Synthesis of green colored photochromic 6'-arylamino spiro [2H]naphth[1,2-b]oxazines

Article abstract of DOI:10.1080/00397910903457423

The published route to a series of 6'-arylamino substituted photochromic spirooxazines has been investigated with improvements made to perform the synthesis in satisfactory yield. The route has been exemplified with several novel derivatives prepared (including hydroxyl functionalised). Additionally, a one-pot procedure for the conversion of suitably functionalized 1,2-naphthoquinones into the photochromic compounds is reported. Copyright

Full text of DOI:10.1080/00397910903457423

Synthetic Communications1, 40: 3618–3628, 2010
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397910903457423
SYNTHESIS OF GREEN COLORED PHOTOCHROMIC
6’-ARYLAMINO SPIRO [2H]NAPHTH[1,2-b]OXAZINES
Mark York and Richard A. Evans
CSIRO Molecular & Health Technologies, CSIRO Future Manufacturing
Flagship, Cooperative Research Centre for Polymers, Victoria, Australia
The published route to a series of 60-arylamino substituted photochromic spirooxazines
has been investigated with improvements made to perform the synthesis in satisfactory
yield. The route has been exemplified with several novel derivatives prepared (including
hydroxyl functionalised). Additionally, a one-pot procedure for the conversion of suitably
functionalized 1,2-naphthoquinones into the photochromic compounds is reported.
Keywords: Photochromic; photochromism; spirooxazine
INTRODUCTION
Spirooxazines are an important class of photochromic dye which on
irradiation with ultraviolet light undergo a reversible colour change (Scheme 1)
from the colourless spirocyclic form, 1 to the coloured merocyanine form, 2.[1,2]
Amongst the spirooxazines in commercial use the 60-arylamino compounds exem-
plified by commercially available material 3 (Fig. 1), Reversacol aqua green,[3] are
of interest due to their green coloration upon exposure to UV light. These com-
pounds were first disclosed by Rickwood et al.,[4] however, the regiochemistry of
the spirooxazine substituents was incorrectly assigned and the correct structures
were later published by Clarke and coworkers.[3] The focus of our research involves
the attachment of polymers to photochromic dyes in order to control their switch-
ing speed in polymer matrices.[5–14] Thus, the preparation of hydroxyl functiona-
lised photochromic dyes is a key requirement. However, during the course of
this work we encountered difficulty in reproducing the published syntheses of
the 60-arylamino spirooxazines. This prompted a study of the synthesis of these
green spirooxazines, both with and without hydroxyl functionalisation, the results
of which are presented herein.
Received October 12, 2009.
Address correspondence to Richard A. Evans, CSIRO Molecular & Health Technologies, Bag 10,
Clayton, VIC 3169, Australia. E-mail: Richard.Evans@csiro.au
3618

60-ARYLAMINO PHOTOCHROMIC SPIROOXAZINES
3619
Scheme 1. Photochromic isomerisation of a spirooxazine.
Figure 1. Reversacol aqua green.
RESULTS AND DISCUSSION
The published synthesis of the 60-arylamino spirooxazines begins with the reac-
tion of a suitably substituted aniline with Folin’s reagent (1,2-naphthoquinone-4-
sulfonate, 4) to yield the corresponding 4-substituted naphthoquinone, 6. This is
then converted to the oxime, 7, which on reaction with a methyleneindoline, 8 gives
the spirooxazine product, 9 (Scheme 2).[3]
Scheme 2. Synthesis of 60-arylamino spirooxazines, 9.

