Preparation of diisocyanates of adamantane and diamantane

Article abstract of DOI:10.1080/00397910701865926

The 1,6- and 4,9-diisocyanates of diamantane have been prepared for the first time by treatment of the corresponding diamines with triphosgene. Also, 1,3-diisocyanatoadamantane was prepared through double Curtius rearrangement of 1,3-adamantanedicarboxylic acid. Copyright Taylor & Francis Group, LLC.

Full text of DOI:10.1080/00397910701865926

This article was downloaded by: [University of Missouri Columbia]
On: 30 March 2013, At: 02:27
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office:
Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
Synthetic Communications: An International
Journal for Rapid Communication of
Synthetic Organic Chemistry
Publication details, including instructions for authors and subscription
information:
http://www.tandfonline.com/loi/lsyc20
Preparation of Diisocyanates of Adamantane
and Diamantane
a
b
b
Matthew C. Davis , Jeremy E. P. Dahl & Robert M. K. Carlson
a
Chemistry and Materials Division, Michelson Laboratory, Naval Air Warfare
Center, China Lake, California, USA
b
Molecular Diamond Technologies, Chevron Technology Ventures, Richmond,
California, USA
Version of record first published: 17 Apr 2008.
To cite this article: Matthew C. Davis , Jeremy E. P. Dahl & Robert M. K. Carlson (2008): Preparation of
Diisocyanates of Adamantane and Diamantane, Synthetic Communications: An International Journal for Rapid
Communication of Synthetic Organic Chemistry, 38:8, 1153-1158
To link to this article: http://dx.doi.org/10.1080/00397910701865926
PLEASE SCROLL DOWN FOR ARTICLE
Full terms and conditions of use: http://www.tandfonline.com/page/terms-and-conditions
This article may be used for research, teaching, and private study purposes. Any substantial
or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or
distribution in any form to anyone is expressly forbidden.
The publisher does not give any warranty express or implied or make any representation that the
contents will be complete or accurate or up to date. The accuracy of any instructions, formulae,
and drug doses should be independently verified with primary sources. The publisher shall not
be liable for any loss, actions, claims, proceedings, demand, or costs or damages whatsoever or
howsoever caused arising directly or indirectly in connection with or arising out of the use of this
material.

w
Synthetic Communications , 38: 1153–1158, 2008
Copyright # Taylor & Francis Group, LLC
ISSN 0039-7911 print/1532-2432 online
DOI: 10.1080/00397910701865926
Preparation of Diisocyanates of
Adamantane and Diamantane
1
Matthew C. Davis, Jeremy E. P. Dahl, and Robert
2
2
M. K. Carlson
1
Chemistry and Materials Division, Michelson Laboratory, Naval Air
Warfare Center, China Lake, California, USA
2
Molecular Diamond Technologies, Chevron Technology Ventures,
Richmond, California, USA
Abstract: The 1,6- and 4,9-diisocyanates of diamantane have been prepared for the
first time by treatment of the corresponding diamines with triphosgene. Also, 1,3-dii-
socyanatoadamantane was prepared through double Curtius rearrangement of 1,3-ada-
mantanedicarboxylic acid.
Keywords: Adamantane, diamantane, diisocyanates, Curtius rearrangement,
triphosgene
Diamondoids are naturally occurring hydrocarbons commonly found in crude
[
1]
oil deposits. As part of a program to discover new materials for high-
temperature applications, the lower diamondoids adamantane and diamantane
were of interest as they are inexpensive and available in larger quantities. For
polyurethane blends such as paints and other coatings, we needed their
diisocyanate derivatives (Fig. 1). Although many derivatives of adamantane
[2,3]
and diamantane have been made, including monoisocyanates,
that their diisocyanates are unknown.
it appears
Received in the USA November 14, 2007
Address correspondence to Matthew C. Davis, Chemistry and Materials Division,
Michelson Laboratory, Naval Air Warfare Center, China Lake, CA 93555, USA.
E-mail: matthew.davis@navy.mil
1
153

