Novel quinazoline ring synthesis by cycloaddition of N-arylketenimines with N,N-disubstituted cyanamides.

Article abstract of DOI:10.1248/cpb.50.426

The reaction of N-aryl-substituted ketenimines with N,N-disubstituted cyanamides or (MeS)2C=N-CN under high pressure afforded 4-(N,N-disubstituted amino) or 4-(MeS)2C=N-substituted quinazoline derivatives, respectively. These products were formed by [4+2] cycloaddition between the aza-diene moieties of the N-arylsubstituted ketenimines and cyano groups. A 4-(unsubstituted amino)quinazoline derivative was synthesized by hydrolysis of the latter product.

Full text of DOI:10.1248/cpb.50.426

426
Notes
Chem. Pharm. Bull. 50(3) 426—428 (2002)
Vol. 50, No. 3
Novel Quinazoline Ring Synthesis by Cycloaddition of N-Arylketenimines
with N,N-Disubstituted Cyanamides
Masao SHIMIZU,* Akihiro OISHI, Yoichi TAGUCHI, Yasuo GAMA, and Isao SHIBUYA
National Institute of Advanced Industrial Science and Technology, Tsukuba Central 5, 1–1–1 Higashi, Tsukuba, Ibaraki
305–8565, Japan. Received October 11, 2001; accepted November 22, 2001
The reaction of N-aryl-substituted ketenimines with N,N-disubstituted cyanamides or (MeS)2C؍N–CN
under high pressure afforded 4-(N,N-disubstituted amino) or 4-(MeS)2C؍N-substituted quinazoline derivatives,
respectively. These products were formed by [4؉2] cycloaddition between the aza-diene moieties of the N-aryl-
substituted ketenimines and cyano groups. A 4-(unsubstituted amino)quinazoline derivative was synthesized by
hydrolysis of the latter product.
Key words quinazoline; ketenimine; cyanamide; high-pressure reaction; cycloaddition
It has been reported that ketenimines reacted with various cyanamides under high pressure.
kinds of reactants and became starting materials of various
When N-(p-tolyl)diphenylketenimine (2) was heated with
compounds.1) Among them, the most attractive reactions N,N-dimethylcyanamide (4) in toluene under reflux, no cy-
were cycloaddition for the synthesis of heterocyclic rings. clized product was obtained and 2 was recovered. Therefore
Intermolecular and intramolecular [4ϩ2] or [2ϩ2] cycload- the reaction of 2 with N,N-disubstituted cyanamides 4—9
ditions of ketenimines were reported, and ketenimines can was carried out under high-pressure conditions as reported
play the role of either the 2- or 4-atom component on cy- for the reactions with enol ethers.4) The ketenimine 2 was
cloaddition.2) When multiple-bond compounds that have dissolved in pyrrolidine-1-carbonitrile (7) and the mixture
electron-donating substituents were treated with N-aryl-sub- was compressed under 800 MPa at 100 °C. The resulting
stituted ketenimines, the [4ϩ2] cycloaddition occurred at crude product was purified with chromatography on silica gel
the CϭC–NϭC moieties of the ketenimines as aza-dienes. to give 2-diphenylmethyl-6-methyl-4-pyrrolidinoquinazoline
For example, 4-aminoquinoline derivatives were synthesized (10f) in 60% yield. The structure of 10f was confirmed by
in the reaction of triphenylketenimine with N,N-disubstituted comparison with spectral data of the compound prepared by
aminoacetylenes.3) We also reported the cycloaddition of cyclodesulfurization of 2,2-diphenyl-N-p-tolylthioacetamide
N-aryl-substituted ketenimines with enol ethers under high with silver perchlorate in 7,5) followed by neutralization with
pressure to form quinoline derivatives in a previous paper.4) base. The same high-pressure reactions of ketenimines 1—3
Therefore it was expected that the cycloaddition of keten- with N,N-disubstituted cyanamides 4—9 were carried out,
imines would occur with N,N-disubstituted cyanamides be- and quinazoline derivatives (10) were obtained in the yields
cause the cyanamides are regarded as electron-rich triple- shown in Table 1. However, nitrile compounds such as ace-
bond compounds. However, to our knowledge there has been tonitrile or benzonitrile did not react with ketenimines under
no report on the cycloaddition of ketenimines with the these reaction conditions.
