β- and γ-amino acetals containing phosphine oxide groups. Synthesis and reactions with resorcinol derivatives

Article abstract of DOI:10.1134/S1070428014060025

New β- and γ-amino acetals containing phosphine oxide groups were synthesized by the Kabachnik-Fields reaction of β- and γ-amino acetals with paraformaldehyde and dialkylphosphine oxides. Heating of the resulting β- and γ-amino acetals with 2-methylresorc

Full text of DOI:10.1134/S1070428014060025

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2014, Vol. 50, No. 6, pp. 778–782. © Pleiades Publishing, Ltd., 2014.
Original Russian Text © L.I. Vagapova, L.R. Amirova, A.R. Burilov, A.R. Garifzyanov, M.A. Pudovik, Kh.E. Kharlampidi, 2014, published in Zhurnal
Organicheskoi Khimii, 2014, Vol. 50, No. 6, pp. 796–800.
Dedicated to Full Member of the Russian Academy of Sciences
O.N. Chupakhin on his 80th anniversary
β- and γ-Amino Acetals Containing Phosphine Oxide Groups.
Synthesis and Reactions with Resorcinol Derivatives
L. I. Vagapovaa, L. R. Amirovab, A. R. Burilova, A. R. Garifzyanovc,
M. A. Pudovika, and Kh. E. Kharlampidib
a Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Center, Russian Academy of Sciences,
ul. Arbuzova 8, Kazan, 420088 Tatarstan, Russia
e-mail: vagapoval@iopc.ru
b Kazan National Research Technological University, ul. Karla Marksa 68, Kazan, 420015 Tatarstan, Russia
c Kazan (Volga Region) Federal University, Kremlevskaya ul. 18, Kazan, 420008 Tatarstan, Russia
Received March 13, 2014
Abstract—New β- and γ-amino acetals containing phosphine oxide groups were synthesized by the Kabach-
nik−Fields reaction of β- and γ-amino acetals with paraformaldehyde and dialkylphosphine oxides. Heating of
the resulting β- and γ-amino acetals with 2-methylresorcinol and pyrogallol in boiling trifluoroacetic acid
afforded (dialkylphosphoryl)(ω,ω-diarylalkyl)ammonium trifluoromethanesulfonates.
DOI: 10.1134/S1070428014060025
Condensation of functionalized acetals with resor-
cinol and its derivatives in acidic medium provides
a general procedure for one-step synthesis of acyclic
and cyclic polyphenols, in particular calix[4]resorcin-
arenes [1], compounds of the diarylmethane series [2],
and heterocycles containing polyphenol fragments [3].
The results of numerous studies have shown that the
synthetic outcome of this reaction depends on the
conditions (acid and solvent nature), reactant structure,
and reactant ratio. For instance, α-amino acetals react
with resorcinol and its derivatives in ethanol in the
presence of aqueous HCl to give diarylmethane deriv-
atives [2], while unsubstituted β- and γ-amino acetals
under analogous conditions give rise to calix[4]resor-
cinarenes [3, 4].
acetals reacted with resorcinol and its derivatives in
ethanol to produce both ammonium salts of the diaryl-
methane series and 2,5-diaryl-1,4-bis(diethoxyphos-
phorylmethyl)piperazines. Dialkyl(2,2-dimethoxy-
ethylaminomethyl)phosphine oxides (Alk = C8H17,
C10H21) reacted with polyphenols on heating in boiling
trifluoroacetic acid with formation of only diaryl-
methane derivatives.
In the present work we tried to elucidate how the
structure of phosphorylated amino acetals (namely, the
length of the hydrocarbon chain connecting the acetal
group and nitrogen atom and substituents on the phos-
phorus atom) affects their reaction with 2-methyl-
resorcinol and pyrogallol. For this purpose, we have
synthesized for the first time β- and γ-amino acetals
containing phosphine oxide groups with alkyl substit-
uents of different lengths on the phosphorus atom.
Compounds IVa–IVc, Va, and Vc were obtained by
While continuing studies in this line, we synthe-
sized new α-amino acetals containing phosphonate and
phosphine oxide groups [5]. Phosphonate α-amino
Scheme 1.
