Isopropyl N-arylmalonamates. Synthesis, structure, conformation and reactions with carbon disulfide

Article abstract of DOI:10.1135/cccc20060059

Acylation of aromatic amines 1 with diisopropyl malonate (2) leads to a mixture of isopropyl N-arylmalonamates 3 and malonanilides 4. The reaction of 3 with carbon disulfide in the presence of sodium hydride gives disodium salts 5. Treatment of 5 with an alkylating agent yields the open-chain or cyclic ketene dithioacetals 6, 7 or 8. The molecular structure, hydrogen bonding and preferential conformation of the isopropyl N-arylmalonamates 3, 6 and 7 were investigated using correlation analyses of IR, ¹³C NMR and AMI semiempirical data.

Full text of DOI:10.1135/cccc20060059

Isopropyl N-Arylmalonamates
59
ISOPROPYL N-ARYLMALONAMATES. SYNTHESIS, STRUCTURE,
CONFORMATION AND REACTIONS WITH CARBON DISULFIDE
a,
b1
c
d
Wolf-Dieter RUDORF *, Dušan LOOS , Joanna WYBRANIEC , Naꢀa PRÓNAYOVÁ ,
c1
b
Ryszard GAWINECKI and Zora ŠUSTEKOVÁ
a
Institute of Organic Chemistry, Martin-Luther-University,
Kurt-Mothes-Str. 2, 06120 Halle, Germany; e-mail: wolf-dieter.rudorf@chemie.uni-halle.de
Department of Organic Chemistry and Institute of Chemistry, Faculty of Natural Sciences,
Comenius University, Mlynská dolina CH-2, 842 15 Bratislava, Slovak Republic;
b
c
1
e-mail: loos@fns.uniba.sk
Department of Organic Chemistry, Academy of Technology and Agriculture,
Faculty of Technology and Engineering, Seminaryjna 3, 85326 Bydgoszcz, Poland;
1
e-mail: gawiner@mail.atr.bydgoszcz.pl
d
Central Laboratories, Faculty of Chemical Technology, Slovak Technical University,
812 37 Bratislava, Slovak Republic; e-mail: pronayova@cvt.stuba.sk
Received March 16, 2005
Accepted July 25, 2005
Dedicated to the memory of Professor Alexander Perjéssy.
Acylation of arom atic am in es 1 with diisopropyl m alon ate (2) leads to a m ixture of isopro-
pyl N-arylm alon am ates 3 an d m alon an ilides 4. Th e reaction of 3 with carbon disulfide in
th e presen ce of sodium h ydride gives disodium salts 5. Treatm en t of 5 with an alkylatin g
agen t yields th e open -ch ain or cyclic keten e dith ioacetals 6, 7 or 8. Th e m olecular structure,
h ydrogen bon din g an d preferen tial con form ation of th e isopropyl N-arylm alon am ates 3, 6
an d 7 were in vestigated usin g correlation an alyses of IR, 13C NMR an d AM1 sem iem pirical
data.
Keyw ord s: Malon ates; N-Arylm alon am ates; Keten e dith ioacetals; AM1 calculation s; Correla-
tion an alysis; Con form ation al an alysis.
Alkyl N-arylm alon am ates are valuable buildin g blocks in th e syn th esis of
n um erous arom atic an d h eterocyclic com poun ds with a wide spectrum of
biological activity1–5. On th e oth er h an d, keten e dith ioacetals bearin g
electron -with drawin g groups are useful an d versatile reagen ts for th e syn -
th esis of h eterocycles6–9. In gen eral, keten e dith ioacetals are obtain ed by
th e reaction of active m eth ylen e com poun ds with carbon disulfide in th e
presen ce of a base followed by alkylation 10
.
Collect. Czech. Chem. Commun. 2006, Vol. 71, No. 1, pp. 59–76
© 2006 Institute of Organic Chemistry and Biochemistry
doi:10.1135/cccc20060059

60
Rudorf et al.:
In our in vestigation s of th e preparative use of push -pull alken es, th e reac-
tion s of carbon disulfide with isopropyl N-arylm alon am ates are to be
proved. From th e viewpoin t of th e con form ation an d in ter- an d in tra-
m olecular in teraction s, isopropyl N-arylm alon am ates are an in terestin g
group of com poun ds, wh ich deserve m ore particular structural in vestiga-
tion s usin g spectral an d th eoretical m eth ods. For th is purpose, a part of th is
study was aim ed at IR, 13C NMR an d AM1 sem iem pirical in vestigation s to
fin d preferen tial structural properties of com poun ds in th e series 3, 6 an d 7.
RESULTS AND DISCUSSION
Alkyl N-arylm alon am ates can be prepared by reaction of arylam in es with
various m alon ic acid derivatives, such as ch lorides11 or an h ydrides of
m on oalkyl esters1,11, but m ost frequen tly dialkyl m alon ates are used11–13
.
We h ave foun d th at acylation of arom atic am in es 1 with diisopropyl
m alon ate (2), both in equim olar ratio an d in an excess of th e latter, at
170 °C is practically always accom pan ied by an un desired side-reaction , th e
form ation of dian ilides 4. Th is fact is in accordan ce with results th at
m alon dian ilides can be syn th esized in h igh yields by h eatin g eth yl
N-arylm alon am ates to 170–220 °C with out an y solven t irrespective of sub-
stituen ts in th e arom atic rin g11 (Sch em e 1).
Reaction s of CH-acid com poun ds such as m alon on itrile, eth yl cyan o-
acetate, cyan oacetam ide or m alon ic esters with carbon disulfide were stud-
ied in ten sively9. Wh ereas m alon on itrile an d eth yl cyan oacetate treated
with carbon disulfide provide h igh yields, m alon ic esters an d cyan oacet-
am ide give on ly m oderate yields of th e correspon din g dith ioacetals.
Isopropyl N-arylm alon am ates 3 were treated with carbon disulfide in
dim eth yl sulfoxide in th e presen ce of sodium h ydride to give gem in al
dith iolates 5 wh ich were n ot isolated. Usin g alcoh olic potassium h ydrox-
ide, sodium eth ylate or sodium tert-pen tylate as bases, dith iolates were
form ed on ly in sm all am oun ts. Treatm en t of disodium salts 5 with two
equivalen ts of m eth yl iodide led to isopropyl N-aryl-2-[bis(m eth ylsulfan yl)-
m eth yliden e]m alon am ates 6 in a on e-pot reaction . Usin g 1,2-dibrom o-
eth an e for th e alkylation of 5, isopropyl N-aryl-2-(1,3-dith iolan -2-yliden e)-
m alon am ates 7 were obtain ed. Usin g 2,3-dich loro-1,4-n aph th oquin on e
gave con den sed dith iol 8.
Th e IR spectra of th e open -ch ain as well as th e cyclic keten e dith ioacetals
6 an d 7 sh ow th e C=C stretch in g vibration in th e region 1578–1610 cm –1
.
Th e ester ban d is sh ifted to lower waven um bers (1674–1693 cm –1). Th e
ban d of th e an ilide group is foun d at 1630–1683 cm –1. Th e selected IR spec-
Collect. Czech. Chem. Commun. 2006, Vol. 71, No. 1, pp. 59–76

