Synthesis of nitroso- and dinitroso compounds by reaction of nitrosyl benzoate and dinitrosylterephthalate with tetrasubstituted alkenes

Article abstract of DOI:10.1055/s-2006-942392

The reaction of nitrosyl benzoate with tetrasubstituted alkenes at 0°C produces monomeric C-nitroso compounds in high yields. Similarly, the reaction of dinitrosyl terephthalate with 2,3-dimethylbut-2-ene affords a monomeric dinitroso compound. Extension

Full text of DOI:10.1055/s-2006-942392

PAPER
1991
Synthesis of Nitroso- and Dinitroso Compounds by Reaction of Nitrosyl
Benzoate and Dinitrosylterephthalate with Tetrasubstituted Alkenes
Synthesis of
Nit
h
roso- and Di
o
nitroso Com
m
pounds as R. Sharpe,a,c Brian G. Gowenlock*b
a
P. O. Box 7288, Wilmington, Delaware, DE 19803, USA
Riccarton, 5 Roselands, Sidmouth, Devon EX10 8PB, UK
E-mail: Brian.gowenlock@btinternet.com
b
c
Explosives Department, E. I. Du Pont de Nemours & Company, Du Pont Experimental Station, Wilmington, Delaware, DE 19898, USA
Received 12 December 2005; revised 12 January 2006
PhCOONO
+
Me2C=CMe2
PhCOOCMe2CMe2NO
PhCOO
Abstract: The reaction of nitrosyl benzoate with tetrasubstituted
alkenes at 0 °C produces monomeric C-nitroso compounds in high
yields. Similarly, the reaction of dinitrosyl terephthalate with 2,3-
dimethylbut-2-ene affords a monomeric dinitroso compound. Ex-
tension to other nitrosyl esters gives similar high yields.
PhCOONO
+
Key words: nitrosyl esters, tetrasubstituted alkenes, cycloalkenes,
nitroso compounds, dinitroso compounds
NO
During the past fifteen years many synthetic routes for the
preparation of C-nitroso compounds have been reported
and the recent publication of two reviews1,2 prompts this
further detailed synthetic approach first explored some
thirty eight years ago. A study on the addition of nitrosyl
formate to various olefins was first reported by Hamann
and Stern3 in 1968, at the same time as this work was in
progress. A conference paper4 resulted in a study5 of the
14N NMR spectra of two of the compounds reported be-
low. The present interest6,7 in the coordination chemistry
of C-nitroso compounds suggests that detailed informa-
tion on the synthetic procedures could lead to the use of
these compounds as ligands.
Me
NO
Me
Me
Me
NO
+
PhCOONO
+
PhCOO
PhCOO
Me
Me
Scheme 2
terephthaloate. Yields of the nitroso compounds were
greater than 65%.
Information concerning the stereochemistry of the ni-
trosyl ester–tetrasubstituted alkene addition reaction was
obtained by carrying out the reaction of nitrosyl benzoate
with 1,2-dimethylcyclopentene in different solvents and
by interpretation of the NMR spectra of the adducts. The
dinitrosyl terephthaloate–tetramethylethylene adduct has
two sharp methyl signals at 1.0 and 2.2 ppm which arise
from CH3CNO and CH3COCO groups, respectively. The
NMR spectrum of the adduct of the nitrosylbenzoate–1,2-
dimethylcyclopentene reaction shows two signals in the 1
ppm region. The relative amounts of the two adducts as
given by integration show that these are markedly depen-
The synthetic routes, employed to produce monomeric ni-
troso compounds and dinitroso compounds, are shown in
Scheme 1.
RCOOCR'2CR'2NO
RCOONO
+
R'2C=CR'2
R"(COOCR'2CR'2NO)2
R"(COONO)2
+
2 R'2C=CR'2
Scheme 1
The reaction of nitrosyl benzoate was carried out using
three different tetrasubstituted alkenes, namely 2,3-di-
methylbut-2-ene, D9-octalin and 1,2-dimethylcyclopen-
tene (Scheme 2).
RCOONO
+ Me2C=CMe2
RCOOCMe2CMe2NO
R = 1-adamantyl, cyclohexyl
COOCMe2CMe2NO
Further nitrosyl esters were reacted with 2,3-dimethylbut-
2-ene, namely nitrosyl 1-adamantane carboxylate, ni-
trosyl cyclohexanecarboxylate (Scheme 3) and dinitrosyl
COONO
+ 2 Me2C=CMe2
COOCMe2CMe2NO
SYNTHESIS 2006, No. 12, pp 1991–1994
x
x.
x
x
.
2
0
0
6
COONO
Advanced online publication: 11.05.2006
DOI: 10.1055/s-2006-942392; Art ID: P19205SS
Scheme 3
© Georg Thieme Verlag Stuttgart · New York