R
OEt
R
P
OEt
PhH
H
+ (CH2O)n
+
P
O
H2N
R
N
–H2O
( )n
I, II
( )n
R
OEt
OEt
H
O
IIIa–IIIc
IVa–IVc, Va–Vc
R = C6H13 (a), C8H17 (b), C10H21 (c); I, IV, n = 2; II, V, n = 3.
778

β- AND γ-AMINO ACETALS CONTAINING PHOSPHINE OXIDE GROUPS.
779
Scheme 2.
O
P
R
OH
R
IVa, IVc, Va
CF3COOH, reflux
NH2
CF3COO–
R'
( )n
HO
OH
2
–2MeOH
R'
R'
OH
HO
OH
VIa, VIc, VII, VIII
VI, n = 2, R′ = Me, R = C6H13 (a), C10H23 (c); VII, R = C6H13, R′ = OH, n = 2; VIII, R = C6H13, R′ = Me, n = 3.
the Kabachnik–Fields reactions of 3,3-diethoxypropan-
1-amine (I) and 4,4-diethoxybutan-1-amine (II) with
dialkylphosphine oxides IIIa–IIIc and paraformalde-
hyde at a ratio of 1:1:1 in the presence of p-toluene-
sulfonic acid (Scheme 1). The structure of IVa–IVc,
Va, and Vc was determined on the basis of their IR,
1H and 31P NMR, and MALDI mass spectra and ele-
mental analyses.
(Scheme 2). The reaction of γ-amino acetal Va with
2-methylresorcinol followed the same path with forma-
tion of 43% of compound VIII.
Ammonium salts VIa, VIc, VII, and VIII were
isolated as white powders which were soluble in ace-
tone and DMSO (VIa, VIc, VIII) or only in DMSO
(VII). Their structure was proved by IR, 31P and
1H NMR, and MALDI mass spectra and elemental
analyses.
Compounds IVa–IVc, Va, and Vc displayed in the
31P NMR spectra only one phosphorus signal in the
region δP 46–47 ppm. The most informative signals in
Compounds VIa, VIc, VII, and VIII showed in the
1H NMR spectra doublets from protons in the benzene
rings at δ 6.28–6.42 (5-H) and 6.78–7.10 ppm (6-H),
a triplet from the CH proton at δ 4.51–5.1 ppm,
a doublet from the PCH2N methylene protons at
δ 3.48–3.61 ppm, and a triplet from the methylene
group attached to nitrogen at δ 2.88–3.14 ppm. The
downfield position of signals from the methylene
protons on the nitrogen atom as compared to the corre-
sponding signals of phosphorylated amino acetals IVa,
IVc, and Va (Δδ = 0.4–0.8 ppm), as well as IR absorp-
tion bands at 1674–1668 (C=O) and 2500–2600 cm–1
(NH+) indicated formation of ammonium trifluoro-
acetates.
1
their H NMR spectra were doublets from the PCH2N
methylene protons (δ 2.67–2.83 ppm), a triplet from
the NCH2 protons in the acetal fragment (δ 2.53–
2.63 ppm), a triplet from the acetal CH proton (δ 4.35–
4.49 ppm), and a multiplet from the OCH2 protons in
the ethoxy groups (δ 3.23–3.61 ppm).
Acetals IVa–IVc, Va, and Vc were brought into
condensation with 2-methylresorcinol and pyrogallol
in acidic medium. Phosphine oxide β-amino acetals
IVa and IVc failed to react with 2-methylresorcinol in
ethanol in the presence of HCl. The 31P NMR spectrum
of the reaction mixture, like the spectra of analogous
phosphine oxide α-amino acetals [5], contained signals
in the region δ 53–55 ppm, indicating concurrent
protonation of the P=O group and deactivation of the
acid catalyst (HCl).