Isopropyl N-Arylmalonamates
61
tral data, n am ely th e waven um bers ν(C3=O), ν(C5=O) an d ν(C4=C7) are
listed in Table I.
1H NMR spectra of com poun ds 6 an d 7 sh ow sin glets at δ 2.44–2.49 an d
3.30–3.37 ppm , respectively, correspon din g to th e SCH3 an d S–CH2–CH2–S
groups.
Th e syn th esized isopropyl m alon am ates 3, 6 an d 7 are con form ation ally
flexible com poun ds wh ich can be fixed by h in dered rotation an d in ter- or
in tram olecular h ydrogen bon ds. Possible structural form s of th ese com -
R
+
(CH3)2CHOCO-CH2-COOCH(CH3)2
NH2
1
2
6e
6b
6d
6f
1a
CH3
R
6c
R
R
6
1
5
4
3
2
6a
NH CO CH2 CO O CH
NH CO CH2 CO NH
+
CH3
1b
4
3a-k
6e
6d
6f
CH3I
1a
CH3
CS2
NaH
R
6c
6
1
5
4
C
3
2
6a
NH CO
CO O CH
6b
CH3
1b
C
7
H3C
7d
S
S CH3
R
7c
7a
7b
NH CO
Na
C
C
COOCH(CH3)2
S Na
6a-g, j, k
6e
6b
S
6d
6f
1a
CH3
5
R
6c
6
1
5
4
C
C7
3
2
(CH2)2Br2
6a
NH CO
CO O CH
O
CH3
1b
7c S
S
7a
Cl
Cl
7d
R = 3,4-Cl2
7b
7a-h, j, k
O
R
3, 6, 7
R
4-CH3
4-Br
NH CO
S
C
C
COOCH(CH3)2
a
b
c
d
e
f
g
h
i
S
2,3-Cl2
3,4-Cl2
3-Cl-4-CH3
4-NO2
4-Cl
2,4-Cl2
2,5-Cl2
H
O
O
8
j
k
4-N(CH3)2
SCHEME 1
Collect. Czech. Chem. Commun. 2006, Vol. 71, No. 1, pp. 59–76

62
Rudorf et al.:
TABLE I
IR spectral data of isopropyl m alon am ates 3, 6 an d 7 in ch loroform a
~
ν, cm –1
Com poun d
ν(C3=O)
ν(C5=O)
ν(C4=C7)
3b
3c
3d
3e
3f
1718.4
1718.4
1718.4
1718.0
1718.4
1717.5
1718.4
1718.4
1718.4
1715.2
1692.8
1692.8
1692.8
1692.8
1692.8
1692.8
1692.8
1692.8
1676.8
1680.0
1680.0
1676.8
1676.8
1679.0
1676.8
1676.8
1676.4
1674.0
1686.4
1692.8
1691.0
1686.4
1697.0
1686.4
1682.8
1692.8
1680.1
1674.0
1672.0
1678.0
1680.0
1680.0
1676.0
1683.0
1675.0
1668.0
1631.0
1634.0
1638.4
1638.4
1633.0
1641.0
1635.0
1638.0
1632.0
1630.0
–
–
–
–
–
3g
3h
3i
–
–
–
3j
–
3k
6a
6b
6c
6d
6e
6f
–
1596.8
1590.4
1584.0
1584.0
1587.2
1600.0
1599.2
1591.6
1593.6
1587.2
1610.0
1580.8
1584.0
1590.3
1590.4
1577.6
1595.6
1590.4
6j
6k
7a
7b
7c
7d
7e
7f
7g
7h
7j
7k
a
For n um berin g atom s see Sch em e 1.
Collect. Czech. Chem. Commun. 2006, Vol. 71, No. 1, pp. 59–76

Isopropyl N-Arylmalonamates
63
poun ds drawn on th e basis of AM1 calculation s are illustrated in Sch em e 2.
Th e aim of th e presen t study was to fin d preferen tial structural form s for
th e in dividual series of com poun ds. For th is purpose th e IR an d NMR spec-
tral ch aracteristics, as well as th e AM1 th eoretical data of com poun ds 3, 6
an d 7 were particularly in vestigated.
R
R
O
O
O
X2
X1
X2
X1
N
H
N
H
O
O
O
H
H
H3C
CH3
H3C
CH3
B
A
CH3
O
R
CH3
X2
X1
O
H
X2
O
X1
O
N
H
H
O
N
H
CH3
H3C
H3C
O
R
O
H
N
R
CH3
O
H
H
N
O
X1
X2
X1
O
X2
O
H
O
CH3
CH3
C
D
SCHEME 2
Table II sh ows th e in fluen ce of th e solven t an d con cen tration on th e IR
spectral data of 4-brom o derivatives 3b, 6b an d 7b. In th e case of com -
poun d 3b th e in ten sity of th e ester C3=O ban d is h igh er th an th at of th e
am ide C5=O ban d. Th e in ten sity ratio of th ese two ban ds does n ot substan -
tially ch an ge on ch an gin g con cen tration . On th e oth er h an d, for com -
poun d 7b th e in ten sity of th e ester C3=O ban d is m uch lower th an th at of
th e am ide C5=O ban d. A com parison of th e in ten sity ratios (η) sh ows th at
th e in ten sity of th e ester C3=O ban d in creases with regard to th e in ten sity
of th e am ide C5=O ban d as th e con cen tration of a solution of com poun d
7b decreases. In th e case of com poun d 7b an addition al absorption ban d
appears in th e region 1645–1640 cm –1, wh ich can be assign ed to th e
in term olecularly h ydrogen bon ded ester carbon yl group, ν(C3=O)b. Th e
above described spectroscopic beh avior well correspon ds to th e idea th at in
solution s of com poun ds 3 a con form ation is preferred wh ich is stabilized
Collect. Czech. Chem. Commun. 2006, Vol. 71, No. 1, pp. 59–76

64
Rudorf et al.:
Collect. Czech. Chem. Commun. 2006, Vol. 71, No. 1, pp. 59–76

Isopropyl N-Arylmalonamates
65
by in term olecular h ydrogen bon din g in wh ich th e am ide carbon yl group
C5=O participates as h ydrogen acceptor (form C, Sch em e 2). Th e ∆ν values
in Table II sh ow th at th e in fluen ce of th e solven t on th e h ydrogen -bon ded
am ide C5=O group is m uch stron ger th an on th e free ester C3=O group. Th e
IR spectroscopic properties of com poun ds 3 are very close to th ose observed
in th e case of substituted acetan ilides14, wh ich form in term olecularly
h ydrogen -bon ded cyclic dim ers. On th e oth er h an d, com poun ds 7 prefer-
en tially exist in m on om eric form with an in tram olecular h ydrogen bon d
(form B). It is eviden t from Table II th at for com poun ds 7 th e differen ce be-
tween th e solven t effects on both carbon yl groups is less pron oun ced bein g
con sisten t with th e in tram olecularly h ydrogen -bon ded structure B. Fin ally,
com poun d 6b exh ibits both in CHCl3 an d CCl4 a con siderable ch an ge in
th e position of th e ester ν(C3=O) values com pared with th e ester ν(C3=O)
values of com poun ds 3b an d 7b. Th is in dicates th at com poun ds 6 probably
exist in th e form of in term olecularly h ydrogen -bon ded cyclic dim ers in
wh ich th e ester carbon yl group C3=O is in volved in th e h ydrogen -bon ded
structure (form D).
Th e 13C NMR ch em ical sh ifts m easured in CDCl3 for th e series of isopro-
pyl m alon am ates 3, 6 an d 7 are given in Tables III–V.
TABLE III
13C NMR ch em ical sh ifts δ(13Cn )a for series of com poun ds 3 in CDCl3
Com poun d
Carbon b
3b
3c
3d
3ec
3f
3g
3h
3i
3j
3kd
1
3
69.97
70.00
70.18
69.88
70.41
70.01
70.07
70.11
69.82
69.61
169.34 169.09 169.45 169.36 169.40 169.46 169.17 169.11 169.44 169.59
41.75 42.05 41.52 41.84 41.58 41.68 41.87 41.90 41.90 41.81
163.36 163.46 163.40 163.34 163.77 163.29 163.35 163.38 163.20 162.79
4
5
1a
1b
6a
6b
6c
6d
6e
6f
21.68
21.68
21.73
21.73
21.68
21.68
21.67
21.67
21.68
21.68
21.70
21.70
21.75
21.75
21.70
21.70
21.68
21.68
21.71
21.71
136.62 136.28 136.99 136.32 143.70 136.14 133.43 135.41 137.54 128.60
121.63 122.03 121.71 120.67 119.50 121.32 122.49 121.31 120.11 121.87
131.92 132.86 132.74 134.38 125.06 129.01 128.86 129.77 128.99 113.15
117.09 125.51 127.65 132.03 143.35 129.47 129.27 124.74 124.50 147.98
131.92 127.61 130.48 130.93 125.06 129.01 127.72 133.32 128.99 113.15
121.64 119.81 119.26 118.37 119.50 121.32 122.49 121.58 120.11 121.87
a
b
c
In ppm . For n um berin g atom s, see Sch em e 1. δ(13C) 19.45 ppm for CH3 group of R.
d
δ(13C) 41.01 ppm for CH3 group of R.
Collect. Czech. Chem. Commun. 2006, Vol. 71, No. 1, pp. 59–76

