Unusual reaction of enhydrazines with oxalyl chloride

Full text of DOI:10.1023/A:1011625126078

Chemistry of Heterocyclic Compounds, Vol. 37, No. 5, 2001
UNUSUAL REACTION OF ENHYDRAZINES
WITH OXALYL CHLORIDE
N. A. Konykhova, O. P. Krasnykh, and A. N. Maslivets
Keywords: enhydrazine, 1,6-dihydro-6-pyridazinone, 2,3-dihydro-2,3-pyrroledione, oxalyl chloride.
The reaction of primary enamines with oxalyl chloride is the most widely used method for synthesis of
substituted 2,3-dihydro-2,3-pyrrolediones [1]. Starting with enhydrazines (substituted N-methyl-N-phenyl- and
N,N-diphenyl-N'-vinylhydrazines), this method enables to obtain the corresponding substituted
1-methyl(phenyl)amino- and 1-diphenylamino-2,3-dihydro-2,3-pyrrolediones in practically quantitative yields
[2,3]; there have been no reports concerning isolation and identification of other products.
When methyl esters of 4-aryl-2-diarylmethylenehydrazino-4-oxo-2-butenoic acids 1a,b react with oxalyl
chloride, in addition to the expected 4-aroyl-1-diarylmethyleneamino-5-methoxycarbonyl-2,3-dihydro-2,3-
pyrrolediones 2a,b, the minor products 4-aroyl-5-hydroxy-3-methoxycarbonyl-1,6-dihydro-6-pyridazinones 3a,b
are formed. Compound 3b was identified by comparison with a known sample whose structure was confirmed
by X-ray diffraction [4].
When the methyl ester of 4-p-chlorophenyl-2-[methyl(p-ethoxyphenyl)methylene]hydrazino-4-oxo-2-
butenoic acid (1c) reacts with oxalyl chloride, instead of the expected 4-p-chlorobenzoyl-5-methoxycarbonyl-1-
[methyl(p-ethoxyphenyl)methylene]amino-2,3-dihydro-2,3-pyrroledione (2c) and 4-p-chlorobenzoyl-5-hydroxy-
3-methoxycarbonyl-1,6-dihydro-6-pyridazinone
(3c),
the
compound
3-p-ethoxyphenyl-5-hydroxy-1-
[methoxycarbonyl(p-chlorophenacylidene)methyl]-1,6-dihydro-6-pyridazinone (5) is formed.
Ar1COC
Ar1COCH CCOOMe
NH
CCOOMe
NH
Ar1CO
O
O
A
–HCl
(COCl)2
R = Ph
CO
COCl
Ph
R
MeOOC
N
N
N
N
C
C
Ar2
Ar2
Ph
O
1a–c
4
C
R = Me
–2HCl
(COCl)2
Ar2
OH
B
2a–c
Ar1CO
COOMe
p-EtOC6H4
Ar1CO
OH
C
C
H2O
O
NH
_
N
NH
–HCl
N
O
+
N
Cl
MeOOC
N
–PhCOAr2
Ph
Ar2
O
C
p-ClC6H4COCH
COOMe
3a–c
5
1-3 a Ar1 = p-MeC6H4, Ar2 = Ph; b Ar1 = Ph, Ar2 = p-MeOC6H4
c Ar1 = p-ClC6H4, Ar2 = p-EtOC6H4
__________________________________________________________________________________________
Perm State University, Perm 614000, Russia; e-mail: info@psu.ru. Translated from Khimiya
Geterotsiklicheskikh Soedinenii, No. 5, pp. 700-702, May, 2001. Original article submitted February 3, 2001.
0009-3122/01/3705-0647$25.00©2001 Plenum Publishing Corporation
647

