Cycloaddition reactions of polyfluoroalkylthioncarboxylic acid derivatives with dimethyl acetylenedicarboxylate (DMAD)

Article abstract of DOI:10.1016/j.jfluchem.2003.11.009

Polyfluoroalkyldithiocarboxylates react with dimethyl acetylenedicarboxylate (DMAD) to give 2-polyfluoroalkyl-1,3-dithioles and/or 2-polyfluoroalkylidene-1,3-dithioles depending on the substituent at the thiolic sulfur atom and on the length of the polyfluoroalkyl chain. Amides of polyfluoroalkylthioncarboxylic acids with DMAD give 2-methoxy-2-polyfluoroalkyl-5-methoxycarbonylmethylene- thiazolidin-4-ones.

Full text of DOI:10.1016/j.jfluchem.2003.11.009

Journal of Fluorine Chemistry 125 (2004) 439–444
Cycloaddition reactions of polyfluoroalkylthioncarboxylic acid
derivatives with dimethyl acetylenedicarboxylate (DMAD)
A.V. Rudnichenko, V.M. Timoshenko, Yu.G. Shermolovich*
Department of Organosulfur Compounds, Institute of Organic Chemistry, National Academy of Sciences of Ukraine,
Murmanska Street, 5, 02094 Kiev-94, Ukraine
Received 22 September 2003; received in revised form 19 November 2003; accepted 24 November 2003
Abstract
Polyfluoroalkyldithiocarboxylates react with dimethyl acetylenedicarboxylate (DMAD) to give 2-polyfluoroalkyl-1,3-dithioles and/or
2-polyfluoroalkylidene-1,3-dithioles depending on the substituent at the thiolic sulfur atom and on the length of the polyfluoroalkyl chain.
Amides of polyfluoroalkylthioncarboxylic acids with DMAD give 2-methoxy-2-polyfluoroalkyl-5-methoxycarbonylmethylene-thiazolidin-
4-ones.
# 2003 Elsevier B.V. All rights reserved.
Keywords: Dithioesters; Thioamides; Dimethyl acethylenedicarboxylate cycloaddition; 1,3-Dithiole; Thiazolidinone; Thiazoline
1. Introduction
It is possible to suppose that the treatment of polyfluor-
oalkyldithiocarboxylates with DMAD should also result in
formation of the intermediate ylide A (R ¼ RF), the further
transformation of which will depend on a nature of sub-
stituents in the dithioester. Considerations of these transfor-
mations are the goal of the present paper.
Recently, we have shown [6] that b-bromoperfluoro-
dithiocrotonate (1) reacts with DMAD to give a new type
of vinylogue of tetrathiafulvalene (2) (Scheme 2).
Reactions of dimethyl acethylenedicarboxylate (DMAD)
with esters and amides of dithiocarboxylic acid are well-
known synthetic routes to five-membered S- and S,N-het-
eroycles [1,2]. Continuing our study of chemical properties
of polyfluoroalkanedithiocarboxylic acids derivatives [3],
we have considered the reactions of their esters and amides
with dimethyl acetylenedicarboxylate to define the influence
of the nature of electron-withdrawing polyfluoroalkyl group
on the progress of these reactions and on the structure of the
resulting products.
2. Results and discussion
The reaction mechanisms of non-fluorinated benzyl and
allyl dithiocarboxylates with DMAD have been explicitly
discussed [4]. The key step is the formation of the ylide A as
a result of 1,3-dipolar cycloaddition reaction (Scheme 1).
The further transformation of this ylide, either 1,2-rearran-
gement (in case of benzyl ester) or allyl-rearrangement (for
allyl ester), leads to final reaction product, a 1,3-dithiole
derivative B. The reactions of other alkyl esters of dithio-
carboxylic esters with DMAD are not described in the
literature (it was reported [5] that methyl dithiobenzoate
does not react with DMAD).
