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Low-temperature X-ray Structure Analysis of Ammonium Carbamate.

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conditions since the silyl group is an ideal protecting and
leaving group for the ylides["].
Received: December 13, 1972 [Z 777b IE]
German version: Angew. Chem. 85, 345 (1973)
[l] Organosilicon Chemistry of Phosphorus Ylides, Part IK-Part 17:
H . Schmidhaur and W Wolj, Angew. Chem. 85,344 (1973); Angew. Chem.
internat. Edit. 12, 320 (1973).
[2] H . Stiihler, Diplomarbeit, Universitat Wiirzburg 1970.
[3] H . Gilnian and R. A. Tomasi, J. Org. Chem. 27, 3647 (1962).
[4] D. R. Marhiason, Diss. Abstr. B 27, (12) 4294 (1967); Chem. Ahstr.
68, 2942m (1968).
[5] H . Schmidhaur and W Tromch. Chem. Ber. 100, 1032 (1967)
[6] G. Wirrrg and G . Geusler, Liebigs Ann. Chem. 580, 44 (1953).
[7] D. Seyferth and G . Singh, J. Amer. Chcm. SOC.87, 4157 (1965).
[8] H . Schmidhaur and W Tronich, Chem. Ber. 101, 595 (1966)
C1 H2 N1.01
O1:NP H2'C1*
[9] N. E . Miller, Inorg. Chem. 4, 1458 (1965).
[lo] H . Schmidbuur and W Tronich, Chem. Ber. 101, 604 (1966).
[ l l ] (3), m.p. 114-11S'C.
'H-NMR (CH,CI,): 6CH, -1.27 (d, 6H)
J(HCP) 13; 6CH -6.42 (d, I H), J(HCP) 15.5; 6C,HS -7.3 Hz (m,
10H). IR: v(P=O) I160cm- I . Relative molecular mass 240 (256.3).
1121 H . Schmidbuur and W Malisch, Chem. Ber. 103. 3007 (1970).
Low-temperature X-ray Structure Analysis
of Ammonium Carbamate
By Aljired G i m w . Walter Hoppe, and
Klaus Fleischmuiirr~']
We have carried out an X-ray structure analysis of
ammonium carbamate (NH: C0,NH;). Not only is this
substance sensitive to moisture but also its relatively high
volatility results in single crystals being unstable at room
temperature even in dry air[']. The analysis was therefore
carried out in a low-temperature room at -50°C while
N z was used as protecting gas. The single crystals were
obtained by passing CO, into liquid ammonia and then
slowly evaporating the excess of ammonia.
Space group: Pbca with a=6.46, b=6.66, c = 17.00A; cell
volume: 731.,A3; p:$'- - 1 . 3 8 g . ~ m - ~ 2; = 8 .> p..
= 1.42 '. The intensities were mostly measured photographically with a Weissenberg camera (oscillating procedure) but some few with a precession camera (MOK,
radiation). Evaluation afforded 1213 independent reflections (407 not observed).
The structure was solved by direct methods using the
triple product rule and a program by Hechrfischerr2'. A
Fourier synthesis calculated with the 300 largest, phased,
unitary structure factors showed the positions of all the
atoms (except H). Refinement, first with isotropic and then
with anisotropic temperature factors, led to an R value
of 10.5%.
The hydrogen atoms of the N H 2 group, but not those
of the NH; group, could be seen after refinement in a
difference Fourier synthesis. However, since the maxima
were not sharp, these H positions were set in calculated
positions(H1 parallel to C 1-02, H 2 parallel to C 1-0 1,
N-H = 1.0 A) and only their temperature factors (isotropic) were included in the refinement ( R= 10.3%).
The planar carbamate ions associate to cyclic dimers (Fig.
l), which are held together by two N-H...O hydrogen
bridges. The dimeric anion has a crystallographic symmetry
[*] Dr. A. Gieren, Prof. Dr. W Hoppe, and
Dr. K. Fleischmann [**I
Max-Planck-lnstitut fur Biochemie, Abteilung Strukturforschung I
8033 Martinsried bei Munchen, Am Klopferspitz (Germany)
New address: Firma EnraFNonius, Delft (Holland).