CN triple bond. In this paper, we describe the cycloaddition
The mechanism of quinazoline ring formation is explained
of N-aryl-substituted ketenimines with N,N-disubstituted by the occurrence of a [4ϩ2] cycloaddition between the
Table 1. Reaction of Ketenimine with Cyanamide
Run
Ketenimine
Cyanamide
Quinazoline
R1
NR2
Yield of 10 (%)
2
1
2
3
4
5
6
7
8
1
2
3
2
2
2
2
2
4
4
4
5
6
7
8
9
10a
10b
10c
10d
10e
10f
H
Me
OMe
Me
Me
Me
Me
Me
NMe2
NMe2
NMe2
71
66
47
65
44
60
67
43
NEt2
N(iPr)2
Pyrrolidino
Piperidino
Morpholino
10g
10h
To whom correspondence should be addressed. e-mail: m.shimizu@aist.go.jp
© 2002 Pharmaceutical Society of Japan

March 2002
427
CϭC–NϭC moieties of N-arylketenimines and the cyano
In conclusion, 4-(N,N-disubstituted amino)-2-substituted
groups of cyanamides, followed by aromatization to the quinazoline derivatives were synthesized by the [4ϩ2] cy-
quinazoline rings (Chart 1). This reaction mechanism is simi- cloaddition of N-aryl-substituted ketenimines with N,N-di-
lar to the cycloaddition of ketenimines with ynamines3) or substituted cyanamides under high pressure. A 4-aminoquina-
enol ethers.4)
zoline derivative was synthesized by hydrolysis of a 4-[N-
It was reported that quinazoline compounds are found in bis(methylthio)methylideneamino]quinazoline, which was
natural products or used in medicines.6) 4-Aminoquinazoline prepared by the reaction of ketenimines with dimethyl N-
derivatives have various bioactivities such as an antimalarial cyanodithioiminocarbonate.
effect.7) Although quinazoline synthesis was performed by
Experimental
cyclization of the ketenimines 1—3 with N,N-disubstituted
Melting points were determined on a Mettler FP90 microscopic plate and
cyanamides 4—9 as described above, the substituents on
the C-4 carbon of quinazolines (10) were restricted to N,N-
disubstituted amino groups. To prepare 4-(N-unsubstituted
amino)quinazolines by the cycloaddition of ketenimines with
cyanamides, an N-unsubstituted cyanamide was used as a
starting material. However, the cyanamides that had hydro-
gen atoms on the amino groups tautomerized to carbodi-
imides. Moreover, ketenimines reacted with free amino
groups to afford amidine derivatives.1) For these reasons, 4-
(unsubstituted amino)quinazoline derivatives were not di-
rectly synthesized. Therefore the reactions of dimethyl N-
cyanodithioiminocarbonate (11), which is regarded as an
are uncorrected. 1H-NMR spectra were obtained with a Varian Gemini
300BB spectrometer, and chemical shifts are reported in parts per million
relative to internal tetramethylsilane. 13C-NMR spectra were obtained with
JEOL LA-500 spectrometer, and chemical shifts are reported in parts per
million relative to internal CDCl3 (77 ppm). IR spectra were recorded on a
JASCO FTIR-5300 spectrophotometer. The apparatus used for the high-
pressure reaction was the same as that described previously.8) Ketenimines
1—3 were prepared by the method described in a previous paper.9)
General Procedure for the Reaction of N-Aryl-substituted Diphenyl-
ketenimines with N,N-Disubstituted Cyanamides under High Pressure
A homogeneous mixture of a ketenimine (0.5 mmol) and a cyanamide
(0.5 ml) in a sealed Teflon tube was compressed to 800 MPa, heated at
100 °C, and maintained for 20 h in a high-pressure apparatus. The resulting
mixture was chromatographed on silica gel with dichloromethane : acetone :
N-protected cyanamide, with ketenimines were investigated. methanol (100 : 5 : 1) mixture as the eluent.
