Oxidation of 1-acyl-2-naphthol oximes: peri- and o-cyclisation and spiro cyclodimerisation of naphthoquinone nitrosomethide intermediates

Article abstract of DOI:10.1016/S0040-4020(01)00189-2

The oxidation of 2-hydroxynaphthaldehyde oxime with lead(IV) acetate (LTA) gave a mixture of naphtho[1,8-de][1,2]oxazine and a spiro dimer. LTA oxidation of 6-bromo (or nitro)-2-hydroxynaphthaldehyde oximes provided only spiro dimers. Similar treatment of (2-hydroxy-1-naphthyl)keto oximes with LTA gave naphtho[1,8-de][1,2]oxazines and benzo[cd]indol-3(1H)-ones. Low temperature oxidation of 1-(2-hydroxy-1-naphthyl)propan-1-one oxime furnished 2-ethylbenzo[cd]indol-3(1H)-one and 1-ethylnaphtho[1,2-d]isoxazole-2-oxide. peri- and o-Naphthoquinone nitrosomethides are invoked as intermediates that undergo peri- and o-cyclisation and intermolecular cyclodimerisation.

Full text of DOI:10.1016/S0040-4020(01)00189-2

TETRAHEDRON
Pergamon
Tetrahedron 57 .2001) 3445±3453
Oxidation of 1-acyl-2-naphthol oximes: peri- and o-cyclisation and
spiro cyclodimerisation of naphthoquinone
nitrosomethide intermediates
a
b
c
a
Â
Paraskevi Supsana, Petros G. Tsoungas, Andre Aubry, Stavroula Skoulika and
George Varvounisa,p
aDepartment of Chemistry, University of Ioannina, 451 10 Ioannina, Greece
bDepartment of Research and Technology, Ministry of Development, Messogeion Ave. 14±18, 115 10 Athens, Greece
Â
Laboratoire de Cristallographie et Modelisation des Materiaux Mineraux et Biologiques *LCM3B), Universite Henri Poincare Nancy I,
ESA7036, BP 239, 54506 Vandoeuvre les Nancy Cedex, France
c
Received 6 December 2000; revised 24 January 2001; accepted 8 February 2001
AbstractÐThe oxidation of 2-hydroxynaphthaldehyde oxime with lead.IV) acetate .LTA) gave a mixture of naphtho[1,8-de][1,2]oxazine
and a spiro dimer. LTA oxidation of 6-bromo .or nitro)-2-hydroxynaphthaldehyde oximes provided only spiro dimers. Similar treatment of
.2-hydroxy-1-naphthyl)keto oximes with LTA gave naphtho[1,8-de][1,2]oxazines and benzo[cd]indol-3.1H)-ones. Low temperature oxi-
dation of 1-.2-hydroxy-1-naphthyl)propan-1-one oxime furnished 2-ethylbenzo[cd]indol-3.1H)-one and 1-ethylnaphtho[1,2-d]isoxazole-2-
oxide. peri- and o-Naphthoquinone nitrosomethides are invoked as intermediates that undergo peri- and o-cyclisation and intermolecular
cyclodimerisation. q 2001 Elsevier Science Ltd. All rights reserved.
Compounds that incorporate the 1,2,5-oxadiazole nucleus
have been reported to possess a wide-range of interesting
and varying biochemical and pharmacological properties.
They are useful herbicides, plant-growth regulators and
pesticides, and in analytical chemistry ¯uorigenic reagents.
Certain nitro-furazans and furoxans can act as propellants
and explosives.1 Monocyclic and fused isoxazoles have
found diverse applications in medicine and agriculture.
Some derivatives are also used in batteries, photographic
emulsion and ®bre dyes.2
pyrano[4,5-c]furazan)}-2-one-110-oxide 3 in 17 and 14%
yield on average, respectively. Compound 2 was identical
in all respects to the respective compound isolated initially.3
1
Compound 3 was fully characterised by H and 13C NMR
spectroscopy, mass spectrometry and with the aid of DQF-
COSY, DEPT, HMQC and HMBC spectra. Furthermore
the structure of 3 was unambiguously assigned by X-ray
crystallography .Fig. 1).
Some characteristic structural features of 3 are given below.
The tetracyclic system and the bicyclic system are almost
planar with the sp3-hybridised carbon deviating from the
Ê
Ê
mean plane by 0.2A from the former and by 0.1 A from
the latter. The angles between the mean planes of the two
ring systems are 948. The arrangement of atoms around the
sp3-hybridised carbon is that of a distorted tetrahedron.
The three sp3±sp2 bond distances are typical of single
bonds. The C22±C13±C14 bond angle of 114.78 is slightly
larger than 1098 due to the extended conjugated system. For
1. Results and discussion
In a recent communication, we described the simultaneous
o- and peri-cyclisation of 2-hydroxy-1-naphthaldehyde
oxime 1 with lead.IV) acetate .LTA) that gave a mixture
of the isomeric naphtho[1,8-de][1,2]oxazine 2 and naph-
tho[1,2-d]isoxazole-2-oxide 7 .Scheme 1).3 In order to
study the chemistry of compounds 2 and 7 scaled-up
preparations were required and so the reaction was repeated
several times. Thorough chromatographic analysis in all
cases revealed, each time, a mixture of two major com-
ponents. The compounds isolated were naphtho[1,8-de][1,2]-
oxazine 2 and spiro{naphthalene-1.2H),40-.naphtho[20,10:2,3]-
Ê
the same reason the C21±C22 bond distance of 1.431 .3) A
Ê
and C19±C20 bond distance of 1.447 .3) A have partial
double bond character. Also the C10±O2bond distance of
Ê
1.373 .2) A is, as expected, shorter than a typical C±O
single bond. The bond lengths and angles of the furoxan
ring are similar to those observed in the non-fused furoxan
ring.1b,e An intramolecular hydrogen bond of the type C2±
H2´´´N1 is probably formed as evidenced by the C2´´´N1
Keywords: naphthalenes; oximes; oxidation; N-oxides; spiro compounds.