2.1. Reactions of fluorinated dithioesters with DMAD
Dithioesters (3) react with DMAD at room temperature
forming dithiole derivatives (4) and/or (5) (Scheme 3). The
structure and yields of the products formed depend on the
length of polyfluoroalkyl substituent and on the nature of the
substituent at thiolic sulfur for the esters with the same
polyfluoroalkyl moiety (Table 1).
Ethyl trifluorodithioacetate 3a reacts with DMAD to
afford a mixture of products. According to 19F NMR data,
the major, isolated in 43% yield, is 2-trifluoromethyl-1,3-
dithiole 5a (entry 1). Upon reaction of ethyl tetrafluoro-
dithiopropionate 3b with DMAD, 2-tetrafluoroethyl-1,3-
dithiole 5b is obtained in 94% isolated yield (entry 2). Ethyl
perfluorodithiobutyrate 3c, having a longer polyfluoroalkyl
* Corresponding author. Tel.: þ380-44-552-8312;
fax: þ380-44-573-2643.
E-mail address: sherm@bpci.kiev.ua (Yu.G. Shermolovich).
0022-1139/$ – see front matter # 2003 Elsevier B.V. All rights reserved.
doi:10.1016/j.jfluchem.2003.11.009

440
A.V. Rudnichenko et al. / Journal of Fluorine Chemistry 125 (2004) 439–444
Scheme 1.
DMAD. It was isolated from reaction mixtures in 92 and
90%, respectively (entries 4 and 5).
It is reasonably to assume that such difference in the
reaction products is bound with reactivity and stability of
intermediate ylides, viz., with variable conversion courses of
fluorine-containing carbanion A, which are outlined in
Scheme 4. Carbanion A can be stabilized by elimination
of a alkyl fluoride affording the ylidene-dithioles (route a) or
by elimination of ethylene/propylene to give dithioles (5)
(route b). The route a is becoming the predominant with
increase of the polyfluoroalkyl chain length. In case of
benzyl dithioester (3f) along with the product of benzyl
fluoride elimination (4f) the formation of dithiole (5f) also
occurs (entry 6), due to migration of the benzyl cation
Scheme 2.
chain upon the treatment with DMAD gives a mixture of
dithiole (5c) and ylidene-1,3-dithiole (4c), with the predo-
minant formation of the latter (entry 3). Compound of the
type (4)—butylylidene-1,3-dithiole (4d)—is an exclusive
product of the reaction of ethyl and n-propyl esters with
Scheme 3.
Scheme 4.

A.V. Rudnichenko et al. / Journal of Fluorine Chemistry 125 (2004) 439–444
441
Table 1
The products of the reaction of dithioesters (3) with DMAD
Entry
Compound
RF
R
X
4:5 (%)a
1
2
3
4
5
6
7
3a
3b
3c
3d
3e
3f
F
Et
H
0:43
0:94
HCF2
CF3CF2
H(CF2)3
H(CF2)3
H(CF2)3
F
Et
H
Et
H
75:20
92:0
Et
H
n-Pr
PhCH2
PhCH2
H
90:0
PhCH2
PhCH2
51:27
0:52
3g
a Isolated yield.
Scheme 5.
Scheme 6.
toward the carbanion centre (route c). The product of 1,2-
migration of the benzyl group is also major for the reaction
of benzyl trifluorodithioacetate (3g) with DMAD (entry 7).
It should be noted that the treatment of dithioester (3b)
with DMAD in the presence of excess of KF as HF acceptor
leads to formation of dithiole (5b) only. Therefore, we can
exclude the another possible way for the formation of
compounds (5) as the result of HF addition to vinylidene-
dithioles (4) and route b seems to be the most acceptable for
the formation of compounds (5).
substituted thiazolidinone (8) depending on the solvent in
which the reaction is carried out (Scheme 5).