1992
T. R. Sharpe, B. G. Gowenlock
PAPER
dent upon the solvent employed for the reaction. There is
no a priori way of knowing which of the two signals arises
from the cis-adduct and which from the trans-adduct. The
question was resolved by the application of catalytic hy-
drogenation to the products obtained from the addition re-
action that was carried out using cyclohexane as the
reaction medium (the ratio of the two products was 95:5).
The product of this reaction was oxazoline 1 (Scheme 4)
indicating that the major product was the cis-isomer. Con-
firmation is obtained by the observation that reduction of
the 18:82 mixture (with nitromethane as solvent) gave
aminoester 2 with only trace amounts of the oxazoline.
Table 1 Isomer Proportions from Reaction of Nitrosyl Benzoate
with 1,2-Dimethylcyclopentene
Solvent
% cis
% trans
Cyclohexane
CH2Cl2
95
73
18
5
27
82
Nitromethane
Because all nitrosyl acylates are highly sensitive to moisture, rapid-
ly yielding the parent carboxylic acid and nitrous acid, all moisture
must be excluded from the system during their preparation and in all
subsequent reactions. The most convenient method for the prepara-
tion of nitrosyl benzoate is to react sodium benzoate with dinitrogen
tetraoxide.
Preparation of Nitrosyl Benzoate
Sodium benzoate (72.0 g, 0.50 mol) and CH2Cl2 (300 mL) were
placed in a 1 L three-necked flask equipped with a dropping funnel,
thermometer and magnetic stirring bar. The mixture was cooled to
0 °C in an ice bath. Dinitrogen tetraoxide (48.0 g, 0.52 mol) in
CH2Cl2 (25 mL) was then added dropwise over 2 h. The reaction
was not noticeably exothermic, and the temperature did not exceed
2 °C. After the addition, the mixture was stirred for 15 min at 0 °C
and for 1.5 h at r.t. The reaction mixture was then filtered through a
filtration apparatus under nitrogen and was rinsed with CH2Cl2 (2 ×
50 mL). The solvent and excess dinitrogen tetraoxide were distilled
at aspirator pressure into a –80 °C trap yielding nitrosyl benzoate
(71.6 g, 95%).
Reaction of Nitrosyl Benzoate with 2,3-Dimethylbut-2-ene
A solution of nitrosyl benzoate (9.7 g, 64 mmol) in CH2Cl2 (80 mL)
was cooled to 0 °C under nitrogen and 2,3-dimethylbut-2-ene (6.4
g, 76 mmol) was added dropwise over 35 min. The solution imme-
diately acquired a blue color and the temperature rose to 5 °C. Stir-
ring was continued for 40 min at 0 °C, followed for 35 min at r.t.
Solvent and excess alkene were removed initially at aspirator pres-
sure and finally at 0.1 mm yielding 2-benzoyloxy-2,3-dimethyl-3-
nitrosobutane (13.9 g, 92%). Analytical and spectroscopic data are
in good agreement with the literature.3
IR (CCl4): 1720 (C=O), 1570 (N=O), 1280 (ester) cm–1.
1H NMR (CCl4): d = 1.0 (s, 6 H), 2.15 (s, 6 H), 7.5 (m, 3 H), 7.8 (m,
2 H).
Scheme 4
UV–Vis (EtOH): lmax (e) = 678 (8.6) nm.
Products 1 and 2 were identified by elemental analyses as
well as IR and NMR spectroscopy in full accord with the
indicated structures. At the time at which this work was
carried out preparative HPLC was not available for the
separation of the two geometric isomers, which were ob-
tained as viscous oils.
Anal. Calcd for C13H17NO3: C, 66.36; H, 7.28; N, 5.95. Found: C,
66.12; H, 7.32; N, 5.93.
Reaction of Nitrosyl Benzoate with D9-Octalin
A solution of nitrosyl benzoate (10.0 g, 66.2 mmol) in anhyd
MeNO2 (100 mL) was cooled to 0 °C and D9-octalin (9.0 g, 66
mmol) was added dropwise over 30 min. After the addition, stirring
was continued at 0 °C for 1 h, followed by r.t. for 2 h. Solvent was
removed in vacuo to give a green crystalline solid (18.6 g). Recrys-
tallization from 73% EtOH (300 mL) gave trans-9-benzoyloxy-10-
nitrosodecalin (12.2 g, 64%) as light blue platelets; mp 75–78 °C.
IR (KBr): 1710 (C=O), 1555 (N=O), 1275 (ester) cm–1.
1H NMR (CDCl3): d = 8.1 (m, 2 H), 7.6 (m, 3 H), 0.2–3.7 (m, 16 H).
The results are shown in Table 1 and suggest that the ni-
trosyl benzoate transfers the nitrosyl cation to the alkene
to give a tight ion pair, which rapidly collapses in a low
dielectric medium to give the cis-adduct, whereas in a
high dielectric medium it may lead to a bridged nitrosoni-
um intermediate.
Anal. Calcd for C17H21NO3: C, 71.05; H, 7.37; N, 4.87. Found: C,
70.95; H, 7.29; N, 4.91.
IR, UV-Vis and 1H NMR (recorded at 60 MHz) spectra as well as
microanalyses were carried out in the analytical laboratories of Du
Pont Experimental Station. Melting points are uncorrected.
Synthesis 2006, No. 12, 1991–1994 © Thieme Stuttgart · New York