3620
M. YORK AND R. A. EVANS
Arylation of Folin’s Reagent
The arylation of Folin’s reagent, 4, with anilines to give 4-arylamino naphtho-
quinones, 6, is a process that has been reported to proceed in the presence of stoi-
chiometric nickel[15] and more recently in the absence of metals.[4] The published
procedure reports the dropwise addition of a methanolic solution of N,N-diethylani-
line to an equimolar solution of Folin’s reagent in 4:1 water:methanol. After stirring
for 24 hours at room temperature the product was obtained by filtration, washing
with water and air drying in 42% yield.[3] In our hands, however, attempts to repeat
this process gave a precipitate containing significant amounts of water and 35% of
the starting aniline by mass. After chromatography a 30% yield of the arylated
naphthoquinone was obtained (Table 1, Entry 1a). In order to remove the need
for chromatography the mixture of Folin’s reagent and N,N-diethylaniline was
heated to 60 ꢀC for 18 hours before removal of the methanol in vacuo and cooling
in an ice bath. Filtration of the precipitate and oven drying gave the pure product
in 48% yield (Table 1, Entry 1b). These conditions were also used to arylate Folin’s
reagent with two further anilines (Table 1, Entries 2 and 3).
Oxime Formation
The published procedure for the conversion of naphthoquinone, 6a into oxime,
7a calls for the addition of 4 molar equivalents of hydroxylamine hydrochloride to
an anhydrous ethanolic solution of the naphthoquinone. The mixture is then
refluxed until the reaction is complete by thin layer chromatography, cooled, diluted
with water and the oxime collected in 75% yield by filtration and water washing.[3]
Unfortunately, attempts to repeat this procedure failed, with refluxing the solution
even for a short time (1 h) leading to the isolation of an impure product containing
predominantly bis oxime material, 10 (Fig. 2), which failed to react to give any
photochromic product in the next stage. If the reaction was performed at room
temperature a small amount of the correct product, 7a (10%) could be obtained
by filtration. It is proposed that the low yield was a result of the product being
retained in the mother liquor. Attempts to improve the isolated yield of the product
by filtration of the reaction mixture without the addition of water, and washing
the precipitate with ether lead to the isolation of hydrochloride salt, 11 (Fig. 2) as
the main product, albeit in increased yield (70%). The salt was unreactive in the
following stage of the synthesis. The desired oxime could be isolated in essentially
quantitative yield by stirring a mixture of the starting naphthoquinone and 2 molar
equivalents of hydroxylamine hydrochloride in ethanol at room temperature for 1
hour, followed by evaporation, partitioning between water and ethyl acetate and
basification of the aqueous phase (Table 1, Entry 1b). Two further novel oximes were
also prepared in this manner (Table 1, Entries 2–3).
Spirooxazine Formation
The formation of photochromic spirooxazines by the condensation of nitroso-
naphthols (or their oxime tautomers) with methyleneindoline compounds is a well
known process.[1] The synthesis of Reversacol aqua green, 3 requires the reaction

60-ARYLAMINO PHOTOCHROMIC SPIROOXAZINES
3621
Table 1. Arylation of Folin’s reagent and subsequent oxime formation
Entry
Aniline
Product
Yield (%)a
Oxime
Yield (%)a
1a
1b
30b
48c
>95
2
54c
>95
3
45c
90
aIsolated yield.
bReaction performed at room temperature for 24 h followed by chromatographic purification.
cReaction performed at 60 ꢀC for 18 h followed by precipitation.
between oxime, 7a and 1-isobutyl-3,3-dimethyl-2-methyleneindoline, 8a which is
synthesized as outlined in Scheme 3. The formation of intermediate indolenium iod-
ide 13 is reported to occur in 85% yield after heating a n-butanol solution of starting
indolenine 12 with isobutyl iodide in an autoclave at 125–130 ꢀC.[16] In our hands,
this procedure gave material contaminated with approximately 20% of a related
indolenium iodide (thought to be a butyl impurity arising from reaction with the

