Reactivity of sulfur-centered radicals with indolinonic and quinolinic aminoxyls

Article abstract of DOI:10.1002/(SICI)1099-0690(199909)1999:9<2405::AID-EJOC2405>3.0.CO;2-R

Indolinonic, phenylimino-indolinonic and quinolinic aromatic aminoxyls readily react with sulfur-centered radicals, generated upon reaction with p- methylthiophenol at room temperature The main product is the deoxygenated derivative i.e the corresponding amine. The other compounds, obtained in low yields, are N-substituted amines and amines substituted in a conjugated position with respect to the amino group by arylthiyl, arylsulphinyl, arylsulphonyl and arylsulphonyloxy radicals. The formation of the products are explained by the initial attack of the thiophenol radical onto the NO· function to give an unstable adduct which decomposes to aminyl and arylsulphinyl radicals. From here the reaction can take two different routes to give the products obtained.

Full text of DOI:10.1002/(SICI)1099-0690(199909)1999:9<2405::AID-EJOC2405>3.0.CO;2-R

FULL PAPER
Reactivity of Sulfur-Centered Radicals with Indolinonic
and Quinolinic Aminoxyls
Elisabetta Damiani,[a] Patricia Carloni,[a] Marco Iacussi,[a] Pierluigi Stipa,[a]
and Lucedio Greci*[a]
Keywords: Aminoxyls / Thiophenols / Arylthiyls / Arylsulphinyls / Arylsulphonyls
Indolinonic,
phenylimino-indolinonic
and
quinolinic
to the amino group by arylthiyl, arylsulphinyl, arylsulphonyl
and arylsulphonyloxy radicals. The formation of the products
are explained by the initial attack of the thiophenol radical
onto the NO· function to give an unstable adduct which
decomposes to aminyl and arylsulphinyl radicals. From here
the reaction can take two different routes to give the
products obtained.
aromatic aminoxyls readily react with sulfur-centered
radicals, generated upon reaction with p-methylthiophenol
at room temperature. The main product is the deoxygenated
derivative i.e. the corresponding amine. The other
compounds, obtained in low yields, are N-substituted amines
and amines substituted in a conjugated position with respect
products were the corresponding amine and N-substituted
products with arylsulphinyl and arylsulphonyl radicals.
Introduction
The use of aminoxyls as spin probes and spin labels for This reaction was explained as a consecutive coupling of
studies of membranes and proteins[1] and their use (even in the arylthiyl radical (or its oxygenated derivatives) with the
living systems) for EPR imaging and in vivo EPR spec- NO· function, followed by cleavage of the NϪO bond.
troscopy[2] has increased significantly recently, and this
This study has now been extended to aromatic (namely,
makes it essential to have better knowledge of the chemical, indolinonic and quinolinic) aminoxyls, whose NO· function
biochemical and biological interactions of aminoxyls in is in conjugation with a π-system. For this reason they dis-
such systems. The reaction of aminoxyls with SH groups is play a different reactivity with respect to aminoxyls bearing
of particular interest owing to the fact that low-molecular the NO• function between sp3 carbons, such as TEMPO.[6]
weight SH-containing compounds such as glutathione are These studies, could therefore contribute to the further
important in many cellular functions including protection understanding of the interaction between aminoxyls and
against oxidative stress. The amino acid cysteine, found in SH groups and of the reactivity of indolinonic and quinol-
water-soluble and membrane proteins, is also an important inic aminoxyls with sulfur-centred radicals.
source of SH groups. The reaction of aliphatic aminoxyls
with these SH-containing compounds has been extensively
studied in biological systems,[3] however, the data on their
reduction by SH groups are controversial, and the real
Results
mechanism of the reaction is not yet known. Therefore, it
is of interest to study the reaction between aminoxyls and
The reactions between indolinonic aminoxyls 1a and 1b
or quinolinic aminoxyl 1c with p-methylthiophenol (2) were
SH groups in order to understand the products, and poss-
carried out in benzene at room temperature, under nitrogen
ibly elucidate the reaction mechanisms of their interaction.
in the ratio 2:1 respectively. The results show that there is
interaction of the p-methylphenylthiyl (arylthiyl) radicals
Secondly, clarification on this particular reaction is import-
ant considering the role played by aminoxyls during rubber
with the NO• function and/or its conjugated benzene ring.
stabilization. In fact, both hindered secondary amines and
The experiments were each performed twice, and in every
sulfur-containing compounds are used in polymers as stabi-
case the same products were isolated. The yields reported
lizers, and during their activity aminoxyls and thiyl radicals
in Table 1 are the average of the two individual runs and
have to be considered indicative since the products were iso-
are formed as intermediates.[4]
As a starting point, we previously studied the reaction of
lated and purified by a series of preparative thin layer chro-
an aliphatic aminoxyl TEMPO (2,2,6,6-tetramethylpiperi-
matographies.
dine-N-oxyl) with a series of thiophenols.[5] The main fea-
The reaction between 2-methyl-3-oxo-2-phenylindoline-
1-oxyl (1a) and p-methylthiophenol (2), led to a number of
products. The main product was the amine 10a[7] corre-
ture of the reaction was the deoxygenation of the aminoxyl
with formation of the corresponding tetramethylpiperidin-
ium arylsulphinates and arylsulphonates. Other isolated
sponding to the starting aminoxyl. Other minor products
were differently substituted amines; an amine with an N-
[a]
`
Dipartimento di Scienze dei Materiali e della Terra, Universita,
arylsulphonyl group (11y/1a), amines substituted in posi-
tions 5 or 7 with an arylthiyl- 12x/1a, 13x/1a, arylsul-
phonyl- 12y/1a, 13y/1a or an arylsulphonyloxy group 12z/
Via Brecce Bianche, I-60131 Ancona, Italy
Fax: (internat.) ϩ39-071/2204714
E-mail: greci@popcsi.unian.it
Eur. J. Org. Chem. 1999, 2405Ϫ2412
WILEY-VCH Verlag GmbH, D-69451 Weinheim, 1999
1434Ϫ193X/99/0909Ϫ2405 $ 17.50ϩ.50/0
2405

E. Damiani, P. Carloni, M. Iacussi, P. Stipa, L. Greci
Table 1. Percentage yields of products 4 and 10Ϫ20 isolated from the reaction of aminoxyls 1aϪc with thiyl radicals
FULL PAPER
[a]
[b]
[c]
The skeleton of these products corresponds to compounds 1a؊c in each column. Ϫ
[d] Compound 20.