PAPER
Synthesis of Nitroso- and Dinitroso Compounds
1993
Reaction of Dinitrosyl Terephthalate with 2,3-Dimethylbut-2-
ene
(27.7 g, 0.118 mol) was placed in a 500 mL flask fitted with a gas
inlet tube, thermometer and magnetic stirrer and the system was
flushed with nitrogen and cooled to –20 °C. Nitrosyl chloride (7
mL, 0.15 mol) was condensed into a calibrated trap and added to the
reaction flask as a gas diluted with nitrogen over a period of 90 min,
the temperature being maintained at –15 °C. After the addition the
mixture was stirred for 60 min at 0 °C and then for 60 min at r.t. The
mixture was than filtered under nitrogen into a 500 mL flask using
CH2Cl2 (50 mL) as a rinse. The excess nitrosyl chloride and solvent
were then distilled at aspirator pressure into a –80 °C trap, yielding
nitrosyl cyclohexanecarboxylate (15.3 g, 83% yield) as an amber
liquid.
Disodium terephthalate (23.2 g, 0.11 mol), dinitrogen tetraoxide
(20.2 g, 0.22 mol) and anhyd CH2Cl2 (200 mL) were stirred under
nitrogen for 5 d at r.t. IR measurements of aliquots of the reaction
mixture indicated that formation of the nitrosyl compound was
complete after 2 d. Any unreacted dinitrogen tetraoxide was re-
moved by stripping off 50 mL of solvent from the reaction mixture
at aspirator pressure. The mixture was cooled to 0 °C under nitrogen
and 2,3-dimethylbut-2-ene (18.5 g, 0.22 mol) was added dropwise
over 90 min. The ice bath was removed and stirring was continued
at r.t. overnight. The mixture was filtered, and the solid product was
washed with CH2Cl2. Removal of solvent from the filtrate gave a
crystalline blue solid (35.3 g). Recrystallization from EtOH (750
mL) gave blue plates of di-(2,3-dimethyl-3-nitrosobutyl) tereph-
thalate (25.8 g, 60%); mp 143–143.5 °C (dec).
Reaction with 2,3-dimethylbut-2-ene was carried out using the ni-
trosyl compound (13.8 g, 87.8 mmol) in CH2Cl2 (150 mL) at 0 °C
with dropwise addition of the alkene (10.0 g, 119 mmol) over 15
min followed by stirring under nitrogen at 0 °C and at r.t. for 16 h.
Solvent and excess alkene were removed as before to give a dark
blue liquid which was fractionally distilled through a column giving
2-cyclohexylcarbonyloxy-2,3-dimethyl-3-nitrosobutane (16.1 g,
76%) as a blue liquid; bp 70–71 °C/0.15 mm.
IR (CCl4): d = 1720 (C=O), 1565 (N=O), 1280 (ester) cm–1.
1H NMR (CDCl3): d = 1.0 (3 × s, 12 H), 2.1 (12 H), 7.8 (4 H).
UV–Vis (cyclohexane): lmax (e) = 241 (17500) nm.
UV–Vis (CHCl3): lmax = 675 nm.
IR (CCl4): d = 1735 (C=O), 1575 (N=O) cm–1.
1H NMR (CDCl3): d = 0.9, 2.0 (CH3), 1.5 (cyclohexyl-H).
Anal. Calcd for C20H28N2O6: C, 61.21; H, 7.19; N, 7.14. Found: C,
61.19; H, 7.24; N, 7.05.
Anal. Calcd for C13H23NO3: C, 64.70; H, 9.61; N, 5.81. Found: C,
64.53; H, 9.74; N, 5.84.
Reaction of Nitrosyl Benzoate with 1,2-Dimethylcyclopentene
(a) CH2Cl2 Solvent
Reaction of Nitrosyl 1-Adamantanecarboxylate with 2,3-Di-
methylbut-2-ene
1,2-Dimethylcyclopentene (7.0 g, 73 mmol) was added dropwise
over 75 min to nitrosyl benzoate (10.0 g, 66 mmol) in CH2Cl2 (75
mL) at 0 °C. The resultant green liquid was stirred under nitrogen at
0 °C for a further 75 min followed by stirring for a further 60 min at
r.t. Solvent and excess olefin were removed at aspirator pressure
and finally at 1 mm giving a dark green liquid (15.1 g). TLC (silica
gel, benzene) showed two blue components with Rf values of 0.56
and 0.54.
Silver 1-adamantane carboxylate (10.0 g, 34.9 mmol) was suspend-
ed in anhyd CH2Cl2 (70 mL) and the mixture was cooled to –10 °C.
Nitrosyl chloride (3 mL, 64 mmol) was added as a gas diluted with
