ISSN 0012-5008, Doklady Chemistry, 2006, Vol. 409, Part 2, pp. 129–132. © Pleiades Publishing, Inc., 2006.
Original Russian Text © T.V. Baulina, I.B. Goryunova, P.V. Petrovskii, E.I. Matrosov, E.I. Goryunov, E.E. Nifant’ev, 2006, published in Doklady Akademii Nauk, 2006, Vol. 409,
No. 4, pp. 486–490.
CHEMISTRY
One-Pot Synthesis of N-Diphenylphosphorylureas
T. V. Baulina, I. B. Goryunova, P. V. Petrovskii, E. I. Matrosov, E. I. Goryunov,
and Corresponding Member of the RAS E. E. Nifant’ev
Received March 29, 2006
DOI: 10.1134/S0012500806080015
Recently, we found that N-diphenylphosphoryl-N'-
SO2Cl2, 20–25°C
Ph2PCl
(IV)
[Ph2P(O)Cl]
alkyl(C6–C10)ureas Ph2P(O)NHC(O)NHCnH2n + 1 (Ia–
Ie: (a) n = 6, (b) n = 7, (c) n = 8, (d) n = 9, (e) n = 10)
are highly efficient extractants capable of extracting
uranium(VI), americium(III), and europium(III) from
acidic radioactive solutions, the N'-octyl derivative (Ic)
being the most active [1, 2]. These ureas were prepared
using the reaction of primary n-alkylamines with diphe-
nylphosphoryl isocyanate Ph2P(O)NCO (II), which
was, in turn, synthesized from diphenylphosphinic
chloride Ph2P(O)Cl (III) and sodium cyanate NaOCN
CCl4
(III)
NaOCN, [MgCl2], 20–25°C
[Ph2P(O)NCO]
MeCN
(II)
1. n-C8H17NH2, 20–25°C; 2. H2O
Ph2P(O)NHC(O)NHC8H17-n
(Ic)
Scheme 1.
1
in the presence of anhydrous magnesium chloride [3].
The first step is the oxidation of chlorophosphine IV
with sulfuryl chloride in carbon tetrachloride at room
temperature to give phosphinic chloride III in an
almost quantitative yield (99.8%, 31P NMR data). To
isolate this product, it is sufficient to remove the solvent
and other volatile components of the reaction mixture
in vacuo. Then anhydrous acetonitrile as the solvent,
anhydrous magnesium chloride (2.5 mol %) as the cat-
alyst, and sodium cyanate are added successively into
the same reactor. After 1 h of stirring at room tempera-
ture, the reaction is over to give phosphoryl isocyanate
II in a nearly quantitative yield (97.8%, 31P NMR data);
the product does not require further purification. After
completion of the process, an equimolar amount of n-
octylamine is added to the reaction mixture obtained at
the previous step and containing isocyanate II in aceto-
nitrile. After stirring for 1 h at room temperature, the
reaction mixture is quenched with water and the precip-
itated N-diphenylphosphoryl-N'-n-octylurea Ic is fil-
tered off, washed, and dried in air. The yield of the final
product containing almost no impurities reached ~98%.
However, despite the relatively high yields of phospho-
rylureas in the reaction, the efficiency and practicability
of the whole two-step process markedly decreases due
to the need to isolate phosphoryl isocyanate II in a pure
2
state. In addition, the starting organophosphorus com-
pound used in the two-step procedure, phosphinic chlo-
ride III, is rather expensive, which increases the cost of
the target diphenylphosphorylureas I.
In order to optimize the synthesis of N-diphe-
nylphosphoryl-N'-alkylureas, we developed, using
compound Ic as an example, a simple and highly effi-
cient one-pot method for the preparation of products of
this type in which cheaper and more readily available
diphenylchlorophosphine (IV) was used as the starting
organophosphorus compound (see Scheme 1).
1
Previously, a similar approach has been used to prepare N-diphe-
nylphosphoryl-N'-n-alkyl(C –C )ureas and a number of other
3
5
N-diphenylphosphorylureas; however, the starting isocyanate II
was prepared by the reaction of phosphinic chloride III with
much more expensive silver cyanate [4].
2
31
According to P NMR data, the content of isocyanate II in
It was found that the one-pot method is general and
can be successfully used for the preparation of other
types of N-diphenylphosphorylureas (see Scheme 2).
The starting amines may be primary ω-alkoxyalkyl-
amines, ω-dialkylaminoalkylamines, alkenylamines,
cycloalkylamines, arylamines, ω-arylalkylamines, sec-
ondary symmetrical and asymmetrical dialkylamines,
and primary and secondary heterocyclic amines.
the reaction mixture reached 98% but due to the inevitable
loss during isolation the product yield sharply decreased,
being only 78% [3].
Nesmeyanov Institute of Organoelement Compounds,
Russian Academy of Sciences, ul. Vavilova 28, Moscow,
119991 Russia
129