24.6%); λmax(DCM)/nm 235 (log ε 3.77), 267 (4.29), 285 inf
(4.37), 289 (4.38), 295 inf (4.35), 343 inf (3.90), 356 (4.03), 423
(3.85), 450 inf (3.98), 475 (4.04), 503 inf (3.98), 539 inf (3.61);
νmax(Nujol)/cmϪ1 3085w (Ar CH), 2230s (CN), 1618m, 1559s,
1531s, 1480m, 1451s, 1436s, 1413s, 1299m, 1218m, 1161s,
1131m, 941s, 825s, 792s, 766s, 750s, 737m, 646m, 623s; δH(400
MHz; DMSO-d6) 8.09–8.05 (1H, m, Ar H), 7.97–7.93 (1H, m,
Ar H), 7.60–7.54 (2H, m, Ar H); δC(100 MHz; DMSO-d6)
152.8, 148.5, 142.8, 142.0, 128.1, 126.0 (Ar CH), 125.53 (Ar
CH), 125.47, 121.0 (Ar CH), 112.5 (Ar CH), 112.3 (CN), 88.0
νmax(CHCl3)/cmϪ1 3357w and 3280m (Ar NH), 1631m (C᎐O),
1602m, 1555m, 1516m, 753m; δH(500 MHz; DMSO-d6) 11.02–
᎐
10.93 (1H, br, NH), 7.98–6.90 (6H, m, Ar H), 6.70–6.55 (2H,
br, NH); δC(126 MHz; DMSO-d6) 157.4, 146.0, 136.0, 135.0,
126.72, 126.66, 126.4, 125.6, 125.2, 123.1, 121.9, 116.5, 114.8;
m/z (EI) 304 (Mϩ, 27%), 286 (49), 221 (43), 215 (51), 193 (25),
168 (44), 166 (100), 155 (28), 140 (36), 139 (27), 130 (23), 115
(24), 93 (CClNSϩ, 22).
9-Chloro-8-cyano[1,2,6]thiadiazino[3Ј,4Ј:5,4]pyrrolo[1,2-a]-
perimidine 20
[᎐C(CN)]; m/z (EI) 285 (Mϩ, 100%), 250 (Mϩ Ϫ Cl, 15), 239
᎐
(Mϩ Ϫ NS, 3), 219 (14), 146 (6), 142 (6), 122 (9), 102 (9), 90
(C6H4Nϩ, 11), 76 (C6H4ϩ, 9), 63 (11), 57 (5) (Found: Mϩ,
284.9878. C12H4ClN5S requires M, 284.9876). Further elution
(DCM–ether, 1:1) gave 4-(2-aminoanilino)-5-cyano[1,2,6]-
thiadiazino[3Ј,4Ј:5,4]pyrrolo[1,2-a]benzimidazole 15 (1 mg,
1%) as a red solid, mp >300 ЊC (from 1,2-dichloroethane)
(Found: C, 60.5; H, 3.15; N, 27.55. C18H11N7S requires C, 60.5;
H, 3.1; N, 27.45%); λmax(DCM)/nm 262 (log ε 4.68), 280 (4.66),
301 inf (4.48), 353 inf (4.31), 495 inf (4.39), 525 (4.40), 563 inf
(4.17); νmax(Nujol)/cmϪ1 3393w and 3316w (NH and NH2),
3085w (Ar CH), 2215m (CN), 1621m, 1601m, 1555s, 1508s,
1455s, 1445s, 1414s, 1192m, 1170m, 832m, 756m, 741m, 668m,
600s; δH(400 MHz; DCM-d2) 8.08–8.04 (1H, m, Ar H), 7.91–
7.87 (1H, m, Ar H), 7.70 (1H, br s, NH), 7.52–7.45 (3H, m, Ar
H), 7.19 (1H, ddd, J 1.4, 7.7, 7.7 Hz, Ar H), 6.93 (1H, dd, J 1.3,
8.0 Hz, Ar H), 6.88 (1H, ddd, J 1.2, 7.6, 7.6 Hz, Ar H), 3.89
(2H, br s, NH2); δC(100 MHz; DMSO-d6) 152.8, 149.5, 148.5,
143.6, 141.0, 128.2, 127.3 (Ar CH), 126.4 (Ar CH), 124.9 (Ar
CH), 124.1 (Ar CH), 121.7, 120.3 (Ar CH), 118.3, 116.0
(Ar CH), 115.7 (Ar CH), 114.0 (CN), 112.1 (Ar CH), 82.8
To a stirred solution of (3,5-dichloro-4H-1,2,6-thiadiazin-4-
ylidene)propanedinitrile 2 (57.5 mg, 0.25 mmol) in EtOH (4 ml)
at ca. 20 ЊC 1,8-diaminonaphthalene (39.5 mg, 0.25 mmol) was
added in one portion. After 12 h at ca. 20 ЊC filtration gave a
black precipitate which on crystallisation gave the title com-
pound 20 (68 mg, 81%) as deep green needles, mp >300 ЊC
(from glacial acetic acid) (Found: C, 57.1; H, 2.1; N, 20.7.
