1,2,3,6-Tetrahydropyrrolo[1,2-d][1,4]diazocines. Reactions of 1-methyl-2-R-tetrahydropyrrolo[1,2-a]pyrazines with alkynes

Article abstract of DOI:10.1007/s11172-010-0119-y

The reactions of 6-formyl-and 6-trifluoroacetyl-1-methyl-2-R- tetrahydropyrrolo[1,2-a]- pyrazines with activated alkynes in methanol and acetonitrile have been studied. Terahydro- pyrrolo[1,2-d][1,4]diazocine derivatives were synthesized at the first time.

Full text of DOI:10.1007/s11172-010-0119-y

Russian Chemical Bulletin, International Edition, Vol. 59, No. 3, pp. 647—653, March, 2010
647
1,2,3,6ꢀTetrahydropyrrolo[1,2ꢀd][1,4]diazocines.
Reactions of 1ꢀmethylꢀ2ꢀRꢀtetrahydropyrrolo[1,2ꢀa]pyrazines
with alkynes
L. G. Voskressensky, T. N. Borisova, T. M. Kamalitdinova, A. A. Titov, A. V. Listratova, and A. V. Varlamov
Peoples´ Friendship University of Russia,
6 ul. MiklukhoꢀMaklaya, 117198 Moscow, Russian Federation.
Fax: +7 (495) 955 0779. Eꢀmail: lvoskressensky@sci.pfu.edu.ru
The reactions of 6ꢀformylꢀ and 6ꢀtrifluoroacetylꢀ1ꢀmethylꢀ2ꢀRꢀtetrahydropyrrolo[1,2ꢀa]ꢀ
pyrazines with activated alkynes in methanol and acetonitrile have been studied. Terahydroꢀ
pyrrolo[1,2ꢀd][1,4]diazocine derivatives were synthesized at the first time.
Key words: tetrahydropyrrolo[1,2ꢀa]pyrazines, pyrrolo[1,2ꢀd][1,4]diazocines, tandem transꢀ
formation, ring expansion.
Recently we have reported a novel tandem transforꢀ
mations involving expansion and cleavage of the terahyꢀ
dropyridine ring fused at the cꢀedge with the heterocyclic or
benzene moiety under the action of alkynes activated by the
electronꢀwithdrawing substituents in protic and aprotic
solvents.1—4 Thus, the tandem transformations of 2ꢀRꢀtetraꢀ
hydropyrrolo[3,2ꢀc]pyridines1 and 2,3,5ꢀtrimethylꢀ7ꢀtriꢀ
fluoroacetylpyrrolo[1,2ꢀc]pyrimidine2 have been studied.
The pathways of transformations of these compounds
governed by the electronic effects of the substituents in the
αꢀposition, the nature of the solvent and substituents at
the nitrogen atoms of the pyrrole and the tetrahydroꢀ
pyridine rings as well as the character of fusion of the latter.
In aprotic solvents, unsubstituted at the N(1) atom as
well as 1ꢀvinylꢀ4,5,7ꢀtrimethyltetrahydropyrrolo[3,2ꢀc]ꢀ
pyridines 1 (R1 = H; R2 = H, CH=CH2) under the action
of acetylenedicarboxylic acid ester (dimethyl acetylenediꢀ
carboxylate, DMAD) furnished exclusively 3ꢀvinylpyrroles
2, while 2ꢀtrifluoroacetylꢀ, formylꢀ, and dicyanovinylꢀsubꢀ
stituted derivatives gave the mixtures of 3ꢀvinylpyrroles 2
and azocines 3. In methanol, tetrahydropyridine ring unꢀ
derwent the cleavage involving one molecule of methanol
to give the mixture of diastereomeric 3ꢀmethoxyethylꢀ
pyrroles 4 (Scheme 1).
The reaction of 7ꢀtrifluoroacetylꢀsubstituted pyrroloꢀ
[1,2ꢀc]pyrimidine with alkynes followed another pattern
(Scheme 2).
In methanol, the ring opening in the presence of
DMAD involved only the aminal moiety to give pyrroles
5. If the reaction was carried out either in ethanol or aceꢀ
tonitrile in the presence of methyl propiolate, the cleavage
of the aminal moiety as well as the N(2)—C(3) bond took
place, which led to the mixtures of pyrroles 5 and 6.
It was of interest to study the reactivity of tetrahydroꢀ
pyrrolo[1,2ꢀa]pyrazines in this reaction as the fusion mode
of the azine and azole rings in the latter differed from that
in the compounds described above.
In the present work the reaction pattern of 1ꢀmethylꢀ
2ꢀmethyl(ethyl)ꢀ6ꢀRꢀtetrahydropyrrolo[1,2ꢀa]pyrazines
7—10 with alkynes in methanol and acetonitrile was studied.
The starting 1ꢀmethylꢀ3,4ꢀdihydropyrrolo[1,2ꢀa]ꢀ
pyrazine was synthesized from acetylfuran by the known
Scheme 1
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 633—638, March, 2010.
1066ꢀ5285/10/5903ꢀ0647 © 2010 Springer Science+Business Media, Inc.

648
Russ.Chem.Bull., Int.Ed., Vol. 59, No. 3, March, 2010
Voskressensky et al.
Scheme 2
X = Y = CO2Me, R1 = H, CH2OMe; X = CO2Et, Y = H, R1 = H; R2 = H, CH2—NMe—CH=CH—CO2Et
1
procedure.5—7 The reduction of acetylfuran and subꢀ
sequent alkylation of the intermediate with methyl
and ethyl iodide in the presence of Hünig´s base furꢀ
nished 2ꢀalkylated tetrahydropyrrolo[1,2ꢀa]pyrazines
(TGPP) 7 and 11, which were converted into 6ꢀformylꢀ
substituted TGPP 9 and 8 by the Vilsmeier—Haack reacꢀ
tion (Scheme 3).
(according to the H NMR spectra) in 36% total yield.
(see Scheme 4).
No reaction of formylꢀsubstituted TGPP 8 and 9 with
even 3—7ꢀfold excess of DMAD was observed in acetoniꢀ
trile upon reflux. In methanol, reaction of 2ꢀethylꢀsubstiꢀ
tuted TGPP 9 with DMAD at 30 °C for 7 days furnished
2ꢀ(1ꢀmethoxyethyl)substituted pyrrole 13 in 47% yield.
Compound 13 is the result of the cleavage process involvꢀ
ing one molecule of methanol. The similar cleavage of
compound 8 took place in aqueous acetonitrile. Hydroxyꢀ
ethylꢀsubstituted pyrrole 14 was isolated in 7% yield (see
Scheme 4).