Corresponding author. Tel.: 130-651-98-382; fax: 130-651-98-799;
e-mail: gvarvoun@cc.uoi.gr
Ê
p
bond distance of 2.981 .2) A, the H2´´´N1 bond distance of
Ê
2.281 .5) A and a C2±H2´´´N1 bond angle of 1308.
0040±4020/01/$ - see front matter q 2001 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020.01)00189-2

3446
P. Supsana et al. / Tetrahedron 57 *2001) 3445±3453
Scheme 1. Reagents: .a) Pb.OAc)4, THF, 08C 2h, room temperature 12h.
According to our earlier proposal, compounds 2 and 7 origi-
nate from an organolead intermediate formed from the
reaction of 1 with LTA. The intermediate decomposes
into the corresponding peri- and o-naphthoquinone nitro-
somethides 4 and 6, which then undergo peri- and o-cycli-
sation, respectively.3 The new ®ndings suggest that the
N-oxide 7 appears to be very sensitive and quite unstable
to the reaction conditions. A similar dif®culty was encoun-
tered in the synthesis of the benzo analogue of 7.4 Further-
more, spiro compound 3 is a dimer of naphthoquinone
nitrosomethides 4/6. An analogous dimer has been synthe-
sised from in situ generated o-benzoquinone methide.5
Taking these facts into consideration it was imperative to
explain the formation of 3 and the instability of 7.
31 were selected as appropriate precursors. Oximes 10 and
14 were prepared from the corresponding aldehydes 96 and
127 by standard methods. Aldehyde 12 and 2-hydroxy-1,6-
dinitronaphthalene 13 were obtained as a mixture by treat-
ing 2-hydroxy-1-naphthaldehyde 1 with 85% nitric acid.
Column chromatography of the mixture gave 12 and 13 in
46 and 50% yield, respectively. Oxidation of oximes 10 and
14 with LTA, using the standard procedure of stirring ®rst at
08C for 2h and then at room temperature for 12h, provided
the corresponding spiro dimers 11 and 15 in 25% yield, in
each case. No traces of any other products were detected in
these two reactions .Scheme 2). All these compounds were
1
characterised by H and 13C NMR spectroscopy, low-reso-
lution mass spectrometry, HRMS measurements or elemen-
tal analyses, and by comparison with the spectra of related
compounds. Furthermore, the carbon atoms of spiro dimer
To this end, aldoximes 10 and 14 and ketoximes 21, 25 and
Figure 1. ORTEP diagram of molecule 3 .thermal ellipsoids at 40% probability).

P. Supsana et al. / Tetrahedron 57 *2001) 3445±3453
3447
Scheme 2. Reagents: .a) H2NOH´HCl, pyridine, n-butanol, re¯ux, 1 h; .b) Pb.OAc)4, THF, 08C 2h, room temperature 12h; .c) 85% HNO 3, 258C 20 min.
11 were fully assigned with the aid of DQF-COSY, DEPT,
HMQC and HMBC spectra. Characteristic features in the 1H
and 13C NMR spectra of spiro dimers 3, 11 and 15 are the
following. The J values 10.0, 10.1 and 10.2Hz of the a,b-
unsaturated protons, the down®eld H-80 protons at d 8.96,
8.81 and 8.98, the sp3-hybridised carbon atoms at d 76.46,
76.21 and 77.28, and the carbonyl carbon atoms at d 190.96,
190.30 and 189.64, respectively.
Ketoximes 21, 25 and 31 were synthesised by reacting the
corresponding ketones 20, 24 and 308 with hydroxylamine
hydrochloride. The reaction of 20 by this method resulted in
the isolation of two isomeric products E-ketoxime 21a
.45%) and Z-ketoxime 21b .14%) .Scheme 4). Vijayakumar
et al.9 have reported the synthesis of oxime 21 as an isomer
mixture. The assignment of 21a to the E-isomer was
con®rmed by NMR spectroscopy. The sharp exchangeable
peak at d 9.79 is characteristic of a hydrogen-bonded
proton. Hydrogen bonding can occur between the hydroxyl
proton of naphthol and the lone-pair of electrons of the
nitrogen atom. In the NOESY spectrum of 21a there is a
cross peak between the methyl group at d 2.14 and H-8 at d
7.76, whereas no such cross peak is seen in the correspond-
Oxidation of oximes 10 and 14 did not furnish the corre-
sponding naphtho[1,8-de][1,2]oxazines. This can be
adequately explained by the conjugative effects of the
substituents at C-6 of the naphthalene nucleus. Thus it
appears that peri-cyclisation is not likely through contri-
bution of resonance structures 17 and 19, which allow free
rotation of the NvO moiety .Scheme 3).
1
ing spectrum of 21b. In the H NMR spectrum of 21b the
chemical shift of H-8 is at d 7.37. The deprotection of H-8 in
Scheme 3.

3448
P. Supsana et al. / Tetrahedron 57 *2001) 3445±3453
Scheme 4. Reagents: .a) H2NOH´HCl, aq. MeCO2Na, n-butanol, re¯ux, 2h; .b) Pb.OAc) 4, THF, 08C 2h, room temperature 12h; .c) Pb.OAc) 4, THF, 08C 2 h.
21a is therefore most likely due to steric hindrance from the
methyl group. In E-isomer 21a the methyl group is in the
vicinity of H-8 because of the six-membered ring formed by
hydrogen bonding. This six-membered ring is co-planar
with the naphthol ring.
opening of the isoxazole-N-oxide ring to give intermediate
peri- and/or o-naphthoquinone nitrosomethides as shown
for isoxazole-N-oxide 7 in Scheme 1. Cyclisation of the
appropriate peri-naphthoquinone nitrosomethide would
then give the more stable oxazine 32.
