Azido-1,2,5-oxadiazoles in reactions with 1,3-dicarbonyl compounds

Article abstract of DOI:10.1070/mc2002v012n04abeh001589

The 1,3-dipolar cycloaddition of azido-1,2,5-oxadiazoles (azidofurazans) to dicarbonyl compounds was studied, and a new procedure for the synthesis of 4-R-3-(4-R¹-5-R²-1,2,3-triazol-1-yl)-1,2,5-oxadiazoles was proposed.

Full text of DOI:10.1070/mc2002v012n04abeh001589

Mendeleev Commun., 2002, 12(4), 159–161
Azido-1,2,5-oxadiazoles in reactions with 1,3-dicarbonyl compounds
Lyudmila V. Batog,* Vladimir Yu. Rozhkov* and Marina I. Struchkova
N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russian Federation.
Fax: +7 095 135 5328; e-mail: mnn@.ioc.ac.ru
10.1070/MC2002v012n04ABEH001589
The 1,3-dipolar cycloaddition of azido-1,2,5-oxadiazoles (azidofurazans) to dicarbonyl compounds was studied, and a new procedure
for the synthesis of 4-R-3-(4-R1-5-R2-1,2,3-triazol-1-yl)-1,2,5-oxadiazoles was proposed.
Previously, we found that the interaction of 3-azido-4-amino-
N3
R
furazan 1a and 5-[4-azido-(1,2,5)-oxadiazol-3-yl]-5H-[1,2,3]-
triazolo[4,5-c][1,2,5]oxadiazole 1b, with substituted acety-
lenes1 or morpholinonitroethylene2 resulted in 1,3-dipolar
cycloaddition products, (1,2,3-triazol-1-yl)furazans 2 (Scheme 1).
1a R = NH2
c R = OMe
d R = Me
e R = Ph
N
N
O
O
O
1a,c–e
N3
R2
R1COCH2COR2
N
N
xii
i–xi
3a–h
3i
O
1a
R = NH2
N
N
N
N
O
1b R = Z = N
O
R1
R2
O
5'
4'
N1'
NH2
R
N
N
' N
3
R1C CR2
3
4
O
N
CH CHNO2
N
N
N5
2'
N
2
N
N
O
O1
R1
N
R2
O2N
H
2m
2a–l
g R = NH2, R1 = Et, R2 = OMe
2a R = NH2, R1 = R2 = Me
R
R
b R = NH2, R1 = Me, R2 = Ph h R = NH2, R1 = Pr, R2 = OEt
N
N
N
c R = NH2, R1 = Ph, R2 = Me
d R = NH2, R1 = R2 = Ph
i R = NH2, R1 = CH2OMe, R2 = OMe
j R = OMe, R1 = R2 = Me
k R = R1 = R2 = Me
N
N
N
N
O
N
N
e R = NH2, R1 = Me, R2 = OEt
f R = NH2, R1 = Ph, R2 = OEt
O
l R = Ph, R1 = R2 = Me
2
2
3a R1 = R2 = Me
b R1 = Me, R2 = Ph
c R1 = R2 = Ph
e R1 = Ph, R2 = OEt
f R1 = Et, R2 = OMe
g R1 = Pr, R2 = OEt
R = NH2, R1 = H, R2 = Alk, CH2Cl, Ph;
R1 = AlkOH, CH2Cl, COOH, COOEt, Ph,
R2 = H, R1 = R2 = CH2OH, CMeEtOH,
COOH, COOMe;
R = NH2; Z
d R1 = Me, R2 = OEt
h R1 = CH2OMe, R2 = OMe
R = Z, R1 = R2 = CH2OH
Scheme 3 Reagents and conditions: i, 1a, 3a, MeOH, MgCO3, 8 h, H2O
(Et3N, K2CO3, Na2CO3), 30 min, 2a; ii, 1a, 3b, EtOH–H2O 1:5, K2CO3,
30 min, 2b, 2c; iii, 1a, 3c, MeOH, MgCO3, 8 h, 2d; iv, 1a, 3d, H2O, Et3N
(EtOH, K2CO3), 30 min (15 min), 2e; v, 1a, 3e, EtOH, MgCO3, 2h, 2f; vi,
1a, 3f, MeOH, MgCO3, 8 h, K2CO3, 2 h, 2g; vii, 1a, 3g, EtOH, MgCO3, 10 h,
2h; viii, 1a, 3h, EtOH, MgCO3, 16 h, 2i; ix, 1c, 3a, MeOH, MgCO3, 10 h, 2j;
x, 1d, 3a, H2O, K2CO3, 8 h, 2k; xi, 1e, 3a, EtOH–H2O 1:1, Et3N, 10 h, 2l;
xii, 1a, 3i, EtOH, MgCO3, 8 h, 2m.
