158
SVINTSITSKAYA et al.
field and with a smaller JHP constant is observed at
4.63 ppm (JHP 7.4 Hz). According to the INDOR ex-
periment, this new doublet corresponds to the phos-
Thus, the reaction of chloroethynylphosphonate
with 1,2,3,4-tetrahydroquinoline is not strictly chemo-
selective and should be studied in mode detail to solve
the problem of fast binding the evolved HCl.
phorus resonance at
25 ppm, which implies
P
It was found that the reaction of dimethyl chloro-
ethynylphosphonate with secondary amines, such as
1,2,3,4-tetrahydroquinoline (pKa 5.00), N-methylani-
line (pKa 4.85), and N-benzylaniniline (pKa 3.92), in
the presence of anhydrous potassium carbonate (HCl
acceptor) at an equimolar reagent ratio in a polar sol-
vent (anhydrous acetonitrile) results in quantitative
formation of phosphorylated ynamines Ia Ic.
formation of a 2,2-bis-aminated vinylphosphonate via
reaction of excess amine with the phosphorylated
ynamine. Knowing that addition of secondary amines
to aminoethynylphosphonates readily occurs in the
presence of acid catalysts [5, 6], we can suggest that
the latter reaction is catalyzed by the formed HCl or
amine hydrochloride.
K2CO3,
P C CCl + HNRR
CH3CN
P C CNRR + KCl + KHCO3,
Ia Ic
N
CH2C6H5
C6H5
CH3
(b), N
(c).
(a), N
P
NRR :
: (CH3O)2P
O
C6H5
After reaction completion, the inorganic salts were
filtered off, and the solvent was removed in a vacuum.
Since ynamines readily add water to form amides [5],
the formed ynamines were not isolated and immedia-
tely introduced in further syntheses. Nevertheless, the
purity and quantitative formation of compounds Ia Ic
solved in acetonitrile was immediately brought in
further transformations.
Dimethyl (1,2,3,4-tetrahydroqunolyl)ethynyl-
phosphonate (Ia). 1H NMR spectrum, , ppm
2
3
(CDCl3): 1.90 q (2H, CH2), 2.67 t (2H, CH2), 3.63 t
(2H, NCH2), 3.69 d (6H, CH3O, 3JHP 12.5 Hz), 6.81 t
(1H, H6), 6.94 d (1H, H8), 7.06 t (1H, H7), 7.13 d (1H,
H5). 13C NMR spectrum, C, ppm (CDCl3): 20.68
1
were confirmed by H, 13C, and 31P NMR spectro-
scopy. The spectra of the reaction mixtures show no
other signals than those of the phosphorylated
ynamines. The 13C NMR spectra are the most infor-
mative; they contain two typical doublet signals
corresponding to the carbon atoms of the triple bond:
2
(C2), 26.12 (C3), 49.95 (C1), 52.69 d (CH3O, JCP
1
5.4 Hz), 57.88 d (CP, JCP 321.5 Hz), 99.92 d (CN,
2JCP 65.1 Hz), 115.33 (C6), 121.99 (C8), 123.96 (C4),
The signal at
57 ppm with a large coupling
C
127.06 (C7), 129.19 (C5), 136.76 (C9). 31P NMR spec-
trum, P, ppm (CDCl3): 1.62.
constant (1JCP 320 Hz) belongs to the carbon atoms
directly bound to phosphorus and that at
100 ppm
(2JCP 64 65 Hz) to the carbon atom boCund to the
amine fragment. The phosphorus chemical shift of
ynamines Ia Ic is close to zero, as expected. These
data fit well the spectral characteristics of phosphoryl-
ated ynamines obtained earlier [1, 3, 4].
1
2
6
3
5
(CH3O)2PC CN
4
9
O
8
7
Aminoethynylphosphonates
Ia Ic
(general
procedure). To a solution of 1 g of dimethyl chloro-
ethynylphosphonate in 3 ml of anhydrous acetonitrile,
1 g of anhydrous potassium carbonate was added,
after which an equimolar amount (5.93 mmol) of the
corresponding secondary amine in 2 ml of anhydrous
acetonitrile was slowly added dropwise with vigorous
stirring. The reaction mixture was refluxed for 2 h.
The inorganic salts were then filtered off, and the
quantitatively formed phosphorylated ynamine dis-
Dimethyl (N-methyl-N-phenylamino)ethynyl-
phosphonate (Ib). 1H NMR spectrum, , ppm
(CDCl3): 3.22 (3H, CH3Ph), 3.67 d (6H, CH3O, JHP
3
12.5 Hz), 6.92 t (1H, p-CH, Ph), 6.99 d (2H, o-CH,
Ph), 7.22 t (2H, m-CH, Ph). 13C NMR spectrum,
,
C
2
ppm (CDCl3): 38.22 (CH3Ph), 52.67 d (CH3O, JCP
1
5.4 Hz), 56.63 d (CP, JCP 320.1 Hz), 100.60 d (CN,
2JCP 63.8 Hz), 114.61 (o-CH, Ph), 122.40 (p-CH, Ph),
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 1 2008