66
Rudorf et al.:
Th e differen tial n uclear Overh auser effect (DIFNOE) experim en ts sh owed
1
in th e H NMR spectra of com poun d 3e th at for isopropyl group th e pro-
ton s on C1a an d C1b atom s are situated in th e close proxim ity of th e ben -
zen e rin g proton s attach ed to C6b an d C6f atom s (i.e. in ortho-position ). On
th e con trary, th e DIFNOE experim en ts exh ibited n egative results for sign als
of isopropyl proton s of com poun ds 6e an d 7e. Th is can be regarded as fur-
th er eviden ce th at com poun ds 6 an d 7 occurred preferably in th e B form
an d th at in th e case of com poun ds 3 th e existen ce of con form ation C is
m ore probable th an th e con form ation wh ere th e isopropyl groups are re-
m ote from th e proton s in th e ortho-position of th e ben zen e rin g.
To con firm th e con clusion s obtain ed from th e results of IR an d NMR ex-
perim en ts th e AM1 th eoretical data were calculated for th e series of isopro-
pyl m alon am ates 3, 6 an d 7. Th e h eats of form ation (∆Hf) calculated for
TABLE IV
13C NMR ch em ical sh ifts δ(13Cn )a for series of com poun ds 6 in CDCl3
Com poun d
Carbon b
6ac
6b
6c
6d
6ed
6f
6j
6ke
1
3
69.74
165.00
130.39
161.62
156.08
21.68
69.98
165.22
129.55
161.57
157.46
21.62
70.05
164.86
129.49
161.74
158.31
21.64
70.12
165.25
128.93
161.70
158.55
21.66
69.90
165.08
129.73
161.65
157.17
21.67
70.11
165.36
128.21
161.92
160.25
21.66
69.69
165.00
130.16
161.70
156.54
21.62
69.60
165.02
130.77
161.52
155.20
21.69
4
5
7
1a
1b
6a
6b
6c
6d
6e
6f
7b
7d
21.68
21.62
21.64
21.66
21.67
21.66
21.67
21.69
135.50
119.99
129.51
134.17
129.57
119.99
18.31
136.70
121.42
131.99
117.08
131.99
121.42
18.48
136.30
121.73
132.76
125.39
127.75
119.65
18.50
137.24
121.52
132.82
129.59
130.49
119.09
18.57
136.49
120.40
134.50
132.05
130.98
118.17
18.47
143.72
119.22
125.11
143.61
128.11
119.26
18.70
137.68
119.93
130.16
124.48
130.16
119.93
18.39
127.53
121.72
113.05
148.17
113.05
121.72
18.19
18.31
18.48
18.50
18.57
18.47
18.70
18.39
18.58
a
b
c
In ppm . For n um berin g atom s, see Sch em e 1. δ(13C) 20.80 ppm for CH3 group of R.
d
e
δ(13C) 19.40 ppm for CH3 group of R. δ(13C) 40.92 ppm for CH3 group of R.
Collect. Czech. Chem. Commun. 2006, Vol. 71, No. 1, pp. 59–76

Isopropyl N-Arylmalonamates
67
form s A–D resultin g from h in dered rotation an d h ydrogen -bon din g in ter-
action s are given in Table VI. Th e C5=O bon d orders an d C5 an d H6 ch arge
den sities are listed in Table VII. It is eviden t from Table VI th at for com -
poun ds 3 th e m ost stable form is C, wh ere two m olecules are in ter-
m olecularly h ydrogen -bon ded form in g
a
cyclic dim er with th e
participation of th e am ide C=O groups. Th is is sim ilar to acetan ilide 9
(ref.14) an d is in good agreem en t with th e previous eviden ce based on th e
IR an d NMR spectral results. On th e oth er h an d, in com poun ds 7 th e form
B h as th e lowest en ergy an d th e calculated distan ce between th e h ydrogen
atom of th e N–H group an d th e oxygen atom of th e ester C3=O group is
on ly 2.03 Å, wh ich is adven tageous for th e form ation of an in tram olecular
h ydrogen bridge.
TABLE V
13C NMR ch em ical sh ifts δ(13Cn )a for series of com poun ds 7 in CDCl3
Com poun d
Carbon b
7b
7d
7e
7f
7g
7h
7j
7kc
1
3
70.69
165.72
110.14
163.06
181.13
22.10
70.79
165.74
109.59
163.14
182.87
22.02
70.61
165.72
110.14
163.06
181.93
22.09
71.10
165.94
109.49
163.53
184.20
22.10
70.63
165.70
110.03
163.11
182.12
22.06
70.61
165.45
110.21
163.22
182.87
22.07
70.46
165.67
110.51
163.13
181.57
22.11
70.26
165.64
110.79
162.73
180.24
22.09
4
5
7
1a
1b
6a
6b
6c
6d
6e
6f
7b
7d
22.10
22.02
22.09
22.10
22.06
22.07
22.11
22.09
137.58
121.75
131.77
116.20
131.77
131.75
38.39
138.04
121.17
132.45
126.40
130.70
119.04
38.37
134.49
124.09
128.71
128.37
127.43
122.75
38.36
143.05
119.40
125.07
144.59
125.07
119.40
38.52
137.06
121.36
128.78
128.51
128.78
121.36
38.35
133.49
124.09
128.71
128.37
127.43
122.75
38.34
138.43
120.87
128.87
123.82
128.87
120.87
38.35
128.67
121.80
113.20
147.59
113.30
121.80
38.28
37.19
37.16
37.17
37.30
37.15
37.21
37.16
37.11
a
b
c
In ppm . For n um berin g atom s, see Sch em e 1. δ(13C) 41.01 ppm for CH3 group of R.
Collect. Czech. Chem. Commun. 2006, Vol. 71, No. 1, pp. 59–76