1154
M. C. Davis, J. E. P. Dahl, and R. M. K. Carlson
Figure 1.
[4]
Since the diaminodiamantanes (7, 8) have been previously prepared, it
was decided to convert them into 2 and 3. A typical method for transforming
amines into isocyanates is through heating the amine in the presence of
phosgene. This reagent is extremely toxic and a safer alternative is triphos-
[
5]
gene. The reaction of triphosgene with 7 and 8 in the presence of triethyl-
amine went well by changing the mode of addition to adding a diamine/
[6]
triethylamine solution to the triphosgene solution. Both 2 and 3 are recrys-
tallizable solids with excellent solubility in common organic solvents
(
Scheme 1).
For adamantane derivative 1, we wanted to determine whether the com-
mercially available 1,3-adamantanedicarboxylic acid 4 could be used by
[
7,8]
way of Curtis rearrangement.
with diphenylphosphoryl azide showed that Curtius reaction takes place,
Two reports of the rearrangement of 4
[9,10]
although 1 was prepared in situ and not isolated.
Conversion of 4 into 5 was carried out in refluxing thionyl chloride in
excellent yield, Scheme 2. If possible, we sought not to isolate the diacyldia-
zide 6 because these compounds are known to be explosive and must be
handled with extreme caution. The diacid dichloride 5 was dissolved in 1,2-
dichloroethane and reacted with an aqueous solution of sodium azide. The
1
reaction was monitored by H NMR, and the chloride/azide exchange was
rapid and complete. Afterward, the 1,2-dichloroethane solution of 6 was
separated and dried over anhydrous magnesium sulfate. The solution was
1
refluxed and monitored by H NMR. Typically within 1 h the double
Curtius rearrangement was complete. Evaporation of solvent gave 1, which
is liquid at room temperature, in nearly quantitative yield. Interestingly, the
electron-impact mass spectrum of 1 showed a base peak of m/z 161 (M-57)
as opposed to the base peaks of 2 and 3, resulting from loss of NCO
Scheme 1. Reagents and conditions: (a) triphosgene, triethylamine (TEA), CHCl
8C to rt.
3
,
0

Diisocyanates of Diamantane
1155
Scheme 2. Reagents and conditions: (a) SOCl
reflux.
2
; (b) NaN
3
, DCE, H
2
O; (c) DCE,
(
M-42). This may be the result of loss of 2CO þ H, but mass spectrometry of
[11]
isocyanates has not been widely studied.
At the time of writing, two reports of the conversion of 4 into 1 by way of
diacyldiazide rearrangement were found.
[12,13]
It was not possible to obtain
and examine these references, however. In conclusion, the 1,6- and 4,9-diiso-
cyanates of diamantane were prepared. Also, 1,3-diisocyanatoadamantane
was synthesized in good yield by double Curtius rearrangement of 1,3-ada-
mantanecarboxylic acid.
EXPERIMENTAL
Melting points were collected with a Mel-Temp II from Laboratory Devices
(Holliston, MA) and are not corrected. NMR data were obtained on a
1
13
Br u¨ ker Avance-300 spectrometer ( H at 300 MHz, C at 75 MHz). NMR
data were processed using NUTS software from Acorn NMR, Inc.
(Livermore, CA). Spectra were referenced to solvent or tetramethylsilane.
The 1,3-adamantanedicarboxylic acid 4 and triphosgene were purchased
from Sigma-Aldrich. Elemental analyses were performed by Atlantic
Microlab, Inc. (Norcross, GA). The mass spectrometer used was an Agilent
model 5973 Network Mass Selective Detector equipped with an Agilent
model 6890 gas chromatograph setup to run capillary columns in splitless
sample injection mode with an Agilent model 7683 autosampler. The GC
column used was an Agilent HP-MS5 (30 m by 0.25 mm I.D., 0.25 m phase
thickness) run with a helium carrier gas flow rate of 1.2 mL/min (constant
flow mode) and inlet pressure of 16 psi. During GC-MS analyses, the GC
oven had a 1.0-min initial hold time at 150 8C followed by oven programming
at 10 8C/min to 320 8C with a final hold time of 15 min. The GC-MS transfer
line temperature was maintained at 320 8C. A solvent delay of 2.5 min applied
to GC-MS data accumulation. Each sample was dissolved in HPLC-grade
dichloromethane at a concentration of ꢀ1 mg/mL, and 1 mL each was
injected into the GCMS instrument using the 7683 autosampler.