Amides (9) and (10) react with DMAD without solvent
to give thiazolidinones (11, 12) as a result of methanol
addition to C¼N double bond of intermediates (13, 14),
activated by the electron-withdrawing influence of poly-
fluoroalkyl group. Confirming methanol addition to inter-
mediate compounds (13, 14) is the fact that compounds
(11, 12) under treatment with P2O5 undergo demethoxyla-
tion to give thiazolines (13, 14), which easily add methanol
giving thiazolidines (11, 12) (Scheme 6).Under treatment
of compounds (11, 12) with PCl5 we obtained thiazolines
(15, 16). When these compounds react with diethylamine,
4-diethylamino-thiazoline derivatives (17, 18) are obtained
(Scheme 7).
2.2. Reactions of thioamides with DMAD
Reactions of amides of non-fluorinated aliphatic thion-
carboxylic acids with DMAD were shown to be a possible
synthetic method for thiazoline derivatives [2,7,8]. Unsub-
stituted thioamides of alkylcarboxylic acids (6) give
2,5-dimethylenethiazolidin-4-one (7) or 2-methoxy-2-alkyl
Scheme 7.

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A.V. Rudnichenko et al. / Journal of Fluorine Chemistry 125 (2004) 439–444
3
2
3. Conclusion
CHS, JHF ¼ 12:3 Hz), 6.14 (1H, tt, HCF2, JHF
¼
52:9 Hz). 19F NMR (CDCl3): d ꢀ126.26 (2F, m, CF2),
ꢀ137.99 (2F, dm, CF2H, 2JFH ¼ 52:9 Hz). Anal. Calculated
for C9H8F4O4S2: C, 33.75; H, 2.52; S, 20.02. Found: C,
33.71; H, 2.47; S, 19.80.
We have shown that the course of cycloaddition reactions
of fluorine containing alkyldithiocarboxylates with DMAD
is strongly dependent both on the polyfluoroalkyl chain
length and the thiolic substituent. 2-Polyfluoroalkylidene
derivatives of 1,3-dithiole are the major product with
increasing of chain length. S-Benzyl dithioesters afford also
the products of 1,2-migration of benzyl group—2-polyflur-
oalkyl-2-benzyl-1,3-dithioles. In contrast to non-fluorinated
series, thioamide of polyfluoroalkylcarboxylic acids form
exclusively 2-methoxy-2-polyfluoroalkylthiazolidin-4-ones.
4.1.3. 4,5-Bis(carbomethoxy)-2-(hexafluoropropylidene)-
1,3-dithiole (4c) and 4,5-bis(carbomethoxy)-2-
(heptafluoropropyl)-1,3-dithiole (5c)
Compound (4c) was collected at Rf ¼ 0:79 (petroleum
ether–dichloromethane, 1:1). Yellow oil. 1H NMR (CDCl3):
d 3.86 (3H, s, CH3), 3.87 (3H, s, CH3). 19F NMR (CDCl3): d
3
3
ꢀ84.34 (3F, dt, CF3, JFF ¼ 6:9, JFF ¼ 3:4 Hz), ꢀ118.02
4. Experimental
(2F, dq, CF2, 3JFF ¼ 15:5, 3JFF ¼ 3:4 Hz), ꢀ122.32 (1F, tq,
CF, JFF ¼ 15:5, JFF ¼ 6:9 Hz). 13C NMR (CDCl3): d
3
4
1
The H, 13C and 19F spectra were recorded on a Varian
53.69 (s, CH3), 53.71 (s, CH3), 109.3 (tqd, CF2,
2
2
VXR-300 instrument at 299.9, 75.4 and 282.2 MHz, respec-
tively. Chemical shifts are given in ppm referenced to signals
of residual protons in CHCl3 (dH ¼ 7:26, dC ¼ 77:16) for 1H
and 13C NMR spectra and from C6F6 (dF ꢀ162.9 ppm) as
internal standard for 19F NMR spectra. MS data were
obtained on a MX-1321 apparatus at 70 eV in the electron
impact mode. All reactions were monitored by 19F NMR
spectroscopy. Silica gel Merck 60 (40–63 mm) was used for
column chromatography. DMAD was obtained from com-
mercial sources and used without further purification. All
reaction solvents were dried and distilled according to
standard procedures. Elemental analysis was performed in
the Analytical Laboratory of the Institute of Organic Chem-
istry, NAS of Ukraine. Dithioesters (3b–f) were prepared
according [9] and dithioesters (3a, 3g) according [10], amide
of 2,2,3,3,4,4,5,5-octafluoropentanoic acid was prepared
according to the procedure described in [11].