Fig. 1. Centrosymmetric dimeric anion in ammonium carbamate: a)
Horizontal section: projection on N 1, C 1 , O 1; b) vertical section: projection along N 1-0 1. Standard deviations: 0.006A.0.4".
center. Its two portions are thus necessarily parallel but
they d o not lie strictly in one plane (separation of the
two planes: 0.39A). HCO; ions also form dimers
in KHC0J3], but the anions in NH4HC0J4I
and NaHC0315.61 and sodium sesquicarbonate
(Na,C03 . N a H C 0 3.2H2O)I7' polymerize-the
with inclusion of H 2 0 molecules. Dimers of our type
are found in, e.g. carboxylic acids and their amides'8j.
Similar cyclic hydrogen bridges play a role in base-pairing
ofnucleic acids[']. The N 1-0 1 hydrogen bridge is 2.96, A
long, which agrees well with the mean value of the
N-H .-.O bridge (2.94A[") for acid amides. The
hydrogen bridge is asymmetric but linear within a few
The C-N (1.36A) and the C-0 distances (1.27A) do
not differ significantly from those in urea['*] (1.356+0.007
and 1.276k 0.008 respectively); they reflect the expected
double-bond character.
The dimeric anions form buckled layers parallel to (001).
On their periphery lie the NH: ions, which, mainly by
hydrogen bridges, cross-link both the layers and the dimeric
anions within the layers. The NH; group has four nearest
0 neighbors at the corners of a distorted tetrahedron
( N 2 . . - 0 2 : 2.74, 2.80A; N 2 . . - 0 1 , 2.80, 2.87A). A fifth
oxygen atom ( 0 2 ) is considerably further removed (3.1 1
but still in the range of a N-H...O bridge, even if a
long one. The second hydrogen atom (H2) of the amin:groupalso takes part in a weak H bridge (N 1...0 1: 3.37 A).
But, unlike the H bridges in the dimeric anion, the bridges
just mentioned show large deviations from the ideal configuration. That the two C-0 distances in the dimeric
anion d o not differ significantly is probably to be ascribed
to the fact that both oxygen atoms act to about the same
extent as acceptors for hydrogen atoms.
Received. November 27, 1972 [Z 778 IE]
German version: Angew Chem 85, 308 (1973)
[I] A. Mente, Liebigs Ann. Chem. 248, 232 (1888).
[2] S. Hechrfischer, W Strigemann. and W Hoppe, Acta Cryst. B 26,
1713 (1970).
[3] I . Nirra. !l Tomiie, and f. HOP Koo, Acta Cryst. 5, 292 (1952).
[4] R. Brooks and 7: C . Alcock. Nature 166, 435 (1950).
[S] R. L. Sass and R. F . Scheuerman, Acta Cryst. 15, 77 (1962).
[6] B. D. Sharma, Acta Cryst. 18, 818 (1965).
[7] C. J . B r o w . H . S. Perser, and A . Turner-Jones, Acta Cryst. 2, 167
( 1949).
Chrm. inrrrrtar. Edit. ! Vol. I2 ( I Y 7 3 ) i No. 4
[ X I (;. (. P ~ m v i i dand A . L. MrClclluii. T h e Hydrogen Bond. Freeman.
Siin Francisco 1960.
(s/CH3), 6.35 (s/CH-N),
and 8.78 ppm
(6:4:6:1:1).--Mass spectrum: nije= 182 ( M ' ) .
L. Priirlhi~g;ind R. 5.C o w - , Arch. Biochem. Biophys. 65. 164 (1956).
[lo] 1.C r r r t ~ iand .I.
Acta Cryat. 17. 544 (1964).
Vilsmeier Formylation of Enediamined']
By C/irisriur?Reichadr and K luus Schagrrer'*"**'
Whereas Vilsmeier formylation of enamines leads to formyl
ketones and formyl aldehydes (dialdehydes)I'], the same
reaction with enediamines should permit preparation of
the hitherto inaccessible (dialkylamino)malondialdehydes.
If 1,2-dipiperidino- ( I t i ) or 1,2-dimorpholino-ethylene
reacts with N-(chloromethy1ene)-N,N-dimethylammonium chloride ( 2 ) (produced from N,N-dimethylformamideand oxalyl chloride) in chloroform, then, after Iiydrolysis of the intermediate trimethinium salt ( 3 ) , the 2-(dialkylamino)-3-(dimethy1amino)acroleins( 4 ) can be isolated; their alkaline hydrolysis affords piperidino- (50)
and morpholino-malondialdehyde ( 5 b ) , respectively.
