typically used in carbonless papers and thermal imaging sys-
tems. They also satisfy the requirements of solubility in suitable
solvents for encapsulation, non-solubility in aqueous media,
non-reactivity with fill solvents, and colour-forming com-
pounds mixed therewith, and compatibility with existing car-
bonless paper and thermal imaging developer systems.
If desired, a mixture of the colour-forming compounds 11
may be used and images of varying colours can be formed by
the reaction between a developer and the colour-forming
compounds. Appropriate mixtures to form black images are
particularly useful. In systems where the colour-forming com-
pounds are encapsulated, the system may provide either one
type of capsule containing a mixture of colour-forming com-
pounds or may comprise a mixture of capsules, each containing
a separate encapsulated colour-forming compound solution.
In the latter instance, colour is formed by the mixing of the
colour-forming compounds upon capsule rupture and reaction
with the developer.
The reaction was then quenched with aqueous NH Cl (10%),
4
extracted with diethyl ether (3×50 ml) and dried over MgSO .
4
Evaporation of the solvent gave a residue, which was chromato-
graphed on silica gel (hexane–ethyl acetate; 351). Yield 60%.
Mp 86–87 °C; d (300 MHz; CDCl ; Me Si) 2.98 (s, 6 H), 6.32
H
3
4
(s, 1 H), 6.80 (m, 1 H), 6.99–7.11 (m, 5 H), 7.23–7.32 (m, 3 H);
d
(75 MHz; CDCl ) 40.3, 108.0, 112.5, 114.7, 118.4, 123.2,
c
3
129.4, 129.7, 141.0. 150.8 (Found: C, 64.32; H, 6.23; N, 10.69.
Calc. for C H N OS: C, 64.59; H, 6.20; N, 10.77%).
14 16
2
Preparation of sultines 11a, b, d–h by lithiation of 10a, b, d–h
To a stirred solution of N-phenylbenzenesulfinamide 10
(10 mmol) in THF (70 ml) at −5 to 0 °C was added butyllith-
ium (20 mmol). The solution was stirred at this temperature
for 2 h. Then Michler’s ketone [4,4∞-bis(dimethylamino)benzo-
phenone] in THF (80 ml) was added slowly. The mixture was
kept at this temperature for 1 h then at room temp. overnight.
Aqueous NH Cl (10%) was added and the solution extracted
Sultine compounds 11 are preferably encapsulated by means
of aminoplast polymerization encapsulation. They are soluble
in the fill solvents commonly used in the encapsulation process.
Such solvents are aqueous immiscible solvents and include but
are not limited to xylene, toluene, cyclohexane, diethyl phthal-
ate, tributyl phosphate, benzyl benzoate, diethyl adipate, butyl
diglyme, and the like. Preferably, the colour-forming compound
11 is present in the microcapsules in an amount from ca.
0.2–10% by weight based on weight of the fill of the
microcapsule.
4
with ethyl acetate (2×100 ml), dried with MgSO and evapor-
4
ated to give a residue. The pure product was obtained by
column chromatographic separation on silica gel (hexane–
ethyl acetate, 351).
3,3-Bis(4-dimethylaminophenyl)-3H-2,1-benzoxathiole 1-oxide
11a
Yield 48%. Mp 174–176 °C; d (300 MHz; CDCl ; Me Si) 2.90
H
3
4
(s, 12 H), 6.62 (4 H, d, J 8.9), 7.20 (br s, 4 H), 7.32–7.35 (m, 1
In summary, a new class of sultine colour-formers has been
prepared in a two-step procedure. These compounds may be
of potential importance in industrial applications.
H), 7.46–7.51 (m, 2 H), 7.70–7.73 (m, 1 H); d (75 MHz;
C
CDCl ) 40.2, 106.3 (sp3 q), 111.5, 123.7, 125.3, 128.7, 129.1,
3
131.8, 144.1, 146.3, 150.1 (Found: C, 70.23; H, 6.31; N, 7.01.
Calc. for C H N O S: C, 70.38; H, 6.17; N, 7.14%).
23 24
2 2
Experimental
3,3-Bis(4-Methoxyphenyl)-3H-2,1-benzoxathiole 1-oxide 11b
Obtained as an oil. Yield 74%; d (300 MHz; CDCl ; Me Si)
Melting points were determined with a Kofler hot stage
apparatus and are uncorrected. 1H and 13C NMR spectra were
recorded on a Gemini VXR 300 MHz spectrometer in deutero-
chloroform using tetramethylsilane as an internal reference for
1H spectra and deuterochloroform for 13C spectra; J/Hz.
Elemental analyses were performed on a Carlo Erba-1106
instrument.
H
3
4
3.73 (s, 3 H), 3.75 (s, 3 H), 6.82 (d, 4 H, J 7.1), 7.13 (d, 2 H, J
8.7), 7.33 (d, 3 H, J 9.1), 7.46–7.58 (m, 2 H), 7.74 (d, 1 H, J
7.9); d (75 MHz; CDCl ) 54.9, 55.0, 104.6 (sp3 q), 113.3, 113.4,
C
3
123.7, 125.1, 128.7, 128.9, 129.4, 131.9, 134.1, 134.6, 143.4, 146.2,
159.2, 159.5 (Found: C, 68.61; H, 4.90; Calc. for C H O S: C,
21 18
4
68.84; H, 4.96%).