3622
M. YORK AND R. A. EVANS
Figure 2. Impurities formed during the synthesis of oxime 7.
solvent). As this impurity is very closely related to the desired product and reacts in
an identical fashion we were not successful in removing this impurity from either the
salt, 13 or indeed any of the following synthetic steps in the synthesis of 3, making
this route unsuitable for the synthesis of pure spirooxazines. The use of solvent
free conditions or 1,4-dioxane as solvent, however, gave material free from the
related impurity, albeit in lower yield. This was then converted with base to pure
methyleneindoline, 8a in 30% (1,4-dioxane) or 18% (solvent free) overall yield.
The condensation between 7a and 8a is reported to proceed in 66% yield when
an equimolar solution of the reagents in anhydrous ethanol is heated to reflux until
complete by TLC. The mixture is then cooled, reduced in volume and the product
collected by filtration and washing with a little cold ethanol.[3] Unfortunately we
were unable to obtain pure material on repetition of this method, as in our experi-
ence the reaction never proceeded to completion by TLC and prolonged heating
for greater than 24 h seemed to result in product decomposition. After heating for
22 h a small amount of highly impure aqua green, 3 could be isolated by precipi-
tation in the fashion described although this readily dissolved on washing with
ethanol. Evaporation of the filtrates and purification by column chromatography
gave 33% of the desired product (Table 2, Entry 1a). This could be increased to
58% by performing the reaction at 100 ꢀC in a sealed tube for 3 h (Table 2, Entry
1b). Improvements in yield for reactions in a sealed tube were also observed when
methyleneindoline, 8a was replaced with 1,3,3-trimethyl-2-methyleneindoline, 8b
(Table 2, Entries 2a vs. 2b). Interestingly, the presence of a free hydroxyl group in
the aniline portion of the starting materials gave an increased yield of the final spir-
ooxazine (Table 2, Entries 3 and 4). However, the electronically similar morpholino
Scheme 3. Synthesis of 1-isobutyl-3,3-dimethyl-2-methyleneindoline, 8a.

60-ARYLAMINO PHOTOCHROMIC SPIROOXAZINES
3623
Table 2. Synthesis of spirooxazines
Entry
Oxime
Indoline
Product
Yield (%)a
33b
1a
7a
1b
58c
2a
2b
52b
68c
7a
3
7b
84c
4a
4b
82c
73d
7b
7c
5
40c
aIsolated yield.
bReaction performed at reflux for 22 h followed by chromatographic purification.
cReaction performed at 100 ꢀC in a sealed tube for 3 h followed by chromatographic purification.
dReaction performed at 100 ꢀC in a sealed tube for 3 h followed by precipitation.
functionalised spirooxazine, 9d was only obtained in a relatively poor 40% yield
(Table 2, Entry 5).
One-Pot Oxime/Spirooxazine Formation
In an effort to speed the discovery and synthesis of new spirooxazine dyes a
one-pot oxime=spirooxazine formation process was developed using naphthoqui-
none, 6a and methyleneindoline, 8b as substrates to give spirooxazine, 9a
(Table 3). In agreement with observations made during the oxime formation,