Probably the -C acid chlorides (4a,b) formed in the first step of the reaction of enhydrazines 1a,b with
β
oxalyl chloride are capable to intramolecular cyclization, with acylation of the secondary amino group and
closure of the pyrroledione ring (pathway A) or with acylation (possibly reversible) of the nitrogen atom of the
azomethine group and closure of the pyridazinone ring (pathway B), followed by hydrolytic cleavage of the
diaryl ketone. Taking special precautions to decrease the water content in the reaction mass makes it possible to
reduce the yield of pyridazinones 3a,b to practically zero.
In contrast to the above, when enhydrazine 1c reacts with oxalyl chloride, acylation of the methyl and
amino group of the methyl(aroyl)methylenehydrazine moiety occurs.
p
5-Methoxycarbonyl-1-diphenylmethyleneamino-4- -toluoyl-2,3-dihydro-2,3-pyrroledione (2a) and
p
A solution of oxalyl chloride
5-Hydroxy-3-methoxycarbonyl-4- -toluoyl-1,6-dihydro-6-pyridazinone (3a).
(0.47 ml, 5.5 mmol) in absolute chloroform (2 ml) was added to a solution of ester 1a (2.00 g, 5.2 mmol) in
absolute chloroform (3 ml). This was refluxed for 100 min and cooled. The precipitate of compound 2a was
filtered off. Yield 1.36 g (60%); mp 144-146°C (hexane). IR spectrum (vaseline oil), , cm-1: 1740 (C(2)=O,
ν
1
COOMe), 1725 (C(3)=O), 1630 (C(4)–C=O). H NMR spectrum (250 MHz, DMSO-d6), , ppm: 2.29 (3H, s,
δ
CH3); 3.80 (3H, s, CH3O); 7.00-7.79 (14H, m, 2C6H5+C6H4). Compound 2a. Found, %: C 71.68; H 4.41;
N 6.20. C27H20N2O5. Calculated, %: C 71.67; H 4.46; N 6.19.
Compound 3a. 3 ml of solvent was distilled off from the mother liquor and cooled. The precipitate was
filtered off. Yield 0.21 g (14%); mp 267-269°C (hexane). IR spectrum (vaseline oil), , cm-1: 3260 (OH), 3170
ν
(NH), 1670 (C(6)=O). 1H NMR spectrum (250 MHz, DMSO-d6), , ppm, J (Hz): 2.44 (3H, s, CH3); 3.70 (3H, s,
δ
CH3O); 7.30 (2H, d, 8.0, 2CH(m)); 7.67 (2H, d, 8.0, 2CH(o)); 13.60 (1H, s, OH). Found, %: C 58.34; H 4.21;
N 9.74. C14H12N2O5. Calculated, %: C 58.33; H 4.20; N 9.72.
p
4-Benzoyl-5-methoxycarbonyl- -methoxyphenylmethyleneamino-1-phenyl-2,3-dihydro-2,3-pyrrole-
dione 2b and 4-Benzoyl-5-hydroxy-3-methoxycarbonyl-1,6-dihydro-6-pyridazinone 3b were synthesized similarly.
Compound 2b, yield 57%; mp 145-147°C (hexane). IR spectrum (vaseline oil), , cm-1: 1735 (C(2)=O,
ν
COOMe), 1715 (C(3)=O), 1660 (C(4)–C=O). 1H NMR spectrum (250 MHz, DMSO-d6, δ, ppm, J (Hz)): 3.75 (6H,
s, MeO+COOMe); 7.03-8.88 (14H, m, 2C6H5+C6H4). Found, %: C 69.21; H 4.29; N 5.99. C27H20N2O6.
Calculated, %: C 69.23; H 4.30; N 9.98.
Compound 3b, yield 18%; mp 264-266°C (acetonitrile). Lit. mp 265-267°C [4]. Found, %: C 56.96;
H 3.70; N 10.22. C13H10N2O5. Calculated, %: C 56.94; H 3.68; N 10.22.
p
p
3- -Ethoxyphenyl-5-hydroxy-1-[methoxycarbonyl( -chlorophenacylidene)methyl]-1,6-dihydro-6-
pyridazinone (5). A solution of oxalyl chloride (0.23 ml, 2.7 mmol) in absolute benzene (2 ml) was added to a
solution of ester 1c (1.00 g, 2.6 mmol) in absolute benzene (7 ml). This mixture was refluxed for 40 min and
cooled, then the precipitate of compound 5 was filtered off. Yield 0.62 g (53%); mp 228-230°C (chloroform). IR
spectrum (vaseline oil), , cm-1: 3250 (OH), 1730 (COOMe), 1685 (C(6)=O), 1640 (COC6H4Cl-p). H NMR
1
ν
spectrum (250 MHz, DMSO-d6, δ, ppm, J (Hz)): 1.36 (3H, t, 6.9, CH3); 3.67 (3H, s, CH3O); 4.05 (2H, q, 6.9,
CH2O); 5.49 (1H, s, CH); 6.00 (1H, s, CH); 6.91 (2H, d, 7.5, 2CH(m) in C6H4OC2H5-p); 7.32 (2H, d, 7.5,
2CH(o) in C6H4OC2H5-p); 7.60 (2H, d, 9.0, 2CH(m) in C6H4Cl-p); 7.94 (2H, d, 9.0, 2CH(o) in C6H4Cl-p).
Found, %: C 60.75; H 4.23; N 6.18; Cl 7.80. C23H19ClN2O6. Calculated, %: C 60.73; H 4.21; N 6.16; Cl 7.79.
This research was done with the financial support of the Russian Foundation for Basic Research (grant
01-03-32641).
REFERENCES
1.
A. N. Maslivets and Yu. S. Andreichikov, in: The Chemistry of Five-Membered 2,3-Dioxoheterocycles
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4.
G. Kollenz, Monatsh. Chem., 109, 249 (1978).
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