4-Dimethylamino-2-diphenylmethylquinazoline (10a): mp 149—150 °C
A mixture of 1 and 11 was dissolved in toluene and the solu-
tion was compressed at 800 MPa. After the reaction, 4-[N-
bis(methylthio)methylideneamino]quinazoline (12) was iso-
lated in 55% yield from the reaction mixture. When hydroly-
sis of the (MeS)2CϭN–moiety of 12 was carried out with
aqueous potassium hydroxide in methanol, the product
showed disappearance of a methylthio group peak in the
1H-NMR spectra and appearance of N–H absorption in
the IR spectra. The CϭN double bond of the (MeS)2Cϭ
N–moiety in 12 was hydrolyzed and 4-amino-2-diphenyl-
methylquinazoline (14) was obtained in 53% yield. Although
the hydrolysis of 12 also occurred under acidic conditions,
the methanolysis product 2-diphenylmethyl-4-methoxyquina-
zoline (15) was formed in 47% yield as a main product as
well as 14 in 40% yield (Chart 2).
(benzene–hexane). 1H-NMR (CDCl3) d: 3.31 (6H, s, NMe2), 5.62 (1H, s, 2-
CH), 7.16—7.36 (7H, m, Ph), 7.47—7.49 (4H, m, Ph), 7.64 (1H, ddd,
Jϭ8.5, 6.9, 1.4 Hz, 6-H), 7.84 (1H, dd, Jϭ8.5, 1.4 Hz, 5-H), 7.97 (1H, dd,
Jϭ8.5, 1.4 Hz, 8-H). 13C-NMR (CDCl3) d: 41.8 (q), 60.8 (d), 114.4 (s),
124.0 (d), 125.3 (d), 126.2 (d), 127.9 (d), 128.2 (d), 129.4 (d), 131.8 (d),
142.9 (s), 152.6 (s), 163.5 (s), 165.4 (s). IR (KBr) cmϪ1: 1566, 1532, 1491,
1381, 750, 702. Anal. Calcd for C23H21N3: C, 81.38; H, 6.24; N, 12.38.
Found: C, 80.98; H, 6.22; N, 12.30.
4-Dimethylamino-2-diphenylmethyl-6-methylquinazoline (10b): mp
104—105 °C (benzene–hexane). 1H-NMR (CDCl3) d: 2.45 (3H, s, 6-Me),
3.27 (6H, s, NMe2). 5.61 (1H, s, 2-CH), 7.17—7.29 (6H, m, Ph), 7.46—7.50
(5H, m, Ph, 7-H), 7.72 (1H, d, Jϭ0.8 Hz, 5-H), 7.74 (1H, d, Jϭ8.5 Hz, 8-H).
13C-NMR (CDCl3) d: 21.8 (q), 41.8 (q), 60.7 (d), 114.4 (s), 124.4 (d), 126.2
(d), 127.9 (d), 128.0 (d), 129.4 (d), 133.7 (s), 133.7 (d), 143.0 (s), 150.9 (s),
163.4 (s), 164.6 (s). IR (KBr) cmϪ1: 1566, 1530, 1385, 1080, 833, 729, 698.
Anal. Calcd for C24H23N3: C, 81.55; H, 6.56; N, 11.89. Found C, 81.35; H,
6.75; N, 11.76.
4-Dimethylamino-2-diphenylmethyl-6-methoxyquinazoline (10c): Oil.