3624
M. YORK AND R. A. EVANS
Table 3. One-pot oxime=spirooxazine formation
Entry
Solvent
Additive
Conditions
Yield (%)a
1
2
EtOH
EtOH
EtOH
EtOH
EtOH
EtOH
IPA
None
Et3N (1eq.)
70 ꢀC, 4 h
70 ꢀC, 3 h
70 ꢀC, 3 h
80 ꢀC, 4 h
80 ꢀC, 5 h
80 ꢀC, 5 h
80 ꢀC, 3 h
70 ꢀC, 4 h
70 ꢀC, 4 h
100 ꢀC, 3 h
100 ꢀC, 3 h
13b
18b
3
K2CO3 (1 eq.)
K2CO3 (1 eq.)
NaOAc (1 eq.)
NaOAc (2 eq.)
K2CO3 (1 eq.)
K2CO3 (1 eq.)
K2CO3 (1 eq.)
K2CO3 (1 eq.)
K2CO3 (1 eq.)
45b
4
46c
5
24b
6
49b
7
15b
8
CH3CN
Toluene
EtOH
EtOH
<10d
<10d
34e
9
10
11
25f
aIsolated yield.
b6a (1 eq.) and NH3OH.Cl (1.1 eq.) were stirred at RT for 1 h. 8b (1.3 eq.) and additive added, then the
mixture was heated as indicated.
c6a (1 eq.), 8a (1.3 eq.), NH3OH.Cl (1.1 eq.) and additive were stirred at RT for 1 h, then the mixture
was heated as indicated.
d6a (1 eq.), NH3OH.Cl (1.1 eq.) and additive were stirred at RT for 1 h. 8b (1.3 eq.) added, then the
mixture was heated as indicated.
eAs bbut 6b used as starting material to yield 9c.
fAs bbut 6c used as starting material to yield 9d.
reaction in the absence of a base or buffer proceeded in poor yield (Table 3, Entry 1).
This could, however, be improved to approximately 50% by the addition of either
K2CO3 (Table 3, Entry 3) or NaOAc (Table 3, Entry 6). While this is somewhat
lower than the 68% obtained when the reactions are performed in a stepwise fashion,
the reaction sequence as a whole can be performed in a much more efficient manner.
Reaction in a number of alternative solvents failed to increase the yield observed and
indeed resulted in a large drop in the isolated yield of the final product (Table 3,
Entries 7–9). The one-pot scheme was also performed successfully in the synthesis
of two further spirooxazines (Table 3, Entries 10–11).
CONCLUSION
In conclusion, the published synthesis of spirooxazine photochromic dye, 3 and
related compounds was investigated and improvements necessary to perform the
synthesis in a satisfactory yield were made. A one-pot oxime=spirooxazine formation
was also developed that allows the removal of a synthetic step from the process and
may be of use in the discovery of novel dyes. Synthesis of hydroxyl functionalised
green spirooxazines was achieved in very high yields and a report on the effect of
polymer conjugation to these dyes will be published elsewhere.
EXPERIMENTAL
All starting materials were purchased from Sigma-Aldrich and used without
further purification with the exception of hydroxylamine hydrochloride which was