Scheme 1
Triazolylfurazans 2, whose derivatives exhibited various bio-
logical activities,3,4 can be studied as potentially biologically
active compounds. In this context, it seems reasonable to develop
new preparative procedures for the synthesis of these compounds.
It is well known that aromatic azides can form 1,2,3-triazoles
by cycloaddition to not only acetylenes or activated olefins but
also compounds containing active CH2 groups, such as 1,3-di-
carbonyl compounds 35–11 (Scheme 2). The position of the RCO
group depends on the reaction mechanism.7,8,12,13 Triazoles are
not always the only products of the above reaction. Amines,
diazo compounds, etc., can be formed depending on the nature
of the azide and the carbonyl component and on reaction con-
ditions.5–7,12,14
tuents: amino (1a), methoxy (1c), methyl (1d), phenyl (1e) and
oxapentaazapentalenyl (1b) groups. Acetylacetone 3a, benzoyl-
acetone 3b, dibenzoylmethane 3c, acetoacetic ester 3d, benzo-
ylacetic ester 3e, their analogues 3f–h and cyclic diketones 3i,j
were used as dicarbonyl compounds. The reactions with azide
1a (Scheme 3, i–viii, xi) were studied most extensively. Solvents
(EtOH, MeOH, H2O and aqueous ethanol) and activating bases
(Et3N, MeONa, Na2CO3, K2CO3 and MgCO3) were varied.
We found that the majority of the tested reactions resulted in
cycloaddition products, triazolylfurazans 2a–m (Scheme 3, i–xii),
which were obtained in high yields.† We also found that, as
distinct from published data, the amount of a base required for
cycloaddition is lower that an equimolar amount by a factor of
2–10. Triazolylfurazans were successfully formed not only in
the presence of Et3N, which is frequently used for the activation
of dicarbonyl compounds, but also under the action of alkali
metal carbonates or MgCO3. Sodium methylate was found to be
inappropriate for the reaction with azide 1a.
In this work, we examined the cycloaddition of azidofura-
zans to 1,3-dicarbonyl compounds (Schemes 3 and 4) in order
to develop a new procedure for the synthesis of compounds 2.
We used azidofurazans 1a–e containing the following substi-
R1(R)
R1(R)
R1
O
R
Ar N3
O
O
N
N
Ar
3
N
Water, which was not used previously in the reactions of azides
with dicarbonyl compounds, and aqueous ethanol were found to
Scheme 2
– 159 –

Mendeleev Commun., 2002, 12(4), 159–161
1
be most favourable for the preparation of triazolylfurazans based
on azide 1a. The reactions rapidly proceeded in aqueous media
(within 30 min with azide 1a or within a few hours with other
azidofurazans) without heating, and almost pure cycloaddition
products 2 were precipitated. Reactions in ethanol as a solvent
were performed on boiling.
Under the specified conditions, azidofurazans reacted with
1,3-dicarbonyl compounds much more rapidly than with substi-
tuted acetylenes.
Reactions shown in Scheme 4 do not result in the synthesis
of products 2. The interaction of azide 1a with indanedione 3k
(Scheme 4, xiii) or azide 1b with acetylacetone (xiv) result in
amine 4 or 5, respectively. Amine 5, which was described pre-
viously, was isolated in 83% yield and identified by TLC and
1H and 13C NMR spectra.
spectrum of 2j exhibited two quartets with J 13C, H 7.3 and
3.8 Hz, which were attributed to C-5' and C-4, respectively, a
narrower signal at 141.5 ppm, which was ascribed to C-3, and
a broadened signal at 142.6 ppm, which was attributed to C-4'.