C16H6ClN5S requires C, 57.3; H, 1.8; N, 20.9%); λmax(DCM)/nm
274 (log ε 4.84), 326 (4.00), 387 (4.35), 406 (4.37), 431 (3.94),
457 inf (3.86), 491 inf (3.60), 568 inf (3.60), 609 (3.75),
662 (3.77), 722 (3.54); νmax(Nujol)/cmϪ1 3103w and 3062w (Ar
CH), 2231m (CN), 1653w, 1623s, 1583s, 1570s, 1527s, 1494s,
1455s, 1417s, 1387s, 1235s, 1221m, 1184m, 1166s, 1132s,
1124m, 1058m, 1005m, 904s, 827s, 801m, 793m, 770s, 708s,
663m, 622s; m/z (EI) 335 (Mϩ, 100%), 299 (Mϩ Ϫ HCl, 29),
267 (6), 212 (5), 167.5 (Mϩϩ, 8), 162 (12), 151 (10), 140 (7),
113 (8), 91 (4), 69 (55) (Found: Mϩ, 335.0027. C16H6ClN5S
requires M, 335.0032). The use of two equivalents of 1,8-
diaminonaphthalene, under similar conditions, gave the title
compound 20 in 96% yield.
[᎐C(CN)]; δ (100 MHz; DMSO-d DEPT 135) 127.3 (Ar CH),
᎐
C
6
126.4 (Ar CH), 124.9 (Ar CH), 124.1 (Ar CH), 120.3 (Ar CH),
116.0 (Ar CH), 115.7 (Ar CH), 112.1 (Ar CH); m/z (EI) 357
(Mϩ, 100%), 341 (Mϩ Ϫ NH2, 49), 311 (Mϩ Ϫ NS, 56), 284
(Mϩ Ϫ CHN2S, 49), 178.5 (Mϩϩ, 12), 162 (4), 107 (5), 91 (4), 80
(5), 69 (28) (Found: Mϩ, 357.0819. C18H11N7S requires M,
357.0797).
4-Piperidino[1,2,6]thiadiazino[3,4-b][1,4]benzothiazine 21
To a solution of 4-chloro[1,2,6]thiadiazino[3,4-b][1,4]benzo-
thiazine 4b (126.5 mg, 0.50 mmol) in DCM (5 ml) at ca. 20 ЊC
piperidine (99 µl, 1 mmol) was added in one portion. The mix-
ture was refluxed for 1 h after which time TLC indicated a new
product and no starting material. The mixture was diluted with
DCM (20 ml), washed with water (3 × 5 ml) and the organic
fraction was dried, filtered and the volatiles were removed.