Recovered aminoxyl. Ϫ Compound 19. Ϫ
1a, 13z/1a, and disubstituted amines 16x/1a with an aryl- an arylsulphonyloxy group 12z/1b. The 7-substituted amine
thiyl group in positions 5 and 7. Futhermore, the hy- 13z/1b with an arylsulphonyloxy group and traces of p-
droxylamine 4a[8] was isolated in addition to the aminoxyls methylphenyldisulphide (17) were also isolated.
substituted in position 5 14y/1a or 7 15y/1a with an arylsul-
Finally, the reaction of 4-ethoxy-1,2-dihydro-2,2-di-
phonyl group. The presence of p-methylphenyldisulphide phenylquinoline-1-oxyl (1c) with the same thiophenol gave
(17) and of S-(p-methylphenyl)-p-methylbenzenethiosul- rise to the amine 19,[11] to the N-substituted amine with an
phonate (18)[9] was confirmed by comparison with auth- arylsulphonyl group 11y/1c, to the 6-substituted amine with
entic samples.
an arylthiyl- 12x/1c, an arylsulphonyl- 12y/1c, or an arylsul-
The reaction of 2-methyl-2-phenyl-3-phenyliminoindo- phonyloxy group 12z/1c, to the 8-substituted amine with an
line-1-oxyl (1b) and p-methylthiophenol (2) led to the for- arylsulphonyl group 13y/1c and to p-methylphenyldisul-
mation of the amine 10b,[10] to the N-substituted amines phide (17). The amine substituted in position 6 with a thiyl
11x/1b, 11w/1b and 11y/1b with an arylthiyl-, an arylsulphi- group (20) was also present in the ketonic form.
nyl-, or an arylsulphonyl group, respectively, as well as to
All the products were identified by their spectroscopic
the 5-substituted amines with an arylsulphonyl- 12y/1b or data (1H NMR, High Resolution Mass Spectroscopy,
2406
Eur. J. Org. Chem. 1999, 2405Ϫ2412

Reactivity of Sulfur-Centered Radicals with Indolinonic and Quinolinic Aminoxyls
FULL PAPER
FT-IR, EPR) and by comparison with the data for similar
compounds.[12]
Discussion
It has been well established that indolinonic aminoxyls
are extremely versatile in reacting with oxygen-centered rad-
icals, such as peroxyl[14] and alkoxyl,[15] with nitrogen-cen-
tered radicals such as aminyl,[16] and with carbon-centered
radicals[17] yielding products substituted on the benzene
ring in the three former cases and alkylated hydroxylamines
in the latter case. To gain more information on the reactiv-
ity of this class of aminoxyls towards different types of rad-
icals, their reaction with sulfur-centered radicals was con-
sidered. These were generated from p-methylthiophenol as
reported previously.[5]
The molecular ratio 2:1 between aminoxyl and p-methyl-
thiophenol was chosen with the aim of generating arylthiyl
radicals via hydrogen abstraction from the thiophenol by
one mole of aminoxyl, followed by entrapment of the aryl-
thiyl radical with a second mole of aminoxyl as reported in
Scheme 1.
With regards to the substituted amines, the position in
which the substituent is attached on the benzene ring of the
indolinic and quinolinic moiety was determined by compar-
1
ing the H NMR spectrum of the unsubstituted amine 10
with those of the substituted amines obtained. Differences
in the pattern of the H-4 (H-5 for quinolinic derivatives),
H-5 (H-6), H-6 (H-7), and H-7 (H-8) signals were observed.
These are mainly due to the loss of the signals from H-5
(H-6) and/or H-7 (H-8) to which the substituent is attached;
as a consequence there is a loss of the ortho-coupling con-
stants for the indolic protons ortho to the substituent.
Therefore, in the 5-substituted (6-) amines 12, the signals
due to H-4 (H-5) and H-6 (H-7) appear as a doublet (J ϭ
1.9Ϫ2.7 Hz) and a doublet of doublets (J ϭ 1.9Ϫ2.7 and
8.4Ϫ8.8 Hz) respectively. In the 7-substituted amines 13 the
signals due to H-6 and H-4 (J ϭ 1.1Ϫ1.3 and 7.3Ϫ7.8 Hz)
differ only by an additional coupling between H-4 and the
NϪH proton (J ϭ 0.6Ϫ0.7 Hz).[13] In the 5,7-disubstituted
amine 16, two doublets due to H-4 and H-6 (J ϭ 1.8 Hz)
are observed, with H-4 showing an additional smaller coup-
ling with the NϪH proton. On the other hand, in the N-
substituted amines 11, H-4, H-5, H-6 and H-7 show similar
coupling constants as the unsubstituted amine but at differ-
ent chemical shifts.
To determine the number of oxygens on the sulfur of the
substituent, we compared the chemical shifts of the protons
in the thiophenol moiety ortho to the sulfur atom of the
substituents (namely “arom-S”) with those of benzene (δ ϭ
7.25 ). We also compared the chemical shifts of H-4 and H-
6 of 5-substituted amines with those of the unsubstituted
amine (δH4 ϭ 7.6 and δH6 ϭ 7.5 ). Therefore, in the case
of ArS substitution (e.g. 12x/1a), the chemical shifts of the
“arom-S” protons (δ ϭ 7.19 ), of H-4 (δ ϭ 7.67 ), and of
H-6 (δ ϭ 7.55 ) appear almost unchanged. In the case of
ArSO2 (e.g. 12y/1a) substitution, however, the “arom-S”
protons (δ ϭ 7.79 ), H-4 (δ ϭ 8.13 ), and H-6 (δ ϭ 7.97 )
appear deshielded due to the electron-withdrawing charac-
ter of the SO2 group. Finally, in the ArSO3-substituted com-
pounds (e.g. 12z/1a), the “arom-S” protons behave similarly
to the ArSO2 derivative (δ ϭ 7.73 ) but H-4 (δ ϭ 7.08 ) and
H-6 (δ ϭ 7.25 ) appear shielded, suggesting the presence of
a mesomeric effect probably due to an extra oxygen linking
the ArSO2 group with the indole moiety. Additional sup-
port for the structural assignments was obtained by the IR
spectra. The compounds bearing a sulphonyl group at-
tached to the nitrogen show the two typical absorptions be-
tween 1365Ϫ1315 and 1180Ϫ1150 cmϪ1, while those bear-
ing this group on the benzene ring typically absorb in the
Scheme 1
The main product in all the reactions was the amine 10
corresponding to the starting aminoxyl. We hypothesize
that the most likely pathway for its formation (Scheme 2)
is via aminyl 6, formed from decomposition of adduct 5
(Scheme 1).
Scheme 2
This proposed intermediate could readily form through
1370Ϫ1290 and 1170Ϫ1110 cmϪ1 ranges. The sulphonyloxy coupling of ArS• with the NO• function (Scheme 1), how-
derivatives show the two characteristic absorption peaks at ever, it was never isolated. The instability of intermediate 5
1375Ϫ1350 and 1185Ϫ1145 cmϪ1. High resolution mass due to the facile homolysis of the oxygen-nitrogen bond is
spectra of new compounds were performed whenever pos- supported by the fact that the same bond in arylsulphinyl
sible. In all cases, mass spectra showed the expected molecu- nitrate[18] or in the pyridine N-oxide-arylsulphenyl chloride
lar ion peak and in most cases the fragmentation due to the adduct[19] behaves in a similar way. Furthermore, similar
different substituents was characteristic.
intermediates have been previously characterized only at
Eur. J. Org. Chem. 1999, 2405Ϫ2412
2407

E. Damiani, P. Carloni, M. Iacussi, P. Stipa, L. Greci
FULL PAPER
low temperatures, but were never isolated.[20] In addition, gated benzene ring and deoxygenation leading to the disub-
semiempirical calculations of compound 5 show that the stituted amine 16 (Scheme 4).