‡
All new compounds exhibited satisfactory elemental analysis data. The
13C and 1H NMR spectra of compounds 2a–m were measured on a
Bruker AM-300 spectrometer (75.5 MHz for 13C and 300 MHz for H)
1
in a Fourier transform pulse mode as solutions in [2H6]DMSO (d13C 39.5,
d1H 2.5) or CDCl3 (d13 77.1, d1H 7.27). The IR spectra were recorded
on a Specord M80 instCrument in KBr pellets. The TLC monitoring was
performed using Silufol UV-254 plates (Czech Republic).
2a (i) yield 81–93%, mp 145 °C (MeOH); Rf 0.55 (PhH–EtOAc, 3:1).
IR (KBr, nmax/cm–1): 3430, 3340 (NH2), 3020 (Me), 1710 (C=O), 1650,
1610, 1580, 1560, 1530, 1480, 1415, 1370, 1310, 1270, 1240, 1205,
1120, 1060, 1025, 1000, 980, 960, 930. 1H NMR (CDCl3) d: 2.48 (s, 3H,
Me), 2.61 (s, 3H, COMe), 4.46 (s, 2H, NH2). 13C NMR ([2H6]DMSO) d:
192.9 (C=O), 152.4 (C-4), 142.7 (C-3), 142.3 (C-4'), 140.2 (C-5'), 27.8
(COMe), 9.6 (Me). MS, m/z (%): 208 (M+, 50), 193 (M+ – Me, 23), 180
(M+ – N2, 5), 165 (M+ – COMe, 24), 150 (18), 149 (45), 138 (42), 123
(60), 108 (79), 53 (100).
Along with amine 4, 2-diazo-1,3-indanedione16 6 and diazo-
bindone16 7 were formed in reaction xiii. Compounds 6 and 4
were identified by mass spectrometry (m/z 172 and 100 corre-
spond to their molecular ions); amine 4 was also identified by
chromatography. Diazobindone 7 (mp 208 °C16) was isolated in
75% yield. This compound is likely formed from indanedione
self-condensation product 8 (Scheme 4), similarly to the reac-
tion of indole with p-tosylazide in an alkaline medium.16 This
hypothesis was supported by control experiments (xv, xvi), which
demonstrated that indanedione 3j was converted into bindone 8
on boiling with MgCO3 in ethanol. The reaction of bindone 8 with
azide 1a under the same conditions afforded diazobindone 7. It
is likely that reactions xiii and xiv occur as described pre-
viously.7,14
2b (ii) yield 91%, mp 176–177 °C (MeOH); Rf 0.63 (PhH–EtOAc,
5:1). IR (KBr, nmax/cm–1), 3480, 3384 (NH2), 3064, 1656 , 1632, 1584,
1560, 1532, 1448, 1404, 1360, 1312, 1248, 1184, 1144, 1092, 1056,
976, 912, 864, 736. 1H NMR ([2H6]DMSO) d: 2,75 (s, 3H, Me), 6.60 (s,
2H, NH2), 7.58 (t, 2H, m-H-Ph, J 7.9 Hz), 7.70 (t, 1H, p-H-Ph, J 7.9 Hz),
8.24 (d, 2H, o-H-Ph, J 7.9 Hz). 13C NMR ([2H6]DMSO) d: 186.2 (C=O),
152.4 (C-4), 142.2 (C-3), 142.5 (C-4'), 142.4 (C-5'), 136.7 (Ci-Ph), 133.2
m z
(Cp-Ph), 130.0 (Co-Ph), 128.3 (Cm-Ph), 9.9 (Me). MS, / (%): 270 (M+, 5),
242 (M+ – N2, 5), 241 (M+ – NH2, 15), 212 (M+ – N2 – NO, 10), 185 (14),
157 (10), 115 (28), 105 (M+ – PhCO, 100), 77 (66).