68
Rudorf et al.:
Fin ally, th e IR an d NMR experim en tal data were correlated with
Ham m ett σ con stan ts15 (Table VIII) an d AM1 bon d orders an d ch arge den si-
ties (Table IX). In all cases on ly th e spectral an d th eoretical ch aracteristics
of th e am ide C5=O an d N6–H groups were con sidered sin ce th e data for
oth er structural fragm en ts did n ot ch an ge m arkedly with structural ch an ges
an d th eir correlation s provided statistically in sign ifican t results. In a few
cases som e ortho-substituted derivatives were excluded from correlation s be-
cause sign ifican t errors resulted from approxim ation of substituen t con -
stan ts for ortho-substitution by σp Ham m ett values. A com parison of th e
correlation s of ν(C5=O) an d δ(H6) values with Ham m ett σ con stan ts (Table
VIII) sh ows th at th e ρ values for series 3 are h igh er th an th ose obtain ed for
series 7. Th is can be reason ably explain ed by an in crease in th e efficien cy of
tran sm ission of substituen t effects in th e in term olecularly h ydrogen -
bon ded cyclic dim ers C, wh ich is in a good agreem en t with earlier results
reported for a series of 3-arylm eth ylen eph th alim idin es16. It follows from
TABLE VI
Heats of form ation for differen t form sa of com poun ds 3j, 6j an d 7j (R = H) an d acetan ilide (9)
–∆Hf
kJ/m ol
∆(∆Hf)b
kJ/m ol
Preferen tial
form
Com poun d
Form
3j
A
437.7
455.3
457.5
430.8
331.0
344.0
310.2
351.2
310.8
314.2
303.7
308.9
55.8
–
C
D
B
C
B
17.6
19.8
–6.9
–
Cc
Dc
A
6j
7j
B
13.0
20.8
20.2
–
Cc
Dc
A
B
3.4
Cc
Dc
Ad
Cc
–7.1
–1.9
–
9
69.4
13.6
a
b
See Sch em e 2.
Differen ce between th e values of ∆Hf for m on om eric form A an d
c
h ydrogen -bon ded form s B–D.
h ydrogen -bon ded cyclic dim er. Mon om eric form .
Calculated for on e m olecule in th e in term olecularly
d
Collect. Czech. Chem. Commun. 2006, Vol. 71, No. 1, pp. 59–76

Isopropyl N-Arylmalonamates
69
TABLE VII
Selected AM1 ch arge den sities (q) an d bon d orders (p) for preferen tial form sa of com poun ds
3, 6 an d 7
Com pd
q(C5)
q(O5)
q(C5=O)
q(C4)
q(C7)
q(H6)
3a
3b
3c
3d
3e
3f
0.325
0.322
0.329
0.322
0.321
0.320
0.321
0.328
0.333
0.320
0.317
0.362
0.364
0.357
0.368
0.362
0.370
0.362
0.359
0.365
0.368
0.368
0.369
0.367
0.371
0.367
0.368
0.366
0.362
–0.375
–0.385
–0.386
–0.384
–0.388
–0.391
–0.387
–0.386
–0.383
–0.390
–0.395
–0.357
–0.352
–0.347
–0.343
–0.352
–0.342
–0.356
–0.363
–0.387
–0.383
–0.384
–0.383
–0.385
–0.376
–0.385
–0.384
–0.386
–0.390
1.7418
1.7272
1.7311
1.7294
1.7239
1.7191
1.7250
1.7313
1.7328
1.7202
1.7136
1.7403
1.7482
1.7545
1.7638
1.7459
1.7634
1.7416
1.7312
1.6402
1.6492
1.6508
1.6514
1.6456
1.6660
1.6466
1.6509
1.6409
1.6329
–0.185
–0.184
–0.185
–0.185
–0.184
–0.184
–0.184
–0.185
–0.183
–0.184
–0.184
–0.206
–0.212
–0.177
–0.229
–0.208
–0.226
–0.207
–0.202
–0.269
–0.271
–0.271
–0.272
–0.269
–0.275
–0.270
–0.269
–0.267
–0.268
–
0.277
0.274
0.276
0.275
0.274
0.273
0.274
0.275
0.281
0.273
0.270
0.262
0.264
0.268
0.266
0.264
0.267
0.262
0.261
0.265
0.268
0.277
0.269
0.268
0.272
0.267
0.277
0.266
0.263
–
–
–
–
–
3g
3h
3i
–
–
–
3j
–
3k
6a
6b
6c
6d
6e
6f
–
–0.335
–0.335
–0.350
–0.325
–0.336
–0.335
–0.335
–0.335
–0.360
–0.360
–0.360
–0.361
–0.360
–0.361
–0.360
–0.360
–0.360
–0.360
6j
6k
7a
7b
7c
7d
7e
7f
7g
7h
7j
7k
a
See Table VI.
Collect. Czech. Chem. Commun. 2006, Vol. 71, No. 1, pp. 59–76

70
Rudorf et al.:
th e in spection of correlation s of th e IR an d NMR spectral ch aracteristics
with AM1 th eoretical data (Table IX) th at satisfactory results are obtain ed,
wh en form C for com poun ds 3, form D for com poun ds 6 an d form B for
com poun ds 7 are con sidered as preferen tial con form ation s.
EXPERIMENTAL
Th eoretical calculation s were perform ed usin g th e sem iem pirical AM1 Ham ilton ian 17 with
program package AMPAC18. Geom etries were com pletely optim ized.
Meltin g poin ts were determ in ed on a Boetius m icro h eatin g stage (Carl Zeiss Jen a) an d are
un corrected. Elem en tal an alyses were perform ed with a CHNS-932 LECO an alyzer. Mass
spectra of positive ion s obtain ed by electron im pact (EI, 70 eV) were taken on an AMD 402
spectrom eter (In tectra Gm bH). In frared spectra were m easured in CHCl3 or CCl4 solution s
on a Zeiss 80 Specord spectrom eter at room tem perature usin g NaCl cells of 0.1, 1.0 an d
TABLE VIII
Lin ear correlation s of IR an d NMR spectral dataa with Ham m ett σ con stan ts for series of
com poun ds 3, 6 an d 7: y = ρσ + z
Com pd
y
nb
rc
sd
Fe
ρ
z
3
ν(C5=O)
δ(H6)
9f
7g
0.993
0.924
1.23
508
29
19.93±0.88
1680.7
9.31
0.120
0.467±0.086
δ(C4)
poor correlation
δ(C5)
10
0.928
0.096
50
0.482±0.068
163.19
6
7
ν(C5=O)
δ(H6)
δ(C4)
δ(C5)
δ(C7)
8
0.987
0.867
0.941
1.02
229
15
11.08±0.73
1673.9
8.22
7h
6i
0.183
0.343
0.532±0.136
–1.491±0.269
31
129.82
poor correlation
7j
0.976
0.285
102
0.230±0.023
156.80
ν(C5=O)
δ(H6)
δ(C4)
δ(C5)
δ(C7)
10
7k
7l
7k
8
0.986
0.932
0.946
0.928
0.895
1.03
289
33
12.37±0.73
1631.4
10.63
0.137
0.164
0.096
0.584
0.644±0.112
–0.842±0.129
0.441±0.079
2.210±0.449
42
110.03
163.05
181.64
31
24
a
b
IR stretch in g vibration s ν in CHCl3, an d NMR ch em ical sh ifts δ in CDCl3. Th e n um ber of
c
d
e
com poun ds used in correlation . Correlation coefficien t.
Sn edecor test for param eters sign ifican t at th e 95% level. Com poun d 3h om itted. Com -
Stan dard deviation . Fish er–
f
g
h
i
poun ds 3h , 3c an d 3i om itted. Com poun d 6d om itted. Com poun ds 6a an d 6c om itted.
j
k
l
Com poun d 6f om itted. Com poun d 7d om itted. Com poun d 7h om itted.
Collect. Czech. Chem. Commun. 2006, Vol. 71, No. 1, pp. 59–76