By varying the reaction conditions, including sol-
vent (chloroform, benzene, toluene, dioxane) and acid
nature (trifluoroacetic acid, trifluoromethanesulfonic
acid) we found that the condensation occurred only on
heating in boiling trifluoroacetic acid. Amino phos-
phine oxides IVa and IVc reacted with 2-methylresor-
cinol and pyrogallol to afford diarylmethane deriva-
tives VIa, VIc, and VII in up to 28% yield, regardless
of the alkyl substituent on the phosphorus atom and
polyphenol nature. The yield of the condensation prod-
uct did not increase when the ratio amino acetal–
2-methylresorcinol was changed from 1:1 to 1:4
The presence in molecules VIa, VIc, VII, and VIII
of phenolic hydroxy groups and phosphorylmethyl-
ammonium fragments opens wide prospects for their
practical application, e.g., as lipophilic extractants of
metal ions from acidic medium [6] and multidentate
ligands [7]. Compounds of the diarylmethane series
offer a wide synthetic potential as intermediate prod-
ucts for the preparation of new macrocyclic com-
pounds, e.g., calix[4]resorcinarenes with alternating
substituents on the lower rim [8].
EXPERIMENTAL
1
The H and 13C NMR spectra were recorded on
a Bruker Avance-600 spectrometer at 600.1 and
150.9 MHz, respectively, using the residual proton and
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 50 No. 6 2014

VAGAPOVA et al.
780
carbon signals of deuterated solvents as reference. The
31P NMR spectra were measured on a Bruker Avance
II-400 instrument (161.9 MHz) relative to 85% H3PO4
(external). The IR spectra were recorded in the range
from 4000 to 400 cm–1 on a Bruker Vector-22 spec-
trometer. The mass spectra (MALDI-TOF) were ob-
tained on a Bruker Ultraflex III spectrometer using
plastic and metal targets and 2,5-dihydroxybenzoic
acid as matrix.
spectrum, m/z: 434 [M + H]+, 456 [M + Na]+, 473 [M +
K]+. Found, %: C 66.34; H 12.08; N 3.19; P 6.99;
C24H52NO3P. Calculated, %: C 66.51; H 12.00; N 3.20;
P 7.10.
Didecyl(3,3-diethoxypropylaminomethyl)phos-
phine oxide (IVc) was synthesized from 1.50 g
(4.55 mmol) of didecylphosphine oxide (IIIc), 0.83 g
(5.64 mmol) of compound I, and 0.16 g of paraformal-
dehyde in the presence of 16.60 mg of p-toluenesul-
fonic acid. Yield 1.89 g (82%). IR spectrum, ν, cm–1:
3436 br (NH), 1220 m (P=O), 1123 w (COC).
1H NMR spectrum (CDCl3), δ, ppm: 0.66 t (6H, CH3,
J = 7.0 Hz), 0.98 t (6H, OCH2CH3, J = 7.1 Hz), 1.03–
1.19 m (28H, CH2), 1.32–1.39 m (4H, PCH2CH2),
1.47–1.51 m (4H, PCH2), 1.53–1.60 m (2H, CHCH2),
2.53 t (2H, NCH2, J = 6.7 Hz), 2.67 d (2H, PCH2N, J =
8.2 Hz), 3.23–3.46 m (4H, OCH2), 4.38 t (1H, CH, J =
5.5 Hz). 31P NMR spectrum (CDCl3): δP 47.36 ppm.
Mass spectrum, m/z: 490 [M + H]+. Found, %:
C 68.64; H 12.28; N 2.90; P 6.36. C28H60NO3P. Calcu-
lated, %: C 68.71; H 12.27; N 2.86; P 6.34.