2c (ii) yield 5%, mp 150 °C (MeOH); Rf 0.32 (PhH–EtOAc, 5:1). IR
(KBr, nmax/cm–1): 3416, 3320, 1696, 1636, 1592, 1544, 1484, 1448, 1432,
1408, 1372, 1352, 1312, 1248, 1200, 1104, 1024, 984, 952, 872, 768, 744.
1H NMR ([2H6]DMSO) d: 2.65 (s, 3H, Me), 6.64 (s, 2H, NH2), 7.44 (m,
5H, Ph). 13C NMR ([2H6]DMSO) d: 192.1 (C=O), 153.6 [(C-4)-NH2],
143.1 (C-4'), 142.5 (C-3), 141.9 (C-5'), 131.1 (Cp-Ph), 130.1 (Co-Ph),
128.8 (Cm-Ph), 124.2 (Ci-Ph), 28.5 (CO–Me). MS, m/z (%): 270 (M+, 5),
255 (M+ – Me, 1), 227 (M+ – COMe, 1), 212 (M+ – N2 – NO, 10), 200
(M+ – N2–H2N–C=N–, 4), 143 (18), 128 (15), 77 (Ph, 8), 43 (COMe, 100).
2d (iii) yield 73%, mp 145 °C (EtOH); Rf 0.68 (PhH–EtOAc, 5:1). IR
(KBr, nmax/cm–1): 3460, 3340, 3250, 1670, 1640, 1610, 1570, 1490, 1460,
1420, 1390, 1340, 1310, 1290, 1260, 1230, 1180, 1110, 1080, 1040, 1020,
990, 920, 860, 850, 810, 780, 750, 700. 1H NMR ([2H6]DMSO) d: 6.72
(s, 2H, NH2), 7.44 (s, 5H, Ph), 7.54 (t, 2H, Ph), 7.68 (t, 1H, Ph), 8.10 (d,
2H, Ph). 13C NMR ([2H6]DMSO) d: 186.0 (C=O), 153.4 (C-4), 143.4
(C-4'), 142.9 (C-5'), 142.4 (C-3), 136.7 (Ci-COPh), 133.5 (Cp-COPh), 130.6
(Cp-Ph), 130.2 (Co-COPh), 129.8 (Co-Ph), 128.5 (Cm-Ph), 128.4 (Cm-COPh),
124.2 (Ci-Ph).
2e (iv) yield 81% (91%), mp 121–122 °C (PhH); Rf 0.53 (PhH–
EtOAc, 3:1). IR (KBr, nmax/cm–1): 3440, 3340 (NH2), 3010 (CH), 1750
(C=O), 1640, 1590, 1480, 1450, 1420, 1390, 1360, 1320, 1240, 1220, 1150,
1120, 1060, 1020, 1000, 980, 870, 850. 1H NMR ([2H6]DMSO) d: 1.34
(t, 3H, Me, J 5.8 Hz), 2.63 (s, 3H, MeCH2), 4.46 (q, 2H, CH2, J 7.1 Hz),
6.65 (s, 2H, NH2). 13C NMR ([2H6]DMSO) d: 160.5 (C=O), 152.4 (C-4),
142.4 (C-5'), 141.7 (C-3), 136.3 (C-4'), 61.0 (OCH2), 14.1 (CH2Me), 9.7
(Me).
The structures of compounds 2a–m were determined from the
1
data of elemental analysis, IR spectroscopy, H and 13C NMR
spectroscopy, and mass spectrometry.‡
In the assignment of signals in the 13C NMR spectra, we used
a selective heteronuclear double resonance procedure and took
into account the multiplicity of signals obtained in the measure-
ment of 13C–1H spin–spin coupling constants (for compounds
2b,j,k,l). Thus, for example, in the region 135–165 ppm, the
N3
NH2
O
O
xv
N
N
O
1a
O
O
O
3j
8
xiii
1a
xvi
O
O
O
H2N
NH2
N2
N
N
O
O
O
N2
4
7
6
2f (v) yield 82%, mp 138–139 °C (MeOH); Rf 0.39 (PhH–EtOAc, 5:1).