60-ARYLAMINO PHOTOCHROMIC SPIROOXAZINES
3625
recrystallised from aqueous 75% ethanol[17] and 1,3,3-trimethyl-2-methyleneindoline
which was distilled under reduced pressure. Melting points were obtained using a
Gallenkamp capillary melting point apparatus and are uncorrected. NMR data were
collected on Bruker Av200 (200 MHz) or Bruker Av400 (400 MHz) spectrometers.
Unless otherwise specified CDCl3 was used as the solvent. Positive ion EI mass spec-
tra were run on a ThermoQuest MAT95XL mass spectrometer using an ionization
energy of 70 eV.
4-(4-(Diethylamino)phenyl)naphthalene-1,2-dione (6a): General
Procedure for the Arylation of Folin’s Reagent
A suspension of 1,2-napthoquinone-4-sulfonic acid sodium salt, 4 (8.00 g,
30.7 mmol) in a 9:1 mixture of water:MeOH (180 mL) was treated in one portion
with N,N-diethylaniline (4.59 g, 30.7 mmol) and stirred at 60 ꢀC for 18 h. The mixture
was then cooled, the MeOH removed in vacuo and the resulting suspension filtered.
The precipitate was then washed with water and oven dried at 50 ꢀC to give the title
1
product as a dark purple solid (4.50 g, 48%). H NMR data were identical to those
reported in the literature.[18]
4-(4-(Ethyl(2-hydroxyethyl)amino)phenyl)naphthalene-1,2-dione (6b).
Was obtained as a dark purple solid (6.80 g, 54%). Mp 161–163 ꢀC (dec). 1H
NMR (400 MHz); d8.20 (dd, 1H, J ¼ 1.3 and 7.5 Hz), 7.61–7.50 (m, 3H), 7.40 (d,
J ¼ 8.8 Hz, 2H), 6.84 (d, 2H, J ¼ 8.8 Hz), 6.43 (s, 1H), 3.89 (q, J ¼ 3.9 Hz, 2H),
3.60–3.50 (m, 4H), 1.63 (t, J ¼ 5.7 Hz, 1H) and 1.25 (t, J ¼ 7.1 Hz, 3H). MS (EI);
m=z ¼ 321 [Mþ].
4-(4-Morpholinophenyl)naphthalene-1,2-dione (6c). Was obtained as a
red solid (0.26 g, 45%). Mp 170–172 ꢀC. 1H NMR (200 MHz); d8.20 (dd, 1H,
J ¼ 1.6 and 7.1 Hz), 7.63–7.38 (m, 5H), 6.99 (d, 2H, J ¼ 8.7 Hz), 6.43 (s, 1H), 3.90
(t, J ¼ 4.9 Hz, 4H) and 3.29 (t, J ¼ 4.9 Hz, 4H). MS (EI); m=z ¼ 319 [Mþ].
4-(4-(Diethylamino)phenyl)-2-(hydroxyimino)naphthalen-1(2h)-one
(7a): General Procedure for Oxime Formation
A suspension of 4-(4-(diethylamino)phenyl)naphthalene-1,2-dione 6a (3.00 g,
9.84 mmol) in absolute ethanol (75 mL) was treated in one portion with hydroxyla-
mine hydrochloride (1.37 g, 19.67 mmol) and stirred at room temperature for 1 h.
The mixture was then evaporated in vacuo and the residue suspended in H2O
(100 mL). The aqueous phase was then basified to pH10 with ammonium hydroxide
solution and extracted into EtOAc (x4). The combined organic phases were then
dried (Na2SO4) and evaporated in vacuo to afford the title compound as a dark
red solid (3.15 g, >95%). Mp 165–168 ꢀC (dec.) (lit. 176–178 ꢀC).[3] 1H NMR
(200 MHz, d6 DMSO); d8.12 (dd, 1H, J ¼ 1.3 and 7.6 Hz), 7.70–7.45 (m, 3H), 7.25
(d, J ¼ 8.7 Hz, 2H), 6.91 (s, 1H), 6.74 (d, J ¼ 8.7 Hz, 2H), 3.36 (q, J ¼ 6.9 Hz, 4H)
and 1.10 (t, J ¼ 6.9 Hz, 6H). MS (EI); m=z ¼ 320 [Mþ].
4-(4-(Ethyl(2-hydroxyethyl)amino)phenyl)-2-(hydroxyimino)naphthalen-
1(2h)-one (7b). Was obtained as a dark red solid (9.10 g, >95%). Mp 180–181 ꢀC.