NϪO bond is weaker [Bond Dissociation Energy (BDE) ϭ
Ϫ10.78 kcal/mol] than the OϪS bond (BDE ϭ 21.77 kcal/
mol) (see Experimental Section). Heterolytic cleavage of in-
termediate 5 to give a nitrenium ion and the sulphinyl anion
can be excluded since no methoxylated products[21] were
obtained when methanol was used instead of benzene as
solvent.
In order to give a possible explanation for the formation
of all the other reaction products bearing sulfur-oxygenated
substituents, namely the arylsulphinyl, arylsulphonyl and
arylsulphonyloxy groups, it is important to first understand
how these are formed. Arylsulphinyl radical 7, arising from
the decomposition of adduct 5, may disproportionate to ar-
ylthiyl 3 and arylsulphonyl 8 according to the literature re-
ports[22] (Equation 1). The latter in turn further dispro-
portionates, faster than the arylsulphinyl radical, to arylsul-
phinyl and arylsulphonyloxy 9 (Equation 2).[23]
Scheme 4
In the case of aminoxyl 1c, compounds 19 and 20 (Figure
1) were isolated.
•
2 ArSO• (7) Ǟ ArS• (3) ϩ ArSO2 (8)
(1)
(2)
Figure 1. Chemical structure of compounds 19 and 20
•
2 ArSO2 (8) Ǟ ArSO• (7) ϩ ArSO2O• (9)
A similar result was previously observed apon acid treat-
ment of 1c;[11] in fact enol ethers are readily hydrolysed by
acids. In our case, even if they were not isolated, arylsul-
phinic and arylsulphonic acids may be formed in the reac-
tion medium, and these may promote the hydrolysis of the
enol ether moiety to the corresponding ketone form. It is
worth recalling that in the reactions between TEMPO and
thiophenols,[5] the main products were the tetramethylpip-
eridinium arylsulphinates and arylsulphonates arising from
the formation of arylsulphinic and arylsulphonic acids as
stated in the introduction.
However, these radicals may also be formed through an
alternative route, as reported in Scheme 3, by reaction of
the starting aminoxyls with all the sulfur-containing rad-
icals at the NO· function.
Aminoxyls 1a and 1b have a similar basic structure, there-
fore their reactivities might be comparable; however the
products obtained (Table 1) are not always the same. The
possibility that different mechanisms can take place during
these reactions is such that, small variations in the rate of
each step could lead to the formation of the different prod-
ucts.
Scheme 3
At this stage, the formation of amines 11, 12 and 13
could be explained by the interaction of aminyl 6 with all
the sulfur-centered radicals (3, 7 and 8) and the arylsul-
phonyloxy radical 9 (Scheme 2). The probability that rad-
Conclusion
Aminoxyls 1 react with nucleophilic radicals, such as
icals 7 and 8 give OϪC instead of SϪC coupling on the alkyl radicals, at the NO• function affording alkoxyam-
benzene ring was ruled out since several studies have dem- ines[17] and with electrophilic radicals such as alkoxyl[15]
onstrated that the unpaired electron resides essentially on and alkylperoxyl[14] radicals at the conjugated benzene ring.
the sulfur.[20][24]
In the present work, it is interesting to observe that sulfur-
Another alternative route for the formation of the prod- centered radicals 3, 7 and 8 and arylsulphonyloxy radical 9
ucts, is the interaction of the sulfur-centered radicals with react at both positions, and this could be ascribed to their
the starting aminoxyl itself at the conjugated positions with polar character, which may be considered somewhere be-
the NO• function as shown in Scheme 4. This route explains tween electrophilic and nucleophilic.
the formation of the substituted aminoxyls 14 and 15 ob-
The reactions described in this paper cannot be con-
tained in traces, which can subsequently undergo deoxygen- sidered of synthetic value due to the number of products
ation as shown in Scheme 1 and Scheme 3 to give the isolated, even if the amines are obtained in good yield based
monosubstituted amines 12 and 13. The substituted ami- on the conversion of the starting aminoxyl. However, they
noxyls may also undergo further substitution on the conju- represent an interesting example for understanding the re-
2408
Eur. J. Org. Chem. 1999, 2405Ϫ2412

Reactivity of Sulfur-Centered Radicals with Indolinonic and Quinolinic Aminoxyls
FULL PAPER
2-Methyl-3-oxo-2-phenyl-1-(p-tolylsulphonyl)indoline (11y/1a): IR
(DRIFT): ν˜ ϭ 1721 (CϭO), 1603, 1460, 1357 and 1170 (SO2N). Ϫ
1H-NMR (200 MHz; CDCl3; Me4Si): δ ϭ 2.11 (3 H, s, Ind-CH3),
2.35 (3 H, s, Ar-CH3), 7.10 (2 H, d, arom-S, J ϭ 8.3 Hz), 7.22 (6
H, m, arom.), 7.39 (2 H, d, arom-S, J ϭ 8.3 Hz), 7.72 (1 H, ddd,
H6, J1 ϭ 8.5, J2 ϭ 7.3, J3 ϭ 1.5 Hz), 7.76 (1 H, ddd, H7, J1 ϭ 7.7,
J2 ϭ 1.5, J3 ϭ 0.8 Hz), 8.03 (1 H, dt, H4, J1 ϭ 8.3, J2 ϭ 0.8 Hz).
Ϫ MS (EIϩ) m/z (rel. int.) 377 (Mϩ, 35%), 222 (MϪ155, 100). Ϫ
HRMS calcd. for C22H19NO3S 377.1086, found 377.1089.
activity of sulphydrilic groups with aminoxyls, particularly
when considering the applications of the latter in biology
and in polymer stabilization. Secondly, the results described
give further insights on the reactivity of this class of aro-
matic aminoxyls towards radical species, demonstrating that
these aminoxyls are also capable of efficiently reacting with
sulfur-centered radicals
Experimental Section
2-Methyl-3-oxo-2-phenyl-5-(p-tolylsulphanyl)indoline (12x/1a): IR
(DRIFT): ν˜ ϭ 3370 (NH), 1708 (CϭO), 1610, 1476. Ϫ H-NMR
1
General Remarks: IR spectra were measured on a Nicolet Fourier
Transform Infrared 20-SX spectrophotometer equipped with a
Spectra Tech “Collector” for DRIFT measurements, or on a
PerkinϪElmer 298 infrared spectrometer. Ϫ 1H NMR spectra were
recorded at room temperature as a solution in CDCl3 or C6D6 on
a Varian Gemini 200 spectrometer (δ in ppm are relative to Me4Si).