1H-NMR (CDCl3) d: 3.26 (6H, s, NMe2), 3.88 (3H, s, 6-MeO), 5.61 (1H, s,
2-CH), 7.18—7.29 (7H, m, Ph, 5-H), 7.34 (1H, dd, Jϭ9.1, 2.7 Hz, 7-H),
7.47—7.50 (4H, m, Ph), 7.79 (1H, d, Jϭ9.1 Hz, 8-H). 13C-NMR (CDCl3) d:
41.6 (q), 55.6 (q), 60.6 (d), 105.1 (d), 115.1 (s), 122.8 (d), 126.2 (d), 127.9
(d), 129.4 (d), 129.7 (d), 143.1 (s), 147.9 (s), 155.8 (s), 163.6 (s), 163.6 (s).
IR (neat) cmϪ1: 1570, 1530, 1399, 1225, 1032, 837, 700. Picrate: mp 190—
192.5 °C (ethanol). Anal. Calcd for C30H26N6O8: C, 60.20; H, 4.38; N, 14.04.
Found: C, 60.20; H, 4.32; N, 13.99.
4-Diethylamino-2-diphenylmethyl-6-methylquinazoline (10d): Oil. 1H-
NMR (CDCl3) d: 1.23 (6H, t, Jϭ7.0 Hz, Et), 2.46 (3H, s, 6-Me), 3.62 (4H,
q, Jϭ7.0 Hz, Et). 5.63 (1H, s, 2-CH), 7.14—7.28 (6H, m, Ph), 7.38—7.42
(4H, m, Ph), 7.47 (1H, d, Jϭ8.5, 1.8 Hz, 7-H), 7.62 (1H, s, 1H, 5-H), 7.74
(1H, d, Jϭ8.5 Hz, 8-H). 13C-NMR (CDCl3) d: 13.0 (q), 21.9 (q), 44.9 (t),
60.5 (d), 114.5 (s), 123.7 (d), 126.1 (d), 127.9 (d), 128.1 (d), 129.4 (d),
Chart 1
133.6 (s), 133.7 (d), 143.1 (s), 150.9 (s), 162.1 (s), 164.8 (s). IR (neat) cmϪ1
:
1562, 1524, 1348, 1086, 833, 698. Picrate: mp 176—177.5 °C (ethanol).
Anal. Calcd for C32H30N6O7: C, 62.94; H, 4.95; N, 13.76. Found: C, 62.87;
H, 4.93; N, 13.72.
4-Diisopropylamino-2-diphenylmethyl-6-methylquinazoline (10e): Oil.
1H-NMR (CDCl3) d: 1.30 (12H, d, Jϭ6.6 Hz, CHMe2), 2.45 (3H, s, 6-Me),
4.09 (2H, hep, Jϭ6.6 Hz, 4-NCH), 5.71 (1H, s, 5-H), 7.15—7.32 (10H, m,
Ph), 7.45 (1H, dd, Jϭ8.5, 1.9 Hz, 7-H), 7.54 (1H, s, 5-H), 7.71 (1H, d,
Jϭ8.5 Hz, 8-H). 13C-NMR (CDCl3) d: 21.8 (q), 21.8 (q), 50.2 (d), 60.4 (d),
115.2 (s), 123.9 (d), 126.1 (d), 128.0 (d), 128.1 (d), 129.6 (d), 133.2 (s),
133.4 (d), 142.8 (s), 151.3 (s), 162.8 (s), 164.8 (s). IR (neat) cmϪ1: 1559,
1526, 1379, 1152, 831, 698. Picrate: mp 205—208 °C (ethanol). Anal. Calcd
for C34H34N6O7: C, 63.94; H, 5.37; N, 13.16. Found: C, 63.77; H, 5.33; N,
Chart 2

428
Vol. 50, No. 3
13.15.