Treatment of ketoximes 21a, 21b or 25 with LTA by the
standard procedure furnished oxazines 22 or 26 and
benzo[cd]indol-3.1H)-ones 23 or 27, respectively .Scheme
4). It is proposed that 23/27 originate from peri-attack by the
nitrogen atom of the nitroso group of 28 to give 29. The
latter tautomerises into 23/27. An analogous dual behaviour
by a nitroso group was reported for the intramolecular cycli-
sation of nitroso intermediates, formed from N-aryl-S,S-
dimethylsul®mides and benzonitrile oxides, that gave
benzimidazole-3-oxides and benzoxadiazines.10 A com-
pound closely related to 23/27 is 1,2,5-trimethylbenzo[cd]-
indol-3.1H)-one, which has been synthesised by heating
4-.1,2-dimethyl-1H-indol-3-yl)butan-2-one in PPA.11 Oxi-
dation of Z-oxime 31 with LTA gave oxazine 32 in 38%
yield. When the reaction of 25 with LTA was stopped after
2h stirring at 0 8C benzo[cd]indol-3.1H)-one 27 .10%) and
isoxazole-N-oxide 33 .23%) were isolated. The last reaction
provides direct evidence that oxazine 26 is formed from
isoxazole-N-oxide 33. Reaction of 33 with LTA for 12h
at room temperature afforded 26 in near quantitative yield.
A most likely route proposed for this transformation is ring
All compounds in Scheme 4 were satisfactorily charac-
1
terised by H and 13C NMR spectroscopy, low-resolution
mass spectrometry and from HRMS measurements or
elemental analyses. The carbon atoms in compounds 22,
23 and 27 were fully assigned from their DQF-COSY,
DEPT, HMQC and HMBC spectra. Characteristic features
in the 1H and 13C NMR spectra of oxazines 2,3 22, 26 and 32
are the following. The protons of the 4-OH groups at d
10.61, 10.39, 10.50 and 10.10, C-4 at d 148.44, 149.97,
149.28 and 149.95, and C-9a at d 150.72, 151.07, 151.10
and 150.97, respectively. On the other hand, the charac-
1
teristic features in the H and 13C NMR spectra of benzo-
[cd]indol-3.1H)-ones 23 and 27 are the J value 9.6 Hz of the
a,b-unsaturated protons for both compounds and the car-
bonyl carbon atoms at d 178.02and 177.50, respectively.
The results in Scheme 4 ®t very well into our initial proposal
regarding naphthoquinone nitrosomethides intermediates 4
and 6 undergoing peri- and o-cyclisation and explain
adequately the instability of isoxazole-N-oxide 7.4 Further-
more, oxidation of oximes E-21a and Z-21b con®rms that

P. Supsana et al. / Tetrahedron 57 *2001) 3445±3453
3449
Scheme 5.
these cyclisation modes occur regardless of the E- or
Z-oxime con®guration.
naphtho[1,8-de][1,2]oxazine. The spiro compounds are
dimers of the proposed intermediate peri- and/or o-naphtho-
quinone nitrosomethides. The oxidation of .2-hydroxy-1-
naphthyl)ethan-1-one.or propan-1-one) oximes at ambient
temperature afforded benzo[cd]indol-3.1H)-ones and
naphtho[1,8-de][1,2]oxazines, products of peri-intramolec-
ular cyclisation of appropriate naphthoquinone nitroso-
methides. In contrast, oxidation of 1-.2-hydroxy-1-
naphthyl).phenyl)methanone oxime gave only 4-hydroxy-
3-phenylnaphtho[1,8-de][1,2]oxazine. Evidence for the
instability of naphtho[1,2-d]isoxazole-2-oxides in solution
is provided both directly and indirectly.
Based on these experimental observations and according to
molecular modelling studies, it is suggested that the for-
mation of spiro dimer 3 is the result of intermolecular cyclo-
dimerisation of 4, 6 or/and 4 and 6, as depicted by paths a
and b .Scheme 5). The reaction is chemoselective in that
the nitroso group can activate the exocyclic double bond.
Addition of carbonyl oxygen of a second molecule gives
intermediate oxime 34. This initial step may be reversible.
Intermediate 34 may react with LTA12 to give the organo-
lead complex 35 .path a), which is then converted to the
dinitrile oxide 36, ultimately leading to product 3 via
carbon±carbon and nitrogen±oxygen bond formation.
Alternatively .path b) intermediate 34 undergoes intra-
molecular cyclisation by carbon±carbon bond formation
to furnish dinitroso pyran 37. The latter tautomerises to
dioxime 38 which oxidatively cyclises to 3. It is interesting
to note that LTA is involved in both rationales either prior to
or after carbon±carbon bond formation. Both dimerisation
of nitrile oxides1 and oxidation of 1,2-dioximes1 are well-
documented precursors of 1,2,5-oxadiazole-N-oxides
.furoxans). In the light of the evidence at hand, alternative
plausible pathways involving free radical mechanisms or
other organolead species cannot be ruled out.
3. Experimental
3.1. General methods
Melting points were taken on a BuÈchi 510 apparatus and are
uncorrected. Infrared spectra were recorded on a Perkin±
Elmer 257 spectrometer, as Nujol mulls between sodium
chloride discs. Elemental analyses were performed on a
Carlo Erba 1106 elemental analyser. Nuclear magnetic reso-
nance spectra were measured at 300 MHz on a BruÈker AC
300 spectrometer or at 400 MHz on a BruÈker AMX 400
spectrometer using tetramethylsilane as internal standard.
Mass spectra were obtained by use of Finnigan 4500 .low
resolution) or JEOL JMS-AX 505W .high resolution)
instruments using EI. Analytical TLC was carried out on
Fluka silica gel 60 F254. Preparative ¯ash chromatography
was carried out using Merck 9385 silica gel. Solvents and
reagents were used as received from the manufacturers
except for dichloromethane, ethanol, ethyl acetate, hexane
and methanol, that were puri®ed and dried according to
recommended procedures.13
The mechanism of Scheme 5 takes into account the fact that
no spiro compound was detected after the oxidation of
ketoximes E-21a, Z-21b, .Z/E)-25 and .Z)-31.