Where compounds are marked by # , the spectroscopic data re-
ported in the reference are incomplete. Ϫ High resolution mass
spectra were recorded on a VG7070-E 5000 spectrometer with PFK
as the resolution and calibration standard. In some cases, mass
spectra were recorded on a Carlo Erba QMD 1000 spectrometer in
EIϩ or CIϩ mode. Ϫ EPR spectra were recorded on a Varian E4
spectrometer interfaced with a computer. Ϫ Calculations were per-
formed by using the semiempirical quantum-mechanical method
AM1 enclosed in the software package HyperChem 4.5.[25] Ϫ Ami-
noxyls 1a,[8] 1b[8]and 1c[26] were prepared according to the litera-
ture methods. p-Methylthiophenol was an Aldrich commercial re-
agent grade product and used as purchased.
(200 MHz; CDCl3; Me4Si): δ ϭ 1.75 (3 H, s, Ind-CH3), 2.31 (3 H,
s, Ar-CH3), 5.06 (1 H, br., NH), 6.91 (1 H, dd, H7, J1 ϭ 8.4, J2
ϭ
0.6 Hz), 7.08 (2 H, d, arom-S, J ϭ 8.4 Hz), 7.19 (2 H, d, arom-S,
J ϭ 8.4 Hz), 7.4 (3 H, m, arom.), 7.49 (2 H, m, arom.), 7.55 (1 H,
dd, H6, J1 ϭ 8.4, J2 ϭ 1.9 Hz), 7.67 (1 H, dt, H4, J1 ϭ 1.9, J2
ϭ
0.6 Hz). Ϫ MS (EIϩ) m/z (rel. int.) 345 (Mϩ, 91%), 222 (MϪ123,
100). Ϫ HRMS calcd. for C22H19NOS 345.1187, found 345.1189.
2-Methyl-3-oxo-2-phenyl-5-(p-tolylsulphonyl)indoline (12y/1a): IR
(DRIFT): ν˜ ϭ 3376 (NH), 1709 (CϭO), 1620, 1493, 1331 and 1135
(SO2). Ϫ 1H-NMR (200 MHz; CDCl3; Me4Si): δ ϭ 1.72 (3 H, s,
Ind-CH3), 2.38 (3 H, s, Ar-CH3), 5.75 (1 H, br., NH), 6.94 (1 H,
dd, H7, J1 ϭ 8.4, J2 ϭ 0.6 Hz), 7.3 (5 H, m, arom.), 7.41 (2 H, m,
arom.), 7.79 (2 H, d, arom-S, J ϭ 8.3 Hz), 7.97 (1 H, dd, H6, J1
ϭ
8.7, J2 ϭ 2.1 Hz), 8.13 (1 H, dd, H4, J1 ϭ 2.0, J2 ϭ 0.5 Hz). Ϫ MS
(EIϩ) m/z (rel. int.) 377 (Mϩ, 80%), 348 (MϪ29, 100), 221
(MϪ156, 3), 193 (MϪ29Ϫ155, 69).
Ϫ HRMS calcd. for
C22H19NO3S 377.1086, found 377.1089.
Reaction of Nitroxides (1a؊c) with p-Methylthiophenol (2). ؊ Gen-
eral Procedure: A solution of nitroxide (300 mg) in 10 mL of anhy-
drous benzene and a solution of thiophenol (half equivalent) in
7 mL of the same solvent were each degassed separately under ni-
trogen for 10 min. The thiophenol was then added dropwise to the
solution of nitroxide under magnetic stirring over 10 minutes. With
nitroxide 1a, the reaction mixture immediately darkened and after
10 min from the addition the reaction was completed as the nitro-
xide had disappeared (TLC analysis using benzene/acetone 9.8:0.2
as eluant). With nitroxide 1b, the reaction was slower, and after 2 h
there was no more change according to TLC analysis (same eluant
as above). With nitroxide 1c the reaction was even slow and after
3 h there was no variation according to TLC analysis (ethyl acetate/
cyclohexane 8.5:1.5). At the end of the reaction, the reaction mix-
ture was evaporated under reduced pressure, taken up with benzene
and purified on silica-gel preparative chromatography plates, by
eluting with different eluants according to the reaction. All the
products were extracted from the silica-gel with ethyl acetate.
2-Methyl-3-oxo-2-phenyl-5-(p-tolylsulphonyloxy)indoline (12z/1a):
IR (DRIFT): ν˜ ϭ 3350 (NH), 1690 (CϭO), 1623, 1487, 1370 and
1173 (SO3). Ϫ 1H-NMR (200 MHz; CDCl3; Me4Si): δ ϭ 1.72 (3
H, s, Ind-CH3), 2.44 (3 H, s, Ar-CH3), 5.05 (1 H, br., NH), 6.87 (1
H, dd, H7, J1 ϭ 8.8, J2 ϭ 0.5 Hz), 7.07 (1 H, dd, H4, J1 ϭ 2.5,
J2 ϭ 0.5 Hz), 7.26 (1 H, dd, H6, J1 ϭ 8.8, J2 ϭ 2.5 Hz), 7.34 (5 H,
m, arom.), 7.47 (2 H, m, arom.), 7.72 (2 H, d, arom-S, J ϭ 8.3 Hz).
Ϫ MS (EIϩ) m/z (rel. int.) 393 (Mϩ, 28%), 238 (MϪ155, 100). Ϫ
HRMS calcd. for C22H19NO4S 393.1035, found 393.1034.
2-Methyl-3-oxo-2-phenyl-7-(p-tolylsulphanyl)indoline (13x/1a): IR
1
(DRIFT): ν˜ ϭ 3355 (NH), 1708 (CϭO), 1602, 1485. Ϫ H-NMR
(200 MHz; CDCl3; Me4Si): δ ϭ 1.67 (3 H, s, Ind-CH3), 2.34 (3 H,
s, Ar-CH3), 5.24 (1 H, br., NH), 6.84 (1 H, t, H5, J ϭ 7.6 Hz), 7.14
(4 H, m, arom.), 7.23 (5 H, m, arom.), 7.6 (1 H, ddd, H4, J1 ϭ 7.7,
J2 ϭ 1.2, J3 ϭ 0.7 Hz), 7.69 (1 H, dd, H6, J1 ϭ 7.3, J2 ϭ 1.2 Hz).
Ϫ MS (EIϩ) m/z (rel. int.) 345 (Mϩ, 685%), 222 (MϪ123, 27), 212
(100). Ϫ HRMS calcd. for C22H19NOS 345.1187, found 345.1183.