1188, 910, 831, 747, 700, 615. Anal. Calcd for C25H23N3S2: C, 69.89; H,
2-Diphenylmethyl-6-methyl-4-pyrrolidinoquinazoline (10f): mp 154.6— 5.40; N, 9.78. Found: C, 69.87; H, 5.33; N, 9.76.
1
155.5 °C (benzene–hexane). H-NMR (CDCl3) d: 1.97—2.02 (4H, m), 2.45
Hydrolysis of 12 The quinazoline (12, 50 mg, 0.12 mmol) was dis-
(3H, s, 6-Me), 3.85—3.90 (4H, m), 5.57 (1H, s, 2-CH), 7.15—7.29 (6H, m, solved in methanol (10 ml) and aqueous potassium hydroxide (0.4 M, 5 ml)
Ph), 7.45—7.51 (5H, m, Ph, 7-H), 7.72 (1H, d, Jϭ8.5 Hz, 8-H), 7.88 (1H, s, was added to the solution. The mixture was stirred at 80 °C for 2 h. Water
5-H). 13C-NMR (CDCl3) d: 21.9 (q), 25.7 (t), 50.8 (t), 60.8 (d), 114.8 (s), was added to the reaction mixture and products were extracted with
124.2 (d), 126.1 (d), 127.8 (d), 127.9 (d), 129.4 (d), 133.4 (s), 133.5 (d), dichloromethane. The organic layer was dried with magnesium sulfate, and
143.2 (s), 150.6 (s), 159.5 (s), 165.1 (s). IR (KBr) cmϪ1: 1562, 1514, 1391, the solvent was evaporated. The residue was recrystallized from a ben-
1333, 835, 718, 698. Anal. Calcd for C26H25N3: C, 82.29; H, 6.64; N, 11.07.
zene–hexane mixture. 14 was obtained in 53% yield.
Found: C, 82.29; H, 6.73; N, 11.04.
4-Amino-2-diphenylmethylquinazoline (14): mp 164—165.5 °C (ben-
2-Diphenylmethyl-6-methyl-4-piperidinoquinazoline (10g): Oil. H-NMR zene–hexane). 1H-NMR (CDCl3) d: 5.66 (1H, s, 2-CH), 6.03 (2H, br s,
(CDCl3) d: 1.64—1.77 (6H, m), 2.47 (3H, s, 6-Me), 3.64 (4H, br s, N-CH2), NH2), 7.25—7.45 (12H, m, Ar), 7.67—7.73 (1H, m, Ar), 7.81 (1H, d,
5.63 (1H, s, 2-CH), 7.15—7.29 (6H, m, Ph), 7.45—7.51 (5H, m, Ph, 7-H), Jϭ8.2 Hz, 8-H). 13C-NMR (CDCl3) d: 60.7 (d), 112.9 (s), 121.4 (d), 125.7
7.58 (1H, s, 5-H), 7.76 (1H, d, Jϭ8.5 Hz, 8-H). 13C-NMR (CDCl3) d: 21.8 (d), 126.5 (d), 128.3 (d), 128.5 (d), 129.6 (d), 133.1 (d), 142.3 (s), 150.4 (s),
(q), 24.8 (t), 26.0 (t), 50.9 (t), 60.6 (d), 114.9 (s), 123.9 (d), 126.2 (d), 127.9 161.7 (s), 167.2 (s). IR (KBr) cmϪ1: 3474, 3306, 1642, 1555, 1499, 1366,
(d), 128.1 (d), 129.4 (d), 134.0 (d), 134.4 (s), 143.0 (s), 150.6 (s), 164.6 (s), 702. Anal. Calcd for C21H17N3·0.1H2O: C, 80.54; H, 5.54; N, 13.42. Found:
164.8 (s). IR (neat) cmϪ1: 1562, 1539, 1508, 1447, 1360, 833, 729, 698. Pi- C, 80.67; H, 5.41; N, 13.39.