2. Conclusion
In summary, it has been observed that the oxidation of
2-hydroxy-1-naphthaldehyde oximes leads to novel spiro
compounds while the parent oxime also produced 4-hydroxy-
3.1.1. Nitration of 2-hydroxy-1-naphthaldehyde. To an

3450
P. Supsana et al. / Tetrahedron 57 *2001) 3445±3453
aqueous solution of 85% nitric acid .10 mL) at 258C 1 .1 g,
6 mmol) was added in small portions during 10 min. After
the addition was complete stirring was continued for another
10 min at 258C. The mixture was poured into ice water and
the precipitate was ®ltered, washed with water and dried.
The residue was subjected to column chromatography .20%
ethyl acetate/hexane) to give two fractions. The ®rst fraction
gave 2-hydroxy-6-nitro-1-naphthaldehyde 12 and the
second fraction gave 1,6-dinitro-2-naphthol 13.
dC .100 MHz, DMSO-d6) 109.91, 120.20, 120.41, 125.02,
126.17, 126.53, 133.63, 134.45, 142.73, 146.43, 159.07; m/z
.EI) 232 .100, M1), 214 .51), 140 .68), 113 .40) 63 .18%);
HRMS .EI): M1, found 232.0478. C11H8N2O4 requires
232.0484.
3.3. Reaction of 1-.2-hydroxy-1-naphthyl)ethan-1-one, 1-
.2-hydroxy-1-naphthyl)propan-1-one and .2-hydroxy-1-
naphthyl).phenyl)methan-1-one with hydroxylamine
hydrochloride:9 general procedure B
3.1.2. 2-Hydroxy-6-nitro-1-naphthaldehyde .12). 0.6 g,
46% as pale yellow powder, mp 235±2378C .lit.7 mp
; dH
Hydroxylamine hydrochloride .3.1 g, 40 mmol) and sodium
acetate .3.7 g, 40 mmol) were dissolved in water .10 mL)
and added to a suspension of 20, 24 or 30 .10 mmol) in
n-butanol .70 mL). The resulting mixture was heated
under re¯ux for 2h. The solvent was removed in vacuo
and to the residue was added cold water .150 mL) and
extracted with dichloromethane .3£50 mL). The combined
organic extracts were dried .Na2SO4), concentrated in
vacuo, and the residue was puri®ed by column chroma-
tography .10, 20, 26, 50% ethyl acetate/hexane) to give in
the ®rst fraction .Z)-1-.2-hydroxy-1-naphthyl)ethan-1-
one oxime 21b and in the second fraction .E)-1-.2-
hydroxy-1-naphthyl)ethan-1-one oxime 21a, or chro-
matographed .20% ethyl acetate/hexane) to give .Z)/.E)-
1-.2-hydroxy-1-naphthyl)propan-1-one oxime 25 or
recrystallised to give .Z)-1-.2-hydroxy-1-naphthyl).phenyl)-
methanone oxime 31.
2398C); nmax .Nujol) 1640, 1550, 1350 cm21
.400 MHz; DMSO-d6) 7.43 .1H, d, Jˆ9.1 Hz, H-3), 8.32
.1H, d, Jˆ9.1 Hz, H-7), 8.43 .1H, d, Jˆ9.1 Hz, H-8), 8.91
.1H, s, H-5), 9.17 .1H, d, Jˆ9.1 Hz, H-4), 10.77 .1H, s,
CHO), 12.21 .1H, s, br, OH); m/z .EI) 217 .100, M1), 171
.31), 115.1 .67), 63 .36%); HRMS .EI): M1, found
217.0248 C11H7NO4 requires 217.0375.
3.1.3. 1,6-Dinitro-2-naphthol .13). 0.7 g, 50% as pale
yellow powder, mp 190±1938C; nmax .Nujol) 3330, 1535,
1345 cm21; dH .400 MHz; DMSO-d6) 7.51 .1H, d, Jˆ
9.1 Hz, H-3), 7.76 .1H, d, Jˆ9.3 Hz, H-8), 8.32.1H, d,
Jˆ9.3 Hz, H-7), 8.37 .1H, d, Jˆ9.1 Hz, H-4), 9.02.1H, s,
H-5), 12.26 .1H, s, br, OH); dC .100 MHz, DMSO-d6)
120.74, 121.29, 122.29, 125.23, 125.29, 128.26, 133.08,
134.87, 143.48, 151.43; m/z .EI) 234 .100, M1), 189 .41),
114 .69), 102.33%); HRMS .EI): M 1, found 234.0279.
C10H6N2O5 requires 234.0276.
3.3.1. .E)-1-.2-Hydroxy-1-naphthyl)ethan-1-one oxime
.21a). 0.9 g, 45% as colourless powder, mp 130±1328C
[Found: C, 71.60; H, 5.48; N, 6.98; C12H11NO2 requires:
C, 71.63; H, 5.51; N, 6.96%]; nmax .Nujol) 3400, 3300,
1650 cm21; dH .360 MHz; DMSO-d6) 2.14 .3H, s, Me),
7.21 .1H, d, Jˆ8.9 Hz, H-3), 7.27 .1H, td, Jˆ8.0, 1.2Hz,
H-7), 7.40 .1H, td, Jˆ8.0, 1.2Hz, H-6) 7.71 .1H, d,
Jˆ8.0 Hz, H-5), 7.76 .2H, m, H-4, H-8), 9.79 .1H, s,
OH), 11.00 .1H, s, NOH); dC .90 MHz, DMSO-d6) 14.07,
20.75, 116.82, 118.12, 127.57, 127.73 .2C), 130.47, 132.82,
150.68, 152.22, 152.57.
3.2. Reaction of 6-bromo-2-hydroxy-1-naphthaldehyde
and 2-hydroxy-6-nitro-1-naphthaldehyde with
hydroxylamine hydrochloride:9 general procedure A
A mixture of 96 or 127 .2g, 8 mmol) and hydroxylamine
hydrochloride .3 g, 40 mmol) in n-butanol .70 mL) contain-
ing pyridine .3 mL) was heated under re¯ux for 1 h. The
solvents were removed in vacuo and to the residue was
added cold water .150 mL). The resulting suspension was
®ltered, washed with water and dried to give either
6-bromo-2-hydroxy-1-naphthaldehyde oxime 10 or
2-hydroxy-6-nitro-1-naphthaldehyde oxime 14.