2-Methyl-3-oxo-2-phenyl-7-(p-tolylsulphonyl)indoline (13y/1a): IR
(DRIFT): ν˜ ϭ 3386 (NH), 1711 (CϭO), 1611, 1480, 1443, 1296
and 1131 (SO2). Ϫ H-NMR (200 MHz; CDCl3; Me4Si): δ ϭ 1.77
(3 H, s, Ind-CH3), 2.44 (3 H, s, Ar-CH3), 6.82 (1 H, br., NH), 6.88
(1 H, t, H5, J ϭ 7.8 Hz), 7.34 (7 H, m, arom.), 7.72 (1 H, ddd, H4,
Reaction with Aminoxyl 1a: The reaction mixture was purified by
eluting the plates with benzene/acetone, 9.8:0.2. Some fractions
were further re-purified by eluting with ethyl acetate/cyclohexane,
2.5:7.5 or 1:9, or with petroleum ether/ethyl ether, 7:3, or acetone/
benzene, 0.5:9.5, or just benzene. The products isolated were: 4a
(2-Methyl-3-oxo-2-phenylindolin-1-hydroxide),[8] 10a,[7] 11y/1a (R ϭ
SO2Ar), 12x/1a (R ϭ SAr), 12y/1a (R ϭ SO2Ar), 12z/1a (R ϭ
SO3Ar), 13x/1a (R ϭ SAr), 13y/1a (R ϭ SO2Ar), 13z/1a (R ϭ
SO3Ar), 14y/1a (R ϭ SO2Ar), 15y/1a (R ϭ SO2Ar), 16x/1a (R ϭ
SAr), 17, and 18.[9] Their spectroscopic data are reported below.
1
J
1 ϭ 7.5, J2 ϭ 1.2, J3 ϭ 0.6 Hz), 7.91 (2 H, d, arom-S, J ϭ 8.4 Hz),
7.97 (1 H, dd, H6, J1 ϭ 7.7, J2 ϭ 1.2 Hz). Ϫ MS (EIϩ) m/z (rel. int.)
377 (Mϩ, 29%), 348 (MϪ29, 20), 285 (MϪ92, 18), 222 (MϪ155, 5),
194 (MϪ29Ϫ154, 20), 149 (100). Ϫ HRMS calcd. for C22H19NO3S
377.1086, found 377.1082.
2-Methyl-3-oxo-2-phenylindoline (10a):[7] 1H-NMR (200 MHz; 2-Methyl-3-oxo-2-phenyl-7-(p-tolylsulphonyloxy)indoline (13z/1a):
CDCl3; Me4Si): δ ϭ 1.74 (3 H, s, Ind-CH3), 5.02 (1 H, br., NH),
6.84 (1 H, ddd, H5, J1 ϭ 7.85, J2 ϭ 7.1, J3 ϭ 0.87 Hz), 6.95 (1 H,
dt, H7, J1 ϭ 8.24 J2 ϭ 0.83 Hz), 7.3 (3 H, m, arom.), 7.5 (4 H, m,
arom.), 7.6 (1 H, ddd, H4, J1 ϭ 7.75 J2 ϭ 1.41 J3 ϭ 0.82 Hz). Ϫ
MS (EIϩ) m/z (rel. int.) 223 (Mϩ, 34%), 194 (100).
IR (DRIFT): ν˜ ϭ 3390 (NH), 1710 (CϭO), 1625, 1497, 1375 and
1177 (SO3) Ϫ 1H-NMR (200 MHz; CDCl3; Me4Si): δ ϭ 1.66 (3 H,
s, Ind-CH3), 2.46 (3 H, s, Ar-CH3), 5.33 (1 H, br., NH), 6.69 (1 H,
t, H5, J ϭ 7.8 Hz), 7.01 (1 H, dd, H6, J1 ϭ 7.8, J2 ϭ 1.1 Hz), 7.33
(5 H, m, arom.), 7.47 (3 H, m, arom.), 7.81 (2 H, d, arom-S, J ϭ
Eur. J. Org. Chem. 1999, 2405Ϫ2412
2409

E. Damiani, P. Carloni, M. Iacussi, P. Stipa, L. Greci
FULL PAPER
8.5 Hz). Ϫ MS (EIϩ) m/z (rel. int.) 393 (Mϩ, 24%), 238 (MϪ155,
2-Methyl-2-phenyl-3-phenylimino-1-(p-tolylsulphinyl)indoline (11w/
1b): IR (DRIFT): ν˜ ϭ 1658 (CϭN), 1595, 1458, 1097 (SϭO). Ϫ
1H-NMR (200 MHz; CDCl3; Me4Si): δ ϭ 2.37 (6 H, s, Ind-CH3
and Ar-CH3), 6.60 (2 H, m, arom.), 6.82 (3 H, m, arom.), 7.10 (3
H, m, arom.), 7.23 (2 H, d, arom-S, J ϭ 8.2 Hz), 7.44 (8 H, m,
arom.). Ϫ MS (CIϩ) m/z (rel. int.) 437 (MϩH, 20%), 298
(Mϩ1Ϫ139, 78).
44), 223 (MϪ154Ϫ16, 45), 194(100).
Ϫ HRMS calcd. for
C22H19NO4S 393.1035, found 393.1032.
2-Methyl-3-oxo-2-phenyl-5-(p-tolylsulphonyl)indoline-1-oxyl (14y/
1a): The EPR spectrum was simulated on the basis of the following
hyperfine coupling constants (hfccs) in Gauss: aN (NO·) ϭ 9.01,
aH (H4, H6) ϭ 1.05, aH (H7) ϭ 2.83, aH (CH3) ϭ 0.21 G. Ϫ
MS(EIϩ) m/z (rel. int.) 392 (Mϩ, 3%), 377 (MϪ15, 42), 348
(MϪ15Ϫ29, 93), 238 (MϪ154, 6), 193 (MϪ15Ϫ29Ϫ155, 100). To
confirm the structure of compound 14y/1a this was reduced to the
corresponding hydroxylamine: IR (DRIFT): ν˜ ϭ 3363 (NOH),
1723 (CϭO), 1608, 1446, 1330 and 1140 (SO2). Ϫ 1H-NMR
(200 MHz; CDCl3; Me4Si): δ ϭ 1.75 (3 H, s, Ind-CH3), 2.40 (3 H,
2-Methyl-2-phenyl-3-phenylimino-1-(p-tolylsulphonyl)indoline (11y/
1b): IR (DRIFT): ν˜ ϭ 1662 (CϭN), 1593, 1458, 1356 and 1171
1
(SO2N). Ϫ H-NMR (200 MHz; CDCl3; Me4Si): δ ϭ 2.33 (3 H, s,
Ind-CH3), 2.35 (3 H, s, Ar-CH3), 6.54 (1 H, br. d, arom.), 6.70 (3
H, m, arom.), 7.08 (3 H, m, arom.), 7.30 (12 H, m, arom.), 7.92 (1
H, d, arom., J ϭ 8.4 Hz). Ϫ MS (EIϩ) m/z (rel. int.) 452 (Mϩ,
16%), 297 (MϪ155, 100). Ϫ HRMS calcd. for C28H24N2O2S
452.1559, found 452.1560.
s, Ar-CH3), 6.8 (1 H, br., OH), 7.32 (1 H, dd, H7, J1 ϭ 8.4, J2
ϭ
0.6 Hz), 7.35 (7 H, m, arom.), 7.83 (2 H, d, arom-S, J ϭ 8.4 Hz),
8.13 (1 H, dd, H6, J1 ϭ 8.5, J2 ϭ 1.9 Hz), 8.20 (1 H, dd, H4, J1
1.9, J2 ϭ 0.6 Hz).