Isopropyl N-Arylmalonamates
71
5.0 m m th ickn esses. Th e con cen tration s of solution s were ch osen to give absorption in th e
ran ge 75–85% (estim ated con cen tration : 2 × 10–2 m ol/l at 0.1 m m , 1 × 10–2 m ol/l at
1.0 m m ). Th e solven ts used for m easurem en ts were of spectral purity (Uvasol, Merck). Th e
waven um bers in th e region 1800–1500 cm –1 were determ in ed with an accuracy of
±0.2 cm –1. Th e 1H an d 13C NMR spectra (δ in ppm ) were recorded for 0.5 m ol/l solution s in
CDCl3 with TMS as in tern al stan dard usin g a 5 m m tube at 23 °C on a VXR Varian spec-
TABLE IX
Lin ear correlation s of IR an d NMR spectral dataa with AM1 bon d orders an d atom ic ch arges
for series of com poun ds 3, 6 an d 7: y = ρx + z
Com pd
y
x
nb
rc
sd
Fe
ρ
z
3
ν(C5=O) p(C5=O) 8f
0.958
2.987
67
1472.428±180.109 –855.609
q(C5)
q(O5)
q(H6)
q(C4)
q(C5)
poor correlation
8f
7g
0.954
0.932
3.124
0.114
61
33
2397.041±307.923 2612.909
δ(H6)
δ(C4)
δ(C5)
153.983±26.745
–32.733
poor correlation
6h
0.991
0.033
228 117.754±7.803
125.493
840.939
6
ν(C5=O) p(C5=O)
q(C5)
8
0.921
0.888
0.942
0.977
0.917
0.982
2.501
2.945
2.148
0.061
0.385
0.028
33
22
47
477.555±82.715
8
1475.604±312.007 1138.816
795.777±115.675 1955.641
q(O5)
8
δ(H6)
δ(C4)
δ(C5)
δ(C7)
q(H6)
q(C4)
q(C5)
q(C7)
7i
7j
6k
105 107.055±10.424
27 76.540±14.872
111 36.352±3.447
–20.032
145.967
148.486
poor correlation
7
ν(C5=O) p(C5=O) 9l
0.951
0.961
0.921
0.974
0.900
0.927
0.901
1.895
1.691
2.387
0.088
0.193
0.089
0.338
66
85
39
867.888±106.547 205.319
2559.488±277.304 695.053
2373.992±378.868 2548.191
q(C5)
q(O5)
q(H6)
q(C4)
q(C5)
q(C7)
9l
9l
8l
7m
8
δ(H6)
δ(C4)
δ(C5)
δ(C7)
109 122.971±11.773
–22.201
145.224
135.284
21
36
17
129.829±28.090
75.812±12.565
6n
–4272.30±1027.52 –1356.448
a
b
IR stretch in g vibration s ν in CHCl3, an d NMR ch em ical sh ifts δ in CDCl3. Th e n um ber of
c
d
e
com poun ds used in correlation . Correlation coefficien t.
Stan dard deviation . Fish er–
f
Sn edecor test for param eters sign ifican t at th e 95% level. Com poun ds 3f an d 3h om itted.
g
h
i
Com poun ds 3f, 3i an d 3h om itted. Com poun ds 3c, 3f, 3i an d 3h om itted. Com poun d
j
k
l
6f om itted. Com poun d 6c om itted. Com poun ds 6b an d 6d om itted. Com poun ds 7c an d
7h om itted.
m
n
Com poun d 7d om itted. Com poun ds 7f an d 7k om itted.
Collect. Czech. Chem. Commun. 2006, Vol. 71, No. 1, pp. 59–76

72
Rudorf et al.:
trom eter operatin g at 299.94 MHz frequen cy for 1H n uclei an d at 75.43 MHz for 13C n uclei.
For sign al assign m en ts, 1H an d 13C APT, HETCOR, DQCOSY, DIFNOE an d SINEPT 19
(sem iselective INEPT) tech n iques were used.
Isopropyl N-Arylm alon am ates 3a–3k. Gen eral Procedure
Diisopropyl m alon ate (28.2 g, 0.15 m ol) an d correspon din g arom atic am in e (0.1 m ol) were
h eated in a m etal bath at 170 °C for 1 h . Th e reaction m ixture was cooled to room tem pera-
ture an d isopropyl alcoh ol (50 m l) was added with stirrin g. After 10 m in th e precipitate was
filtered off an d th e solution diluted with water (50 m l). After coolin g th e solid was filtered
off an d recrystallized.
Isopropyl N-(4-methylphenyl)malonamate (3a)20. Yield 15.8 g (67%); m .p. 82–83 °C (dieth yl
eth er). For C13H17NO3 (235.3) calculated: 66.36% C, 7.28% H, 5.95% N; foun d: 66.16% C,
7.21% H, 5.71% N. 1H NMR: 1.28 d, 6 H (2 CH3); 2.30 s, 3 H (4-CH3); 3.40 s, 2 H (CH2);
5.09 m , 1 H (CH); 7.09–7.43 m , 4 H (arom ); 9.14 s (br), 1 H (NH).
Isopropyl N-(4-bromophenyl)malonamate (3b). Yield 22.9 g (76%); m .p. 90–92 °C (isopropyl
alcoh ol–water). For C12H14BrNO3 (300.2) calculated: 48.02% C, 4.70% H, 26.62% Br, 4.67% N;
foun d: 48.23% C, 4.58% H, 26.57% Br, 4.68% N. 1H NMR: 1.28 d, 6 H (2 CH3); 3.43 s, 2 H
(CH2); 5.10 m , 1 H (CH); 7.40–7.48 m , 4 H (arom ); 9.42 s (br), 1 H (NH).
Isopropyl N-(2,3-dichlorophenyl)malonamate (3c). Yield 17.1 g (59%); m .p. 65–66 °C (isopro-
pyl alcoh ol–water). For C12H13Cl2NO3 (290.2) calculated: 49.68% C, 4.52% H, 24.44% Cl,
4.83% N; foun d: 49.66% C, 4.49% H, 24.43% Cl, 4.89% N. 1H NMR: 1.31 d, 6 H (2 CH3);
3.51 s, 2 H (CH2); 5.16 m , 1 H (CH); 7.20–8.34 m , 3 H (arom ); 9.94 s (br), 1 H (NH).
Isopropyl N-(3,4-dichlorophenyl)malonamate (3d )20. Yield 17.7 g (61%); m .p. 93–95 °C (iso-
propyl alcoh ol). For C12H13Cl2NO3 (290.2) calculated: 49.68% C, 4.52% H, 24.44% Cl,
4.83% N; foun d: 49.48% C, 4.35% H, 24.22% Cl, 4.80% N. 1H NMR: 1.30 d, 6 H (2 CH3);
3.44 s, 2 H (CH2); 5.11 m , 1 H (CH); 7.37–7.60 m , 3 H (arom ); 9.51 s (br), 1 H (NH).
Isopropyl N-(3-chloro-4-methylphenyl)malonamate (3e). Yield 12.4 g (46%); m .p. 85–87 °C
(isopropyl alcoh ol–water). For C13H16ClNO3 (269.7) calculated: 57.89% C, 5.98% H, 13.14% Cl,
5.19% N; foun d: 57.85% C, 5.97% H, 13.06% Cl, 5.24% N. 1H NMR: 1.30 d, 6 H (2 CH3);
2.31 s, 3 H (4-CH3); 3.42 s, 2 H (CH2); 5.10 m , 1 H (CH); 7.15–7.64 m , 3 H (arom ); 9.31 s
(br), 1 H (NH).
Isopropyl N-(4-nitrophenyl)malonamate (3f). Yield 9.6 g (36%); m .p. 87–89 °C (isopropyl
alcoh ol–water). For C12H14N2O5 (266.3) calculated: 54.13% C, 5.30% H, 10.52% N; foun d:
53.98% C, 5.35% H, 10.32% N. 1H NMR: 1.30 d, 6 H (2 CH3); 3.49 s, 2 H (CH2); 5.13 m , 1 H
(CH); 7.74–8.22 m , 4 H (arom ); 9.86 s (br), 1 H (NH).
Isopropyl N-(4-chlorophenyl)malonamate (3g)20. Yield 12.3 g (48%); m .p. 90–92 °C (isopropyl
alcoh ol–water). For C12H14ClNO3 (255.7) calculated: 56.37% C, 5.52% H, 13.86% Cl, 5.48% N;
foun d: 56.26% C, 5.51% H, 13.85% Cl, 5.53% N. 1H NMR: 1.30 d, 6 H (2 CH3); 3.43 s, 2 H
(CH2); 5.11 m , 1 H (CH); 7.27–7.52 m , 4 H (arom ); 9.41 s (br), 1 H (NH).
Isopropyl N-(2,4-dichlorophenyl)malonamate (3h )20. Yield 17.7 g (61%); m .p. 85–87 °C (iso-
propyl alcoh ol–water). For C12H13Cl2NO3 (290.2) calculated: 49.68% C, 4.52% H, 24.44% Cl,
4.83% N; foun d: 49.68% C, 4.49% H, 24.44% Cl, 4.88% N. 1H NMR: 1.30 d, 6 H (2 CH3);
3.49 s, 2 H (CH2); 5.15 m , 1 H (CH); 7.22–8.37 m , 3 H (arom ); 9.86 s (br), 1 H (NH).
Isopropyl N-(2,5-dichlorophenyl)malonamate (3i). Yield 16.8 g (58%); m .p. 68–70 °C (isopro-
pyl alcoh ol–water). For C12H13Cl2NO3 (290.2) calculated: 49.68% C, 4.52% H, 24.44% Cl,
Collect. Czech. Chem. Commun. 2006, Vol. 71, No. 1, pp. 59–76