Scheme 3
The reaction of formylꢀsubstituted derivatives 8 and 9
with terminal alkynes, methyl propiolate, and pꢀtosylꢀ
acetylene at 30 °C for 7 and 14 days, respectively, resulted
in the multiꢀcomponent mixtures, from which pyrroꢀ
lodiazocines 15—17 were isolated. Compound 9 reacted
with acetylacetylene only upon reflux (14 days) giving pyrꢀ
rolodiazocine 18 in the 31% yield. The reaction of comꢀ
pounds 8 and 9 with methyl propiolate and acetyl aceꢀ
tylene in MeOH at 30 °C afforded 2ꢀ(1ꢀmethoxyethyl)ꢀ
substituted pyrroles 19, 20, and 21 in the yields of 9, 25,
and 54%, respectively. No reaction of 6ꢀtrifluoromethylꢀ
substituted TGPP 10 with methyl propiolate was found
in acetonitrile upon reflux. If this reaction was carried out
in methanol at 30 °C, pyrrolodiazocine 22 and 2ꢀmeꢀ
thoxyethylꢀsubstituted pyrrole 23 were formed in 1 : 1.5
ratio. The reaction of compound 10 with DMAD in methꢀ
anol led to the tetrahydropyrazine ring cleavage affordꢀ
ing pyrrole 24 in 89% yield. The attempts to obtain pyrꢀ
rolodiazocines from 2ꢀmethoxyethylꢀsubstituted pyrroles
13, 14, 19—21, and 24 applying the conditions, which
were used in the case of 3ꢀmethoxymethyl(methoxyꢀ
ethyl)pyrroles, namely, boron trifluorideꢀmediated cyꢀ
clization, failed. In contrast with studied previously
pyrrolopyridines and pyrrolopyrimidines, pyrrolopyrꢀ
azines reacted with alkynes mainly upon heating and the
reactions accompanied by a significant resinification.
Column chromatography has to be used for the isolation
of the products.
Compound
7
8
9
10
11
R1
Et
Me
Et
Et
Me
R2
H
CHO
CHO
CF3CO
H
Treatment of compound 7 with trifluoroacetic anꢀ
hydride afforded 6ꢀtrifluoroacetyl derivative 10. Introꢀ
duction of the acyl groups in the position 6 of TGPP 7
is could be explained by the fact that the reaction of comꢀ
pound 7 with DMAD in acetonitrile at 50 °C, in conꢀ
trast with the previously described tetrahydropyrroloꢀ
[3,2ꢀc]pyridines,1 resulted in the αꢀvinylation of the pyrꢀ
role ring instead of the tetrahydropyridine fragment transꢀ
formations. (Scheme 4). Vinylꢀsubstiuted TGPP 12 was
isolated as the mixture of Zꢀ and Eꢀisomers in 1 : 1 ratio
The structures of synthesized pyrrolodiazocines 15—18,
22 and substituted pyrroles 13, 14, 19—21, and 23, 24
1
were confirmed by the IR, H NMR, and mass spectroꢀ
scopic data. The mass spectra of all compounds revealed

1,2,3,6ꢀTetrahydropyrrolo[1,2ꢀd][1,4]diazocines
Russ.Chem.Bull., Int.Ed., Vol. 59, No. 3, March, 2010
649
Scheme 4
Compound
R1
Et
Me
Me
Et
R2
X (R3)
(Me)
(H)
CO2Me
CO2Me
Ts
Compound
R1
Me
Et
Et
Et
R2
CHO
CHO
CHO
CF3CO
CF3CO
CF3CO
X (R3)
CO2Me
CO2Me
Ac
CO2Me
CO2Me
(Me)
13
14
15
16
17
18
CHO
CHO
CHO
CHO
CHO
CHO
19
20
21
22
23
24
Et
Et
Et
Et
Ac
the peaks of different intensity attributed to the molecular
ions. In the IR spectra, the stretching vibrations of the
carbonyl group, which were attributed to the formyl
(1641—1660 cm–1), acetyl (1683—1689 cm–1), trifluoroꢀ
In the aprotic solvent, the C(1)—N bond in the zwitterion
A is loosened, which facilitated the nucleophilic attack of
the C(1) atom by the anionic center, thus favoring the
formation of pyrrolodiazocines 15—18 and 22 (pathway a).
Therefore, one cannot exclude the cleavage of the C(1)—N
bond of the zwitterion A to form the second intermediate
zwitterion B (pathway b), which, from one hand, could
underwent ring closure to give diazocines, and, from the
other hand, could be involved in many transformations
typical of carbocations. In our opinion, the formation of
the multiꢀcomponent mixtures could be regarded as indiꢀ
rect evidence of the formation of the zwitterion B. In methꢀ
anol, the zwitterion A gave substituted pyrroles 13, 14,
19—21, 23, and 24. The latter compounds formed via the
transition state C, which is the result of the cleavage of the
C(1)—N bond of the zwitterion A involving one molecule
of methanol (pathway c). The methanol nucleophilic asꢀ
sistance favored the formation of pyrrolodiazocines via
the transition state D (pathway d).
In summary, the possibility of the transformation of
tetrahydropyrrolo[1,2ꢀa]pyrazines into tetrahydropyrroꢀ
lo[1,2ꢀd][1,4]diazocines and 2ꢀRꢀ5ꢀmethoxyethylpyrroles
with the vinylaminoethyl substituent at the nitrogen atom
in the presence of alkynes was demonstrated. The effects
of the solvents, the substituents at the nitrogen atom of the
piperazine ring as well as the nature of the fused aromatic
system1,2 on the facility and the direction of the transforꢀ
mations was demonstrated.
acetyl (1680—1681 cm–1), and ester (1702—1750 cm–1
)
fragments, were observed. The 1H NMR spectra contained
the signals for all protons of compounds 12—24 with reaꢀ
sonable chemical shifts and coupling constant values. The
1H NMR spectra of pyrrolodiazocines 15—18 and 22 exꢀ
hibited the singlet signals at δ 7.20—7.52 characteristic of
the H(4) protons. The 1H NMR spectra of pyrroles 13, 14,
and 24 contained characteristic signals of the vinyl fragꢀ
ment at δ 4.79—4.91. In the case of pyrroles 19—21 and
23, the characteristic signals are broadened singlets in the
range of δ 4.67—5.08 and doublet signals in the range of
δ 7.36—7.43 (J = 13.1—13.2 Hz), which indicated the
transꢀconfiguration of the vinyl group. The reactions of
pyrrolopyrazines 8—10 with alkynes proceeded similarly
to that for other fused tetrahydropyridazines studied by us
(Scheme 5).
The initial step of the reaction is the formation of the
zwitterion A. In such a process, the accessibility of the
lone electron pair of the nitrogen atom is important. The
latter depended on the bulkiness of the substituents R1,
as well as the geometry of the hydrogenated azine ring.
