Cycloaddition of chloral N-alkoxycarbonylimines to substituted 1,2,4-thiadiazol-5(2H)-imines

Full text of DOI:10.1023/A:1012406624611

Russian Journal of Organic Chemistry, Vol. 37, No. 4, 2001, pp. 594 595. Translated from Zhurnal Organicheskoi Khimii, Vol. 37, No. 4, 2001,
pp. 628 629.
Original Russian Text Copyright
2001 by Zyabrev, Renskii, Drach.
SHORT
COMMUNICATIONS
Cycloaddition of Chloral N-Alkoxycarbonylimines to Substituted
,2,4-Thiadiazol-5(2H)-imines
1
V. S. Zyabrev, M. A. Renskii, and B. S. Drach
Bioorganic Chemistry and Petrochemistry Institute, Ukrainian Academy of Sciences, Kiev, 102094 Ukraine
Received September 12, 2000
Recently was found that the avalabbe multycenter
nucleophilic reagents, substituted 1,2,4-thiadiazol-
The cycloaddition of other chloral N-acylimines to
I and reactivity of compounds III will be considered
in details in future publications.
5(2H)-imines (I) are capable of [3+2]-cycloaddition
to nitriles and heterocumulenes [1]. In this publication
we report on the fact that the similar process easily
proceeds in the reaction of I with chloral N-alkoxy-
carbonylimines (II), possessing emphasized electro-
philicity of their C=N bond. Structure of the formed
cycloaddition compounds III was established by
spectral and x-ray structural investigations which
prove formation of 1,2,4-thiadiazolidine ring with the
sulfur atom coordinated additionally with the terminal
nitrogen in the side chain of 1,3- diaza-1,3-diene
group. Such coordination is obviously significant not
only for stabilization of structure of compounds III
Ethyl 4-methyl-3-trichloromethyl-5-[(E)-N-
phenylbenzimidoyl-(Z)-imino]-1,2,4-thiadiazo-
lidyne 2-carboxylate (IIIa). To a solution of 4.55 g
(
15 mmol) of base Ia hydrochloride [2] in 15 ml of
CH Cl was added with stirring in 0.5 h a solution of
2
2
3.28 g (15 mmol) of N-ethoxycarbonylchloralimine
[3] and 1.52 g (15 mmol) of triethylamine in 10 ml of
CH Cl . The mixture was stirred for 5 h at room
2
2
temperature, 30 ml of water, was added, the organic
layer was separated, the solvent was removed in
vacuo. To the residue 15 ml of ethanol was added, the
crystalline precipitate was filtered off and recrystal-
lized from ethyl acetate. Yield of compound IIIa
but also in the process of IIIa
IV ethylation:
5
.1 g (70%), colorless crystals, mp 146 147 C.
1
H NMR spectrum (CDCl3), , ppm: 1.27 t (3H,
_
3
2
3
3
2
5
.90 s (1H, CCl CH), 7.03 7.57 m (10H, H arom.).
3
Found, %: Cl 21.65; N 11.29. C H Cl N O S.
2
0
19
3
4
2
Calculated, %: Cl 21.89; N 11.53.
Methyl-4-n-methoxyphenyl-5-[(E)-N-n-tolyl-
benzimidoyl-(Z)-imino]-3-trichloromethyl-1,2,4-
thiadiazolidine 2-carboxylate (IIIb). To a suspen-
sion of 2.24 g (6 mmol) of compound Ib obtained by
the general procedure for the synthesis of base I [1]
in 15 ml anhydrous dioxane was added 1.23 g
(6 mmol) of N-methoxycarbonylchloralimine. The
mixture was stirred for 5 h at 20 25 C, the pre-
cipitate formed was filtered off and recrystallized
from benzene. Yield of compound IIIb 2.29 g (66%),
1
colorless crystals, mp 179 C (decomp.) H NMR
spectrum (CDCl ), , ppm: 2.38 s (3H, C_ _H C H ),
3
3
6
4
3
7
.80 s (3H, CH O), 6.45 s (1H, CCl CH), 6.93
.56 m (13H, H arom.). Found, %: Cl 18.25; S 5.51.
3 3
I, III, Ar = Ph, R = Me (a), Ar = 4-MeC H , R =
C H Cl N O S. Calculated, %: Cl 18.40; S 5.55.
6
4
26 23 3 4 3
4
-MeOC H (b); II, III, Alk = Et (a), Me (b).
According to X-ray structural analysis, the bond
6
4
1
070-4280/01/3704-0594$25.00 2001 MAIK Nauka/Interperiodica

CYCLOADDITION OF CHLORAL N-ALKOXYCARBONYLIMINES
595
1
2
1
lengths (d, ) are: S N 1.916 (2); S N 1.960
CCl CH), 7.30 7.58 m (10H, H arom.). Found, %:
exo
3
2
3
3
4
4
5
(
2); N C 1.421 (3); C N 1.466 (3); N C
.351 (3); C S 1.733 (3). 5-[N-Methyl-N-(1-di-
Cl 2.50; S 5.14. C H Cl N O S. Calculated, %: Cl
2
2
24
4
4
6
5
1
1
1
2
3.08; S 5.22. The H NMR spectra were registered
ethoxymethylenamino-2,2,2-trichloro)ethyl]amino-
,3-diphenyl-1,2,4-thiadiazolium perchlorate (IV).
To a solution of 1.46 g (3 mmol) of compound IIIa in
0 ml of CH Cl was added 0.57 g (3 mmol) of tri-
ethyloxonium tetrafluoroborate. The mixture was
stirred for 0.5 h and left for 48 h at 20 25 C. Volatile
components were removed in vacuo and to the residue
was added 5 ml of ethyl acetate, the precipitate was
filtered off and then dissolved in 10 ml of methanol.
To the solution was added 3 ml of 3N solution of
sodium perchlorate in methanol and after 24 h the
precipitate was filtered off. Yield of compound IV
on Varian VXR-300 (compounds IIIa and IV) and
Bruker WP-100 (IIIb) instruments with internal TMS.
H-ray structural investigation of compound IIIb was
performed in cooperation with dr. Nernega on an
Enraf Nonius CAD-4 difractometer (MoK irradia-
2
1
2
2
tion,
0.71069 ).
REFERENCES
1. Goerdeler, J. and Lubach, W., Chem. Ber., 1979,
vol. 112, no. 2, pp. 517 531.
2. Zyabrev, V.S., Kharhenko, A.V., Pirozhenko, V.V.,
and Drach, B.S., Zh. Org. Khim., 1988, vol. 24, no. 7,
pp. 1754 1762.
was 1.03 g (55%), mp 167 C (decomp.) (MeOH).
1
H NMR spectrum (CDCl ), , ppm: 1.40 m (6H,
3
_
C _H CH ), 3.85 s (3H, CH N), 4.42 m (2H,
3. Ulrich, U., Tucker, B., and Sayigh, A.A.R., J. Org.
Chem., 1968, vol. 33, no. 7, pp. 2887 2889.
3
2
3
CH _C _H ), 4.64 m (2H, CH _C _H ), 5.79 c (1H,
3
2
3
2
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 4 2001