Crystallisation of the residue gave the title compound 21 (149
mg, 99%) as red prisms, mp 101–103 ЊC (from EtOH–water);
λmax(DCM)/nm 240 (log ε 4.24), 269 (3.93), 389 inf (4.14), 382
(3.82), 492 (3.90); νmax(Nujol)/cmϪ1 3030w (Ar CH), 1588m,
1558m, 1515s, 1505s, 1461s, 1435s, 1417m, 1370s, 1351m, 1299s,
1285s, 1275s, 1257m, 1237m, 1227m, 1203m, 1133m, 1125m,
1036m, 1026m, 968m, 955m, 916s, 883m, 855m, 815s, 804m,
790m, 760s, 739m, 721s, 625s, 601s; δH(300 MHz; DCM-d2)
7.25–7.21 (1H, m, Ar H), 7.15–7.09 (2H, m, Ar H), 6.92–6.89
(1H, m, Ar H), 3.57 [4H, br s, 2(CH2N)], 1.69 [6H, br s,
Method 2. To a stirred solution of 3,5-dichloro-4H-1,2,6-
thiadiazin-4-one 1 (91 mg, 0.50 mmol) in EtOH (5 ml) at ca.
20 ЊC 2-benzimidazolylacetonitrile (78.5 mg, 0.50 mmol) was
added in one portion. The mixture was refluxed at 80 ЊC for
12 h and only a trace of the title compound 14 was observed
by TLC comparison with an authentic sample under several
solvent systems.
4-(2-Aminoanilino)-5-cyano[1,2,6]thiadiazino[3Ј,4Ј:5,4]-
pyrrolo[1,2-a]benzimidazole 15
To a stirred suspension of 4-chloro-5-cyano[1,2,6]thiadiazino-
[3Ј,4Ј:5,4]pyrrolo[1,2-a]benzimidazole 14 (23 mg, 0.08 mmol)
in EtOH (3 ml) 1,2-diaminobenzene (37 mg, 0.34 mmol) was
added. The mixture was refluxed for 8 h, allowed to cool to ca.
20 ЊC and filtered to give a deep red precipitate, crystallisation
of which gave the title compound 15 (24 mg, 83%) as deep red
prisms, mp >300 ЊC (from 1,2-dichloroethane), identical to
that described above.
3(CH )]; δ (76 MHz; DCM-d ) 149.3 (C᎐N), 144.4 (C᎐N),
᎐
᎐
2
C
2
139.9 (C᎐N), 135.7, 130.2 (Ar CH), 129.7, 128.2 (Ar CH),
᎐
127.5 (Ar CH), 125.4 (Ar CH), 48.0 (CH2N), 25.7
(CH2CH2N), 24.8 (CH2CH2CH2); m/z (EI) 302 (Mϩ, 41%),
267 (4), 236 (3), 220 (6), 186 (3), 161 (26), 134 (2), 108 (6), 84
(C5H10Nϩ, 100) (Found: Mϩ, 302.0650. C14H14N4S2 requires
M, 302.0660).
3-(8-Aminonaphthalen-1-ylamino)-5-chloro-1,2,6-thiadiazin-4-
one 19
Acknowledgements
To a stirred solution of 3,5-dichloro-4H-1,2,6-thiadiazin-4-
one 1 (184 mg, 1.01 mmol) in DCM (10 ml) at 20 ЊC 1,8-
diaminonaphthalene (317 mg, 2.01 mmol) was added in one
portion. The mixture was heated at reflux for 18 h and then
cooled to ca. 20 ЊC. The volatiles were removed and flash
chromatography (DCM–light petroleum) of the residue gave the
title compound 19 (134 mg, 46%) as brick-red needles, mp 219–
220 ЊC decomp. (from ethyl acetate) (Found: C, 51.1; H, 2.9;
N, 18.0. C13H9ClN4OS requires C, 51.2; H, 3.0; N, 18.4%);
We thank the EPSRC for a Research Studentship (P. A. K.),
Professor D. J. Williams and Dr A. J. P. White for X-ray
crystallography, Mr R. Sheppard for expert help with NMR
spectroscopy, Dr M. A. Gray for the preparation of 4a and
7a and Dr M.-H. Wang for the preparation of 8 and 19,
MDL Information Systems (UK) Ltd for financial support
and the Wolfson Foundation for establishing the Wolfson
Centre for Organic Chemistry in Medical Science at Imperial
College.
2606
J. Chem. Soc., Perkin Trans. 1, 2000, 2601–2607