Dihexyl(3,3-diethoxypropylaminomethyl)phos-
phine oxide (IVa). A mixture of 1.50 g (6.88 mmol) of
dihexylphosphine oxide (IIIa), 1.04 g (7.07 mmol) of
3,3-diethoxypropan-1-amine (I), 0.21 g of paraformal-
dehyde, and 21 mg of p-toluenesulfonic acid in 20 mL
of benzene was heated for 4 h under reflux in a flask
equipped with a Dean−Stark trap. When the reaction
was complete, 85 mg of potassium carbonate was
added, the mixture was heated for 10 min under reflux
and cooled, and the precipitate was filtered off. The
organic layer was washed with three portions of water
and dried over MgSO4, and the solvent was distilled
off. Yield 2 g (75%). IR spectrum, ν, cm–1: 3438 br
Dihexyl(4,4-diethoxybutylaminomethyl)phos-
phine oxide (Va) was synthesized from 2 g
(9.17 mmol) of dihexylphosphine oxide (IIIa), 1.48 g
(9.19 mmol) of 4,4-diethoxybutan-1-amine (II), and
0.28 g of paraformaldehyde in the presence of 30 mg
of p-toluenesulfonic acid. Yield 2.9 g (81%). IR spec-
trum, ν, cm–1: 3436 br (NH), 1151 m (P=O), 1126 w
1
(NH), 1151 m (P=O), 1125 w (COC). H NMR spec-
trum (CDCl3), δ, ppm: 0.79 t (6H, CH3, J = 7.0 Hz),
1.10 t (6H, OCH2CH3, J = 7.1 Hz), 1.18–1.31 m (12H,
CH2), 1.45–1.51 m (4H, CH2), 1.59–1.61 m (2H,
CHCH2), 1.62–1.72 m (4H, PCH2), 2.65 t (2H, NCH2,
J = 6.8 Hz), 2.79 d (2H, PCH2N, J = 8.3 Hz), 3.36–
3.59 m (4H, OCH2), 4.49 t (1H, CH, J = 5.6 Hz).
31P NMR spectrum (CDCl3): δP 47.41 ppm. Mass spec-
trum, m/z: 378 [M + H]+, 400 [M + Na]+, 416 [M + K]+.
Found, %: C 63.47; H 11.69; N 3.79; P 8.13.
C20H44NO3P. Calculated, %: C 63.66; H 11.67;
N 3.71; P 8.22.
1
(COC). H NMR spectrum (CDCl3), δ, ppm: 0.76 t
(6H, CH3, J = 7.0 Hz), 1.07 t (6H, OCH2CH3, J =
7.1 Hz), 1.15–1.28 m (16H, CH2), 1.41–1.53 m (4H,
CHCH2), 1.56–1.62 m (4H, PCH2CH2), 2.55 t (2H,
NCH2, J = 6.9 Hz), 2.75 d (2H, PCH2N, J = 8.1 Hz),
3.32–3.54 m (4H, OCH2), 4.35 t (1H, CH, J = 5.6 Hz).
31P NMR spectrum (CDCl3): δP 47.33 ppm. Mass spec-
trum, m/z: 414 [M + Na]+, 430 [M + K]+. Found, %:
C 64.11; H 11.88; N 3.44; P 8.02. C21H46NO3P. Cal-
culated, %: C 64.45; H 11.76; N 3.58; P 7.93.
Compounds IVb, IVc, Va, and Vc were synthe-
sized in a similar way.
(3,3-Diethoxypropylaminomethyl)dioctylphos-
phine oxide (IVb) was synthesized from 1.50 g
(5.47 mmol) of dioctylphosphine oxide (IIIb), 0.83 g
(5.64 mmol) of compound I, and 0.17 g of paraformal-
dehyde in the presence of 16.6 mg of p-toluenesulfonic
acid. Yield 1.6 g (68%). IR spectrum, ν, cm–1: 3283 br
Didecyl(4,4-diethoxybutylaminomethyl)phos-
phine oxide (Vc) was synthesized from 1.5 g
(4.55 mmol) of didecylphosphine oxide (IIIc), 0.73 g
(4.53 mmol) of amino acetal II, and 0.14 g of para-
formaldehyde in the presence of 15 mg of p-toluene-
sulfonic acid. Yield 2.0 g (88%). IR spectrum, ν, cm–1:
3277 br (NH), 1143 m (P=O), 1125 w (COC).