ϭ
2-Methyl-2-phenyl-3-phenylimino-5-(p-tolylsulphonyl)indoline (12y/
1b): IR (DRIFT): ν˜ ϭ 3355 (NH), 1655 (CϭN), 1601, 1481, 1319
and 1153 (SO2). Ϫ H-NMR (200 MHz; CDCl3; Me4Si): δ ϭ 1.89
(3 H, s, Ind-CH3), 2.40 (3 H, s, Ar-CH3), 5.33 (1 H, br. s, NH),
6.74 (3 H, m, arom.), 7.22 (4 H, m, arom.), 7.35 (6 H, m, arom.),
7.50 (3 H, m, arom.), 7.78 (1 H, dd, H6, J1 ϭ 8.5, J2 ϭ 1.9 Hz). Ϫ
MS (EIϩ) m/z (rel. int.) 452 (Mϩ, 1%), 314 (MϪ138, 2), 223 (1) Ϫ
MS (CIϩ) m/z (rel. int.) 453 (MϩH, 8%), 361 (MϪ91, 2)
1
2-Methyl-3-oxo-2-phenyl-7-(p-tolylsulphonyl)indoline-1-oxyl (15y/
1a): The EPR spectrum was simulated on the basis of the following
hyperfine coupling constants (hfccs) in Gauss: aN (NO·) ϭ 8.09,
aH (H4, H6) ϭ 0.99, aH (H5) ϭ 3.12, aH (CH3) ϭ 0.26 G. Ϫ To
confirm the structure of compound 15y/1a this was reduced to the
corresponding hydroxylamine: IR (DRIFT): ν˜ ϭ 3382 (OH), 1723
1
(CϭO), 1600, 1468, 1301 and 1151 (SO2). Ϫ H-NMR (200 MHz;
2-Methyl-2-phenyl-3-phenylimino-5-(p-tolylsulphonyloxy)indoline
(12z/1b): IR (DRIFT): ν˜ ϭ 3384 (NH), 1649 (CϭN), 1604, 1479,
1369 and 1171 (SO3). Ϫ 1H-NMR (200 MHz; CDCl3; Me4Si): δ ϭ
1.89 (3 H, s, Ind-CH3), 2.48 (3 H, s, Ar-CH3), 4.79 (1 H, br. s,
NH), 5.87 (1 H, d, H4, J ϭ 2.4 Hz), 6.60 (2 H, m, arom.), 6.72 (1
H, d, H7, J ϭ 8.5 Hz), 7.04 (2 H, m, arom.), 7.22 (4 H, m, arom.),
7.38 (4 H, m, arom.), 7.52 (3 H, m, arom.). Ϫ MS (EIϩ) m/z (rel.
int.) 468 (Mϩ, 39%), 313 (MϪ155, 100), 298 (MϪ154Ϫ16, 17). Ϫ
HRMS calcd. for C28H24N2O3S 468.1508, found 468.1510.
CDCl3; Me4Si): δ ϭ 1.76 (3 H, s, Ind-CH3), 2.44 (3 H, s, Ar-CH3),
7.16 (1 H, t, H5, J ϭ 7.7 Hz), 7.36 (6 H, m, arom.), 7.48 (2 H, m,
arom.), 7.83 (2 H, d, arom-S, J ϭ 7.5 Hz), 7.87 (1 H, dd, H6, J1
7.7, J2 ϭ 1.4 Hz), 8.17 (1 H, dd, H4, J1 ϭ 7.9, J2 ϭ 1.4 Hz). Ϫ MS
(EIϩ) m/z (rel. int.) 393 (Mϩ, 28%), 377 (MϪ16, 34), 348
(MϪ16Ϫ29, 67), 239 (MϪ154, 4), 193 (MϪ15Ϫ29Ϫ155, 100).
ϭ
2-Methyl-3-oxo-2-phenyl-5,7-bis(p-tolylsulphanyl)indoline (16x/1a):
IR (DRIFT): ν˜ ϭ 3343 (NH), 1703 (CϭO), 1599, 1465. Ϫ 1H-
NMR (200 MHz; CDCl3; Me4Si): δ ϭ 1.66 (3 H, s, Ind-CH3), 2.32
(3 H, s, Ar-CH3), 2.35 (3 H, s Ar-CH3), 5.28 (1 H, br., NH), 7.11
(4 H, m, arom.), 7.2 (9 H, m, arom.), 7.62 (1 H, dd, H4, J1 ϭ 1.8,
J2 ϭ 0.4 Hz), 7.75 (1 H, d, H6, J ϭ 1.8 Hz). Ϫ MS (EIϩ) m/z (rel.
int.) 467 (Mϩ, 100%), 334 (56). Ϫ HRMS calcd. for C29H25NOS2
467.1378, found 467.1370.
2-Methyl-2-phenyl-3-phenylimino-7-(p-tolylsulphonyloxy)indoline
(13z/1b): IR (DRIFT): ν˜ ϭ 3401 (NH), 1654 (CϭN), 1489, 1371
1
and 1176 (SO3). Ϫ H-NMR (200 MHz; CDCl3; Me4Si): δ ϭ 1.82
(3 H, s, Ind-CH3), 2.46 (3 H, s, Ar-CH3), 5.10 (1 H, br. s, NH),
6.25 (2 H, m, arom.), 6.75 (3 H, m, arom.), 7.09 (1 H, m, arom.),
7.30 (6 H, m, arom.), 7.55 (2 H, m, arom.), 7.79 (2 H, d, arom-S,
J ϭ 8.4 Hz). Ϫ MS (EIϩ) m/z (rel. int.) 468 (Mϩ, 29%), 313
(MϪ155, 100), 298 (MϪ154Ϫ16, 37). Ϫ HRMS calcd. for
C28H24N2O3S 468.1508, found 468.1508.
Reaction with Aminoxyl 1b: The reaction mixture was purified by
chromatography by eluting the plates with petroleum ether/ethyl
acetate 9.5:0.5 and then some fractions were further purified by
eluting with ethyl acetate/cyclohexane 1.5:8.5, or 2:8, or petroleum
ether/ethyl ether 8:2 or 8.5:1.5. The products isolated were: 1b,[8]
10b,[10] 11x/1b, 11w/1b, 11y/1b, 12y/1b, 12z/1b, 13z/1b. Their spec-
troscopic data are reported below.
Reaction with Aminoxyl 1c: The reaction mixture was purified by
chromatography, by eluting the plates twice with ethyl acetate/
cyclohexane (8.5:1.5). Some fractions were further purified by elut-
ing with ethyl acetate/cyclohexane (2:8), or petroleum ether/ethyl
ether (9:1), or acetone/benzene (1:9), or benzene. The products iso-
lated were 1c,[26] 17, 19 (2,3-dihydro-2,2-diphenyl-1H-quinolin-4-
one),[11] 11y/1c, 12x/1c, 20, 12y/1c, 12z/1c, and 13y/1c. Their spec-
troscopic data are reported below.