1JCF ¼ 256:4, JCF ¼ 40:9, JCF ¼ 34:5 Hz), 118.4 (qtd,
1
2
3
CF3, JCF ¼ 287:7, JCF ¼ 38:6, JCF ¼ 3:7 Hz), 128.6 (q,
2
3
4
CS2, JCF ¼ JCF ¼ 25:7 Hz), 130.2 (d, C–C¼O, JCF
¼
1
2
2:8 Hz), 131.1 (dt, CF, JCF ¼ 244:0, JCF ¼ 33:5 Hz),
131.5 (t, C–C¼O, JCF¼5JCF¼ 3:7 Hz), 159.0 (d, C¼O,
4
5JCF ¼ 2:3 Hz), 159.1 (s, C¼O). EIMS 70 eV, m/z (rel.
int.): 368 [Mþ] (90), 337 [Mþ–OCH3] (51), 299 [Mþ–
CF3] (100). Anal. Calculated for C10H6F6O4S2: C, 32.61;
H, 1.64. Found: C, 32.46; H, 1.56.
Compound (5c) was collected at Rf ¼ 0:58 (petroleum
ether–dichloromethane, 1:1). Yellow oil. 1H NMR (CDCl3):
d 3.82 (6H, s, 2CH3), 5.29 (1H, t broad, 3JHF ¼ 12:2 Hz). 19
F
3
NMR (CDCl3): d ꢀ81.20 (3F, t, CF3, JFF ¼ 10:9 Hz),
ꢀ120.16 (2F, m, CF2), ꢀ124.09 (2F, m, CF2). 13C NMR
2
(CDCl3): d 50.8 (t, CH, JCF ¼ 26:8 Hz), 53.5 (s, CH3),
1
109.7 (tm, CF2, JCF ¼ 267:5 Hz), 113.3 (tt, CF2CH,
1JCF ¼ 259:5, JCF ¼ 29:6 Hz), 117.5 (qt, CF3, JCF
¼
2
1
2
288:0, JCF ¼ 33:9 Hz), 130.3 (s, 2C–C¼O), 160.1 (s,
C¼O). EIMS 70 eV, m/z (rel. int.): 388 [Mþ] (56), 357
[Mþ–OCH3] (65), 219 [Mþ–CF3CF2CF2] (100). Anal. Cal-
culated for C10H7F7O4S2: C, 30.93; H, 1.82. Found: C,
30.96; H, 1.76.
4.1. Reactions of dithioesters (3) with DMAD. General
procedure
An equimolar mixture of dithioester (3) and DMAD was
stirred at room temperature for 12–24 h. The end of reaction
was determined by 19F NMR. The resulting yellow oil was
chromatographed over silica gel with appropriate mixture of
solvents. Yields of products are given in Table 1.
4.1.4. 4,5-Bis(carbomethoxy)-2-(1,2,2,3,3,4,4-
heptafluorobutylidene)-1,3-dithiole (4d)
Compound (4d) was collected at Rf ¼ 0:79 (ethyl acet-
ate–hexane, 9:1). Yellow oil. 1H NMR (CDCl3): d 3.86 (3H,
s, CH3), 3.87 (3H, s, CH3), 6.00 (1H, tt, HCF2, 2JHF ¼ 52:3,
3JHF ¼ 5:3 Hz). 19F NMR (CDCl3): d ꢀ116.52 (2F, m, CF2),
ꢀ121.53 (1F, m, CF), ꢀ131.55 (2F, m, CF2), ꢀ137.95 (2F,
dm, CF2H, 2JFH ¼ 52:3 Hz). EIMS 70 eV, m/z (rel. int.): 400
[Mþ] (30), 369 [Mþ–OCH3] (14), 299 [Mþ–HCF2CF2]
(100). Anal. Calculated for C11H7F7O4S2: C, 33.01; H,
1.76; S, 16.02. Found: C, 33.10; H, 1.69; S, 16.22.