1H NMR spectrum (CDCl3), δ, ppm: 0.82 t (6H, CH3,
J = 6.9 Hz), 1.14 t (6H, OCH2CH3, J = 7.1 Hz), 1.20–
1.35 m (28H, CH2), 1.45–1.53 m (4H, PCH2CH2),
1.55–1.62 m (4H, CHCH2), 1.63–1.72 m (4H, PCH2),
2.63 t (2H, NCH2, J = 6.9 Hz), 2.83 d (2H, PCH2N, J =
1
(NH), 1222 m (P=O), 1125 w (COC). H NMR spec-
trum (CDCl3), δ, ppm: 0.76 t (6H, CH3, J = 7.0 Hz),
1.07 t (6H, OCH2CH3, J = 7.1 Hz), 1.15–1.28 m (20H,
CH2), 1.41–1.49 m (4H, PCH2CH2), 1.56–1.62 m (4H,
PCH2), 1.64–1.69 m (2H, CHCH2), 2.62 t (2H, NCH2,
J = 6.7 Hz), 2.76 d (2H, PCH2N, J = 8.17 Hz), 3.33–
3.56 m (4H, OCH2), 4.47 t (1H, CH, J = 5.5 Hz).
31P NMR spectrum (CDCl3): δP 47.46 ppm. Mass
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β- AND γ-AMINO ACETALS CONTAINING PHOSPHINE OXIDE GROUPS.
781
8.0 Hz), 3.39–3.61 m (4H, OCH2), 4.42 t (1H, CH, J =
5.5 Hz). 31P NMR spectrum (CDCl3): δP 47.40 ppm.
Mass spectrum, m/z: 504 [M + H]+. Found, %:
C 69.02; H 12.38; N 2.76; P 6.24. C29H62NO3P. Cal-
culated, %: C 69.18; H 12.33; N 2.78; P 6.16.
(VII) was synthesized from 0.50 g (1.33 mmol) of
compound IVa and 0.42 g (3.33 mmol) of pyrogallol in
2 mL of trifluoroacetic acid. The residue was washed
with acetone. Yield 0.27 g (31%), mp 197°C. IR spec-
trum, ν, cm–1: 3421 br (OH), 2550 br (NH+), 1672 s
1
(C=O), 1630 m (C=Carom), 1202 m (P=O). H NMR
N-(Dihexylphosphorylmethyl)-3,3-bis(2,4-dihy-
droxy-3-methylphenyl)propan-1-aminium trifluoro-
acetate (VIa). A mixture of 0.5 g (1.33 mmol) of
compound IVa and 0.41 g (3.31 mmol) of 2-methyl-
resorcinol in 2 mL of trifluoroacetic acid was heated
for 4 h under reflux. When the reaction was complete,
trifluoroacetic acid was removed under reduced pres-
sure (water-jet pump), and the oily residue was either
ground or washed with diethyl ether. The precipitate
was filtered off and dried under reduced pressure (oil
pump). Yield 0.24 g (28%), mp 186°C. IR spectrum, ν,
cm–1: 3403 br (OH), 2652 br (NH+), 1674 s (C=O),
spectrum (DMSO-d6), δ, ppm: 0.88 t (6H, CH3, J =
6.8 Hz), 1.32–1.47 m (16H, CH2), 1.75–1.84 m (4H,
PCH2), 2.16–2.18 m (2H, CHCH2), 2.88 t (2H, NCH2,
J = 7.9 Hz), 3.56 d (2H, PCH2N, J = 6.3 Hz), 4.42 t
(1H, CH, J = 7.6 Hz), 6.23 d (2H, 5′-H, J = 8.4 Hz),
6.37 d (2H, 6′-H, J = 8.4 Hz). 31P NMR spectrum
(DMSO-d6): δP 47.10 ppm. Mass spectrum, m/z: 538
[M – CF3COOH + H]+. Found, %: C 55.21; H 6.79;
N 2.20; P 4.81. C28H44NO7P·CF3COOH. Calculated,
%: C 55.30; H 6.91; N 2.15; P 4.76.
N-(Dihexylphosphorylmethyl)-4,4-bis(2,4-dihy-
droxy-3-methylphenyl)butan-1-aminium trifluoro-
acetate (VIII) was synthesized from 0.30 g
(0.77 mmol) of compound Va and 0.25 g (2.02 mmol)
of 2-methylresorcinol. Yield 0.22 g (43%), mp 118°C.
IR spectrum, ν, cm–1: 3439 br (OH), 2497 br (NH+),
1667 s (C=O), 1620 m (C=Carom), 1143 m (P=O).