1
crate: mp 199—200.4 °C (ethanol). Anal. Calcd for C33H30N3O7: C, 63.66;
The quinazoline (12, 100 mg, 0.24 mmol) and p-toluenesulfonic acid
H, 4.86; N, 13.50. Found: C, 63.49; H, 4.82; N, 13.54.
monohydrate (200 mg, 1.02 mmol) were dissolved in methanol (20 ml). The
2-Diphenylmethyl-6-methyl-4-morpholinoquinazoline (10h): mp 115.5— mixture was stirred at reflux for 3 h. Water was added to the reaction mixture
1
117 °C (CH2Cl2–hexane). H-NMR (CDCl3) d: 2.48 (3H, s, 6-Me), 3.69— and products were extracted with dichloromethane. The organic layer was
3.75 (4H, m, N-CH2), 3.78—3.81 (4H, m, O-CH2), 5.67 (1H, s, 2-CH), dried with magnesium sulfate, and the solvent was evaporated. The resulting
7.16—7.29 (6H, m, Ph), 7.41—7.44 (4H, m, Ph), 7.53 (1H, dd, Jϭ8.5, mixture was chromatographed on silica gel with dichloromethane : acetone :
1.9 Hz, 7-H), 7.58 (1H, s, 5-H), 7.80 (1H, d, Jϭ8.5 Hz, 8-H). 13C-NMR methanol (100 : 5 : 1) mixture as eluent. 14 and 15 were isolated in 40% and
(CDCl3) d: 21.8 (q), 50.3 (t), 60.6 (d), 66.7 (t), 114.8 (s), 123.4 (d), 126.3 47% yield, respectively.
(d), 128.0 (d), 128.5 (d), 129.3 (d), 134.4 (d), 135.1 (s), 142.8 (s), 150.8 (s),
2-Diphenylmethyl-4-methoxyquinazoline (15): mp 93—95 °C (hexane).
164.4 (s), 164.9 (s). IR (neat) cmϪ1: 1562, 1505, 1433, 1358, 1115, 700. Pi- 1H-NMR (CDCl3) d: 4.10 (3H, s, MeO), 5.73 (1H, s, 2-CH), 7.19—7.32
crate: mp 190—192.5 °C (ethanol). Anal. Calcd for C32H28N6O8: C, 61.53;
H, 4.52; N, 13.46. Found: C, 61.36; H, 4.36; N, 13.47.
(6H, m, Ph), 7.44—7.53 (5H, m, Ph, 7-H), 7.78 (1H, ddd, Jϭ8.5, 7.1,
1.6 Hz, 6-H), 7.91 (1H, dd, Jϭ8.5, 1.6 Hz, 5-H), 8.10 (1H, dd, Jϭ8.5,
General Procedure for the Reaction of N-Aryl-substituted Diphenyl- 1.4 Hz, 8-H). 13C-NMR (CDCl3) d: 54.2 (q), 60.8 (d), 114.9 (s), 123.3 (d),
ketenimines with Dimethyl N-Cyanodithioiminocarbonate under High 126.5 (d), 126.5 (d), 127.6 (d), 128.1 (d), 129.4 (d), 133.4 (d), 142.3 (s),
Pressure A homogeneous mixture of ketenimine (1 or 2, 0.5 mmol) and 151.4 (s), 166.3 (s), 137.1 (s). IR (KBr) cmϪ1: 1620, 1568, 1497, 1453,
dimethyl N-cyanodithioiminocarbonate (11, 366 mg, 2.5 mmol) in toluene
(1 ml) in a sealed Teflon tube was compressed to 800 MPa, heated at 100 °C,
and maintained for 20 h in a high-pressure apparatus. After the reaction, the
1375, 1107, 774. Anal. Calcd for C22H18N2O·0.1H2O: C, 80.51; H, 5.59; N,
8.54. Found: C, 80.58; H, 5.54; N, 8.51.
solvent was evaporated and the resulting mixture was chromatographed on References
alumina with ethyl acetate : hexane (15 : 2) mixture as eluent.