2-Methyl-2-phenyl-3-phenyliminoindoline
(10b):[10]
1H-NMR
(200 MHz; CDCl3; Me4Si): δ ϭ 1.92 (3 H, s, Ind-CH3), 4.76 (1 H,
br. s, NH), 6.42 (2 H, m, arom.), 6.81 (3 H, br. d, arom., J ϭ
8.34 Hz), 7.11 (1 H, tt, arom., J1 ϭ 7.5, J2 ϭ 1.3), 7.32 (6 H, m,
arom.), 7.62 (2 H, br. d, arom., J ϭ 6.5). Ϫ MS (EIϩ) m/z (rel. int.)
298 (Mϩ, 73%), 221 (100).
4-Ethoxy-1,2-dihydro-2,2-diphenyl-1-(p-tolylsulphonyl)quinoline
(11y/1c): IR (DRIFT): ν˜ ϭ 1608, 1458, 1317 and 1149 (SO2N). Ϫ
1H-NMR (200 MHz; CDCl3; Me4Si): δ ϭ 1.43 (3 H, t, CH2CH3,
J ϭ 7.0 Hz), 2.34 (3 H, s, Ar-CH3), 4.09 (2 H, q, CH2CH3, J ϭ
7.0 Hz), 4.54 (1 H, s, H3), 6.64 (1 H, d, arom., J ϭ 7.8 Hz), 6.61
(1 H, td, arom., J1 ϭ 7.6, J2 ϭ 1.0 Hz), 7.10 (5 H, m, arom.), 7.23
(2 H, m, arom.), 7.36 (6 H, m, arom.), 7.67 (3 H, m, arom.). Ϫ MS
(EIϩ) m/z (rel. int.) 481 (Mϩ, 19%), 452 (MϪ29, 2), 404 (MϪ77,
2-Methyl-2-phenyl-3-phenylimino-1-(p-tolylsulphanyl)indoline (11x/
1b): IR (Nujol): ν˜ ϭ 1665 (CϭN), 1595, 1450,1300, 1085. Ϫ 1H-
NMR (200 MHz; CDCl3; Me4Si): δ ϭ 2.24 (3 H, s, Ind-CH3), 2.41
(3 H, s, Ar-CH3), 6.51 (1 H, ddd, arom., J1 ϭ 8.0, J2 ϭ 1.3, J3
ϭ
0.3 Hz), 6.61 (1 H, ddd, arom., J1 ϭ 8.0, J2 ϭ 7.1, J3 ϭ 1.0 Hz),
6.76 (2 H, m, arom.), 6.94 (1 H, dt, arom., J1 ϭ 8.2, J2 ϭ 0.7 Hz),
7.11 (2 H, m, arom.), 7.30 (2 H, d, arom-S, J ϭ 8.3 Hz), 7.34 (5 H,
m, arom.), 7.54 (2 H, m, arom.), 7.63 (2 H, d, arom-S, J ϭ 8.3 Hz).
Ϫ MS (EIϩ) m/z (rel. int.) 420 (Mϩ, 2%), 298 (MϪ122, 77), 139 4-Ethoxy-1,2-dihydro-2,2-diphenyl-6-(p-tolylsulphanyl)quinoline
(100). Ϫ HRMS calcd. for C28H24N2S 420.1660, found 420.1669.
100), 326 (MϪ155, 24).
Ϫ HRMS calcd. for C30H27NO3S
481.1712, found 481.1720.
(12x/1c): IR (DRIFT): ν˜ ϭ 3375 (NH), 1649, 1601, 1491. Ϫ 1H-
2410
Eur. J. Org. Chem. 1999, 2405Ϫ2412

Reactivity of Sulfur-Centered Radicals with Indolinonic and Quinolinic Aminoxyls
NMR (200 MHz; CDCl3; Me4Si): δ ϭ 1.40 (3 H, t, CH2CH3, J ϭ bond dissociation energies were then obtained according to Equa-
FULL PAPER
7.0 Hz), 2.37 (3 H, s, Ar-CH3), 3.93 (2 H, q, CH2CH3, J ϭ 7.0 Hz),
4.63 (1 H, br. s, NH), 4.97 (1 H, s, H3), 6.50 (1 H, d, H8, J ϭ
8.4 Hz), 7.30 (13 H, m, arom.), 7.49 (2 H, d, arom-S, J ϭ 8.2 Hz),
7.71 (1 H, d, H5, J ϭ 2.0 Hz). Ϫ MS (CIϩ) m/z (rel. int.) 450
(MϩH, 85%), 478 (Mϩ29, 8), 328 (MϪ123ϩ1, 9).
tion 3.
Acknowledgments
1,2,3,4-Tetrahydro-2,2-diphenyl-6-(p-tolylsulphanyl)-1H-quinolin-4-
one (20): IR (Nujol): ν˜ ϭ 3310 (NH), 1660 (CϭO), 1600, 1450. Ϫ
1H-NMR (200 MHz; CDCl3; Me4Si): δ ϭ 2.29 (3 H, s, Ar-CH3),
3.38 (2 H, s, H3), 5.21 (1 H, br. s, NH), 6.71 (1 H, d, H8, J ϭ
8.4 Hz), 7.03 (2 H, d, arom-S, J ϭ 8.4 Hz), 7.13 (2 H, d, arom-S,
J ϭ 8.4 Hz), 7.30 (11 H, m, arom.), 7.84 (1 H, d, H5, J ϭ 2.0 Hz).
Ϫ MS (EIϩ) m/z (rel. int.) 421 (Mϩ, 100%), 344 (MϪ77, 91), 299
(MϪ122, 13). Ϫ HRMS calcd. for C28H23NOS 421.1500, found
421.1507.
We are grateful to Dr. Roberta Galeazzi for performing the semi-
empirical calculations and to Mrs. Carla Conti for running most
of the FT-IR measurements. Thanks are due to the Italian C.N.R.
(Consiglio Nazionale delle Ricerche) and to the University of An-
cona for financial support.
[1]
[1a] J. F. W. Keana, in Spin Labeling II: Theory and Applications
(Ed.: J. L. Berliner), Academic Press Inc., New York, 1979,
[1b]
chapter 3, p. 115Ϫ172. Ϫ
L. H. Piette, J. Carleton Hsia in
Spin Labeling II: Theory and Applications (Ed.: J. L. Berliner),
Academic Press Inc., New York, 1979, chapter 6, p. 247Ϫ290.
H. M. Swartz in Advances in Magnetic Resonance Imaging (Ed.:
E. Feig) Ablex Publishing Co., Norwood, NJ, 1989, p. 49.
N. Kocherginsky, H. M. Swartz in Nitroxide Spin Labels: Reac-
tions in Biology and Chemistry (Eds.: N. Kocherginsky, H. M.
Swartz) CRC Press, Boca Raton, New York, 1995, chapter 3,
p. 46Ϫ48.