nitrogen over 30 min and stirring at 0 °C was continued for 30 min.
The cold reaction mixture was filtered under nitrogen into a three-
necked flask containing a magnetic stirring bar. CH2Cl2 (30 mL)
was used to rinse the filtration apparatus and the excess nitrosyl
chloride was removed from the filtrate by distilling solvent (30 mL)
at aspirator pressure. The resulting orange solution showed charac-
teristic IR bands at 1790 (N=O) and 1715 (C=O) cm–1. The solution
was then cooled to 0 °C and 2,3-dimethylbut-2-ene (8.4 g, 0.10 mol)
was added dropwise over 20 min. The mixture was stirred under ni-
trogen for 2.5 h at 0 °C followed by stirring overnight at r.t. The blue
solution was filtered, solvent and excess alkene were removed in
vacuo to give a blue crystalline solid (8.8 g). Recrystallization from
70% EtOH (100 mL) gave 2-(1-adamantanecarbonyloxy)-2,3-di-
methyl-3-nitrosobutane (6.9 g, 68% yield) as blue platelets; mp
64.5–66 °C.
IR (CCl4): 1725 (C=O), 1565 (N=O), 1280 (ester) cm–1.
1H NMR of the mixture gives two overlapping methyl signals at d =
1.88 (OCCH3) and two methyl signals at 0.90 and 0.97
(O=NCCH3), which were well separated at a 50 cps sweep width
with relative areas shown by integration to be 73% and 27% respec-
tively. In accordance with the catalytic reduction described above
the major component was assigned the cis-structure.
(b) Cyclohexane Solvent
With similar quantities and workup as for CH2Cl2 solvent a similar
yield of a dark blue-green liquid was obtained the NMR of which
showed that cis- and trans-addition occurred to the extent of 95%
and 5%, respectively.
IR (CCl4): 1725 (C=O), 1565 (N=O) cm–1.
1H NMR (benzene): 0.7(6 H, CH3), 9 (6 H, CH3), 1.8 (9 H, adaman-
tine-H), 1.5 (6 H, adamantine-H).
(c) Nitromethane Solvent
With similar quantities using freshly purified8 MeNO2 the follow-
ing variation was adopted in the workup following removal of most
of the solvent at aspirator pressure. The blue-green residue was dis-
solved in CH2Cl2 and washed with sat. NaHCO3 (3 × 75 mL) and
H2O (100 mL). After drying over MgSO4 removal of the solvent
gave a green liquid in similar yield to the use of the other solvents.
NMR showed the product composition to be 18% cis and 82%
trans.
UV–Vis (cyclohexane): lmax (e) = 685 (9.8) nm.
Anal. Calcd for C17H27NO3: C, 69.59; H, 9.28; N, 4.77. Found: C,
69.63; H, 9.35; N, 5.06.
Acknowledgment
One of the authors (TRS) thanks the DuPont Company for the sup-
port of this research, to Drs Herbert S. Eleuterio and Allan E. Nader
for their many helpful discussions, to Mr. William F. Herd for skil-
ful technical assistance. We gratefully acknowledge the assistance
of Dr Allan E. Nader in producing the reaction schemes.
Reaction of Nitrosyl Cyclohexanecarboxylate with 2,3-Di-
methylbut-2-ene
Nitrosyl cyclohexanecarboxylate was prepared from reaction of sil-
ver cyclohexanecarboxylate with nitrosyl chloride. The silver salt
Synthesis 2006, No. 12, 1991–1994 © Thieme Stuttgart · New York

1994
T. R. Sharpe, B. G. Gowenlock
PAPER
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Rev. 1990, 19, 355.
(7) Lee, J.; Chen, L.; West, A. H.; Richter-Addo, G. B. Chem.
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References
(1) Gowenlock, B. G.; Richter-Addo, G. B. Chem. Rev. 2004,
104, 3315.
(2) Gowenlock, B. G.; Richter-Addo, G. B. Chem. Soc. Rev.
2005, 34, 797.
(3) Hamann, H. C.; Swern, D. J. Am. Chem. Soc. 1968, 90, 6481.
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Synthesis 2006, No. 12, 1991–1994 © Thieme Stuttgart · New York