Apparently, these facts explained the significant decrease
in the reactivity of pyrrolopyrazines in the tandem transꢀ
formations as compared with tetrahydropyrrolopyridines.1

650
Russ.Chem.Bull., Int.Ed., Vol. 59, No. 3, March, 2010
Voskressensky et al.
Scheme 5
1,2ꢀDimethylꢀ1,2,3,4ꢀtetrahydropyrrolo[1,2ꢀa]pyrazine (11).
A solution of 1ꢀmethylꢀ1,2,3,4ꢀtetrahydropyrrolopyrazine (8.17 g,
0.06 mol), Hünig's base (17.41 g, 0.14 mol), and methyl iodide
(14.02 g, 0.1 mol) in MeCN (30 mL) was kept at 20 °C for 3 days
under argon (TLC monitoring). The solvent was removed
in vacuo, the residue was diluted with CH2Cl2 (20 mL) and exꢀ
tracted with water (3×20 mL), the organic layer was dried with
MgSO4. Removal of the solvent and purification of the residue
by column chromatography (aluminum oxide) afforded comꢀ
pound 11 (2.44 g, 30%), brown oil. Found (%): C, 71.97; H, 9.42;
N, 20.35. C9H14N2. Calculated (%): C, 72.00; H, 9.33; N, 18.66.
1H NMR, δ: 1.45 (d, 3 H, Me, J = 6.0 Hz); 2.46 (s, 3 H, NMe);
2.75 (ddd, 1 H, C(4)H, J = 4.5 Hz, J = 11.6 Hz, J = 16.0 Hz);
3.05 (dq, 1 H, C(3)H, J = 6.6 Hz, J = 12.1 Hz); 3.36 (q, 1 H,
J = 6.0 Hz); 3.93 (dq, 1 H, C(3)H, J = 6.2 Hz, J = 12.1 Hz); 4.09
(ddd, 1 H, C(4)H, J = 4.5 Hz, J = 11.6 Hz, J = 16.0 Hz); 5.89
(t, 1 H, C(8)H, J = 3.4 Hz); 6.17 (t, 1 H, C(7)H, J = 3.4 Hz);
6.54 (br.s, 1 H, C(6)H). MS, m/z: 151 [M + 1]+.
2ꢀEthylꢀ1ꢀmethylꢀ1,2,3,4ꢀtetrahydropyrrolo[1,2ꢀa]pyrazine
(7) was obtained analogously to compound 11 from NHꢀpyrroloꢀ
pyrazine (5.97 g, 0.04 mol), Hünig's base (8.51 g, 0.07 mol),
and ethyl iodide (7.55 g, 0.05 mol) in MeCN (50 mL). Yield of
pyrrolopyrazine 7 was 3.90 g (54%) 7, brown oil. Found (%):
C, 73.25; H, 9.81; N, 17.05. C10H16N2. Calculated (%): C, 73.17;
H, 9.77; N, 17.26. 1H NMR, δ: 1.15 (t, 3 H, NCH2Me, J = 7.4 Hz);
1.43 (d, 3 H, Me, J = 6.7 Hz); 2.50—2.54 (m, 1 H, NCH2Me); 2.75
(ddd, 1 H, C(4)H, J = 4.7 Hz, J = 9.4 Hz, J = 12.3 Hz); 2.89—2.92
(m, 1 H, NCH2Me); 3.20 (dt, 1 H, C(4)H, J = 4.7 Hz, J = 12.3 Hz);
3.73 (q, 1 H, C(1)H, J = 6.7 Hz); 3.93—4.04 (m, 2 H, C(3)H2);
5.86—5.93 (m, 1 H, C(8)H); 6.13—6.17 (m, 1 H, C(7)H); 6.51—6.55
(m, 1 H, C(6)H). MS, m/z (Irel (%)): 164 [M]+ (5), 163 (6),
149 (100), 121 (10), 106 (9), 94 (9), 92 (7), 65 (6), 42 (10).
Experimental
The IR spectra were recorded on an Infralum FTꢀ801 Fouriꢀ
erꢀtransform IR spectrometer in KBr pellets or films (in the case
of liquid samples). The mass spectra were obtained on a Finniꢀ
gan MAT 95 XL instrument (EI, 70 eV). The LC/MS was perꢀ
formed on a Agilent 1100 Series chromatograph coupled with an
Agilent Technologies LC/MSD VL mass spectrometer (electroꢀ
spray ionization, APCI), ELSD Sedex 75. The 1H NMR were
recorded on a Brukerꢀ400 instrument in CDCl3 using Me4Si as
internal standard. TLC was performed on precoated plates Siluꢀ
fol UVꢀ254 and Alufol (the spots were visualized in an iodine
chamber). Column chromatography was performed with neutral
aluminum oxide (Fluka, Brockmann II, 60 mesh).
1ꢀMethylꢀ1,2,3,4ꢀtetrahydropyrrolo[1,2ꢀa]pyrazine. To a soꢀ
lution of 1ꢀmethylꢀ3,4ꢀdihydropyrrolo[1,2ꢀa]pyrazine5,6 (16.5 g,
0.12 mol) in MeOH (70 mL), sodium borohydride (5.14 g,
0.14 mol) was added portionwise at 20 °C. After 3 days (TLC
monitoring), the solvent was removed in vacuo. The residue was
diluted with water (40 mL), the mixture that formed was extꢀ
racted with diethyl ether (3×150 mL), the combined extract
was dried with MgSO4, and the solvent was removed in vacuo.
Purification of the residue by column chromatography affordꢀ
ed the title compound in a yield of 8.17 g (49%). Found (%): C,
70.54; H, 8.89; N, 20.50. C8H12N2. Calculated (%): C, 70.59;
H, 8.82; N, 20.59. 1H NMR, δ: 1.45 (d, 3 H, 1ꢀMe, J = 6.7 Hz);
3.15—3.22 (m, 1 H, C(4)H); 3.34 (dt, 1 H, C(4)H, J = 3.3 Hz,
J = 12.7 Hz); 3.90—3.96 (m, 2 H, C(3)H2); 4.06 (q, 1 H, C(1)H,
J = 6.7 Hz); 5.88—5.92 (m, 1 H, C(8)H); 6.14—6.18 (m, 1 H,
C(7)H); 6.55—6.66 (m, 1 H, C(6)H). MS, m/z (Irel (%)):
136 [M]+ (10), 135 (12), 121 (100), 94 (14), 65 (9), 42 (9),
41 (9), 39 (12).

