norway) for
further financial support. The Jotun Polymer companies now
belong to Reichhold.
3 × C(qt)], 163.9, 164.4 (2 × C᎐O). m/z (HRMS, EI) found
᎐
(M)ϩ = 178.0262; calc. for C9H6O4 = 178.0266.
References
Preparation of 4-bromophthalic anhydride
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2 J. W. Thanassi and T. C. Bruice, J. Am. Chem. Soc., 1966, 88, 747.
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A mixture of 4-bromophthalic acid (1 g, 4.1 mmol) and acetic
anhydride (5 ml, 53 mmol) was heated under reflux for 2 h.
After cooling, the acetic acid and excess acetic anhydride were
distilled off and the solid was dissolved in dichloromethane (25
ml) and washed with 0.5 Na2CO3 (2 × 5 ml). The organic
layer was dried (MgSO4), filtered and the solvent evaporated off
to yield 0.9 g (97%) of a white crystalline solid, mp 106–109 ЊC
(lit. mp 108–110 ЊC26). δH(CDCl3) 7.90 (1 H, d of d, Ar), 8.06
(1 H, d of d, Ar), 8.17 (1 H, d, Ar); δC(CDCl3) 126.9, 128.9,
139.3 (Ar, 3 × C), 129.8, 131.5, 132.9 [Ar, 3 × C(qt)], 161.4,
161.9 (2 × C᎐O). m/z (EI) (M)ϩ = 226 (79Br), 228 (81Br)
᎐
(C8H3O3Br).
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crystallographic details, excluding structure factor tables, for
2-methoxyethyl hydrogen phthalate have been deposited at the
Cambridge Crystallographic Data Centre (CCDC). For details of
the deposition scheme, see ‘Instructions for Authors’, J. Chem. Soc.,
authors). Any request to the CCDC for this material should quote
the full literature citation and the reference number 188/125.
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Preparation of 2-methoxyethyl hydrogen 4-hydroxyphthalate
A mixture of 4-hydroxyphthalic anhydride (0.5 g, 3.0 mmol)
and 2-methoxyethanol (0.25 ml, 3.2 mmol) was heated at
108 ЊC for 1.5 h with stirring. After cooling, dichloromethane
(50 ml) was added when a white product precipitated from the
solution. The solid was filtered, washed with dichloromethane
(2 × 10 ml) and dried under vacuum to give 0.39 g (54%) of a
white crystalline solid. δH(CDCl3) 3.26 (3 H, s, OCH3), 3.59
(2 H, q, CH2OCH3), 4.29 [2 H, m, C(O)OCH2O], 6.84 (1 H, d,
Ar), 6.92 (1 H, d of d, Ar), 7.72 (1 H, d, Ar), 10.55 [1 H, br s,
C(O)OH]; δC(CDCl3) 58.0 (OCH3), 64.0, 69.4 (2 × OCH2),
114.2, 116.6, 131.8 (Ar, 3 × C), 120.3, 136.3, 160.4 [Ar, 3 ×
C(qt)], 166.8, 168.1 (2 × C᎐O).
᎐
Assignment of the meta orientation of the hydroxy group to
the ester function was achieved by the use of the 1H coupled 13
C
spectrum and a number of selective 1H decoupled 13C spectra of
the product in the region 165–170 ppm.
Titanium tetraalkoxide ligand exchange
A mixture of titanium tetra-n-butoxide (5 g, 14.7 mmol) and
2-(2-methoxyethoxy)ethanol (28 ml, 0.235mol) was stirred at
ambient temperature. On mixing the titanium tetra-n-butoxide
appeared to dissolve but after a delay of ca. 30 s the appearance
of a milky white emulsion was observed. After a further delay
of ca. 20 s the emulsion disappeared and the mixture was stirred
for a further 10 min. o-Xylene (3 ml) was added to the mixture
as an azeotrope for the displaced n-butanol. The o-xylene–n-
butanol mixture was distilled under reduced pressure (0.06
mmHg) at ambient temperature and then the remaining 2-(2-
methoxyethoxy)ethanol was distilled off under reduced pres-
sure (bp 66–68 ЊC/0.06 mmHg) to leave the product as a yellow
liquid in quantitative yield (7.7 g). δH(CDCl3) 3.35 (12 H,
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26 M. G. Van Campen, Jr. and J. R. Johnson, J. Am. Chem. Soc., 1933,
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Paper 7/08468D
Received 24th November 1997
Accepted 26th February 1998
1256
J. Chem. Soc., Perkin Trans. 2, 1998