3.3.2. .Z)-1-.2-Hydroxy-1-naphthyl)ethan-1-one oxime
.21b). 0.28 g, 14% as colourless powder, mp 140±1418C
[Found: C, 71.59; H, 5.49; N, 7.01; C12H11NO2 requires:
C, 71.63; H, 5.51; N, 6.96%]; nmax .Nujol) 3315,
1620 cm21; dH .360 MHz; DMSO-d6) 2.11 .3H, s, Me),
7.19 .1H, d, Jˆ8.8 Hz, H-3), 7.27 .1H, td, Jˆ8.1, 1.5 Hz,
H-7), 7.37±7.42.2H, m, H-6, H-8), 7.74 .1H, d, Jˆ8.8 Hz,
H-4), 7.78 .1H, d, Jˆ8.2Hz, H-5), 9.73 .1H, s, br, OH),
10.27 .1H, s, br, NOH); dC .90 MHz, DMSO-d6) 15.96,
20.48, 118.20, 122.57, 123.69, 124.10, 126.22, 126.33,
127.87 .2C), 128.96, 129.25.
3.2.1. .E)-6-Bromo-2-hydroxy-1-naphthaldehyde oxime
.10). 1.2g, 57% as pale green needles .toluene), mp 244±
2478C; nmax .Nujol) 3310, 1630 cm21; dH .400 MHz;
DMSO-d6) 7.24 .1H, d, Jˆ9.0 Hz, H-3), 7.60 .1H, d,
Jˆ9.0 Hz, H-7), 7.83 .1H, d, Jˆ9.0 Hz, H-8), 8.10 .1H, s,
H-5), 8.49 .1H, d, Jˆ9.0 Hz, H-4), 8.96 .1H, s, CHvN),
11.11 .1H, s, OH), 11.53 .1H, s, NOH); dC .100 MHz,
DMSO-d6) 109.52, 116.44, 119.83, 125.87, 129.72, 130.26
.2C), 130.50, 130.96, 147.25, 156.58; m/z .EI) 265 .11,
M1), 249 .100), 219 .8) 194 .9), 170 .21), 140 .25), 113
.32), 87 .9), 63 .12%); HRMS .EI): M1, found 264.9727.
C11H8BrNO4 requires 264.9738.
3.3.3. .Z)/.E)-1-.2-Hydroxy-1-naphthyl)propan-1-one
oxime .25). 2.1 g, 98% as colourless powder, mp 112±
1168C [Found: C, 72.50; H, 6.12; N, 6.55; C13H13NO2
requires: C, 72.54; H, 6.09; N, 6.51%]; nmax .Nujol) 3320,
1620 cm21; dH [250 MHz, DMSO-d6, data assigned from a
mixture of .E)/.Z)ˆ1:1, diastereomeric ratio] 1.38 .3H, t,
Jˆ7.6 Hz, CH2CH3, Z-isomer), 1.53 .3H, t, Jˆ7.6 Hz,
CH2CH3, E-isomer), 3.07 .2H, q, Jˆ7.6 Hz, CH2CH3,
E-isomer), 3.21 .2H, q, Jˆ7.6 Hz, CH2CH3, Z-isomer),
7.68±7.94 .7H, m, benzenoid), 8.18±8.30 .5H, m,
3.2.2. .E)-2-Hydroxy-6-nitro-1-naphthaldehyde oxime
.14). 1.12g, 60% as yellow powder .propan-2-ol), mp
254±2578C; nmax .Nujol) 3420, 1660 cm21; dH .250 MHz;
DMSO-d6) 7.39 .1H, d, Jˆ9.0 Hz, H-3), 8.15±8.20 .2H, m,
H-7, H-8), 8.76 .1H, d, Jˆ9.0 Hz, H-4), 8.89 .1H, s, H-5)
8.94 .1H, s, CHvN) 11.57 .1H, s, OH) 11.64 .1H, s, NOH);

P. Supsana et al. / Tetrahedron 57 *2001) 3445±3453
3451
benzenoid), 10.00±11.00 .3H, s, br, NOH, OH, Z-isomer,
OH, E-isomer), 11.45 .1H, s, NOH, E-isomer); m/z .EI) 215
.43, M1), 197 .35), 182.28), 169 .100), 153 .8), 141 .17),
114 .25), 88 .6), 57 .8), 43 .27%).
as yellow needles .acetonitrile), mp 211±2148C; nmax
.Nujol) 1670, 1220 cm21; dH .400 MHz; CDCl3) 6.22
.1H, d, Jˆ10.0 Hz, H-3), 7.23 .1H, d, Jˆ9.0 Hz, H-30),
7.46±7.56 .5H, m, H-5, H-6, H-7, H-8, H-60), 7.60 .1H, d,
Jˆ10.0 Hz, H-4), 7.70 .1H, t, Jˆ8.3 Hz, H-70), 7.86 .1H, d,
Jˆ8.1 Hz, H-50), 7.96 .1H, d, Jˆ9.0 Hz, H-40), 8.96 .1H, d,
Jˆ8.5 Hz, H-80); dC .100 MHz; CDCl3) 76.46 .C-1/10),
104.02.C-8b 0), 108.92.11a 0), 118.00 .C-30), 123.05
.C-3), 125.53 .C-60), 125.70 .C-80), 128.70 .C-50), 128.78
.C-5), 129.17 .C-70), 129.44, .C-8a0), 129.83 .C-4a0),
130.01 .C-8), 130.87, .C-4a), 130.92.C-6), 131.03 .C-7),
3.3.4. .Z)-1-.2-Hydroxy-1-naphthyl).phenyl)methanone
oxime .31). 1.6 g, 61% as colourles powder .benzene/
hexane), mp 205±2068C [Found: C, 77.58; H, 5.02; N,
5.29; C17H13NO2 requires: C, 77.55; H, 4.98; N, 5.32%];
nmax .Nujol) 3410, 1620 cm21; dH .250 MHz; DMSO-d6)
7.24±7.44 .9H, m, benzenoid), 7.82±7.86 .2H, m, benze-
noid), 9.97 .1H, s, br, OH), 11.29 .1H, s, br, NOH); dC
.90 MHz; DMSO-d6) 114.13, 118.26, 122.65, 123.89,
125.93 .2C), 126.42, 127.65, 127.99, 128.32, 128.56,
129.56, 131.69, 136.30, 151.70, 152.19, 152.37; m/z .EI)
263 .44, M1), 245 .100), 231 .12), 217 .36), 202 .9), 140
.12), 114 .28), 103 .18), 78 .34), 51 .18), 44 .13%).