4.1.1. 4,5-Bis(carbomethoxy)-2-trifluoromethyl-1,3-
dithiole (5a)
Yellow oil. Rf ¼ 0:65 (ethyl acetate–hexane, 9:1). 1H
NMR (CDCl3): d 3.83 (3H, s, CH3), 3.84 (3H, s, CH3),
5.03 (1H, t, CH, JHF ¼ 7:1 Hz). 19F NMR (CDCl3): d
3
3
ꢀ79.20 (d, CF3, JFH ¼ 7:1 Hz). Anal. Calculated for
C8H7F3O4S2: C, 33.33; H, 2.45; S, 22.25. Found: C,
33.58; H, 2.27; S, 22.41.
4.1.5. 4,5-Bis(carbomethoxy)-2-benzyl-2-(1,1,2,2,3,3,4,4-
octafluorobutylidene)-1,3-dithiole (5f)
Reaction of dithioester (3f) with DMAD was proceeding
according to the general procedure above. Column chroma-
tography of the reaction mixture gave compound (4d) at
4.1.2. 4,5-Bis(carbomethoxy)- 2-(1,1,2,2-tetrafluoroethyl)-
1,3-dithiole (5b)
Yellow oil. Rf ¼ 0:70 (ethyl acetate–hexane, 9:1). 1H
NMR (CDCl3): d 3.83 (6H, s, 2CH3), 5.12 (1H, t broad,

A.V. Rudnichenko et al. / Journal of Fluorine Chemistry 125 (2004) 439–444
443
Rf ¼ 0:51 and compound (5f) at Rf ¼ 0:41 (petroleum
ether–dichloromethane, 1:0.9).
(2F, dm, CF2H, 2JFH ¼ 52:0 Hz). EIMS 70 eV, m/z (rel. int.):
261 [Mþ] (100). Anal. Calculated for C5H3F8NS: C, 23.00;
H, 1.16; N, 5.36; S, 12.28. Found: C, 22.49; H, 1.05; N, 5.48;
S, 13.33.
1
Compound (5f). Yellow oil. H NMR (CDCl3): d 3.31
(2H, s broad, CH2), 3.71 (6H, s, 2CH3), 6.10 (1H, tt, HCF2,
3
2JHF ¼ 52:2, JHF ¼ 5:2 Hz), 7.35 (5H, m, Ph). 19F NMR
(CDCl3): d ꢀ109.91 (2F, m, CF2), ꢀ119.02 (2F, m, CF2),
ꢀ130.77 (2F, m, CF2), ꢀ137.92 (2F, dm, CF2H,
2JFH ¼ 52:2 Hz). EIMS 70 eV, m/z (rel. int.): 510 [Mþ]
(38), 419 [MþꢀPhCH2] (100). Anal. Calculated for
C18H14F8O4S2: C, 42.36; H, 2.76; S, 12.56. Found: C,
42.19; H, 2.86; S, 12.41.
4.3. Reactions of thioamides (9, 10) with DMAD.
Common procedure
An equimolar mixture of thioamide (9, 10) and DMAD
was kept at room temperature until reaction was complete
(72 h for (9) and 96 h for (10)). Compounds (11, 12) were
purified by crystallization from the mixture of petroleum
ether–diethyl ether (1:1) at ꢀ20 8C for 40 h.
4.1.6. 4,5-Bis(carbomethoxy)-2-benzyl-2-trifluoromethyl-
1,3-dithiole (5g)
Yellow oil. Rf ¼ 0:54 (ethyl acetate–hexane, 9:1). 1H
NMR (CDCl3): d 3.39 (2H, s, CH2), 3.76 (3H, s, CH3),
3.84 (3H, s, CH3), 7.34 (5H, m, Ph). 19F NMR (CDCl3):
d ꢀ78.93 (s, CF3). EIMS 70 eV, m/z (rel. int.): 378 [Mþ] (9),
287 [Mþ–PhCH2] (100). Anal. Calculated for C15H13-
F3O4S2: C, 47.61; H, 3.46; S, 16.95. Found: C, 47.56; H,
3.46; S, 17.10.