4-Ethoxy-1,2-dihydro-2,2-diphenyl-5-(p-tolylsulphonyl)quinoline
(12y/1c): IR (Nujol): ν˜ ϭ 3320 (NH), 1590, 1450, 1290 and 1135
(SO2). Ϫ 1H-NMR (200 MHz; CDCl3; Me4Si): δ ϭ 1.42 (3 H, t,
CH2CH3, J ϭ 7.0 Hz), 2.37 (3 H, s, Ar-CH3) Ϫ 3.93 (2 H, q,
CH2CH3, J ϭ 7.0 Hz), 4.78 (1 H, br. s, NH), 4.98 (1 H, d, H3, J ϭ
1.8 Hz), 6.49 (1 H, d, H8, J ϭ 8.5 Hz), 7.30 (12 H, m, arom.), 7.56
(1 H, dd, H7, J1 ϭ 8.5, J2 ϭ 2.2 Hz), 7.78 (2 H, d, arom-S, J ϭ
8.1 Hz), 7.96 (1 H, d, H5, J ϭ 2.2 Hz). Ϫ MS (CIϩ) m/z (rel. int.)
482 (MϩH, 100%), 510 (Mϩ29, 17), 329 (MϪ154ϩ1, 2).
[2]
[3]
[4] [4a]
S. Al-Malaika in Comprehensive Polymer Science (Eds.: C.
Booth, C. Price) Pergamon Press, Oxford, 1989, Vol. 2, p. 539.
[4b] F. Gugumus, Polym. Deg. Stab., 1993, 40, 167.
Ϫ
[5]
[6]
P. Carloni, E. Damiani, M. Iacussi, L. Greci, P. Stipa, P. Cauzi,
C. Rizzoli, P. Sgarabotto, Tetrahedron, 1995, 51, 12445Ϫ12452.
L. Greci, E. Damiani, P. Carloni, P. Stipa in Free Radicals in
Biology and Environment (Ed.: F. Minisci) Kluwer Academic
Publishers, Dordrecht, Boston, London, 1997, p. 223Ϫ232.
C. Berti, L. Greci, L. Marchetti, J. Chem. Soc. Perkin Trans. 2,
1979, 233Ϫ236.
4-Ethoxy-1,2-dihydro-2,2-diphenyl-5-(p-tolylsulphonyloxy)quinoline
(12z/1c): IR (Nujol): ν˜ ϭ 3360 (NH), 1635, 1460, 1370 and 1150
(SO3). Ϫ 1H-NMR (200 MHz; CDCl3; Me4Si): δ ϭ 1.33 (3 H, t,
CH2CH3, J ϭ 7.0 Hz), 2.43 (3 H, s, Ar-CH3) Ϫ 3.89 (2 H, q,
CH2CH3, J ϭ 7.0 Hz), 4.37 (1 H, br. s, NH), 4.95 (1 H, s, H3),
[7]
[8]
C. Berti, M. Colonna, L. Greci, L. Marchetti, Tetrahedron,
1975, 31, 1745Ϫ1753.
6.33 (1 H, d, H8, J ϭ 8.7 Hz), 6.60 (1 H, dd, H7, J1 ϭ 8.7, J2
ϭ
[9]
2.7 Hz), 6.99 (1 H, d, H5, J ϭ 2.7 Hz), 7.30 (12 H, m, arom.), 7.71
(2 H, d, arom-S, J ϭ 8.2 Hz). Ϫ MS (EIϩ) m/z (rel. int.) 497 (Mϩ,
4%), 420 (MϪ77, 100), 342 (MϪ155, 7), 326 (MϪ155Ϫ16, 1). Ϫ
HRMS calcd. for C30H27NO4S 497.1661, found 497.1668.
A. K. Bhattacharya, A. G. Hortmann, J. Org. Chem., 1978,
43, 2728Ϫ2730.
[10]
[11]
C. Berti, L. Greci, L. Marchetti, J. Chem. Soc. Perkin Trans. 2,
1977, 1032Ϫ1035.
P. Carloni, E. Damiani, L. Greci, P. Stipa, C. Rizzoli, P. Sgara-
botto, F. Ugozzoli, Tetrahedron, 1993, 49, 5099Ϫ5108.
4-Ethoxy-1,2-dihydro-2,2-diphenyl-7-(p-tolylsulphonyl)quinoline
(13y/1c): IR (DRIFT): ν˜ ϭ 3365 (NH), 1718, 1595, 1491, 1290 and
1110 (SO2). Ϫ 1H-NMR (200 MHz; CDCl3; Me4Si): δ ϭ 1.41 (3
H, t, CH2CH3, J ϭ 7.0 Hz), 2.28 (3 H, s, Ar-CH3) Ϫ 3.95 (2 H, q,
CH2CH3, J ϭ 7.0 Hz), 4.95 (1 H, d, H3, J ϭ 1.8 Hz), 5.58 (1 H, s,
NH), 6.62 (1 H, t, H6, J ϭ 7.4 Hz), 6.93 (4 H, s, arom-S), 7.17 (10
H, m, arom.), 7.35 (1 H, dd, H7, J1 ϭ 7.7, J2 ϭ 1.6 Hz), 7.50 (1
H, d, H5, J ϭ 7.7, 1.3 Hz). Ϫ MS (EIϩ) m/z (rel. int.) 481 (Mϩ,
5%), 326 (MϪ155, 23), 268 (100). Ϫ HRMS calcd. for C30H27NO4S
497.1661, found 497.1669.
[12] [12a] L. Greci, Tetrahedron, 1983, 39, 677Ϫ681. Ϫ [12b] C. Berti,
L. Greci, J. Org. Chem., 1981, 46, 3060Ϫ3063. Ϫ [12c] P. Carloni,
E. Damiani, L. Greci, P. Stipa, Acta Chem. Scand., 1998, 52,
137Ϫ140. Ϫ [12d] C. Berti, M. Colonna, L. Greci, L. Marchetti,
Tetrahedron, 1977, 33, 3149Ϫ3154; C. Berti, M. Colonna, L.
[12e]
Greci, L. Marchetti, Tetrahedron, 1977, 33, 2321Ϫ2327. Ϫ
L. Greci, J. Chem. Res. ( S) , 1979, 204Ϫ205. Ϫ [12f] L. Cardel-
lini, P. Carloni, E. Damiani, L. Greci, P. Stipa, C. Rizzoli, P.
Sgarabotto, J. Chem. Soc. Perkin Trans.2, 1994, 769Ϫ773.
H. Friebolin in Basic One- and Two- Dimensional NMR Spec-
troscopy (Ed.: E. E. Wille) Weinheim: VCH, 1991, chapter 3,
[13]
p.84.
[14]
P. Carloni, L. Cardellini, L. Greci, P. Stipa, A. Faucitano, Gazz.
AM1 Calculations: The structure of compound 5 was optimised,
and a conformational search performed varying all the rateable
bonds present in the molecule always using AM1 Hamiltonian[27]
at UHF level (Unrestricted HartreeϪFock) for open-shell systems
and a statistical algorithm. The UHF computation is used for
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Eur. J. Org. Chem. 1999, 2405Ϫ2412
2411

E. Damiani, P. Carloni, M. Iacussi, P. Stipa, L. Greci
FULL PAPER
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Received February 14, 1998
[O99088]
2412
Eur. J. Org. Chem. 1999, 2405Ϫ2412