IR (KBr, nmax/cm–1): 3470, 3420, 3350 (NH2), 3010, 1750, 1740 (C=O),
1650, 1590, 1560, 1490, 1455, 1430, 1390, 1360, 1320, 1290, 1260,
1230, 1220, 1150, 1125, 1040, 1010, 990, 874, 870, 770, 700. 1H NMR
([2H6]DMSO) d: 1.16 (t, 3H, Me, J 7.5 Hz), 4.25 (q, 2H, CH2, J 8.3 Hz),
6.67 (s, 2H, NH2), 7.50 (m, 5H, Ph). 13C NMR ([2H6]DMSO) d: 159.7
(C=O), 153.3 (C-4), 143.4 (C-5'), 142.2 (C-3), 136.4 (C-4'), 130.6 (Cp-Ph),
129.9 (Co-Ph), 128,3 (Cm-Ph), 123.9 (Ci-Ph), 60.9 (OCH2), 13.8 (Me). MS,
m/z (%): 300 (M+, 15), 270 (M+ – NO, 5), 242 (M+ – NO – N2, 4), 215
(M+ – C – COOCH2Me, 25), 145 (100).
N
N
N
N
N
N
N
N3
NH2
O
N
O
N
xiv
3a
N
N
N
N
N
O
O
1b
5
Scheme 4 Reagents and conditions: xiii, EtOH, MgCO3, 5 min; xiv, EtOH,
MgCO3, 6 min.
2g (vi) yield 83% (76%), mp 157 °C (MeOH); Rf 0.32 (PhH–EtOAc,
5:1). IR (KBr, nmax/cm–1): 3720, 3408, 3320, 3256, 3216, 2984, 2952,
2888, 2848, 2168, 1720,1644, 1600, 1564, 1452, 1424, 1368, 1328, 1304,
1288, 1236, 1216, 1132, 1068, 1016, 988, 952, 864, 816, 792, 736, 712,
696, 656. 1H NMR ([2H6]DMSO) d: 1.14 (t, 3H, Me, J 8.9 Hz), 3.07 (q,
2H, CH2, J 8.9 Hz), 3.92 (s, 3H, OMe), 6.67 (s, 2H, NH2). 13C NMR
([2H6]DMSO) d: 160.7 (C=O), 152.5 (C-4), 146.6 (C-5'), 142.1 (C-3),
135.5 (C-4'), 52.0 (OMe), 16.9 (CH2), 12.5 (Me).
2h (vii) yield 87%, mp 69–70 °C (EtOH–H2O, 1:1); Rf 0.48 (PhH–EtOAc,
5:1). IR (KBr, nmax/cm–1): 3460, 3340, 3260, 3220, 3000, 2950, 2920,
1740, 1720, 1640, 1600, 1580, 1480, 1460, 1410,1390, 1380, 1340, 1310,
1290, 1240, 1220, 1190, 1130, 1120, 1090, 1030, 1020, 990, 950, 910,
†
General preparation procedure for triazoles 2a–m. A mixture of azide
1 and dicarbonyl compound 3 in water or aqueous ethanol was stirred in
the presence of a catalyst at room temperature until vigorous precipi-
tation. The precipitate was filtered off, washed with water and dried in
air. The mixture of reactants was boiled in ethanol until the complete
reaction of the azide. The reaction mixture was evaporated to dryness in
a vacuum; the residue was washed with water and dried in air. In reac-
tions with MgCO3, a hot ethanolic solution was initially filtered from the
inorganic salt and then evaporated to dryness; the residue was washed
with water and dried in air.
– 160 –

Mendeleev Commun., 2002, 12(4), 159–161
A comparison between chemical shifts in the 13C NMR spectra
of 2a,j ([2H6]DMSO) and 2k,l (CDCl3) suggests that a substi-
tuent at the 4-position has almost no effect on the chemical shift
of a triazole ring (< 0.3 ppm). The structures of compounds 2b
and 2c were unambiguously derived from 13C NMR spectra
based on the difference between the chemical shifts of carbonyl
groups in acetyl (192 ppm) and benzoyl (186 ppm) units, which
is consistent with the chemical shift of carbonyl in the structures
containing analogous groups (2a, 2j–l and 2d, respectively).