1) Barker M. W., McHenry W. E., “The Chemistry of Ketenes, Allenes
4-[N-Bis(methylthio)methylideneamino]-2-diphenylmethylquinazoline
(12): Yield 55%. mp 110—112 °C (benzene–hexane). H-NMR (CDCl3) d:
and Related Compounds,” ed. by Patai S., Wiley, Chichester, 1980, pp.
706—718.
2) Cossío F. P., Arrieta A., Lecea B., Alajarín M., Vidal A., Tovar F., J.
Org. Chem., 65, 3633—3643 (2000).
3) Ghosez L., de Pérez C., Angew Chem. Int. Ed. Engl., 10, 184—185
(1971).
4) Shimizu M., Oishi A., Taguchi Y., Sano T., Gama Y., Shibuya I., Hete-
rocycles, 55, 1971—1980 (2001).
5) Shibuya I., Gama Y., Shimizu M., Heterocycles, 55, 381—386 (2001).
6) Coates W. J., “Comprehensive Heterocyclic Chemistry, II,” Vol. 6, ed.
by Boulton A. J., Pergamon, Oxford, 1996, pp. 225—231.
7) For example, Elslager E. F., Hess C., Johnson J., Ortwine D., Chu V.,
Werbel L. M., J. Med. Chem., 24, 127—140 (1981).
8) Kurabayashi M., Yanagiya K., Yasumoto M., Bull. Chem. Soc. Jpn.,
44, 3413—3418 (1971).
1
2.55 (6H, s, MeS), 5.85 (1H, s, 2-CH), 7.17—7.30 (6H, m, Ph), 7.42—7.45
(4H, m, Ph), 7.51 (1H, ddd, Jϭ8.2, 6.9, 1.1 Hz, 6-H), 7.79 (1H, ddd, Jϭ8.2,
6.9, 1.4 Hz, 7-H), 7.94 (1H, d, Jϭ8.2 Hz, 8-H), 8.20 (1H, dd, Jϭ8.2, 1.4 Hz,
5-H). 13C-NMR (CDCl3) d: 16.0 (q), 60.8 (d), 118.7 (s), 125.0 (d), 126.3 (d),
126.5 (d), 128.0 (d), 128.1 (d), 129.6 (d), 133.3 (d), 142.2 (s), 151.9 (s),
164.0 (s), 167.0 (s), 174.8 (s). IR (KBr) cmϪ1: 1543, 1497, 1472, 1009, 924,
774, 700, 617. Anal. Calcd for C24H21N3S2: C, 69.36; H, 5.09; N, 10.11.
Found: C, 69.36; H, 5.04; N, 9.99.
4-[N-Bis(methylthio)methylideneamino]-2-diphenylmethyl-6-methyl-
quinazoline (13): Yield 37%. mp 122.4—123.4 °C (benzene–hexane). 1H-
NMR (CDCl3) d: 2.51 (3H, s, 6-Me), 2.45 (6H, s, MeS), 5.38 (1H, s, 2-CH),
7.15—7.21 (2H, m, Ph), 7.24—7.30 (4H, m, Ph), 7.41—7.44 (4H, m, Ph),
7.62 (1H, dd, Jϭ8.5, 1.9 Hz, 7-H), 7.84 (1H, d, Jϭ8.5 Hz, 8-H), 7.91 (1H, s,
5-H). 13C-NMR (CDCl3) d: 16.0 (q), 21.8 (q), 60.7 (d), 118.4 (s), 123.7 (d),
126.3 (d), 127.8 (d), 128.0 (d), 129.6 (d), 135.5 (d), 136.5 (s), 142.4 (s),
150.4 (s), 163.7 (s), 166.2 (s), 173.9 (s). IR (KBr) cmϪ1: 1553, 1478, 1414,
9) Shimizu M., Gama Y., Takagi T., Shibakami M., Shibuya I., Synthesis,
2000, 517—520.