4.3.1. 2-Methoxy-2-trifluoromethyl-5-
methoxycarbonylmethylenethiazolidin-4-one (11)
Yield 95%. Yellow crystals, mp 115–117 8C. H NMR
(CDCl3): d 3.47 (3H, s, CH3), 3.85 (3H, s, CH3), 6.92 (1H, s,
CH¼), 7.72 (1H, broad, NH). 19F NMR (CDCl3): d ꢀ82.00
(s, CF3). 13C NMR with C–H coupling (CDCl3): d 51.3 (q,
1
CH3O, JCH ¼ 146:3 Hz), 52.7 (q, CH3O, JCH ¼ 148:9 Hz),
2
96.85 (qm, C-2, JCF ¼ 35:0 Hz), 115.6 (d, C-6, JCH
¼
4.2. Synthesis of thioacetamides (9, 10)
173:0 Hz), 121.7 (q, CF3, JCF ¼ 283:5 Hz), 143.7 (s, C-
5), 166.0 (d, C-4, 3JC4H6 ¼ 5:4 Hz), 166.8 (q, C-þ7,
2JC7H6 ¼ 5:0 Hz). EIMS 70 eV, m/z (rel. int.): 271 [M ]
(27), 240 [Mþ–CH3O] (26), 202 [Mþ–CF3] (48). Anal.
Calculated for C8H8F3NO4S: S, 11.82; N, 5.16. Found: S,
12.25; N, 4.68.
4.2.1. Trifluorothioacetamide (9)
Phosphorous pentasulfide (110.7 g, 0.249 mol) was added
to a suspension of trifluoroacetamide (47 g, 0.416 mol) in
mixture of hexamethyldisiloxane (134.8 g, 0.830 mol) and
200 ml of toluene. The reaction mixture was stirred at 45 8C
for 15 h. Solvents were removed at vacuum (20 mmHg) up
to 1/2 of volume and residue was diluted with 50 ml of
diethyl ether. Organic solution was consecutively washed
with NaHCO3 solution (4 ꢁ 50 ml), saturated aqueous NaCl
solution (2 ꢁ 100 ml) and water (2 ꢁ 100 ml). Water phase
was additionally washed with diethyl ether (2 ꢁ 100 ml).
Combined ethereal solution was dried over Na2SO4 and
solvent was removed in vacuum. The residue was crystal-
lized from hexane.
4.3.2. 2-Methoxy-2-(2,2,3,3,4,4,5,5-octafluorobuthyl)-5-
methoxycarbonylmethylenethiazolidin-4-one (12)
Yield 96%. Yellow crystals, mp 89–91 8C. 1H NMR
(CDCl3): d 3.48 (3H, s, CH3), 3.85 (3H, s, CH3), 6.05
2
3
(1H, tt, HCF2, JHF ¼ 52:3, JHF ¼ 5:1 Hz). 19F NMR
(CDCl3): d ꢀ116.76 and ꢀ119.73 (2F, AB, H(CF2)3CF2,
JAB ¼ 290:6 Hz), ꢀ121.49 and ꢀ123.19 (2F, AB, H(CF2)2-
CF2, JAB ¼ 309:8 Hz), ꢀ131.14 (2F, m, HCF2CF2),
2
ꢀ138.40 (2F, dm, HCF2, JFH ¼ 52:3 Hz). 13C NMR
Yield 23.64 g (44%). Yellowish crystals, mp 42–44 8C
([12] mp 43–44 8C). 1H NMR (CDCl3): d 7.40 (1H, broad,
NH), 7.63 (1H, broad, NH). 19F NMR (CDCl3): d ꢀ71.18 (s,
CF3).