1,2,3,6ꢀTetrahydropyrrolo[1,2ꢀd][1,4]diazocines
Russ.Chem.Bull., Int.Ed., Vol. 59, No. 3, March, 2010
651
1ꢀMethylꢀ2ꢀRꢀ1,2,3,4ꢀtetrahydropyrrolo[1,2ꢀa]pyrazineꢀ6ꢀ
carbaldehyde 8 and 9 (general procedure). To DMF (7.01 g,
0.096 mol) phosphorus oxychloride (4.91 g, 0.032 mol) was addꢀ
ed dropwise at –5 °C. The mixture was heated to room temperaꢀ
ture and stirred for 40 min. To a resulting mixture, a solution of
pyrrolopyrazine 7 or 11 (0.016 mol) in DMF (5 mL) was added
dropwise. After completion of the reaction (TLC monitoring),
the reaction mixture was alkalized with 10% aqueous NaOH to
pH 10, extracted with diethyl ether (3×50 mL), and the comꢀ
bined extract was dried with MgSO4. Removal of the solvent
in vacuo and purification of the residue by column chromatoꢀ
graphy (aluminum oxide) afforded the target compound.
(Z)ꢀ and (E)ꢀDimethyl 2ꢀ(2ꢀethylꢀ1ꢀmethylꢀ1,2,3,4ꢀtetrahyꢀ
dropyrrolo[1,2ꢀa]pyrazinꢀ6ꢀyl)ꢀ2ꢀbutenedioate (12). A solution
of pyrrolopyrazine 7 (0.4 g, 2.4 mmol) and DMAD (0.77 g,
5.4 mmol) in MeCN (15 mL) was heated at 50 °C (TLC moniꢀ
toring). The solvent was removed and the residue was purified by
column chromatography (aluminum oxide). Yield 0.26 g (36%),
yellow oil. Found (%): C, 63.00; H, 6.95; N, 9.25. C16H22N2O4.
Calculated (%): C, 62.85; H, 7.22; N, 9.20. IR, ν/cm–1: 1735
(CO2Me). 1H NMR, δ: 1.08 (t, 3 H, CH2Me, J = 7.2 Hz); 1.12
(t, 3 H, CH2Me, J = 7.2 Hz); 1.39 (d, 3 H, Me, J = 6.7 Hz); 1.42
(d, 3 H, Me, J = 6.7 Hz); 2.50—2.55 (m, 2 H, CH2Me);
2.68—2.73 (m, 2 H, C(3)H2); 2.85—2.90 (m, 2 H, CH2Me);
3.13—3.18 (m, 2 H, C(3)H2); 3.66 (s, 3 H, OMe); 3.68—3.73
(m, 2 H, C(1)H); 3.73 (s, 3 H, OMe); 3.74—3.77 (m, 2 H,
C(4)H2); 3.80 (s, 3 H, OMe); 3.96 (s, 3 H, OMe); 4.03—4.07
(m, 2 H, C(4)H2); 5.85 (s, 1 H, CH=); 5.92 (d, 1 H, C(8)H,
J = 3.7 Hz); 5.97 (d, 1 H, C(8)H, J = 4.1 Hz); 6.25 (d, 1 H,
C(7)H, J = 3.7 Hz); 6.41 (d, 1 H, C(7)H, J = 4.1 Hz); 6.86
(s, 1 H, CH=). MS, m/z: 307 [M + 1]+.
Reaction of pyrrolopyrazines 8—10 with dimethyl acetyleneꢀ
dicarboxylate (general procedure). A solution of pyrrolopyrazine
9 or 10 (2.8 mmol) and DMAD (5.6 mmol) in MeOH (20 mL)
was kept at 30 °C. In the case of pyrrolopyrazoline 8, a solution
of 8 (2.8 mmol) and DMAD (9.6 mmol) in MeCN (20 mL) was
refluxed. After completion of the reaction (TLC monitoring),
the solvent was removed in vacuo. Purification of the residue by
column chromatography (aluminum oxide, eluent — ethyl aceꢀ
tate—heptane, 1 : 10) afforded pyrroles 13, 14, and 24.
1,2ꢀDimethylꢀ1,2,3,4ꢀtetrahydropyrrolo[1,2ꢀa]pyrazineꢀ6ꢀ
carbaldehyde (8). Yield 82%, brown oil. Found (%): C, 67.48;
H, 7.90; N, 15.62. C10H14N2O. Calculated (%): C, 67.42; H, 7.87;
1
N, 15.73. IR, ν/cm–1: 1655 (CHO). H NMR, δ: 1.45 (d, 3 H,
Me, J = 6.5 Hz); 2.44 (s, 3 H, NMe); 2.71 (ddd, 1 H, C(4)H,
J = 4.0 Hz, J = 11.1 Hz, J = 12.4 Hz); 3.01 (ddd, 1 H, C(3)H,
J = 2.6 Hz, J = 4.6 Hz, J = 13.4 Hz); 3.41 (q, 1 H, C(1)H,
J = 6.5 Hz); 4.21 (ddd, 1 H, C(4)H, J = 4.0 Hz, J = 11.1 Hz,
J = 12.4 Hz); 4.59 (ddd, 1 H, C(3)H, J = 2.6 Hz, J = 4.6 Hz,
J = 13.4 Hz); 6.02 (d, 1 H, C(8)H, J = 4.1 Hz); 6.89 (d, 1 H,
C(7)H, J = 4.1 Hz); 9.44 (s, 1 H, CHO). MS, m/z (Irel (%)):
178 [M]+ (6), 163 (100), 56 (7), 54 (6), 43 (8), 42 (59), 40 (12).
2ꢀEthylꢀ1ꢀmethylꢀ1,2,3,4ꢀtetrahydropyrrolo[1,2ꢀa]pyrazineꢀ
6ꢀcarbaldehyde (9). Yield 64%, brown oil. Found (%): C, 68.82;
H, 8.37; N, 14.69. C11H16N2O. Calculated (%): C, 68.75;
1
H, 8.33; N, 14.58. IR, ν/cm–1: 1655 (CHO). H NMR, δ: 1.14
(t, 3 H, MeCH2, J = 7.2 Hz); 1.41 (d, 3 H, Me, J = 6.6 Hz); 2.51
(dq, 1 H, CH2Me, J = 7.2 Hz, J = 14.2 Hz); 2.71 (ddd, 1 H,
C(4)H, J = 4.3 Hz, J = 8.8 Hz, J = 12.8 Hz); 2.85 (dq, 1 H,
CH2Me, J = 7.2 Hz, J = 14.2 Hz); 3.17 (dt, 1 H, C(4)H, J = 4.5 Hz,
J = 12.8 Hz); 3.78 (q, 1 H, C(1)H, J = 6.6 Hz); 4.25 (ddd, 1 H,
C(3)H, J = 4.5 Hz, J = 8.8 Hz, J = 13.5 Hz); 4.49 (dt, 1 H,
C(3)H, J = 4.5 Hz, J = 13.5 Hz); 6.00 (d, 1 H, C(8)H,
J = 4.0 Hz); 6.86 (d, 1 H, C(7)H, J = 4.0 Hz); 9.42 (s, 1 H,
CHO). MS, m/z: 193 [M + 1]+.