0
134.06 .C-8a), 134.92.C-4 ), 146.54 .C-8c0), 147.24 .C-4),
155.17 .C-2a0), 190.96 .C-2); m/z .EI) 368 .73, M1), 324
.27), 308 .30), 394 .41), 280 .63), 250 .100), 183 .63), 154
.26), 140 .30), 126 .45%); HRMS .EI): M1, found
368.0795. C22H12N2O4 requires 368.0797.
Crystal data of .3). C22H12N2O4. Mˆ368.34, monoclinic,
Ê
Ê
space group P21/c, aˆ9.3953 .4) A, bˆ13.9612.5) A ,
3.4. Oxidation of 2-hydroxy-1-naphthaldehyde oxime,
.E)-6-bromo-2-hydroxy-1-naphthaldehyde oxime,
.E)-2-hydroxy-6-nitro-1-naphthaldehyde oxime, .E)-1-
.2-hydroxy-1-naphthyl)ethan-1-one oxime, .Z)-1-.2-
hydroxy-1-naphthyl)ethan-1-one oxime, .Z/E)-1-.2-
hydroxy-1-naphthyl)propan-1-one oxime or .Z)-1-.2-
hydroxy-1-naphthyl).phenyl)methanone oxime with
lead.IV) acetate: general procedure
Ê
Ê 3
cˆ12.7471 .5) A, bˆ90.945 .10)8, Uˆ1671.81 .11) A ,
Zˆ4, DCˆ1.463 g cm23, mˆ0.103 mm21 .MoKa, lˆ
Ê
0.71073 A), Tˆ293 K. Of 7365 re¯ections measured on
an Enraf±Nonius Kappa CCD diffractometer and corrected
semiempirically for absorption, 3909 were unique
.Rintˆ0.058). The structure was solved by direct methods
and re®ned on F2 values. Hydrogen atoms were located by
difference Fourier maps and re®ned isotropically. Rˆ0.0449
[F values, I.2s.I)], wR2ˆ0.1186 .F2 values, all data),
goodness-of-®tˆ0.882, ®nal difference map extremes
A stirred solution of 10, 14, 21a, 21b, 25 or 31 .5 mmol) in
dry tetrahydrofuran .60 mL) under argon was cooled to 08C.
Lead.IV) acetate .4.43 g, 10 mmol) was added slowly over
a period of 30 min. The mixture was stirred at this tempera-
ture for 1.5 h and then stirred for a further 12h at room
temperature. The reaction mixture was ®ltered, the solid
was washed with tetrahydrofuran and the ®ltrate was evapo-
rated in vacuo to leave a residue. The residue was chro-
matographed .25, 33, 50% dichloromethane/hexane, 33,
50% ethyl acetate/hexane) to give in the ®rst fraction
.^)-spiro{naphthalene-1.2H),40-.naphtho[20,10:2,3]pyrano-
[4,5-c]furazan)}-2-one-110-oxide 3 and in the second
fraction 4-hydroxynaphtho[1,8-de][1,2]oxazine 2 or .25,
33%, dichloromethane/hexane) to give .^)-6,60-dibromo-
spiro-{naphthalene-1.2H),40-.naphtho[20,10:2,3]pyrano-
[4,5-c]furazan)}-2-one-110-oxide 11, or .25, 33%, ethyl
acetate/hexane) to give .^)-6,60-dinitrospiro{naphtha-
lene-1.2H),40-.naphtho-[20,10:2,3]pyrano[4,5-c]furazan)}-
2-one-110-oxide 15 or was triturated with acetonitrile and
®ltered to give 1-hydroxy-2-methyl-benzo[cd]indol-
3.1H)-one 23, the ®ltrate evaporated and the residue chro-
matographed .25% ethyl acetate/hexane) to give 4-hydroxy-
3-methyl-naphtho[1,8-de][1,2]oxazine 22, or chromato-
graphed .25, 33, 50% ethyl acetate/hexane, ethyl acetate) to
give 3-ethyl-4-hydroxynaphtho[1,8-de][1,2]oxazine 26
1-hydroxy-2-ethylbenzo[cd]indol-3.1H)-one 27 or was
chromatographed .25% ethyl acetate/hexane) to give
4-hydroxy-3-phenylnaphtho[1,8-de][1,2]oxazine 32.
Ê 23
10.145 and 20.184 e A . Software: shelxs-97, shelxl-
97.
3.4.3. .^)-6,60-Dibromospiro{naphthalene-1.2H),40-.naph-
tho[20,10:2,3]pyrano[4,5-c]furazan)}-2-one-110-oxide
.11). 0.65 g, 25% as yellow powder, mp 243±2458C
[Found: C, 50.19; H, 1.88; N, 5.35; C22H10Br2N2O4 requires:
C, 50.22; H, 1.92; N, 5.32%]; nmax .Nujol) 1680,
1240 cm21; dH .400 MHz; CDCl3) 6.25 .1H, d, Jˆ10.1
Hz, H-3), 7.25 .1H, d, Jˆ9.0 Hz, H-30), 7.44 .1H, d,
Jˆ8.0 Hz, H-8), 7.53 .1H, d, Jˆ10.1 Hz, H-4), 7.57±7.59
.2H, m, H-5, H-7), 7.76 .1H, d, Jˆ9.0 Hz, H-70), 7.87 .1H,
d, Jˆ9.0 Hz, H-40), 8.02.1H, s, H-5 0), 8.81 .1H, d,
Jˆ9.0 Hz, H-80); dC .100 MHz; CDCl3) 76.21 .C-1/10),
104.05 .C-8b0), 103.75 .C-11a0), 119.09 .C-30), 119.56
.C-60), 124.13 .C-3), 125.32 .C-6), 127.35 .C-80), 127.88
.C-8a0), 130.18 .C-8), 130.69 .C-50), 131.10 .C-4a0), 132.42
.C-70), 132.65 .C-4a), 132.69 .C-5, C-8a), 133.80 .C-7),
133.86 .C-40), 145.77 .C-4), 148.33 .C-8c0), 155.07
.C-2a0), 190.30 .C-2); m/z .EI) 524 .4, M1), 508 .2), 440
.5), 371 .9), 286 .6), 249 .62), 217 .11), 165 .34), 140 .24),
113 .29) 44 .100%).
