5472 J. Am. Chem. Soc., Vol. 123, No. 23, 2001
SriniVasan et al.
performed on a Varian 3700 instrument attached to a Hewlett-Packard
at 40 °C followed by an increase of 8 °C/min to 250 °C. We conducted
HPLC employing either a Waters Symmetry column (4.6 × 250 mm),
using acetonitrile/water with a gradient of [time (min), % water] (0,
80), (8, 80), (15, 65), (40, 50), (45, 50), (55, 80), or a reversed phase
column from Phenomenex (Luna C18(2) 4.6 × 250 mm), using isocratic
acetonitrile:water (55:45). In both cases, products were detected at 254
nm with a flow rate of 1.0 mL/min.
3
590E Chemstation. GC-mass spectral (GC-MS) analysis was con-
ducted on a Hewlett-Packard 5890 Series II gas chromatograph attached
to a 5971A mass selective detector using HP-G10341B software.
Ultraviolet (UV) data were obtained with a Hewlett-Packard 8451A or
8453 diode array spectrophotometer. Infrared (IR) spectra were recorded
on a Nicolet-510 FTIR spectrometer or a Bruker IFS-55 Fourier
transform IR spectrometer at 4-cm-1 resolution. HPLC analysis was
performed with one of two systems: (1) a Waters system equipped
with a 680 gradient controller, two Waters 510 pumps, a Waters 440
fixed wavelength detector, and a Hewlett-Packard 3590E Chemstation;
and (2) a Perkin-Elmer Series 4 chromatograph equipped with PE 85B
variable wavelength detector. Capillary electrophoresis was done using
a Beckman P/ACE System 2000 equipped with a diode array detector
and System Gold data station. Elemental analysis was done by Atlantic
Microlab, Inc. (Norcross, GA).
Assays for Nitrous Oxide and Nitric Oxide. The presence of nitric
oxide and nitrous oxide was confirmed by GC-MS. Nitrous oxide was
analyzed by gas chromatography on a Quardrex Mol Sieve 5-Å Plot
column (30 m, 0.32 mm i.d.; Alltech, Deerfield, IL) and a mass selective
detector. Nitric oxide was quantified indirectly as nitrate and nitrite.
Oxygen was injected into the reaction vessel after the irradiation and
the reaction mixture was allowed to stand for 1 h, after which it was
directly analyzed by capillary electrophoresis with UV detection at 214
nm on a polyacrylamide-coated fused silica column (column dimen-
sions: total length ) 57 cm; detection length ) 50 cm; i.d. ) 75 µm)
and 10 mM phosphate buffer of pH 3.2 containing 0.1% of Brij-30
3
7
Sodium 1-(N,N-diethylamino)diazen-1-ium-1,2-diolate and com-
6
3a
38
39
pounds 1 (R ) H), 4, 6, and 19 were prepared as separately
described.
(Calbiochem, La Jolla, CA).
2
O -Benzyl 1-(N,N-Diethylamino)diazen-1-ium-1,2-diolate (5). A
Trapping of the O-Nitrene Intermediate upon Photolysis of 4
slurry of sodium 1-(N,N-diethylamino)diazen-1-ium-1,2-diolate (7.0 g,
by 2,3-Dimethyl-2-butene. In a typical experiment, 49 mg (0.22 mmol)
of 4, 5.3 mg (0.043 mmol) of 2-methoxytoluene as internal standard,
and 296 mg (3.35 mmol) of 2,3-dimethyl-2-butene were dissolved in
0
.045 mol) and 2 g of anhydrous sodium carbonate in 50 mL of
dimethyl sulfoxide was cooled to 0 °C. To this mixture, under nitro-
gen, was added 18 mg (0.11 mmol) of silver acetate, then 4.76 mL
1
0 mL of acetonitrile. The mixture was degassed and then irradiated
(0.04 mol) of benzyl bromide dropwise. The reaction mixture was
at 254 nm for 1 h. The reaction mixture was analyzed by GC-MS and
the presence of 1-methoxy-2,2,3,3-tetramethylaziridine was confirmed
from the mass spectra and by peak enhancement with an authentic
sample prepared according to Brois.2 The amount of aziridine was
estimated to be 0.013 mmol (6% yield).