Dimethyl 2ꢀ(Nꢀethylꢀ{2ꢀ[2ꢀformylꢀ5ꢀ(1ꢀmethoxyethyl)ꢀ1Hꢀ
pyrrolꢀ1ꢀyl]ethyl}amino)maleate (13). Yield 47%, yellow oil.
Found (%): C, 60.10; H, 6.91; N, 7.49. C18H26N2O6. Calculated
(%): C, 59.02; H, 7.10; N, 7.65. IR, ν/cm–1: 1650 (CHO); 1737
(CO2Me). 1H NMR, δ: 1.10 (t, 3 H, CH2Me, J = 7.1 Hz); 1.54
(d, 3 H, CHMe, J = 6.5 Hz); 3.04—3.13 (m, 1 H, CβH);
3.15—3.22 (m, 1 H, CβH); 3.30 (s, 3 H, OMe); 3.39—3.48
(m, 2 H, CH2Me); 3.65 (s, 3 H, CO2Me); 3.95 (s, 3 H, CO2Me);
4.41—4.52 (m, 2 H, CαH2); 4.59 (q, 1 H, CHMe, J = 6.5 Hz);
4.84 (br.s, 1 H, CH=); 6.26 (d, 1 H, C(4)H, J = 4.1 Hz); 6.93
(d, 1 H, C(3)H, J = 4.1 Hz); 9.49 (s, 1 H, CHO). MS, m/z
(Irel (%)): 366 [M]+ (5), 335 (6), 334 (7), 247 (5), 213 (6), 201 (9),
200 (100), 179 (8), 164 (7), 158 (9), 154 (29), 126 (9), 122 (10),
112 (11), 96 (51), 94 (11), 82 (16), 68 (16), 59 (49), 56 (9),
45 (41), 42 (12), 41 (8).
Dimethyl 2ꢀ(Nꢀmethylꢀ{2ꢀ[2ꢀformylꢀ5ꢀ(1ꢀhydroxyethyl)ꢀ1Hꢀ
pyrrolꢀ1ꢀyl]ethyl}amino)maleate (14). Yield 7%, yellow oil.
Found (%): C, 56.89; H, 6.32; N, 8.07. C16H22N2O6. Calculatꢀ
ed (%): C, 56.80; H, 6.51; N, 8.28. IR, ν/cm–1: 1661 (CHO);
1743 (CO2Me). 1H NMR, δ: 1.63 (d, 3 H, CHMe, J = 6.0 Hz);
2.87 (s, 3 H, NMe); 3.39—3.49 (m, 1 H, CβH); 3.50—3.59
(m, 1 H, CβH); 3.65 (s, 3 H, CO2Me); 3.94 (s, 1 H, CO2Me);
4.33 (q, 1 H, CHMe, J = 6.0 Hz); 4.63—4.74 (m, 2 H, CαH2);
4.94 (br.s, 1 H, CH=); 6.28 (d, 1 H, C(4)H, J = 4.0 Hz); 6.92
(d, 1 H, C(3)H, J = 4.0 Hz); 9.49 (s, 1 H, CHO). MS, m/z
(Irel (%)): 338 [M]+ (3), 307 (10), 306 (15), 279 (20), 199 (22),
188 (32), 186 (100), 140 (19), 126 (16), 108 (11), 182 (90), 68 (19),
59 (73), 45 (53).
1ꢀ(2ꢀEthylꢀ1ꢀmethylꢀ1,2,3,4ꢀtetrahydropyrrolo[1,2ꢀa]ꢀ
pyrazinꢀ6ꢀyl)ꢀ2,2,2ꢀtrifluotoethanone (10). To a solution of pyrroloꢀ
pyrazine 7 (2.0 g, 0.012 mol) and pyridine (2.0 g, 0.029 mol) in
anhydrous CH2Cl2 (40 mL), trifluoroacetic anhydride (5.12 g,
0.024 mol) was added dropwise at 35 °C. After completion of the
reaction (TLC monitoring), water (40 mL) was added and the
mixture alkalized by aqueous NaHCO3 to pH 10. The organic
layer was separated, the aqueous phase was extracted with
CH2Cl2 (2×20 mL), the combined organics was dried with
MgSO4. Removal of the solvent in vacuo and purification of the
residue by column chromatography afforded compound 10 in
a yield of 1.87 g (60%), brown oil. Found (%): C, 55.44; H, 5.81;
N, 10.85. C12H15F3N2O. Calculated (%): C, 55.38; H, 5.77;
N, 10.77. IR, ν/cm–1: 1660 (COCF3). 1H NMR, δ: 1.14 (t, 3 H,
CH2Me, J = 7.9 Hz); 1.44 (d, 3 H, Me, J = 6.6 Hz); 2.55 (ddd,
1 H, CH2Me, J = 6.6 Hz, J = 7.9 Hz, J = 14.4 Hz); 2.75 (dq, 1 H,
C(3)H, J = 7.9 Hz, J = 13.1 Hz); 2.86 (ddd, 1 H, CH2Me,
J = 6.6 Hz, J = 7.9 Hz, J = 14.4 Hz); 3.22 (dt, 1 H, C(3)H,
J = 5.3 Hz, J = 13.1 Hz); 3.83 (q, 1 H, C(1)H, J = 6.6 Hz);
4.27—4.33 (m, 1 H, C(4)H); 4.50 (dt, 1 H, C(4)H, J = 5.3 Hz,
J = 14.4 Hz); 6.09 (d, 1 H, C(8)H, J = 3.4 Hz); 7.20 (br.s, 1 H,
C(7)H). MS, m/z (Irel (%)): 260 [M]+ (3), 245 (100), 163 (7),
147 (7), 91 (7), 69 (88), 65 (18), 56 (40), 55 (11), 54 (14), 43 (21),
42 (72), 41 (19).
Dimethyl 2ꢀ(Nꢀethylꢀ{2ꢀ[2ꢀ(2´,2´,2´ꢀtrifluoroacetyl)ꢀ5ꢀ(1ꢀ
methoxyethyl)ꢀ1Hꢀpyrrolꢀ1ꢀyl]ethyl}amino)maleate (24). Yield
89%, yellow oil. Found (%): C, 52.28; H, 6.00; N, 6.30.