1156
M. C. Davis, J. E. P. Dahl, and R. M. K. Carlson
1,3-Adamantanedicarbonyl Dichloride (5)
A 100-mL round-bottomed flask equipped with magnetic stirbar was charged
with 50 mL of SOCl followed by 4 g of 4 (18 mmol). A condenser was
2
attached that was equipped with an aqueous NaOH gas scrubber. The
mixture was stirred and refluxed for 6 h. The excess SOCl was distilled
2
under reduced pressure, leaving a pale yellow solid (4.52 g, 97%). The solid
was slurried with hexanes and filtered on a medium frit to give the title
[14]
compound as an off-white, crystalline solid. Mp 83–86 8C (lit.
90 8C).
d (CDCl ): 2.35 (pent, J ¼ 2.5 Hz, 2H), 2.24 (s, 2H), 2.01 (q, J ¼ 14.0 Hz,
H
3
8
H), 1.75 (t, J ¼ 2.9 Hz, 2H); d (CDCl ): 178.82, 51.44, 40.14, 38.07,
C
3
3
4.84, 27.95.
1,3-Diisocyanatoadamantane (1)
A 100-mL round-bottomed flask equipped with magnetic stirbar was charged
with 5 and 1,2-dichloroethane. The mixture was cooled in an ice bath, and a
previously prepared solution of NaN in H O was added in one portion. The
3
2
mixture was vigorously stirred, and the cooling bath was removed. After 1 h,
1
H NMR of an aliqout of the organic phase showed complete formation of
,3-adamantanedicarbonyl diazide (6) [dH (CDCl ): 2.19 (pent, J ¼ 3.1 Hz,
1
3
2
H), 1.95 (s, 2H), 1.82 (q, J ¼ 11.1 Hz, 8H), 1.68 (t, J ¼ 2.8 Hz, 2H); d
C
(CDCl ): 184.39, 43.16, 39.41, 37.77, 35.18, 27.87]. The organic layer was
3
separated and washed once with 5% NaHCO and then brine. The organic
3
layer was dried over anhydrous MgSO and transferred to a 100-mL round-
4
bottomed flask equipped with magnetic stirbar. The solution was refluxed, and
1
after 1 h H NMR showed complete consumption of 6. The solution was
rotary evaporated (10 torr, rt) leaving the title compound as a colorless liquid
that was more than 98% pure by NMR and GCMS. The compound could be
recrystallized from hexanes at 220 8C. d (CDCl ): 2.26 (pent, J ¼ 2.8 Hz,
H
3
2
H), 1.98 (s, 2H), 1.82 (d, J ¼ 2.8 Hz, 8H), 1.56 (t, J ¼ 2.8 Hz, 2H); d
C
(CDCl ): 123.43, 56.25, 52.14, 43.89, 34.17, 30.39. Elemental analysis calcu-
lated for C H N O : C, 66.04; H, 6.47; N, 12.84. Found: C, 65.68; H, 6.63;
3
1
2
14
2
2
þ†
N, 13.71. EI-MS: M (%): 218 (41); 176 (44); 161 (100); 120 (39).
1,6-Diisocyanatodiamantane (2)
A 100-mL round-bottomed flask was charged with 25 mL of anhydrous
CH Cl and 1.38 g of triphosgene (4.9 mmol, 1 equiv). The solution was
cooled in an ice bath while a solution of 1.07 g of 7 (4.9 mmol) and 1.97 g
2
2
of TEA (19.5 mmol, 4 equiv) in 5 mL of CH Cl was added dropwise over
2
2
10 min. Copious solids precipitated during this time. After the addition, the
cooling bath was removed, and the mixture was stirred at rt for 2 h. The