3626
M. YORK AND R. A. EVANS
1H NMR (200 MHz, d6 DMSO); d8.12 (dd, 1H, J ¼ 1.2 and 7.6 Hz), 7.71–7.40 (m,
3H), 7.25 (d, J ¼ 8.5 Hz, 2H), 6.90 (s, 1H), 6.76 (d, 2H, J ¼ 8.6 Hz), 3.60–3.30 (m,
6H) and 1.10 (t, J ¼ 6.8 Hz, 3H). MS (EI); m=z ¼ 336 [Mþ].
2-(Hydroxyimino)-4-(4-morpholinophenyl)naphthalen-1(2H)-one (7c). Was
obtained as a red solid (0.11 g, 90%). Mp 104–107 ꢀC (dec.). 1H NMR (200 MHz, d6
DMSO); d8.13 (dd, 1H, J ¼ 1.3 and 7.8 Hz), 7.70–7.30 (m, 5H), 7.05 (d, J ¼ 8.7 Hz,
2H), 6.92 (s, 1H), 3.75 (t, J ¼ 4.6 Hz, 4H) and 3.18 (t, J ¼ 4.7 Hz, 4H). MS (EI); m=
z ¼ 334 [Mþ].
1-Isobutyl-3,3-dimethyl-2-methyleneindoline (8a). A mixture of 2,3,3-
trimethylindolenine (3.15 g, 19.78 mmol) and 1-iodo-2-methylpropane (3.44 mL,
29.70 mmol) in 1,4-dioxane were heated in a sealed tube at 115 ꢀC for 72 h. The
mixture was then cooled, poured into Et2O (150 mL) and the liquors decanted.
The residue was then washed with three further Et2O portions and dried in vacuo.
The residual hygroscopic purple glass was suspended in H2O (100 mL), treated with
KOH (1.12 g, 19.83 mmol) and stirred rapidly at room temperature for 30 min after
which time the mixture was extracted with Et2O (x3), dried with Na2SO4 and evapo-
rated to a brown oil which was purified by column chromatography eluting with
0–10% v=v EtOAc=petroleum ether 40–60 to afford the title product as an orange
1
oil (1.28 g, 30%) which was stored in a freezer until used. H NMR (200 MHz); d
7.14–7.06 (m, 2H), 6.74 (t, J ¼ 7.7 Hz, 1H), 6.54 (d, J ¼ 7.6 Hz, 1H), 3.85 (dd,
J ¼ 1.8 and 8.7 Hz, 2H), 3.29 (d, J ¼ 7.5 Hz, 2H), 2.21 (septet, J ¼ 6.9 Hz, 1H), 1.34
(s, 6H) and 0.95 (d, J ¼ 6.7 Hz, 6H).
2-(Ethyl(4-(1,3,3-trimethylspiro[indoline-2,2’-naphtho[1,2-
b][1,4]oxazine]-6’yl)phenyl)amino)ethanol (9c): General Procedure
for Spirooxazine Formation
A suspension of 4-(4-(ethyl(2-hydroxyethyl)amino)phenyl)-2-(hydroxyimino)
naphthalen-1(2H)-one, 7b (4.00 g, 11.89 mmol) in anhydrous ethanol (100 mL) was
treated with 1,3,3-trimethyl-2-methyleneindoline, 8b (2.68 g, 15.46 mmol) in one por-
tion and heated to 100 ꢀC in a sealed tube for 3 h. The mixture was then cooled to
room temperature and left to stand overnight. The resulting suspension was evapo-
rated in vacuo to approx. 25 mL total volume, MeOH added (25 mL) and the mixture
stored in the freezer for 3 hrs. After this time the product was collected by filtration
and washed with a little MeOH to afford the title compound as pale green fibres
1
(4.15 g, 73%). Mp 174–175 ꢀC. H NMR (200 MHz); d 8.10–7.88 (m, 2H), 7.72 (s,
1H), 7.49 (s, 1H), 7.42–7.19 (m, 5H), 7.12 (d, J ¼ 6.9 Hz, 1H), 6.96–6.83 (m, 3H),
6.60 (d, J ¼ 7.7 Hz, 1H), 3.87 (q, J ¼ 4.8 Hz, 2H), 3.60–3.20 (m, 4H), 2.78 (s, 3H),
1.83 (t, J ¼ 5.7 Hz, 1H), 1.39 (d, J ¼ 3.7 Hz, 6H) and 1.25 (t, J ¼ 7.0 Hz, 3H). MS
(EI); m=z ¼ 491 [Mþ].
N,N-diethyl-4-(1-isobutyl-3,3-dimethylspiro[indoline-2,2’-naphtho[1,2-b]
[1,4]oxazine]-6’-yl)aniline (3). Was obtained as a green solid (0.17 g, 58%) after
purification by column chromatography eluting with 0–5% v=v EtOAc=petroleum
ether 40–60. Mp 161–163 ꢀC (lit. 166.5–168.5 ꢀC).[3] 1H NMR (200 MHz); d8.06–
7.94 (m, 2H), 7.72 (s, 1H), 7.47 (s, 1H), 7.42–7.17 (m, 5H), 7.09 (dd, J ¼ 1.1 and