C19H25F3N2O6. Calculated (%): C, 52.53; H, 5.76; N, 6.45. IR,
1
ν/cm–1: 1648 (CO); 1750 (CO2Me). H NMR, δ: 1.12 (t, 3 H,

652
Russ.Chem.Bull., Int.Ed., Vol. 59, No. 3, March, 2010
Voskressensky et al.
CH2Me, J = 7.2 Hz); 1.56 (d, 3 H, CHMe, J = 6.5 Hz);
3.09—3.26 (m, 2 H, CβH2); 3.33 (s, 3 H, OMe); 3.43 (q, 2 H,
CH2Me, J = 7.2 Hz); 3.65 (s, 3 H, CO2Me); 3.95 (s, 3 H,
CO2Me); 4.43—4.50 (m, 1 H, CHMe); 4.56—4.64 (m, 2 H,
CαH2); 4.79 (s, 1 H, CH=); 6.34 (d, 1 H, C(4)H, J = 4.5 Hz);
7.27 (d, 1 H, C(3)H, J = 4.5 Hz). MS, m/z (Irel (%)): 434 [M]+
(16), 419 (15), 403 (17), 402 (31), 232 (8), 201 (20), 200 (100),
172 (7), 154 (10), 112 (11), 96 (26), 59 (10), 45 (17).
1.53 (d, 3 H, Me, J = 7.2 Hz); 2.43 (s, 3 H, CH3—Ar); 3.28—3.35
(m, 2 H, CH2Me); 3.65 (dt, 1 H, C(2)H, J = 3.9 Hz, J = 15.0 Hz);
3.90—3.97 (m, 1 H, C(1)H); 4.09 (q, 1 H, C(6)H, J = 7.2 Hz);
4.45 (dt, 1 H, C(2)H, J = 3.9 Hz, J = 15.0 Hz); 5.20 (d, 1 H,
C(7)H, J = 3.9 Hz); 5.28—5.35 (m, 1 H, C(1)H); 7.26 (d, 2 H,
H arom., J = 8.3 Hz); 7.58 (s, 1 H, C(4)H); 7.67 (d, 2 H,
H arom., J = 8.3 Hz); 9.34 (s, 1 H, CHO). MS, m/z (Irel (%)):
372 [M]+ (89), 357 (31), 261 (17), 218 (30), 217 (73), 216 (100),
215 (49), 202 (34), 188 (21), 172 (25), 168 (15), 161 (27), 158 (37),
146 (35), 131 (27), 122 (19), 108 (23), 94 (15), 78 (20), 64 (23).
5ꢀAcetylꢀ3ꢀethylꢀ6ꢀmethylꢀ1,2,3,6ꢀtetrahydropyrrolo[1,2ꢀd]ꢀ
[1,4]diazocineꢀ9ꢀcarbaldehyde (18). Yield 31%, brown oil.
Found (%): C, 69.03; H, 7.82; N, 10.64. C15H20N2O2. Calculatꢀ
ed (%): C, 69.23; H, 7.69; N, 10.77. IR, ν/cm–1: 1589 (CO);
1658 (CHO). 1H NMR, δ: 1.12 (t, 3 H, CH2Me, J = 7.2 Hz);
1.49 (d, 3 H, Me, J = 7.3 Hz); 2.20 (s, 3 H, MeCO); 3.25—3.33
(m, 2 H, CH2Me); 3.65 (ddd, 1 H, C(2)H, J = 3.0 Hz, J = 5.8 Hz,
J = 15.9 Hz); 3.95 (ddd, 1 H, C(1)H, J = 4.7 Hz, J = 11.9 Hz,
J = 16.2 Hz); 4.30—4.37 (m, 1 H, C(2)H); 4.95 (q, 1 H, C(6)H,
J = 7.3 Hz); 5.47 (ddd, 1 H, C(1)H, J = 4.7 Hz, J = 16.2 Hz);
6.00 (d, 1 H, C(7)H, J = 3.9 Hz); 6.82 (d, 1 H, C(8)H, J = 3.9 Hz);
7.37 (s, 1 H, C(4)H); 9.35 (s, 1 H, CHO). MS, m/z (Irel (%)):
260 [M]+ (100), 245 (42), 231 (8), 217 (55), 203 (27), 188 (19),
174 (15), 172 (29), 160 (13), 149 (11), 147 (21), 146 (28), 118 (10),
108 (10), 96 ( 9), 71 (13), 43 (17).
Reaction of tetrahydropyrrolo[1,2ꢀa]pyrazines 8—10 with terꢀ
minal alkynes (general procedure). To a solution of compound
8—10 (2.4 mmol) in MeCH (20 mL) or MeOH (15 mL), methyl
propiolate or pꢀtosylacetylene (4.8 mmol) was added at 30 °C
The reaction mixture was stirred at 30 °C, or refluxed in the case
of the reaction of compound 9 with acetyl acetylene. After comꢀ
pletion of the reaction (TLC monitoring), the solvent was reꢀ
moved in vacuo, the residue was purified by column chromatogꢀ
raphy. Pyrrolodiazocines 15—18 were obtained by the reaction
in MeCN, the reaction of 8 and 9 with methyl propiolate in
MeOH afforded pyrroles 19—21. Pyrrolopyrazine 10 gave in
methanol a mixture of pyrrolodiazocine 22 and pyrrole 23.
Methyl 9ꢀformylꢀ3,6ꢀdimethylꢀ1,2,3,6ꢀtetrahydropyrroloꢀ
[1,2ꢀd][1,4]diazocineꢀ5ꢀcarboxylate (15). Yield 13%, yellow crysꢀ
tals, m.p. 122—124 °C (from ethyl acetate—hexane). Found (%):
C, 63.90; H, 7.00; N, 10.78. C14H18N2O3. Calculated (%):
C, 64.12; H, 6.87; N, 10.69. IR, ν/cm–1: 1641 (CHO); 1710
(CO2Me). 1H NMR, δ: 1.55 (d, 3 H, Me, J = 7.4 Hz); 3.00
(s, 3 H, NMe); 3.60 (dt, 1 H, C(2)H, J = 4.5 Hz, J = 15.6 Hz);
3.69 (s, 3 H, CO2Me); 3.89 (ddd, 1 H, C(1)H, J = 4.5 Hz,
J = 11.4 Hz, J = 15.4 Hz); 4.41 (dt, 1 H, C(2)H, J = 4.5 Hz,
J = 15.6 Hz); 4.68 (q, 1 H, C(6)H, J = 7.4 Hz); 5.38 (ddd, 1 H,
J = 4.5 Hz, J = 11.4 Hz, J = 15.4 Hz); 6.07 (d, 1 H, C(7)H,
J = 4.0 Hz); 6.86 (d, 1 H, C(8)H, J = 4.0 Hz); 7.47 (s, 1 H,
C(4)H); 9.38 (s, 1 H, CHO). MS, m/z (Irel (%)): 262 [M]+ (82),
247 (73), 261 (29), 219 (12), 215 (18), 204 (18), 203 (42), 188 (18),
187 (47), 172 (30), 159 (20), 152 (21), 146 (42), 132 (20), 118 (24),
117 (26), 94 (25), 93 (19), 80 (22), 77 (20), 65 (23), 57 (70),
53 (22), 42 (100), 41 (27), 39 (37).