Note that the chemical shifts of 13Ci in a phenyl ring at a
double bond (~124 ppm) (2c,d,f) and in a benzoyl moiety
(~136 ppm) (2b,d) are significantly different.
3 R. M. Paton, in Comprehensive Heterocycl. Chem., eds. A. K. Katritzky
and C. W. Rees, Pergamon Press, Oxford, 1984, vol. 6, p. 425.
4 R. Bohm and Cr. Karov, Pharmazie, 1981, 4, 243.
5
6
7
8
E. Yu. Gudrinietse and V. V. Solov’eva, Izv. Akad. Nauk Latv. SSR,
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(Engl. Transl.), 1983, 19, 1116].
9
O. Dimroth, Ber. Dtsch. Chem. Ges., 1902, 35, 1029.
10 G. R. Humphery and St. H. B. Wright, J. Heterocycl. Chem., 1991, 28,
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11 M. Julino and M. F. G. Stevens, J. Chem. Soc., Perkin Trans. 1, 1998,
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References
1 L. V. Batog, L. S. Konstantinova, V. Yu. Rozhkov, Yu. A. Strelenko, O. V.
Lebedev and L. I. Khmel’nitskii, Khim. Geterotsikl. Soedin., 2000, 100
[Chem. Heterocycl. Compd. (Engl. Transl.), 2000, 36, 91].
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1
870, 850, 830, 790, 775, 730, 710. H NMR ([2H6]acetone) d: 0.98 (t,
3H, MeCH2O, J 7.0 Hz), 1.40 (t, 3H, Me, J 7.0 Hz), 1.72 (m, 2H, CH2–
CH2Me, J 7.0 Hz), 3.26 [t, 2H, C(5')-CH2, J 7.0 Hz], 4.44 (q, 2H, Me–
CH2O, J 7.0 Hz), 6.20 (s, 2H, NH2). 13C NMR (CDCl3) d: 160.6 (C=O),
150.9 (C-4), 144.9 (C-5'), 142.2 (C-3), 137.1 (C-4'), 61.6 (OCH2), 25.6
[C(5')-CH2], 21.8 [C(5')-CH2-CH2].
16 M. Regitz and G. Heck, Chem. Ber., 1964, 97, 1482.
2i (viii) yield 94%, mp 126–127 °C (EtOH); Rf 0.37 (PhH–EtOAc,
5:1). IR (KBr, nmax/cm–1): 3460, 3250 (NH2), 3010, 2960, 2940, 2910,
2890, 2850, 2830 (Alk), 1720 (C=O), 1640, 1590, 1570, 1480, 1460,
1390, 1360, 1290, 1250, 1220, 1200, 1140, 1110, 1090, 1050, 1000,
1
980, 950, 830, 800, 780. H NMR ([2H6]DMSO) d: 3.20 (s, 3H, MeO),
3.94 (s, 3H, COOMe), 4.92 (s, 2H, CH2), 6.62 (s, 2H, NH2). 13C NMR
([2H6]DMSO) d: 160.4 (C=O), 152.8 (C-4), 142.7 (C-3), 141.2 (C-5'),
136.7 (C-4'), 61.6 (CH2), 58.3 (OMe), 52.3 (COOMe).
2j (ix) yield 61%, mp 97–98 °C (MeOH); Rf 0.63 (PhH–EtOAc, 3:1);
IR (KBr, nmax/cm–1): 3000, 2944 (Me), 1692 (C=O), 1600, 1576, 1556,
1452, 1424, 1392, 1368, 1304, 1232, 1104, 1056, 1024, 992, 976, 952,
1
920, 868, 720, 688, 656. H NMR ([2H6]DMSO) d: 2.53 (s, 3H, Me),
2.54 (s, 3H, COMe), 4.40 (s, 3H, OMe). 13C NMR ([2H6]DMSO) d:
192.5 (C=O, 2JCH 6.3 Hz), 160.4 (C-4, 3JCH 3.8 Hz), 142.6 (C-4'), 141.5
2
1
(C-3), 140.0 (C-5', JCH 7.3 Hz), 60.3 (OMe, JCH 149.5 Hz), 27.6
1
1
(COMe, JCH 132.3 Hz), 9.1 (Me, JCH 132.4 Hz). MS, m/z (%): 223
(M+, 3), 208 (M+ – Me, 1), 195 (M+ – N2, 1), 180 (M+ – COMe, 1), 43
(COMe, 100).