3.4.4. .^)-6,60-Dinitrospiro{naphthalene-1.2H),40-.naph-
tho[20,10:2,3]pyrano[4,5-c]furazan)}-2-one-110-oxide
.15). 0.58 g, 25% as yellow powder, mp 255±2588C
[Found: C, 57.61; H, 2.17; N, 12.26; C22H10N4O8 requires:
C, 57.65; H, 2.20; N, 12.22%]; nmax .Nujol) 1690,
1230 cm21; dH .400 MHz; DMSO-d6) 6.52.1H, d, Jˆ
10.2Hz, H-3), 7.64 .1H, d, Jˆ9.1 Hz, H-30), 8.16 .1H, d,
Jˆ10.2Hz, H-4), 8.24 .1H, d, Jˆ8.6 Hz, H-8), 8.38 .1H,
dd, Jˆ8.6, 2.3 Hz, H-7), 8.52±8.66 .3H, m, H-5, H-40,
H-70), 8.98 .1H, d, Jˆ9.3 Hz, H-80), 9.16 .1H, d,
Jˆ2.4 Hz, H-50); dC .100 MHz; DMSO-d6) 77.28, 104.09,
3.4.1. 4-Hydroxynaphtho[1,8-de][1,2]oxazine .2). 0.15 g,
17% as pale green powder .benzene/hexane), mp 130±
1348C .lit.3 mp 130±1348C), identical in all respects to an
authentic sample.
3.4.2. .^)-Spiro{naphthalene-1.2H),40-.naphtho[20,10:2,3]-
pyrano[4,5-c]furazan)}-2-one-110-oxide .3). 0.23 g, 14%

3452
P. Supsana et al. / Tetrahedron 57 *2001) 3445±3453
118.50, 120.39, 122.74, 124.44 .3C), 125.26 .3C), 125.56,
126.29 .2C), 130.94, 131.26, 132.84, 137.40, 146.03,
149.55, 157.41 .C-2a0), 189.64 .C-2); m/z .EI) 458 .37,
M1), 442 .7), 414 .45), 384 .20), 353 .22), 324 .40), 279
.41), 239 .22), 230 .11), 214 .22), 165 .21), 98 .22), 44
.100%).
.32). 0.5 g, 38% as pale green powder, mp 148±1508C;
nmax .Nujol) 1640 cm21; dH .400 MHz; DMSO-d6) 6.72
.1H, d, Jˆ7.4 Hz, H-9), 7.00 .1H, d, Jˆ9.1 Hz, H-5), 7.17
.1H, t, Jˆ8.0 Hz, H-8), 7.24 .1H, d, Jˆ8.0 Hz, H-7), 7.41
.5H, m, benzenoid) 7.71 .1H, d, Jˆ9.1 Hz, H-6), 10.10 .1H,
s, OH); dC .100 MHz; DMSO-d6) 99.74, 105.19, 119.19,
121.46, 122.45, 125.05, 127.41 .2C), 128.25 .3C), 128.45,
131.80, 135.30, 149.95, 150.97, 157.75; m/z .EI) 261 .100,
M1), 244 .35), 204 .7), 156 .8), 78 .39%); HRMS .EI): M1,
found 261.0780. C17H11NO2 requires 261.0790.
3.4.5. 4-Hydroxy-3-methylnaphtho[1,8-de][1,2]oxazine
.22). 0.1 g, 10% as a pale green powder, mp 180±1828C;
nmax .Nujol) 1650 cm21; dH .400 MHz; DMSO-d6) 2.37
.3H, s, Me), 6.63 .1H, d, Jˆ7.4 Hz, H-9), 7.10±7.19 .3H,
m, H-5, H-7, H-8), 7.69 .1H, d, Jˆ9 Hz, H-6), 10.39 .1H, s,
br, OH); dC .100 MHz; DMSO-d6) 20.74 .Me), 100.92
.C-3a), 104.96, .C-9), 118.78 .C-7), 121.06 .C-5), 121.42
.C-9b), 125.12 .C-8), 127.45 .C-6a), 131.29 .C-6), 149.97
.C-4), 151.07 .C-9a), 153.92.C-3); m/z .EI) 199 .100, M1),
184 .57), 171 .80), 128 .46), 102 .89), 75 .48%); HRMS
.EI): M1, found 199.0617. C12H9NO2 requires 199.0633.
3.4.10. Oxidation of .Z/E)-1-.2-hydroxy-1-naphthyl)pro-
pan-1-one oxime with lead.IV) acetate. A stirred solution
of 25 .5 mmol) in dry tetrahydrofuran .60 mL) under argon
was cooled to 08C. Lead.IV) acetate .4.43 g, 10 mmol) was
added slowly over a period of 30 min. The reaction mixture
was stirred at this temperature for 1.5 h and then ®ltered, the
solid was washed with tetrahydrofuran and the ®ltrate was
evaporated in vacuo to leave a residue. The residue was
chromatographed .25% ethyl acetate/hexane) to give
1-ethylnaphtho[1,2-d]isoxazole-2-oxide 33 in the ®rst
fraction. The second fraction was evaporated and the resi-
due triturated with acetonitrile to give 1-hydroxy-2-ethyl-
benzo[cd]indol-3.1H)-one 27.
3.4.6. 1-Hydroxy-2-methylbenzo[cd]indol-3.1H)-one .23).