Methyl 3ꢀethylꢀ9ꢀformylꢀ6ꢀmethylꢀ1,2,3,6ꢀtetrahydropyrroꢀ
lo[1,2ꢀd][1,4]diazocineꢀ5ꢀcarboxylate (16). Yield 11%, yellow
crystals, m.p. 104—106 °C (from ethyl acetate—hexane). Found (%):
C, 65.07; H, 7.31; N, 10.00. C15H20N2O3. Calculated (%):
C, 65.22; H, 7.25; N, 10.14. IR, ν/cm–1: 1656 (CHO); 1716
(CO2Me). 1H NMR, δ: 1.10 (t, 3 H, CH2Me, J = 7.2 Hz); 1.53
(d, 3 H, Me, J = 7.4 Hz); 3.19—3.26 (m, 2 H, CH2Me); 3.68
(s, 3 H, CO2Me); 3.74 (br.s, 1 H, C(1)H); 3.84 (ddd, 1 H,
C(2)H, J = 4.1 Hz, J = 9.2 Hz, J = 15.3 Hz); 4.44 (dt, 1 H,
C(2)H, J = 4.1 Hz, J = 15.3 Hz); 4.68 (q, 1 H, C(6)H, J = 7.4 Hz);
5.35—5.41 (m, 1 H, C(1)H); 6.05 (d, 1 H, C(7)H, J = 4.0 Hz);
6.85 (d, 1 H, C(8)H, J = 4.0 Hz); 7.52 (s, 1 H, C(4)H); 9.36
(s, 1 H, CHO). MS, m/z (Irel (%)): 276 [M]+ (100), 261 (98),
245 (27), 229 (12), 217 (46), 201 (17), 176 (12), 173 (16), 172 (26),
160 (14), 148 (14), 147 (21), 146 (43), 130 (15), 122 (23), 118 (22),
117 (22), 108 (17), 104 (12), 94 (13), 80 (17), 77 (21), 71 (51),
65 (20), 59 (28), 58 (25), 56 (32), 54 (15), 53 (25), 42 (31),
41 (31), 40 (25), 39 (37).
Methyl 3ꢀethylꢀ9ꢀ(2,2,2ꢀtrifluoroacetyl)ꢀ6ꢀmethylꢀ1,2,3,6ꢀ
tetrahydropyrrolo[1,2ꢀd][1,4]diazocineꢀ5ꢀcarboxylate (22).
Yield 35%, yellow oil. Found (%): C, 56.00; H, 5.31; N, 8.00.
C16H19F3N2O3. Calculated (%): C, 55.81; H, 5.52; N, 8.14. IR,
1
ν/cm–1: 1681 (CO); 1702 (CO2Me). H NMR, δ: 1.13 (t, 3 H,
CH2Me, J = 7.2 Hz); 1.55 (d, 3 H, Me, J = 7.3 Hz); 3.21—3.29
(m, 2 H, CH2Me), 3.73 (t, 1 H, C(2)H, J = 4.9 Hz); 3.70 (s, 3 H,
CO2Me); 3.82 (ddd, 1 H, C(1)H, J = 5.3 Hz, J = 9.2 Hz,
J = 15.1 Hz); 4.55 (dt, 1 H, C(2)H, J = 4.5 Hz, J = 15.5 Hz);
4.70 (q, 1 H, C(6)H); 5.26 (ddd, 1 H, C(1)H, J = 5.3 Hz, J = 9.2 Hz,
J = 15.1 Hz); 6.13 (d, 1 H, C(7)H, J = 4.3 Hz); 7.22 (d, 1 H,
C(8)H, J = 4.3 Hz); 7.53 (s, 1 H, C(4)H). MS, m/z (Irel (%)):
344 [M]+ (66), 329 (100), 313 (21), 297 (29), 285 (69), 269 (16),
243 (23), 214 (23), 188 (10), 154 (7), 144 (9), 122 (13), 118 (8),
108 (9).
(E)ꢀMethyl 3ꢀ(Nꢀmethylꢀ{2ꢀ[2ꢀformylꢀ5ꢀ(1ꢀmethoxyethyl)ꢀ
1Hꢀpyrrolꢀ1ꢀyl]ethyl}amino)acrylate (19). Yield 9%, yellow oil.
Found (%): C, 61.37; H, 7.19; N, 9.37. C15H22N2O4. Calculatꢀ
ed (%): C, 61.22; H, 7.48; N, 9.52. IR, ν/cm–1: 1656 (CHO);
1692 (CO2Me). 1H NMR, δ: 1.54 (d, 3 H, MeCH, J = 6.2 Hz);
2.17 (s, 3 H, NMe); 3.45—3.53 (m, 2 H, CαH2); 3.67 (s, 3 H,
OMe); 3.71 (s, 3 H, CO2Me); 4.27—4.35 (m, 2 H, CβH2); 4.49
(q, 1 H, CHMe, J = 6.2 Hz); 4.67 (d, 1 H, CH=CH, J = 13.2 Hz);
6.26 (d, 1 H, C(4)H, J = 3.8 Hz); 6.93 (d, 1 H, C(3)H,
J = 3.8 Hz); 7.36 (d, 1 H, CH=CH, J = 13.2 Hz); 9.49 (s, 1 H,
CHO). MS, m/z: 295 [M + 1]+.
(E)ꢀMethyl 3ꢀ(Nꢀethylꢀ{2ꢀ[2ꢀformylꢀ5ꢀ(1ꢀmethoxyethyl)ꢀ
1Hꢀpyrrolꢀ1ꢀyl]ethyl}amino)acrylate (20). Yield 25%, yellow oil.