2k (x) yield 82%, mp 63–64 °C (MeOH); Rf 0.62 (PhH–EtOAc, 5:1).
IR (KBr, nmax/cm–1): 3740, 3370, 3015, 2320, 2170, 1690, 1590, 1530,
1420, 1390, 1370, 1300, 1230, 1100, 1070, 1025, 980, 950, 890, 705.
1H NMR (CDCl3) d: 2.73 (s, 3H, Me), 2.77 (s, 3H, Me), 2.90 (s, 3H,
Me). 13C NMR (CDCl3) d: 193.4 (C=O, 2JCH 6.3 Hz), 149.7 (C-3), 147.7
(C-4, 2JCH 6.3 Hz), 143.6 (C-4'), 139.8 (C-5', 2JCH 6.3 Hz), 28.1 (COMe,
1JCH 128.4 Hz), 10.4 (Me, 2JCH 132.6 Hz), 9.8 (Me, 1JCH 132.6 Hz). MS,
m/z (%): 207 (M+, 7), 192 (M+ – Me, 1), 179 (M+ – N2, 1), 149 (M+ –
– N2 – NO, 6), 43 (MeCO, 100).
2l (xi) yield 76%, mp 82 °C (MeOH); Rf 0.62 (PhH–EtOAc, 5:1). IR
(KBr, nmax/cm–1): 3720, 3370, 2930, 2350, 2310, 2170, 1690, 1610, 1560,
1540, 1490, 1460, 1410, 1360, 1310, 1290, 1240, 1120, 1080, 1000, 980,
1
950, 910, 870, 860, 780, 740, 700. H NMR (CDCl3) d: 2.61 (s, 3H,
Me), 2.78 (s, 3H, Me), 7.50 (m, 5H, Ph). 13C NMR (CDCl3) d: 193.4
2
(C=O, JCH 6.6 Hz), 151.4 (C-4), 147.8 (C-3), 143.6 (C-4'), 140.3 (C-5',
2JCH 6.1 Hz), 131.7 (Cp-Ph), 128.2 (Co-Ph), 123.0 (C-5'), 27.9 (COMe,
1JCH 128.6 Hz), 9.5 (Me, 1JCH 132.4 Hz). MS, m/z (%): 269 (M+, 6), 254
(M+ – Me, 1), 241 (M+ – N2, 1), 226 (M+ – COMe, 1), 43 (MeCO, 100).
2m (xii) yield 75%, mp 224–225 °C (MeOH); Rf 0.37 (PhH–EtOAc,
3:1). IR (KBr, nmax/cm–1): 3420, 3320, 3250, 3210 (NH2), 2970, 2920,
2890 (Alk), 1710 (C=O), 1640, 1590, 1580, 1560, 1470, 1430, 1410,
1290, 1250, 1190, 1100, 1090, 1080, 1050, 1030, 1020, 990, 900, 860,
730. 1H NMR ([2H6]DMSO) d: 2.20 (m, 2H, CH2, J 7.2 Hz), 2.62 (t, 2H,
CH2, J 7.2 Hz), 3.20 (t, 2H, CH2, J 7.2 Hz) 6.68 (s, 2H, NH2). 13C NMR
([2H6]DMSO) d: 190.0 (C=O), 151.6 (C-4), 149.7 (C-4'), 141.5 (C-5'),
142.4 (C-3), 37.9 (COCH2), 20.9 [(C-5')-CH2], 22.1 (CO-CH2-CH2).
MS, m/z (%): 220 (M+, 11), 136 (6), 135 (92), 65 (100).
Received: 8th April 2002; Com. 02/1915
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