Isopropyl N-Arylmalonamates
73
4.83% N; foun d: 49.87% C, 4.48% H, 24.17% Cl, 4.79% N. 1H NMR: 1.29 d, 6 H (2 CH3);
3.47 s, 2 H (CH2); 5.13 m , 1 H (CH); 6.99–8.48 m , 3 H (arom ); 9.91 s (br), 1 H (NH).
Isopropyl N-phenylmalonamate (3j)20,21. Yield 15.0 g (68%); m .p. 86–87 °C (isopropyl
alcoh ol–water). For C12H15NO3 (221.3) calculated: 65.14% C, 6.83% H, 6.33% N; foun d:
65.46% C, 6.55% H, 6.53% N. 1H NMR: 1.28 d, 6 H (2 CH3); 3.43 s, 2 H (CH2); 5.11 m , 1 H
(CH); 7.09–7.57 m , 5 H (arom ); 9.29 s (br), 1 H (NH).
Isopropyl N-[4-(dimethylamino)phenyl]malonamate (3k). Yield 9.5 g (36%); m .p. 82–83 °C
(isopropyl alcoh ol–water). For C14H20N2O3 (264.3) calculated: 63.62% C, 7.63% H, 10.60% N;
foun d: 63.43% C, 7.58% H, 10.31% N. 1H NMR: 1.28 d, 6 H (2 CH3); 2.90 s, 6 H (N(CH3)2);
3.39 s, 2 H (CH2); 5.06 m , 1 H (CH); 6.68–7.32 m , 4 H (arom ); 9.99 s (br), 1 H (NH).
Isopropyl N-Aryl-2-[bis(m eth ylsulfan yl)m eth yliden e]m alon am ates 6a–6g, 6j, 6k an d
Isopropyl N-Aryl-2-(1,3-dith iolan -2-yliden e)m alon am ates 7a–7h , 7j, 7k. Gen eral Procedure
Sodium h ydride (0.48 g, 0.02 m ol) was added portion wise, durin g 10 m in an d at 10 °C, to a
solution of isopropyl N-arylm alon am ate 3 (0.01 m ol) an d carbon disulfide (0.76 g, 0.01 m ol)
in dry dim eth yl sulfoxide (25 m l) un der n itrogen atm osph ere wh ile stirrin g. Th e stirrin g was
con tin ued at th e sam e tem perature for 2 h an d th en m eth yl iodide (2.84 g, 0.02 m ol) or
1,2-dibrom oeth an e (1.88 g, 0.01 m ol) was added dropwise m ain tain in g th e tem perature be-
low 10 °C. Th e stirrin g was con tin ued for an oth er 3 h . Th e reaction m ixture was th en
poured in to ice/water (90 m l). Th e resultin g solid was filtered off an d recrystallized.
Isopropyl 2-[bis(methylsulfanyl)methylidene]-N-(4-methylphenyl)malonamate (6a). Yield 2.3 g
(68%); m .p. 175–176.5 °C (isopropyl alcoh ol). For C16H21NO3S2 (339.5) calculated: 56.61% C,
6.24% H, 4.13% N, 18.89% S; foun d: 56.45% C, 6.54% H, 3.95% N, 18.69% S. 1H NMR:
1.32 d, 6 H (2 CH3); 2.32 s, 3 H (4-CH3); 2.45 s, 6 H (2 SCH3); 5.15 m , 1 H (CH); 7.12–7.47 m ,
4 H (arom ); 8.06 s (br), 1 H (NH).
Isopropyl 2-[bis(methylsulfanyl)methylidene]-N-(4-bromophenyl)malonamate (6b). Yield 2.1 g
(52%); m .p. 223–224 °C (isopropyl alcoh ol). For C15H18BrNO3S2 (404.4) calculated: 44.56% C,
4.49% H, 19.76% Br, 3.46% N, 15.86% S; foun d: 44.60% C, 4.68% H, 19.50% Br, 3.30% N,
15.76% S. 1H NMR: 1.31 d, 6 H (2 CH3); 2.46 s, 6 H (2 SCH3); 5.15 m , 1 H (CH); 7.45 m , 4 H
(arom ); 8.22 s (br), 1 H (NH).
Isopropyl 2-[bis(methylsulfanyl)methylidene]-N-(2,3-dichlorophenyl)malonamate (6c). Yield 1.8 g
(46%); m .p. 117–118 °C (isopropyl alcoh ol). For C15H17Cl2NO3S2 (394.3) calculated: 45.69% C,
4.35% H, 17.98% Cl, 3.55% N, 16.26% S; foun d: 45.91% C, 4.27% H, 17.81% Cl, 3.29% N,
16.31% S. 1H NMR: 1.32 d, 6 H (2 CH3); 2.48 s, 6 H (2 SCH3); 5.18 m , 1 H (CH); 7.22–8.40 m ,
3 H (arom ); 8.73 s (br), 1 H (NH).
Isopropyl 2-[bis(methylsulfanyl)methylidene]-N-(3,4-dichlorophenyl)malonamate (6d). Yield 1.6 g
(41%); m .p. 129–131 °C (isopropyl alcoh ol). For C15H17Cl2NO3S2 (394.3) calculated: 45.69% C,
4.35% H, 17.98% Cl, 3.55% N, 16.26% S; foun d: 45.58% C, 4.44% H, 17.78% Cl, 3.39% N,
16.15% S. 1H NMR: 1.32 d, 6 H (2 CH3); 2.47 s, 6 H (2 SCH3); 5.15 m , 1 H (CH); 7.38–7.85 m ,
3 H (arom ); 8.40 s (br), 1 H (NH).
Isopropyl 2-[bis(methylsulfanyl)methylidene]-N-(3-chloro-4-methylphenyl)malonamate (6e).
Yield 1.5 g (40%); m .p. 126–128 °C (isopropyl alcoh ol). For C16H20ClNO3S2 (373.9) calcu-
lated: 51.40% C, 5.39% H, 9.48% Cl, 3.75% N, 17.15% S; foun d: 51.22% C, 5.39% H, 9.27% Cl,
3.51% N, 17.04% S. 1H NMR: 1.31 d, 6 H (2 CH3); 2.33 s, 3 H (4-CH3); 2.46 s, 6 H (2 SCH3);
5.15 m , 1 H (CH); 7.15–7.68 m , 3 H (arom ); 8.19 s (br), 1 H.
Collect. Czech. Chem. Commun. 2006, Vol. 71, No. 1, pp. 59–76