1H NMR spectrum (acetone-d6), δ, ppm: 0.90 t (6H,
CH3, J = 6.7 Hz), 1.33–1.54 m (4H, PCH2), 1.96–
2.00 m (16H, CH2), 1.99 s (6H, 3′-CH3), 2.09–2.14 m
(2H, NCH2CH2), 3.25 t (2H, NCH2, J = 7.7 Hz), 3.56 d
(2H, PCH2N, J = 6.3 Hz), 4.45 t (1H, CH, J = 7.7 Hz),
6.44 d (2H, 5′-H, J = 8.4 Hz), 6.90 d (2H, 6′-H, J =
8.4 Hz). 31P NMR spectrum (acetone-d6): δP 47.00 ppm.
Mass spectrum, m/z: 548 [M – CF3COOH + H]+, 570
[M – CF3COOH + Na]+, 586 [M – CF3COOH + K]+.
Found, %: C 59.71; H 7.47; N 2.18; P 4.76.
C31H50NO3P·CF3COOH. Calculated, %: C 59.90;
H 7.71; N 2.12; P 4.69.
1
1608 m (C=Carom), 1183 m (P=O). H NMR spectrum
(acetone-d6), δ, ppm: 0.91 t (6H, CH3, J = 6.8 Hz),
1.31–1.65 m (16H, CH2), 2.08–2.13 m (4H, PCH2),
2.16 s (6H, 3′-CH3), 2.57 m (2H, CHCH2), 3.14 t (2H,
NCH2, J = 7.5 Hz), 3.61 d (2H, PCH2N, J 6.4 = Hz),
4.61 t (1H, CH, J = 8.0 Hz), 6.47 d (2H, 5′-H, J =
8.4 Hz), 6.82 d (2H, 6′-H, J = 8.4 Hz). 31P NMR spec-
trum (acetone-d6): δP 46.92 ppm. Mass spectrum, m/z:
534 [M – CF3COOH + H]+, 556 [M – CF3COOH +
Na]+, 572 [M – CF3COOH + K]+. Found, %: C 59.23;
H 7.54; N 2.15; P 4.66. C30H48NO5P·CF3COOH. Cal-
culated, %: C 59.35; H 7.57; N 2.16; P 4.79.
Compounds VIc, VII, and VIII were synthesized in
a similar way.
N-(Didecylphosphorylmethyl)-3,3-bis(2,4-dihy-
droxy-3-methylphenyl)propan-1-aminium trifluoro-
acetate (VIc) was synthesized from 0.50 g
(1.02 mmol) of compound IVc and 0.31 g (2.55 mmol)
of 2-methylresorcinol. Yield 0.21 g (27%), mp 190°C.
IR spectrum, ν, cm–1: 3386 br (OH), 2614 br (NH+),
1610 m (C=Carom), 1670 s (C=O), 1182 m (P=O).
1H NMR spectrum (acetone-d6), δ, ppm: 0.84 t (6H,
CH3, J = 6.8 Hz), 1.99–2.04 m (4H, PCH2), 2.07 s (6H,
3′-CH3), 1.24–1.59 (32H, CH2), 2.42 m (2H, CHCH2),
3.19 t (2H, NCH2, J = 7.6 Hz), 3.64 d (2H, PCH2N, J =
6.4 Hz), 4.55 t (1H, CH, J = 7.7 Hz), 6.35 d (2H, 5′-H,
J = 8.3 Hz), 6.51 d (2H, 6′-H, J = 8.4 Hz). 31P NMR
spectrum (acetone-d6): δP 47.17 ppm. Mass spectrum,
m/z: 646 [M – CF3COOH + H]+. Found, %: C 63.12;
H 8.59; N 1.99; P 4.11. C38H64NO5P·CF3COOH. Cal-
culated, %: C 63.24; H 8.56; N 1.84; P 4.08.
This study was performed under financial support
by the Ministry of Education and Science of the
Russian Federation in the framework of the base part
of PNIL 02.14 and by the Russian Foundation for
Basic Research (project no. 14-03-00191-a).
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