(CDCl3): d 51.2 (s, CH3O), 52.7 (s, CH3O), 99.9 (t, C-2,
2
3
2JCF ¼ 30:9 Hz), 107.8 (tt, HCF2, JCF ¼ 254:6, JCF
¼
32:1 Hz), 104–114 (m, 3 CF2), 116.4 (s, C-6), 143.6 (s,
C-5), 166.2 (s, CO), 166.9 (s, CO). EIMS 70 eV, m/z (rel.
int.): 403 [Mþ] (10), 372 [Mþ–CH3O] (22), 202 [Mþ–
H(CF2)4] (91). Anal. Calculated for C11H9F8NO4S: C,
32.76; H, 2.25; N, 3.47; S, 7.95. Found: C, 32.94; H,
2.40; N, 3.27; S, 7.76.
4.2.2. Thioamide of 2,2,3,3,4,4,5,5-octafluoropentanoic
acid (10)
Compound (10) was prepared analogously to compound
(9) from 13.04 g (0.05 mol) amide of 2,2,3,3,4,4,5,5-ocata-
fluoropentanoic acid, 26.68 g (0.06 mol) of phosphorous
pentasulfide, 13.43 g, (0.1 mol) of hexamethyldisiloxane
and 100 ml of toluene. The reaction mixture was stirred
at 80 8C for 40 h.
4.4. Chlorination of (11, 12). Common procedure
The two-fold excess of PCl5 was added to a solution of
thiazolidinone (11, 12) in benzene and mixture was refluxed
at stirring for 20 h (for (11)) or 35 h (for (12)). Solvent was
removed at vacuum (20 mmHg), the residue was treated
with mixture hexane–diethyl ether (1:1) and solid material
was filtered off. After evaporation of mother liquor at
20 mmHg, the compound (16) was obtained as viscous
Yield 11.6 g (89%). Yellowish crystals, mp 38–41 8C
1
(from hexane). H NMR (CDCl3): d 6.12 (1H, tt, HCF2,
3
2JHF ¼ 52:0, JHF ¼ 5:3 Hz), 7.44 (1H, broad, NH), 7.91
(1H, broad, NH). 19F NMR (CDCl3): d ꢀ111.84 (2F, m,
CF2), ꢀ123.83 (2F, m, CF2), ꢀ130.33 (2F, m, CF2), ꢀ138.26

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A.V. Rudnichenko et al. / Journal of Fluorine Chemistry 125 (2004) 439–444
oil, pure enough to be used for further reactions. Compound
(15) was purified by vacuum distillation.
Calculated for C12H17F3N2O3S: C, 44.17; H, 5.25; N,
8.58, S, 9.83. Found: C, 44.67; H, 5.40; N, 8.96; S, 9.47.
4.4.1. 2-Methoxy-2-trifluoromethyl-4-chloro-5-
methoxycarbonylmethylenethiazoline (15)
4.5.2. 2-(2,2,3,3,4,4,5,5-Octafluorobutyl)-2-methoxy-4-
diethylamino-5-methoxycarbonylmethylene-thiazoline (18)
Yield 62%. Brownish crystals, mp 50–52 8C. H NMR
(CDCl3): d 1.25 (6H, t, 2CH3CH2N), 3.27 (3H, s, OCH3),
3.51 (4H, q, 2CH3CH2N), 3.82 (3H, s, OCH3), 6.23 (1H, tt,
1
Yield 36%. Viscous yellow oil, bp 110–115 8C
(0.05 mmHg). 1H NMR (CDCl3): d 3.38 (3H, s, CH3),
3.87 (3H, s, CH3), 6.79 (1H, s, CH¼). 19F NMR (CDCl3):
d ꢀ80.87 (s, CF3). EIMS 70 eV, m/z (rel. int.): 289 [Mþ]
(10), 220 [Mþ–CF3] (52). Anal. Calculated for
C8H7ClF3NO3S: Cl, 12.20. Found: Cl, 12.24.
