1406
Can. J. Chem. Vol. 80, 2002
Table 1. Summary of 31P NMR spectroscopic data for reaction mixtures of PCl3 DippNH2 at seven different stoichiometric combinations.
148
182
161
195
ꢀ
31P (ppm)
155
221
139
140
8
224
242
118
133
136
211
165
Assignments
Reaction stoichiometry
PCl3:DippNH2
1
100
PCl3
80
(2)
(3)
(8)
(5)
(6)
9
7
4
2:1
1:1
1:2
1:3
1:4
1:5
1:6
100
100
10
20
15
100
100
100
100
30
10
40
30
10
5
60
90
10
5
5
2
5
10
1
1
5
2
5
2
5
1
10
5
10
5
10
5
10
1
5
70
Note: Chemical shifts are listed in order of peak intensity. Approximate peak intensities in each spectrum are given relative to the most intense peak
(100%). Assignments are confirmed for 1, 4, 7, and 9 (3) by characterization of isolated samples. Parentheses indicating assignments for 2, 3, 5, 6, and 8
are tentative and other minor signals are not assigned.
3
3.25 (sept, JHH = 12 Hz), 4.53 (s), 6.93–6.96 (m). 31P NMR:
155. Anal. calcd. for DippN(H)PCl2: C 51.81, H 6.52,
N 5.03; found: C 51.36, H 6.79, N 5.08.
(17), 935 (13), 923 (7), 907 (2), 801 (1), 537 (12), 529 (18),
1
3
496 (5), 421 (3), 379 (20). H NMR: 1.31 (d, JHH = 10 Hz),
3
3.04 (sept, JHH = 8 Hz), 7.2–7.4 (m). 31P NMR: 211. Anal.
calcd.: C 59.63, H 7.09, N 5.80; found: C 59.54, H 7.20,
N 5.76.
DippN(PCl2)2 (4)
PCl3 (20 mL) and NEt3 (40 mL) were distilled onto a
frozen solution of DippNH2 (5.0 g, 28 mmol) in hexane
(30 mL). A yellow solution and a white precipitate formed
on warming to room temperature. After stirring for 7 days,
the solution was filtered and the solvent removed in vacuo.
The resulting solid was sublimed onto a water cooled finger,
under static vacuum with warming to 80°C, to give tan crys-
tals of 4. Yield 5.3 g (14 mmol, 50%); mp 69–71°C. IR
(Nujol mull) (cm–1): 1584 (20), 1433 (9), 1362 (8), 1322
(15), 1309 (18), 1158 (7), 1104 (12), 1095 (13), 1050 (17),
1040 (19), 903 (6), 883 (1), 799 (6), 718 (16), 515 (4), 490
X-ray crystallography
Crystals of 1, 4, and 7 were selected and mounted in
Pyrex capillaries in the dry box. Data were corrected for
Lorentz and polarization effects, and absorption. Structures
were solved by direct methods and expanded using Fourier
techniques. For compound 4, only the chlorine atoms, the
phosphorus atoms, and C(11) and C(12) were refined aniso-
tropically. The standard reflections decreased by 25% during
data collection, and a linear correction factor was applied.
For compound 7, only the chlorine atoms, phosphorus at-
oms, and C(9)-C(12) and C(19)-C(24) were refined aniso-
tropically. Extinction corrections were not applied for
compounds 4 and 7. Hydrogen atoms were allowed to ride
on the heavy atoms to which they are bonded, with C-H dis-
tances of 0.95 Å and fixed isotropic temperature factors.
Calculations were performed using the teXsan crystallo-
graphic package (17). A summary of the crystallographic
data is given in Table 2.3
1
(3), 481 (2), 451 (10), 437 (11), 417 (14). H NMR: 1.19 (d,
3JHH = 7 Hz), 3.12 (sept, JHH = 7 Hz), 7.26 (m). 31P NMR:
3
165 (reaction mixture), 165 and 211 (assigned to 7). Anal.
calcd.: C 38.03, H 4.52, N 3.70; found: C 38.08, H 4.52,
N 3.75.
[DippNPCl]2 (7)
DippNH2 (10 mL, 53 mmol) in toluene (20 mL) was
added via cannula to a three-chamber reaction vessel con-
taining a stirring solution of PCl3 (2.3 mL, 26 mmol) in tolu-
ene (15 mL) at 0°C. The solution was warmed to room
temperature and a white precipitate formed. After stirring
overnight, the mixture was degassed and filtered through a
fine glass frit. Toluene was removed under vacuum and the
resulting oil was dissolved in hexane (20 mL) to promote
precipitation. The mixture was filtered and NEt3 (3.7 mL,
26 mmol) was added, with the immediate production of a
yellow solution and white precipitate. The mixture was fil-
tered again and the solvent was slowly removed to give large
white crystals, which were washed with fresh hexane. Yield
1.4 g (3.0 mmol, 23%); mp 208–215°C. IR (Nujol mull)
(cm–1): 1444 (4), 1363 (8), 1320 (11), 1276 (15), 1260 (14),
1249 (10), 1198 (5), 1180 (16), 1104 (9), 1056 (19), 1039
Results and discussion
Reaction mixtures of PCl3 and DippNH2 with different
stoichiometric combinations have been examined using
31P NMR spectroscopy. Contrary to the reports describing
isolation of phosphetidine (7) for many RNH2 derivatives
(R = alkyl and aryl) (4, 18), a number of products were ob-
served for DippNH2, with 7 as a minor component even at
high excess of amine. Table 1 lists the 31P chemical shifts
observed for each stoichiometric combination, according to
the relative peak intensity with respect to the most intense
peak (100%). Chemical shift assignments for compounds 1,
7, and 9 (3) have been confirmed by characterization of iso-
lated materials. In contrast to reactions involving amines
3 Supplementary data may be purchased from the Depository of Unpublished Data, Document Delivery, CISTI, National Research Council
191247–191249 contain the supplementary data for this paper. These data can be obtained, free of charge, via
+44 1223 336033; or deposit@ccdc.cam.ac.uk).
© 2002 NRC Canada