Found (%): C, 62.41; H, 8.00; N, 9.13. C16H24N2O4. Calculatꢀ
ed (%): C, 62.34; H, 7.79; N, 9.09. IR, ν/cm–1: 1655 (CHO);
1689 (CO2Me).1H NMR, δ: 1.06 (t, 3 H, CH2Me, J = 7.1 Hz);
1.49 (d, 3 H, Me, J = 6.7 Hz); 3.07—3.16 (m, 2 H, CβH2);
3.28 (s, 3 H, OMe); 3.36—3.45 (m, 2 H, CH2Me); 3.40—3.49
(m, 2 H, CαH2); 3.62 (s, 3 H, CO2Me); 4.32 (q, 1 H, CHMe,
J = 6.7 Hz); 4.78 (br.s, 1 H, CH=CH); 6.21 (d, 1 H, C(4)H,
J = 4.0 Hz); 6.88 (d, 1 H, C(3)H, J = 4.0 Hz); 7.36 (d, 1 H,
3ꢀEthylꢀ6ꢀmethylꢀ5ꢀtosylꢀ1,2,3,6ꢀtetrahydropyrrolo[1,2ꢀd]ꢀ
[1,4]diazocineꢀ9ꢀcarbaldehyde (17). Yield 16%, colorless crysꢀ
tals, m.p. 117—119 °C (from ethyl acetate—hexane). Found (%):
C, 64.77; H, 6.28; N, 7.48. C20H24N2O3S. Calculated (%):
C, 64.52; H, 6.45; N, 7.53. IR, ν/cm–1: 1165 (SO); 1340 (SO);
1655 (CHO). 1H NMR, δ: 1.17 (t, 3 H, CH2Me, J = 7.3 Hz);

1,2,3,6ꢀTetrahydropyrrolo[1,2ꢀd][1,4]diazocines
Russ.Chem.Bull., Int.Ed., Vol. 59, No. 3, March, 2010
653
CH=CH, J = 13.2 Hz); 9.44 (s, 1 H, CHO). MS, m/z (Irel (%)):
308 [M]+ (12), 293 (26), 276 (45), 261 (25), 142 (100), 96 (27),
82 (13), 59 (24), 55 (9).
This work was financially supported by the Russian
Foundation for Basic Research (Project No. 08ꢀ03ꢀ00226).
1ꢀ(2ꢀ{NꢀEthylꢀ[5ꢀ(1ꢀmethoxyethyl)ꢀ(E)ꢀ3ꢀoxobutꢀ1ꢀenꢀ1ꢀ
yl]amino}ethyl)ꢀ1Hꢀpyrrolꢀ2ꢀcarbaldehyde (21). Yield 54%, yelꢀ
low oil. Found (%): C, 65.79; H, 8.31; N, 9.43. C16H24N2O3.
Calculated (%): C, 65.75; H, 8.22; N, 9.59. IR, ν/cm–1: 1655
(CHO); 1683 (CO). 1H NMR, δ: 1.03 (t, 3 H, CH2Me, J = 6.9 Hz);
1.45 (d, 3 H, MeCH, J = 6.6 Hz); 2.50 (s, 3 H, MeCO); 3.15
(q, 2 H, CH2Me, J = 6.9 Hz); 3.34 (s, 3 H, OMe); 3.40—3.49
(m, 2 H, CβH2); 4.35—4.46 (m, 2 H, CαH2); 4.58 (q, 1 H,
CHMe, J = 6.6 Hz); 5.08 (br.s, 1 H, CH=CH); 6.30 (d, 1 H,
C(4)H, J = 3.9 Hz); 7.07 (d, 1 H, C(3)H, J = 3.9 Hz); 7.40
(d, 1 H, CH=CH, J = 13.5 Hz); 9.48 (s, 1 H, CHO). MS, m/z:
293 [M + 1]+.
(E)ꢀMethyl 3ꢀ(Nꢀethylꢀ{2ꢀ[5ꢀ(2,2,2ꢀtrifuoroacetyl)ꢀ2ꢀ(1ꢀ
methoxyethyl)ꢀ1Hꢀpyrrolꢀ1ꢀyl]ethyl}amino)acrylate (23). Yield
35%, yellow oil. Found (%): C, 54.03; H, 6.30; N, 7.24.
C17H23F3N2O4. Calculated (%): C, 54.26; H, 6.12; N, 7.45. IR,
ν/cm–1: 1680 (CF3CO); 1710 (CO2Me). 1H NMR, δ: 1.13 (t, 3 H,
CH2Me, J = 7.1 Hz); 1.55 (d, 3 H, CHMe, J = 6.5 Hz); 3.19
(q, 2 H, CH2Me, J = 7.1 Hz); 3.35 (s, 3 H, OMe); 3.44 (d, 2 H,
CβH2, J = 7.4 Hz); 3.67 (s, 3 H, CO2Me); 4.38 (q, 1 H, CHMe,
J = 6.5 Hz); 4.55 (ddd, 2 H, CαH2, J = 7.4 Hz, J = 13.9 Hz); 5.26
(br.s, 1 H, CH=CH); 6.31 (d, 1 H, C(4)H, J = 4.4 Hz); 7.27
(d, 1 H, C(3)H, J = 4.4 Hz); 7.40 (d, 1 H, CH=CH, J = 13.1 Hz).
MS, m/z (Irel (%)): 376 [M]+ (8), 361 (14), 345 (12), 344 (39),
329 (23), 313 (10), 232 (11), 216 (8), 143 (7), 142 (100), 96 (7),
82 (11), 45 (11).
References
1. L. G. Voskressensky, T. N. Borisova, T. A. Vorob´eva, A. I.
Chernyshev, A. V. Varlamov, Izv. Akad. Nauk, Ser. Khim.,
2005, 2513 [Russ. Chem. Bull., Int. Ed., 2005, 54, 2594].
2. L. G. Voskressensky, T. N. Borisova, L. N. Kulikova, A. V.
Varlamov, Khim. Geterosikl. Soedin., 2007, 1082 [Chem. Hetꢀ
erocycl. Compd. (Engl. Transl.), 2007, 43, 913].
3. L. G. Voskressensky, T. N. Borisova, I. S. Kostenev, L. N.
Kulikova, A. V. Varlamov, Tetrahedron Lett., 2006, 47, 999.
4. L. G. Voskressensky, A. V. Listratova, T. N. Borisova, G. G.
Alexandrov, A. V. Varlamov, Eur. J. Org. Chem., 2007, 6106.
5. A. P. Dunlop, S. Swadesh, US Pat. 265512; Chem. Abstrs,
1954, 48, 11495.
6. A. M. Likhosherstov, V. P. Peresada, V. G. Vinokurov, A. P.
Skoldinov, Zh. Org. Khim., 1986, 22, 2610 [J. Org. Chem. USSR
(Engl. Transl.), 1986, 22].
7. B. A. Trofimov, A. I. Mikhaleva, S. E. Korostova, L. N. Sobeꢀ
nina, A. N. Vasiliev, L. B. Balashenko, Zh. Org. Khim., 1979,
15, 2042 [J. Org. Chem. USSR (Engl. Transl.), 1979, 15].
Received May 25, 2009;
in revised form October 1, 2009