allowed to warm gradually to room temperature and was stirred
overnight. Water (200 mL) was added, the mixture was filtered, and
the filtrate was extracted with ether. The organic layer was dried
over sodium sulfate and filtered through a layer of magnesium sul-
fate; evaporation of the solvent gave an orange oil. Purification was
carried out on a 250-mL glass column packed with silica gel and
eluted with 5:1 dichloromethane:ethyl acetate to give 3.9 g (51%) of 5
1a
Time-Resolved IR Methods. We conducted TRIR experiments
4
1
following the method of Hamaguchi and co-workers as described
previously.42 Briefly, the broadband output of a MoSi2 IR source
(JASCO) is crossed with excitation pulses from a Nd:YAG laser.
Changes in IR intensity are monitored by an MCT photovoltaic IR
detector (Kolmar Technologies, KMPV11-1-J1), amplified, and digi-
tized with a Tektronix TDS520A oscilloscope. The experiment is
conducted in the dispersive mode with a JASCO TRIR-1000 spec-
trometer. We collected the TRIR difference spectra using either a
Continuum HPO-300 diode pumped Nd:YAG laser (266 nm, 10 ns,
0.4 mJ) or a Quantronix Q-switched Nd:YAG laser (266 nm, 90 ns,
0.4 mJ) operating at 200 Hz. Kinetic traces were collected by means
of a Continuum Minilite II Nd:YAG laser (266 nm, 5 ns, 0.2-4 mJ)
operating at 20 Hz.
1
as a pale yellow oil: H NMR δ 1.01 (6H, t, J ) 7.1 Hz), 3.05 (4H,
1
3
q, J ) 7.1 Hz), 5.28 (2H, s), 7.38 (5H, m); C NMR δ 11.31, 48.57,
7
1
5.51, 128.35, 128.37, 128.38, 138.58; IR (neat) 3071, 3036, 2875,
-
1
728, 1510, 1461, 1414, 1377, 1243, 1053, 1004, 843, 758, 702 cm ;
-
1
-1
UV λmax (CH CN) 238 nm (ꢀ ) 9.9 mM cm ). Anal. Calcd for
C H N O : C, 59.17; H, 7.67; N, 18.82. Found: C, 59.16; H, 7.67;
11 17 3 2
3
N, 18.64.
Continuous Photolysis. Irradiations were performed on solutions
of the reactants in acetonitrile or acetonitrile-d in 1.0-cm path length
3
quartz cuvettes, sealed with a rubber septum, and purged prior to
irradiation with argon or oxygen for 15-20 min. Solutions were
irradiated in a Rayonet reactor equipped with either 254- or 350-nm
low-pressure Hg lamps. Quantum yields were determined with respect
4
0
to the Crystal Violet actinometer.
Acknowledgment. J.P.T. gratefully acknowledges the Cam-
ille Dreyfus Teacher-Scholar Awards Program, the National
Institutes of Health (R01 GM58109), and the American Cancer
Society (IRG-58-005-39) for generous support of this research.
N.K. gratefully acknowledges support from a UNCF/Parke-
Davis Postdoctoral Fellowship. We also thank Professors Gerald
J. Meyer and Alex Nickon for helpful comments. This work
was supported in part by the National Cancer Institute under
contract No. NO1-CO-56000.
Analysis of the Reaction Mixtures. The products of photolysis were
preliminarily identified by GC-MS and confirmed by GC and HPLC
through co-injection of authentic compounds. The nongaseous products
were quantified by GC or HPLC and NMR spectroscopy. Gas
chromatography was done on a DB5 column (30 m, 0.32 mm ID,
Alltech Associates, Deerfield, IL) and a temperature program of 5 min
(
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