74
Rudorf et al.:
Isopropyl 2-[bis(methylsulfanyl)methylidene]-N-(4-nitrophenyl)malonamate (6f). Yield 1.3 g
(35%); m .p. 182–183 °C (isopropyl alcoh ol). For C15H18N2O5S2 (370.5) calculated: 48.63% C,
4.90% H, 7.56% N, 17.31% S; foun d: 48.72% C, 5.01% H, 7.56% N, 17.39% S. 1H NMR:
1.33 d, 6 H (2 CH3); 2.49 s, 6 H (2 SCH3); 5.17 m , 1 H (CH); 7.77–8.22 m , 4 H (arom ); 8.86 s
(br), 1 H (NH).
Isopropyl 2-[bis(methylsulfanyl)methylidene]-N-(4-chlorophenyl)malonamate (6g). Yield 1.7 g
(47%); m .p. 200–201 °C (isopropyl alcoh ol). For C15H18ClNO3S2 (359.9) calculated: 50.06% C,
5.04% H, 9.85% Cl, 3.89% N, 17.82% S; foun d: 49.87% C, 4.96% H, 9.72% Cl, 3.71% N,
17.90% S. 1H NMR: 1.30 d, 6 H (2 CH3); 2.44 s, 6 H (2 SCH3); 5.14 m , 1 H (CH); 7.25–7.52 m ,
4 H (arom ); 8.16 s (br), 1 H (NH).
Isopropyl 2-[bis(methylsulfanyl)methylidene]-N-phenylmalonamate (6j). Yield 2.2 g (68%); m .p.
150–151 °C (isopropyl alcoh ol). For C15H19NO3S2 (325.5) calculated: 55.36% C, 5.88% H,
4.30% N, 19.70% S; foun d: 55.25% C, 5.85% H, 4.15% N, 19.59% S. 1H NMR: 1.31 d, 6 H
(2 CH3); 2.45 s, 6 H (2 SCH3); 5.15 m , 1 H (CH); 7.10–7.58 m , 5 H (arom ); 8.14 s (br), 1 H
(NH).
Isopropyl 2-[bis(methylsulfanyl)methylidene]-N-[4-(dimethylamino)phenyl]malonamate (6k ).
Yield 1.6 g (43%); m .p. 154–157 °C (isopropyl alcoh ol). For C17H24N2O3S2 (368.5) calculated:
55.41% C, 6.56% H, 7.60% N, 17.40% S; foun d: 55.40% C, 6.81% H, 7.81% N, 17.68% S.
1H NMR: 1.30 d, 6 H (2 CH3); 2.45 s, 6 H (2 SCH3); 2.95 s, 6 H (N(CH3)2); 5.14 m , 1 H (CH);
6.64–7.43 m , 4 H (arom ); 7.92 s (br), 1 H (NH).
Isopropyl 2-(1,3-dithiolan-2-ylidene)-N-(4-methylphenyl)malonamate (7a). Yield 2.1 g (62%);
m .p. 110–112 °C (isopropyl alcoh ol). For C16H19NO3S2 (337.5) calculated: 56.95% C, 5.68% H,
4.15% N, 19.00% S; foun d: 56.73% C, 5.75% H, 4.03% N, 19.05% S. 1H NMR: 1.49 d, 6 H
(2 CH3); 2.29 s, 3 H (4-CH3); 3.31 s, 4 H (2 CH2); 5.24 m , 1 H (CH); 7.07–7.49 m , 4 H (arom );
10.40 s (br), 1 H (NH).
Isopropyl N-(4-bromophenyl)-2-(1,3-dithiolan-2-ylidene)malonamate (7b). Yield 2.1 g (52%);
m .p. 146–148 °C (isopropyl alcoh ol). For C15H16BrNO3S2 (402.3) calculated: 44.78% C,
4.01% H, 19.86% Br, 3.48% N, 15.94% S; foun d: 44.63% C, 3.96% H, 19.71% Br, 3.53% N,
15.96% S. 1H NMR: 1.43 d, 6 H (2 CH3); 3.34 s, 4 H (2 CH2); 5.25 m , 1 H (CH); 7.42–7.54 m ,
4 H (arom ); 10.72 s (br), 1 H (NH).
Isopropyl N-(2,3-dichlorophenyl)-2-(1,3-dithiolan-2-ylidene)malonamate (7c). Yield 1.7 g (43%);
m .p. 186–188 °C (isopropyl alcoh ol). For C15H15Cl2NO3S2 (392.3) calculated: 45.92% C,
3.85% H, 18.07% Cl, 3.57% N, 16.35% S; foun d: 45.73% C, 3.73% H, 17.96% Cl, 3.31% N,
16.41% S. 1H NMR: 1.43 d, 6 H (2 CH3); 3.35 s, 4 H (2 CH2); 5.30 m , 1 H (CH); 7.25–8.35 m ,
3 H (arom ); 10.90 s (br), 1 H (NH).
Isopropyl N-(3,4-dichlorophenyl)-2-(1,3-dithiolan-2-ylidene)malonamate (7d). Yield 1.8 g (46%);
m .p. 119–121 °C (isopropyl alcoh ol). For C15H15Cl2NO3S2 (392.3) calculated: 45.92% C,
3.85% H, 18.07% Cl, 3.57% N, 16.35% S; foun d: 45.69% C, 3.56% H, 18.05% Cl, 3.33% N,
16.20% S. 1H NMR: 1.43 d, 6 H (2 CH3); 3.35 s, 4 H (2 CH2); 5.24 m , 1 H (CH); 7.32–7.94 m ,
3 H (arom ); 10.89 s (br), 1 H (NH).
Isopropyl N-(3-chloro-4-methylphenyl)-2-(1,3-dithiolan-2-ylidene)malonamate (7e). Yield 1.6 g
(43%); m .p. 115–116.5 °C (isopropyl alcoh ol). For C16H18ClNO3S2 (371.9) calculated: 51.67% C,
4.88% H, 9.53% Cl, 3.77% N, 17.24% S; foun d: 51.68% C, 4.83% H, 9.49% Cl, 3.52% N,
17.15% S. 1H NMR: 1.43 d, 6 H (2 CH3); 2.32 s, 3 H (4-CH3); 3.34 s, 4 H (2 CH2); 5.26 m , 1 H
(CH); 7.13–7.76 m , 3 H (arom ); 10.62 s (br), 1 H (NH).
Isopropyl 2-(1,3-dithiolan-2-ylidene)-N-(4-nitrophenyl)malonamate (7f). Yield 2.0 g (54%);
m .p. 225–226 °C (isopropyl alcoh ol). For C15H16N2O5S2 (368.4) calculated: 48.90% C, 4.38% H,
Collect. Czech. Chem. Commun. 2006, Vol. 71, No. 1, pp. 59–76