60-ARYLAMINO PHOTOCHROMIC SPIROOXAZINES
3627
6.9 Hz, 1H), 6.93–6.77 (m, 3H), 6.61 (d, J ¼ 7.7 Hz, 1H), 3.44 (q, J ¼ 7.1 Hz, 4H),
3.10–2.86 (m, 2H), 2.19–1.97 (m, 1H), 1.39 (d, J ¼ 2.1 Hz, 6H), 1.24 (t, J ¼ 7.1 Hz,
6H) and 0.95 (dd, J ¼ 6.6 and 10.5 Hz, 6H). MS (EI); m=z ¼ 517 [Mþ].
N,N-Diethyl-4-(1,3,3-trimethylspiro[indoline-2,2’-naphtho[1,2-b][1,4]
oxazine]-6’-yl)aniline (9a). Was obtained as a light green foam (0.10 g, 68%) after
purification by column chromatography eluting with 0–3% v=v EtOAc=petroleum
ether 40–60. Mp 128–131 ꢀC. 1H NMR (200 MHz); 8.07–7.94 (m, 2H), 7.72 (s,
1H), 7.49 (s, 1H), 7.42–7.18 (m, 5H), 7.11 (d, J ¼ 7.2 Hz, 1H), 6.95–6.77 (m, 3H),
6.60 (d, J ¼ 7.8 Hz, 1H), 3.44 (q, J ¼ 7.1 Hz, 4H), 2.80 (s, 3H), 1.39 (d, J ¼ 3.5 Hz,
6H) and 1.24 (t, J ¼ 7.0 Hz, 6H). d MS (EI); m=z ¼ 475 [Mþ].
2-(Ethyl(4-(1-isobutyl-3,3-dimethylspiro[indoline-2,2’-naphtho[1,2-b][1,4]
oxazine]-6’-yl)phenyl)amino)ethanol (9b). Was obtained as a light green foam
(1.60 g, 84%) after purification by column chromatography eluting with 10–50%
1
v=v EtOAc = petroleum ether 40–60. Mp 180–183 ꢀC (dec.). H NMR (200 MHz);
8.06–7.89 (m, 2H), 7.73 (s, 1H), 7.46 (s, 1H), 7.39–7.29 (m, 4H), 7.19 (dd, J ¼ 1.2
and 7.6 Hz, 1H), 7.10 (d, J ¼ 6.4 Hz, 1H), 6.91–6.81 (m, 3H), 6.62 (d, J ¼ 7.8 Hz,
1H), 3.89 (q, J ¼ 5.8 Hz, 2H), 3.58–3.45 (m, 4H), 3.10–2.80 (m, 2H), 2.19–2.00 (m,
1H), 1.39 (d, J ¼ 2.1 Hz, 6H), 1.24 (t, J ¼ 7.0 Hz, 3H) and 0.95 (dd, J ¼ 6.6 and
10.6 Hz, 6H). d MS (EI); m=z ¼ 533 [Mþ].
1,3,3-Trimethyl-6’-(4-morpholinophenyl)spiro[indoline-2,2’-naphtho[1,2-
b][1,4]oxazine] (9d). Was obtained as a pale brown foam (0.05 g, 40%) after
purification by column chromatography eluting with 0–25% v=v EtOAc=petroleum
1
ether 40–60. Mp 200–204 ꢀC. H NMR (200 MHz); 8.08–8.03 (m, 1H), 7.89–7.85
(m, 1H), 7.72 (s, 1H), 7.48 (s, 1H), 7.44–7.31 (m, 4H), 7.25–6.84 (m, 5H), 6.60 (d,
J ¼ 7.7 Hz, 1H), 3.91 (t, J ¼ 4.8 Hz, 4H), 3.26 (t, J ¼ 4.8 Hz, 4H), 2.80 (s, 3H) and
1.39 (d, J ¼ 3.3 Hz, 6H). d MS (EI); m=z ¼ 489 [Mþ].
ACKNOWLEDGMENTS
The authors thank the Co-operative Research Centre for Polymers and CSIRO
Molecular and Health Technologies for their support.
REFERENCES
1. Lokshin, V.; Samat, A.; Metelitsa, A. V. Spirooxazines: Synthesis, structure, spectral and
photochromic properties. Russ. Chem. Rev. 2002, 71, 893–916.
2. Bouas-Laurent, H.; Durr, H. Organic photochromism. Pure Appl. Chem. 2001, 73, 639–
665.
3. Clarke, D. A.; Heron, B. M.; Gabbutt, C. D.; Hepworth, J. D.; Partington, S. M.; Corns,
S. N. Photochromic compounds. U.S. Patent 6,303,673, Oct. 16, 2001.
4. Rickwood, M.; Marsden, S. D.; Askew, V. E. Photochromic spiroxazine compounds. U.S.
Patent 5,446,150, Apr. 29, 1995.
5. Ercole, F.; Davis, T. P.; Evans, R. A. Comprehensive modulation of naphthopyran photo-
chromism in a rigid host matrix by applying polymer conjugation. Macromolecules 2009,
42, 1500–1511.