(5 a )
Compound ( 4 a ) (1.82g, IOmmol) and NaOH ( 0 . 5 ~in
water (Bml) were stirred together for 2 h at 100 C. A
little 1-propanol was added for homogenization and the
pH wasestablished at 4-5 by meansof2 N HCI. Extraction
with ether, removal of the ether, and sublimation of the
residue at 120 C (bath temperature) and 0.1 torr yielded
thin colorless crystals (0.99g, 64%) of m. p. 195 C-IHNMR (CDCI,): 1.90 (m), 3.65 (m), 7.95 (s/OH), and 8.66
ppm (s/CH) (6:4: 1 :2).-Mass spectrum: m / e = 155 (M').
Morpholinomalondialdehyde ( 5 b ) , m. p. 205 C (dec.), was
obtained analogously.
Rccei\,ed: December 27. 1972 [Z 782 IE]
G e r m a n version: Angew. Chem. KS, 346 (1973)
[ I ] Syntheses with Substituted Malondialdehydes. Part 14. Part 13.
C. Rrir/ior~/rand P. Miudtwr. Liebigs Ann. Chem., in press.
[2] A . G . Cook. Enamtnes: Synthesis. Structiirc, and Reactions. Dckker.
New York 1969. p. 391.
[3] L. Duhunirl, P. Dirliuiii~4,and G . P/& Bull. Soc. Chim. France IY6X.
4423; IY71. 4169; L. Duhuniel, P. Duhoriirl, and I/: 7 r l i s r / / o , C R Acad.
Sci. Paris C 775, 225 (1972).
5,6-Dihydro-4H-I ,3-oxazines and
y-Amino Alcohols from a-Metalated
Isocyanides and Epoxided']
By Ulricli S d d l k o p f and Reinhad J c n t . s d ~ [ * ~
The structures of all the new products were proved by
elemental analysis and by IR, I H-NMR, and mass spectra.
The (dialkylamino)malondialdehydes ( 5 ) thus prepared
for the first time are valuable starting materials for synthesis
of dialkylamino-substituted polymethine dyes and heterocycles.
2- Piperiilino-3-( rli~~ieth~la~~iino)
( 4 a)
Oxalyl chloride (21.6g, 170mmol) is added dropwise to
a solution of N,N-dimethylformamide ( 1 1.9g, 163mmol)
in chloroform (30ml) with ice-cooling. Then a solution
of 1,2-dipiperidin0ethyleneI~~
(29g, I50 mmol) in chloroform (30ml) is added dropwise at - 5 C to the reaction
mixture, which is next stirred for 12 h at room temperature
and subsequently heated at 65-C for 12h. After cooling
to 0 'C, this mixture is hydrolyzed first with ice-water
(15 ml) and then with saturated potassium carbonate solution (180ml) with subsequent heating at 70 C for 2h.
Extraction with chloroform, removal of the solvent, and
distillation of the residue in a high vacuum gave a forerun
at 77' C/O.03 torr, followed by the main fraction at
126 C/0.03 torr, the latter solidifying to yellowish crystals
in the receiver. Recrystallization from light petroleum (b. p.
40-60 C) afforded colorless crystals (5.5 g, 20%) of m. p.
76---77 C.-'H-NMR (CDCI,): 1.50 (m), 3.03 (m), 3.25
( 8 ) without a substitueiit
at position 2 or y-amino alcohols ( 7 ) deserve attention
as precursors of tetrahydro-l,3-oxazines which are of interest chemotherapeutically[21or as intermediates in syntheses. We have found that these compounds can be
obtained simply and in relatively good yield by treating
r-lithiated isocyanides ( 2 ) with epoxides ( 3 ) , although
give only poor yields. Investigations so
far have shown that unsymmetrically substituted epoxides
are attacked prefgrentially or exclusively at the less hindered carbon atom. The lithium compounds (2) can be
obtained from alkyl isocyanides ( I ) and butyllithium.
I "/
[*] Prof Dr. Chr. Reichardt and Dip].-Chem. K . Schagerer
tachbereich Chemie der UnivcrsitPt
3 5 5 Marburg. Lahnberge (Germany)
[**I W e thank the Fonds der Chemischen Industrie for financial support.
[*] Prof. Dr. U. Schiillkopf and Dipl.-Chem. R . .Ici~tscIi
Organisch-Chemisches lnstitut der Universitiit
34 Gdttingen, Windausweg 2 (Germany)
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structure, low, temperature, analysis, ammonium, carbamate, ray
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