HCF2, 2JHF ¼ 51:9, 3JHF ¼ 5:4 Hz), 6.41 (1H, s, CH¼). 19
F
NMR (CDCl3): d ꢀ116.20 and ꢀ118.57 (2F, AB,
H(CF2)3CF2, JAB ¼ 274:3 Hz), ꢀ122.13 and ꢀ123.16
(2F, AB, H(CF2)2CF2, JAB ¼ 296:3 Hz), ꢀ130.28 and
4.4.2. 2-Methoxy-2-(2,2,3,3,4,4,5,5-octafluorobuthyl)-4-
chloro-5-methoxycarbonylmethylene-thiazoline (16)
Yield 99%. Viscous yellow oil. 1H NMR (CDCl3): d 3.35
(3H, s, CH3), 3.85 (3H, s, CH3), 6.06 (1H, tt, HCF2,
ꢀ133.02 (2F, AB, HCF2CF2, JAB ¼ 282:2 Hz), ꢀ137.94
2
and ꢀ139.46 (2F, d AB, HCF2, JAB ¼ 303:6, JFH
¼
51:9 Hz). EIMS 70 eV, m/z (rel. int.): 458 [Mþ] (53), 443
[Mþ–CH3] (100). Anal. Calculated for C15H18F8N2O3S: C,
39.31; H, 3.96; N, 6.11; S, 7.00. Found: C, 39.61; H, 4.10; N,
6.19; S, 7.23.
3
2JHF ¼ 52:4, JHF ¼ 5:6 Hz), 6.77 (1H, s, CH¼). 19F
NMR (CDCl3): d ꢀ114.83 and ꢀ117.03 (2F, AB, H(CF2)3-
CF2, JAB ¼ 278:5 Hz), ꢀ120.23 and ꢀ121.22 (2F, AB,
H(CF2)2CF2, JAB ¼ 291:8 Hz), ꢀ129.36 and ꢀ130.74
(2F, AB, HCF2CF2, JAB ¼ 283:9 Hz), ꢀ137.20 (2F, dm,
References
2
HCF2, JFH ¼ 52:4 Hz). EIMS 70 eV, m/z (rel. int.): 421
[Mþ] (7), 220 [Mþ–H(CF2)4] (100). Anal. Calculated for
C11H8ClF8NO3S: Cl, 8.41. Found: Cl, 8.46.
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(1998) 2133–2136.
4.5. Reactions of compounds (15, 16) with ethylamine.
Common procedure
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[4] V.N. Drozd, Zh. Org. Khim., 29 (1993) 1089–1094; Chem. Abstr.
120 270188z (1994).
The two-fold excess of diethylamine was added to a
solution of compound (15, 16) in diethyl ether. After stirring
for 5 h, diethylamine chlorohydrate salt was filtered and
solvent was removed at 20 mmHg. The oily residue was
treated several times with cold hexane and crystallized from
a mixture of hexane–diethyl ether (10:1).
[5] V.N. Drozd, O.A. Popova, Zh. Org. Khim., 16 (1980) 2047–2054;
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4.5.1. 2-Trifluoromethyl-2-methoxy-4-diethylamino-5-
methoxycarbonylmethylenethiazoline (17)
Yield 19%. Brownish crystals, mp 54–56 8C. H NMR
[9] C. Portella, Yu.G. Shermolovich, O. Tschenn, Bull. Soc. Chim. Fr.
134 (1997) 697–702.
[10] F. Laduron, C. Nyns, Z. Janousek, H.G. Viehe, J. Prakt. Chem. 339
(1997) 697–707.
1
(CDCl3): d 1.27 (6H, t, 2CH3CH2N), 3.31 (3H, s, CH3O),
3.51 (4H, q, 2CH3CH2N), 3.83 (3H, q, OCH3), 6.40 (1H, s,
CH¼). 19F NMR (CDCl3): d ꢀ81.67 (s, CF3). Anal.
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(1971) 366–371.
[12] E. Lindner, U. Kunze, Chem. Ber. 102 (1969) 3347–3356.