0.17 g, 17% as pale yellow powder, mp 220±2228C; nmax
.Nujol) 3340, 1620 cm21; dH .400 MHz; DMSO-d6) 2.75
.3H, s, Me), 6.51 .1H, d, Jˆ9.6 Hz, H-4), 7.37 .1H, t, Jˆ
7.6, Hz, H-7), 7.57 .1H, d, Jˆ7.6 Hz, H-6), 7.66 .1H, d,
Jˆ7.6 Hz, H-8), 7.75 .1H, d, Jˆ9.6 Hz, H-5), 12.23 .1H,
s, br, OH); dC .100 MHz; DMSO-d6) 10.75 .Me), 105.05
.C-2a), 111.69 .C-8), 120.90 .C-8b), 121.89 .C-5a), 122.53
.C-6), 122.98 .C-7), 130.12 .C-8a), 132.54 .C-4), 136.33
.C-4), 143.59 .C-2), 178.02 .C-3); m/z .EI) 199 .24, M1),
183 .100), 169 .31), 154 .25), 140 .14), 127 .17), 114 .15),
102.7), 77 .10), 63 .10), 41 .34%); HRMS .EI): M 1, found
199.0624. C12H9NO2 requires 199.0633.
3.4.11. 1-Ethyl-9-hydroxynaphtho[1,2-d]isoxazole .27).
0.1 g, 10% as pale yellow powder, mp 181±1828C, identical
in all respects to an authentic sample prepared above.
3.4.12. 1-Ethylnaphtho[1,2-d]isoxazole-2-oxide .33).
0.25 g, 28% as yellow powder, mp 97±1008C; nmax
.Nujol) 1200 cm21; dH .400 MHz; CDCl3) 1.45 .3H, t,
Jˆ7.6 Hz, CH2CH3), 3.25±3.19 .2H, q, Jˆ7.6 Hz,
CH2CH3), 7.35 .1H, d, Jˆ9.0 Hz, H-4), 7.55 .1H, t,
Jˆ7.2Hz, H-7), 7.66 .1H, t, Jˆ7.2Hz, H-8), 7.90 .1H, d,
Jˆ9.0 Hz, H-5), 7.94 .1H, d, Jˆ8.2Hz, H-9), 8.11 .1H, d,
Jˆ8.2Hz, H-6); dC .100 MHz; CDCl3) 10.42, 19.53,
107.92, 108.04, 122.07, 123.40, 125.43, 125.50, 128.09,
129.69, 130.03, 130.70, 148.57; m/z .EI) 213 .100, M1),
196 .21), 183 .29), 165 .79), 153 .48), 139 .29), 155
.34%); HRMS .EI): M1, found 213.0818. C13H11NO2
requires 213.0790.
3.4.7. 3-Ethyl-4-hydroxynaphtho[1,8-de][1,2]oxazine .26).
0.23 g, 22% as a pale green powder, mp 180±1838C; nmax
.Nujol) 1630 cm21; dH .400 MHz; DMSO-d6) 1.17 .3H, t,
Jˆ7.3 Hz, CH2CH3), 2.77±2.86 .2H, q, CH2CH3), 6.63 .1H,
d, Jˆ7.3 Hz, H-9), 7.04±7.17 .3H, m, H-5, H-7, H-8), 7.66
.1H, d, Jˆ9 Hz, H-6), 10.50 .1H, s, br, OH); dC .100 MHz;
DMSO-d6) 12.18 .Me), 26.98 .CH2), 99.98 .C-3a), 104.96,
.C-9), 118.77 .C-7), 121.16 .C-5), 121.82 .C-9b), 125.05
.C-8), 127.65 .C-6a), 131.16 .C-6), 149.28 .C-4), 151.10
.C-9a), 157.77 .C-3); m/z .EI) 213 .58, M1), 198 .32),
185 .100), 156 .15), 139 .22), 128 .12), 115 .12), 102
.54), 75 .38), 63 .25), 60 .15%); HRMS .EI): M1, found
213.0789. C13H11NO2 requires 213.0790.
Acknowledgements
This work was supported by grants from Program Interreg
II, Greece Italy, Action 5±2of the University of Ioannina
.to P. S.) and a PENED grant from the General Secretariat of
Research and Technology, Athens .to G. V.). We thank Dr
A. J. Boulton for naming the spiro compounds and Dr A.
Troganis for NMR spectra measured on a BruÈker AMX 400
spectrometer ®nanced by the University of Ioannina. We are
particularly grateful to J. Cobb for NMR spectra recorded on
a BruÈker AM 360 spectrometer, and A. Cakebread and R.
Tye for mass spectra obtained on a JEOL JMS-AX 505W,
machines funded by the University of London Intercollegi-
ate Research Services Scheme.
3.4.8. 1-Hydroxy-2-ethylbenzo[cd]indol-3.1H)-one .27).
0.12g, 11% as yellow powder, mp 180±182 8C; nmax
.Nujol) 3400, 1620 cm21; dH .400 MHz; DMSO-d6) 1.33
.3H, t, CH2CH3), 3.15±3.20 .2H, q, CH2CH3), 6.51 .1H,
d, Jˆ 9.6 Hz, H-4), 7.38 .1H, t, Jˆ7.6 Hz, H-7), 7.57 .1H,
d, Jˆ 7.6 Hz, H-6), 7.67 .1H, d, Jˆ7.6 Hz, H-8), 7.75 .1H,
d, Jˆ9.6 Hz, H-5), 12.23 .1H, s, br, OH); dC .100 MHz;
DMSO-d6) 12.04 .CH2CH3), 18.04 .CH2CH3), 106.78
.C-2a), 111.85 .C-8), 121.02 .C-8b), 122.06 .C-5a),
122.62 .C-6), 123.05 .C-7), 130.16 .C-8a), 132.61 .C-4),
136.31 .C-5), 148.79 .C-2), 177.50 .C-3); m/z 213 .19,
M1), 196 .100), 183 .15), 162 .21), 151 .20), 132 .12),
113 .10), 81 .4%); HRMS .EI): M1, found 213.0841.
C13H11NO2 requires 213.0790.
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