Diisocyanates of Diamantane
1157
mixture was poured into 50 mL of cold H O, and the organic phase was
2
separated. The organic layer was washed again with 25 mL of H O followed
2
by 25 mL of brine. The organic layer was dried over anhydrous MgSO . The
4
solution was diluted with 25 mL of hexanes and filtered through a thin pad
of SiO . The filtrate was rotary evaporated, leaving a white solid, which was
2
recrystallized from MeCN to give 930 mg of the title compound as white
microcrystals (70%). Mp 96–98 8C. d (CDCl ): 2.13 (d, J ¼ 13.5 Hz, 4H),
H
3
2
d (CDCl ): 122.27, 59.91, 46.75, 44.25, 32.61, 28.17. Elemental analysis
.05 (pent, J ¼ 2.8 Hz, 2H), 1.96–1.88 (m, 8H), 1.53 (d, J ¼ 13.5 Hz, 4H);
C 3
calculated for C H N O : C, 71.09; H, 6.71; N, 10.36. Found: C, 70.82; H,
1
6
18
2
2
þ†
6
.77; N, 10.38. EI-MS: M (%): 270 (10); 227 (100); 91 (67); 77 (46).
4
,9-Diisocyanatodiamantane (3)
Starting with 8, an analogous procedure to that described for 2 was used to
prepare the title compound in 85% yield. The crude product was recrystallized
from MeCN to give the title compound as white, blocky crystals. Mp 150–
1
3
1
52 8C. dH (CDCl ): 1.92 (s, 18H); d (CDCl ): 123.19, 54.22, 44.75,
3
C
3
7.48. Elemental analysis calculated for C H N O : C, 71.09; H, 6.71; N,
þ†
1
6 18 2 2
0.36. Found: C, 70.57; H, 6.73; N, 10.30. EI-MS: M (%): 270 (37); 228
(100); 91 (27).
ACKNOWLEDGMENTS
The generous financial support of this research by the Office of Naval
Research is gratefully acknowledged. Thanks go to Chrissy Everett
(NAWCWD) for assistance collecting the combustion analyses.
REFERENCES
1
2
3
. Dahl, J. E.; Liu, S. G.; Carlson, R. M. K. Isolation and structure of higher diamond-
oids, nanometer-sized diamond molecules. Science 2003, 299, 96–99.
. Paulshock, M.; Watts, J. C. Adamantane isocyanate and isothiocyanate. U.S.
Patent 3,203,970, August 31, 1965.
. Farooq, O.; Wang, Q.; Wu, A.; Olah, G. A. Preparation of tertiary alkyl isocyanates
by the zinc iodide catalyzed reaction of tertiary alkanoyl chlorides with trimethyl-
silyl azide. J. Org. Chem. 1990, 55, 4282–4283.
4
5
6
. Davis, M. C.; Nissan, D. A. Preparation of diamines of adamantane and diaman-
tane from the diazides. Synth. Commun. 2006, 36, 2113–2119.
. Cotarca, L.; Eckert, H. Phosgenations—A Handbook; Wiley-VCH: Weinheim,
2004.
. Sakai, R.; Satoh, T.; Kakuchi, R.; Kaga, H.; Kakuchi, T. Helicity induction of poly-
isocyanate with a crown cavity on the main chain synthesized by cyclopolymeriza-
tion of a,v-diisocyanate. Macromolecules 2004, 37, 3996–4003.

1158
M. C. Davis, J. E. P. Dahl, and R. M. K. Carlson
7
. Curtius, T. Hydrazide und Azide organischer S a¨ uren I. Abhandlung. J. Prakt.
Chem. 1894, 50, 275–294.
8
9
. Smith, P. A. S. The Curtius reaction. Org. React. 1946, 3, 337–449.
. Sasaki, T. 1,3-Diisocyanatoadamantane. Japanese Patent 79,46,762, September 21,
1
979.
1
0. Keizer, H. M.; Gonz a´ lez, J. J.; Segura, M.; Prados, P.; Sijbesma, R. P.;
Meier, E. W. de Mendoza, J. Self-assembled pentamers and hexamers linked
through quadruple-hydrogen-bonded 2-ureido-4[1H]-pyrimidones. Chem. Eur. J.
2
005, 11, 4602–4608.
1. Ruth, J. M.; Philippe, R. J. Mass spectra of isocyanates. Anal. Chem. 1966, 38,
20–723.
2. Novikov, S. S.; Moiseev, I. K.; Mratkhuzina, T. A.; Doroshenko, R. I.;
Konovalova, V. P. Curtius reaction of adamantane acids. Chem. Abstr. 1975, 82,
1
1
7
473, 31002z.
3. Gureev, N. G.; Radchenko, S. S. Synthesis of 1,3-diisocyanatoadamantane. Chem.
Abstracts 1974, 80, 394, 145540n.
¨
4. Prelog, V.; Seiwerth, R. Uber eine neue, ergiebigere darstellung des adamantans.
Chem. Ber. 1941, 74, 1769–1772.
1
1