Improved synthesis of 1-aminoethylidenediphosphonic acid

Full text of DOI:10.1134/S107036320610029X

ISSN 1070-3632, Russian Journal of General Chemistry, 2006, Vol. 76, No. 10, pp. 1673 1674.
Pleiades Publishing, Inc., 2006.
Original Russian Text L.V. Kaabak, N.E. Kuz’mina, A.V. Khudenko, A.P.Tomilov, 2006, published in Zhurnal Obshchei Khimii, 2006, Vol. 76, No. 10,
pp. 1745 1746.
LETTERS
TO THE EDITOR
Improved Synthesis of 1-Aminoethylidenediphosphonic Acid
L. V. Kaabak, N. E. Kuz’mina, A. V. Khudenko, and A. P. Tomilov
State Research Institute of Organic Chemistry and Technology,
sh. Entuziastov 23, Moscow, 111024 Russia
Received May 5, 2006
DOI: 10.1134/S107036320610029X
Aminoalkylidenediphosphonic acids are used as
selective chelation agents, surfactants, corrosion
inhibitors, and compounds preventing calcium car-
bonate precipitation from salt solutions.
In more recent patents [4, 5], the reaction of nitriles
with phosphorous acid to obtain 1-aminoalkylidene-
diphosphonic acid was considered to require heating
above 100 C.
Comparing the two methods of synthesis of com-
pound I [1, 4, 5] we suggested that the reactive
species in the PBr3 acetonitrile system is phosphorous
acid P(OH)3 formed by the reaction of PBr3 with the
hydroxylcontaining compound [PBr3 + 3CH3COOH =
P(OH)3 + 3CH3COBr], rather than its four-coordi-
nate phosphorus form (HO)2P(O)H. Hydrogen halides
formed by side reactions of phosphorus trihalides with
hydroxyl-containing compounds [6, 7] activates nit-
riles by converting them to a series of products [8 10].
Therefore, we considered it promising to prepare
compound I under mild conditions, using available
commercial phosphorus trichloride, by the following
scheme.
1-Aminoethylidenediphosphonic acid was first
prepared in 50% yield by the reaction of acetonitrile
with phosphorus tribromide in presence of acetic or
phosphorous acid and subsequent treatment of the re-
action mixture with water [1]. With water instead of
acetic or phosphorous acid, the yield of the target
product was no more than 8% [1]. However, later
[2, 3] the reaction of nitriles with phosphorus trichlo-
ride and water was reported as the principal synthetic
route to 1-aminoalkylidenediphosphonic acid. There-
with, Purdela and Vilceanu [3] referred precisely to
[1], where the reaction with phosphorus trichloride is
not presented at all.
PCl3 + 3H2O
P(OH)3 + 3HCl,
OH
HO P+ OH
OH
HCl
P(OH)3, HCl
H3C C N
[CH3 C NH]+Cl
Cl
HO P=O
HCl
CH3 C=NH
CH3 C=NH
OH
OH
HO P=O
CH3 C=NH2
Cl
OH
HO P=O
HO P=O
P(OH)3
HCl
Cl
CH3 C=NH2
CH3 C=NH2
HO P+ OH
OH
HCl
HO P=O
OH
I
1673

1674
KAABAK et al.
This scheme agrees with our data: Acetonitrile does
The IR spectra were registered on a Nicolet Avatar-
360 spectrometer. The 1H, 13C, and 31P NMR
spectra were taken on a Bruker Avance-300 spectro-
not react with PCl3 even under reflux and with
(HO)2P(O)H at room temperature and in the presence
of HCl. By the rate of permanganate discoloration and
31P NMR spectroscopy we established that phos-
phorous acid obtained by PCl3 hydrolysis already after
4 5 min exists exclusively in the form of (HO)2P(O)H
1
meter (300 MHz for H, 75.476 MHz for 13C, and
121.50 MHz for 31P) in D2O against internal TMS
(1H, 13C) and H3PO4.
1
[31P (D2O), P, ppm: 5.80; JPH 692.0 Hz]. The ex-
REFERENCES
perimental data gave evidence for our suggestion. The
synthesis of compound I from PCl3 under mild
conditions is presented below.
1. FRG Patent 1002355, 1954, Chem. Abstr., 1959,
21814c.
2. Nifant’ev, E.E., Khimiya fosfororganicheskikh soedi-
nenii (Chemistry of Organophosphorus Compounds),
Moscow: Mosk. Gos. Univ., 1971.
1-Aminoethylidenediphosphonic acid. To a solu-
tion of 10 ml of PCl3 in 70 ml of acetonitrile, 6.2 ml
of water was added with vigorous stirring and cooling
with ice. The temperature of the reaction mixture was
maintained between 5 and 20 C. After vigorous 3-h
stirring at 15 20 C, the reaction mixture with an
abundant colorless precipitate was left overnight. On
the next day it was filtered off on a glass frit and
washed with dry methanol to obtain 13.77 g (63.6%)
of compound I, mp 273 276 C (decomp.). Published
data [1]: mp 277 C (decomp.). The molecule of com-
pound I probably contains ionic bonds between the
acid hydroxyls and amino group, which ensures such
3. Purdela, D. and Vilceanu, R., Chimia Compulsor
Organici ai Fosforului si ai Acizilor lui, Bucharest:
Acad. Rep. Soc. Romania, 1965.
4. FRG Patent 2754821 (1979), Ref. Zh. Khim., 1980,
6N105P.
5. US Patent 4239695, 1980, Ref. Zh. Khim., 1981,
16N90P.
6. Preparativnaya organicheskaya khimiya (Preparative
Organic Chemistry), Moscow: GosNTIKhimLit, 1959.
1
7. Weygand Hilgetag Organisch-chemische Experi-
mentierkunst, Hilgetag, G. and Martini, A., Eds.,
Leipzig: Barth, 1964, 3rd ed.
a high melting point. IR spectrum, , cm : 1538.41;
1
1601.05; 3234.15; 3438.33 (primary NH). H NMR
3
spectrum, , ppm: 1.58 t (3H, JPH 13.4 Hz). 13C
1
NMR spectrum, C, ppm: 51.26 t (C1, JCP 131.8 Hz);
8. Orlovskii, V.V. and Vovsi, B.A., Zh. Obshch. Khim.,
2
15.18 t (C2, JPC 3.0 Hz). 31P NMR spectrum,
,
1976, vol. 46, no. 2, p. 297.
P
ppm: 13.36 q (3JPH 13.4 Hz). Found, %: C 11.78; H
4.34; N 6.85; P 29.47. C2H9NO6P2. Calculated, %:
C 11.71; H 4.42; N 6.82; P 30.21.
9. Zilberman, E.N., Usp, Khim., 1962, vol. 31, p. 1309.
10. Zilberman, E.N., Reaktsii nitrilov (Nitrile Reac-
tions), Moscow: Khimiya, 1972.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 76 No. 10 2006