Isopropyl N-Arylmalonamates
75
7.60% N, 17.41% S; foun d: 48.92% C, 4.64% H, 7.65% N, 17.40% S. 1H NMR: 1.43 d, 6 H
(2 CH3); 3.37 s, 4 H (2 CH2); 5.26 m , 1 H (CH); 7.78–8.18 m , 4 H (arom ); 11.32 s (br), 1 H
(NH).
Isopropyl N-(4-chlorophenyl)-2-(1,3-dithiolan-2-ylidene)malonamate (7g). Yield 1.6 g (45%);
m .p. 157–159 °C (isopropyl alcoh ol). For C15H16ClNO3S2 (357.9) calculated: 50.34% C,
4.51% H, 9.91% Cl, 3.91% N, 17.92% S; foun d: 50.70% C, 4.20% H, 9.73% Cl, 3.66% N,
17.85% S. 1H NMR: 1.43 d, 6 H (2 CH3); 3.34 s, 4 H (2 CH2); 5.25 m , 1 H (CH); 7.25–7.59 m ,
4 H (arom ); 10.72 s (br), 1 H (NH).
Isopropyl N-(2,4-dichlorophenyl)-2-(1,3-dithiolan-2-ylidene)malonamate (7h ). Yield 1.6 g
(41%); m .p. 151–152 °C (isopropyl alcoh ol). For C15H15Cl2NO3S2 (392.3) calculated: 45.92% C,
3.85% H, 18.07% Cl, 3.57% N, 16.35% S; foun d: 45.69% C, 3.56% H, 17.95% Cl, 3.33% N,
16.21% S. 1H NMR: 1.43 d, 6 H (2 CH3); 3.35 s, 4 H (2 CH2); 5.32 m , 1 H (CH); 7.20–8.49 m ,
3 H (arom ); 10.96 s (br), 1 H (NH).
Isopropyl 2-(1,3-dithiolan-2-ylidene)-N-phenylmalonamate (7j). Yield 1.7 g (53%); m .p.
121–123 °C (isopropyl alcoh ol). For C15H17NO3S2 (323.4) calculated: 55.70% C, 5.30% H,
4.33% N, 19.83% S; foun d: 55.60% C, 5.17% H, 4.21% N, 19.78% S. 1H NMR: 1.42 d, 6 H
(2 CH3); 3.32 s, 4 H (2 CH2); 5.25 m , 1 H (CH); 7.05–7.57 m , 5 H (arom ); 10.54 s (br), 1 H
(NH).
Isopropyl N-[4-(dimethylamino)phenyl]-2-(1,3-dithiolan-2-ylidene)malonamate (7k). Yield 1.4 g
(38%); m .p. 141–142 °C (isopropyl alcoh ol). For C17H22N2O3S2 (366.5) calculated: 55.71% C,
6.05% H, 7.64% N, 17.50% S; foun d: 55.65% C, 5.91% H, 7.52% N, 17.71% S. 1H NMR:
1.40 d, 6 H (2 CH3); 2.89 s, 6 H (N(CH3)2); 3.30 s, 4 H (2 CH2); 5.20 m , 1 H (CH); 6.68 d,
2 H (arom ); 7.39 d, 2 H (arom ); 10.22 s (br), 1 H (NH).
Isopropyl N-(3,4-Dich loroph en yl)-2-(4,9-dioxo-4,9-dih ydron aph th o[2,3-d][1,3]dith iol-
2-yliden e)m alon am ate (8)
Sodium h ydride (1.44 g, 0.06 m ol) was added portion wise, at 10 °C an d durin g 30 m in , to a
solution of isopropyl m alon am ate (3d ; 8.70 g, 0.03 m ol) an d carbon disulfide (2.28 g,
0.03 m ol) in dry dim eth yl sulfoxide (100 m l) un der n itrogen an d wh ile stirrin g an d coolin g.
Th e stirrin g was con tin ued for 4 h at th e sam e tem perature. Th en a solution of 2,3-dich loro-
1,4-n aph th oquin on e (6.81 g, 0.03 m ol) in dim eth yl sulfoxide (30 m l) was added dropwise
m ain tain in g th e tem perature below 10 °C an d stirrin g was con tin ued for an oth er 3 h . Th e
reaction m ixture was th en poured in to ice/water (300 m l). Th e solid was filtered off an d
recrystallized to afford 12.6 g (78%) of 8, m .p. 261–263 °C (toluen e). For C23H15Cl2NO5S2
(520.4) calculated: 53.08% C, 2.91% H, 13.62% Cl, 2.69% N, 12.32% S; foun d: 52.90% C,
2.92% H, 13.83% Cl, 2.70% N, 12.25% S. IR: 3447, 1677, 1664, 1623, 1582, 1564, 1533,
1479, 1418, 1279, 1099. 1H NMR: 1.53 d, 6 H (2 CH3); 5.34 m , 1 H (CH); 7.34–8.19 m , 7 H
(arom ); 11.01 s (br), 1 H (NH). MS (EI), m/z (rel.%): 519 (44) [M+], 359 (100) [M+
–
NHC6H3Cl2], 317 (100), 301 (14), 279 (29), 233 (4), 189 (8), 161 (2), 104 (6), 85 (9), 76 (5).
The authors appreciate financial support of the International Bureau of the Bundesministerium
für Bildung und Forschung (project No. SVK-98/003), the Slovak Ministry of Education (project
No. Nem/SLA-00318) and the Scientific Grant Agency of the Ministry of Education and the Slovak
Academy of Sciences (grant No. 1/1374/04).
Collect. Czech. Chem. Commun. 2006, Vol. 71, No. 1, pp. 59–76

76
Rudorf et al.:
REFERENCES
1. Katagi T., Aoki M., Kashiwagi M., Ohata K., Kohno S., Murata T., Inoi T.: Chem. Pharm.
Bull. 1985, 33, 4878.
2. Ukrainets I. V., Bezuglyi P. A., Treskach V. I., Turov A. V., Slobodzyan S. V.: Khim.
Geterotsikl. Soedin. 1992, 636.
3. Ukhov S. V., Konshin M. E.: Khim. Geterotsikl. Soedin. 1992, 89.
4. Ukrainets I. V., Bezuglyi P. A., Treskach V. I., Slobodzyan S. V.: Khim. Geterotsikl. Soedin.
1991, 1123.
5. Negwer M.: Organic-Chemical Drugs and Their Synonyms, 7th ed. Akademie Verlag, Berlin
1994.
6. Junjappa H., Ila H., Asokan C. V.: Tetrahedron 1990, 46, 5423.
7. Kolb M.: Synthesis 1990, 171.
8. Dieter R. K.: Tetrahedron 1986, 42, 3029.
9. Dunn A. D., Rudorf W.-D.: Carbon Disulphide in Organic Chemistry. Ellis Horwood
Limited, Chichester 1989.
10. Rudorf W.-D.: Sulfur Rep. 1991, 11, 51.
11. Ukrainets I. V., Bezugly P. A., Treskach V. I., Taran S. G., Gorokhova O. V.: Tetrahedron
1994, 50, 10331.
12. Dhawan A. K., Hora V., Hora I. M.: J. Indian Chem. Soc. 1981, 58, 199.
13. Lutz R. E., Ashburn G., Freek J. A., Jordan R. H., Leake N. H., Maftin T. A., Rowlett R. J.,
Wilson J. W.: J. Am. Chem. Soc. 1946, 68, 1285.
14. Perjéssy A., Rasała D., Loos D., Piorun D.: Monatsh. Chem. 1997, 128, 541.
15. Hansch C., Leo A.: Substituent Constants for Correlation Analysis in Chemistry and Biology.
Wiley, New York 1981.
16. Perjéssy A., Melikian G., Lácová M.: Acta Fac. Rerum Nat. Univ. Comenianae, Chim. 1976,
24, 1; Chem. Abstr. 1977, 87, 22028.
17. Dewar M. J. S., Zoebisch E. G., Healy E. F., Stewart J. J. P.: J. Am. Chem. Soc. 1985, 107,
3902.
18. AMPAC 6.0, 1997, Semichem, 7128 Summit, Shawnee, KS 66216, U.S.A.
19. Uhrín D., Liptaj T.: J. Magn. Reson. 1989, 81, 82.
20. Shindo N., Uesaka T.: Meiji Daigaku Nogakubu Kenkyu Hokoku 1986, 73, 47; Chem. Abstr.
1987, 106, 28796.
21. López-Alvarado P., Avendañ o C., Carlos Menéndez J.: Tetrahedron Lett. 2001, 42, 4479.
Collect. Czech. Chem. Commun. 2006, Vol. 71, No. 1, pp. 59–76