Compound 10a was prepared according to the literature
procedure11: mp 113–114 °C (lit., mp 113–114 °C). Compounds
10b, d were prepared by adaptation of a literature procedure.11
6-Methyl-3,3-bis(4-dimethylaminophenyl)-3H-2,1-benzoxathiole
1-oxide 11d
N-Phenyl-3-methylbenzenesulfinamde 10b
Yield 41%. Mp 100–103 °C; d (300 MHz; CDCl ; Me Si) 2.39
H
3
4
(s, 3 H), 2.89 (s, 12 H), 6.61 (d, 4 H, J 8.8), 7.29 (br s, 4 H),
7.31(d, 2 H, J 7.9), 7.49 (s, 1 H); d (75 MHz; CDC1 ) 20.9,
Yield 90%. Mp 60–61 °C; d (300 MHz; CDCl , Me Si) 2.34
H
3
4
(s, 3 H), 6.95–7.02 (m, 1 H), 7.04–7.10 (m, 3 H), 7.15–7.35 (m,
C
3
40.2, 106.1 (sp3 q), 111.4, 123.6, 124.9, 128.6, 132.0, 132.9, 139.4,
141.4, 146.5, 150.0 (Found: C, 70.88; H, 6.56; N, 7.00. Calc. for
C H N O S: C, 70.91; H, 6.45; N, 6.90%).
4 H), 7.45 (d, 1 H, J 7.6), 7.51 (s, 1 H); d (75 MHz; CDCl )
c
3
21.2, 118.5, 122.5, 123.0, 125.8, 128.7, 129.2, 131.8, 138.9, 140.7,
144.1 (Found: C, 67.85; H, 5.86; N, 5.89. Calc. for C H NOS:
24 26
2 2
13 13
C, 67.51; H, 5.67; N, 6.06%).
6-Dimethylamino-3,3-bis(4-dimethylaminophenyl)-3H-2,1-benz-
oxathiole 1-oxide 11e
N-Phenyl-3-methoxybenzenesulfinamde 10d
Yield 34%. Mp 183–184 °C; d (300 MHz; CDC1 ; Me Si)
Yield 81%. Mp 128–129 °C; d (300 MHz; CDCl , Me Si) 3.80
H
3
4
H
3
4
2.91 (s, 12 H), 2.98 (s, 6 H), 6.63 (d, 4 H, J 9.0), 6.85 (dd, 1 H,
J 8.6, 2.5), 6.92 (d, 1 H, J 2.4), 7.14 (d, 2 H, J 8.6), 7.13–7.23
(m, 3 H); d (75 MHz; CDCl ) 40.3, 40.5, 105.1 (sp3 q), 111.6,
(s, 3 H), 6.76 (s, 1 H), 6.99–9.10 (m, 4 H), 7.22–7.37 (m, 5 H);
d
(75 MHz; CDCl ) 55.5, 109.9, 117.6, 117.7, 118.8, 123.4,
c
3
129.3, 129.9, 140.7, 145.9, 160.1 (Found: C, 63.31; H, 5.33; N,
C
3
116.4, 125.4, 128.7, 131.0, 131.4, 147.8, 150.0, 151.2 (Found: C,
68.77; H, 6.75; N, 9.57. Calc. for C H N O S: C, 68.93; H,
5.61. Calc. for C H NO S: C, 63.14; H, 5.30; N, 5.67%).
13 13
2
25 29
3 2
6.72; N, 9.65%).
N-Phenyl-3-(dimethylamino)benzenesulfinamide 10c
A solution of N,N-dimethyl-3-bromoaniline (20 mmol) in dry
THF (60 ml) was added dropwise to magnesium turnings and
a trace of iodine at room temp. The mixture was heated under
reflux for 4 h to give Grignard reagent 9c. To a solution of N-
thionylaniline (15 mmol) in dry diethyl ether (50 ml) Grignard
reagent 9c was added at ca. −10 °C. The mixture was stirred
at this temperature for 30 min then at room temp. for 10 h.
6-Dimethylamino-3,3-diphenyl-3H-2,1-benzoxathiole 1-oxide
11f
Yield 45%. Mp 140–142 °C; d (300 MHz; CDC1 ; Me Si)
H
3
4
2.99 (s, 6 H), 6.86–6.93 (m, 2 H), 7.18–7.31 (m, 9 H), 7.43 (dd,
2 H, J 8.0, 1.3); d (75 MHz; CDCl ) 40.4, 104.3 (sp3 q), 105.1,
C
3
116.3, 125.5, 127.4, 127.5, 127.8, 128.1, 128.2, 128.3, 129.8, 142.9,
J. Mater. Chem., 1997, 7(8), 1399–1404
1401