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6. Malic, N.; Campbell, J. A.; Evans, R. A. Superior photochromic performance of
napthopyrans in a rigid host matrix using polymer conjugation: Fast, dark and tuneable.
Macromolecules 2008, 41, 1206–1214.
7. Such, G. K.; Evans, R. A.; Davis, T. P. The use of block copolymers to systematically
modify photochromic behaviour. Macromolecules 2006, 39, 9562–9570.
8. Malic, N.; Evans, R. A. Synthesis of carboxylic acid and ester mid-functionalized
polymers using RAFT polymerization and ATRP. Aust. J. Chem. 2006, 59, 763–771.
9. Such, G. K.; Evans, R. A.; Davis, T. P. Rapid photochromic switching in a rigid polymer
matrix using living radical polymerisation (ATRP). Macromolecules 2006, 39, 1391–1396.
10. Evans, R. A.; Such, G. K. Research trends in photochromism: Control of photochromism
in rigid polymer matrices and other advances. Aust. J. Chem. 2005, 58, 825–830.
11. Evans, R. A.; Hanley, T. L.; Skidmore, M. A.; Davis, T. P.; Such, G. K.; Yee, L. H.; Ball,
G. E.; Lewis, D. A. The generic enhancement of photochromic dye switching speeds in
rigid polymer matrices. Nat. Mater. 2005, 4, 294–253.
12. Such, G. K.; Evans, R. A.; Davis, T. P. Tailoring photochromic performance of
polymer-dye conjugates using living radical polymerization (ATRP). Liq. Cryst. Mol.
Cryst. 2005, 430, 273–279.
13. Such, G.; Evans, R. A.; Davis, T. P. Control of photochromism through local environ-
ment effects using living radical polymerisation. Macromolecules 2004, 37, 9664–9666.
14. Such, G.; Evans, R. A.; Yee, L. H.; Davis, T. P. Factors influencing photochromism of
spiro—compounds with polymeric matrices. J. Macromol. Sci. Part C Polymer Reviews
2003, C43, 547.
15. Yoshida, K.; Koujiri, T.; Oga, N.; Ishiguro, M.; Kubo, Y. The effect of metal chelate
complexation on the reactivity and absorption spectra of 1,2-naphthoquinones: The
synthesis of new types of near i.r. absorbing dyes. J. Chem. Soc., Chem. Commun. 1989,
708–710.
16. Arsenov, V. D.; Gorelik, A. M.; Strokach, Y. P.; Barachevsky, B. A.; Alfimov, M. V.
1-N-alkyl-50-[(N’-(un)substituted)amido]spiroindolino naphthoxazines, their preparation,
compositions and (co)polymer matrices containing them. European Patent 1044978,
Oct. 18, 2000.
17. Armarego, W. L. F.; Perrin, D. D. Purifcation of Laboratory Chemicals; Butterworth
Heinemann: Oxford, 1997.
18. Ooyama, Y.; Nagano, S.; Okamura, M.; Yoshida, K. Solid-State Fluorescence
changes of 2-(4-cyanophenyl)-5-[4-(diethylamino)-phenyl]-3H-imidazo[4,5-a]naphthalene
upon inclusion of organic solvent molecules. Eur. J. Org. Chem. 2008, 5899–5906.

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