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Crystal Structure of Triisopropylidenecyclopropane.

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Simplified Process for Preparation of Anhydrides
of Aromatic Acids
By P. Rambacher and S. Make[*]
Anhydrides of aromatic carboxylic acids are prepared by reaction of an acid chloride with the sodium salt of the same or
another acid[]], or by treating the acid chloride with pyridine
and decomposing the reaction mixture with water [Zl. The
procedure becomes appreciably simpler if the acid chloride is
allowed t o react with a solution of sodium hydrogen carbonate t o which a small amount of a weak tertiary base such as
pyridine has been added. Use of a water-insoluble base o r
alkali hydroxide in place of the hydrogen carbonate leads to
considerably lower yields [3]. The reaction is also suitable for
preparation of large amounts of anhydride in very good yield
and high purity.
o-Efhoxybenzoic anhydride: 16.8 g (0.2 mole) of sodium hydrogen carbonate is dissolved in 300 ml of water. 4 ml of
pyridine is added, then 36.9 g (0.2 mole) of u-ethoxybenzoyl
chloride is added dropwise during 30 min. The temperature
is kept at 20 "C by cooling. 29.1 g (92.7 %) of the anhydride
(m.p. 74-75 "C) is isolated after 1 hour's stirring. Recrystallization from benzene/ethanol gives rod-shaped crystals of
m.p. 77.5 "C.
Received: April 8, 1968
[Z 763 IEI
German version: Angew. Chem. 80, 487 (1968)
[*I Dr. P. Rambacher and S. Make
Forschungslaboratorium des Werkes Pharmazell der
Aschaffenburger Zellstoffwerke A.G.
8201 Redenfelden (Germany)
[l] N . V . Iparieff and B. S . Friedman, J. Amer. chern. SOC.61,
684 (1939).
121 Houben- Weyl-Miller: Methoden der organischen Chemie.
4 th. Edit., Thieme, Stuttgart 1952, Vol. VIII, p. 477.
[31 L. Edeieanu and A. Zaharia, Bull. SOC.Sciinte Fizice 3, 80
The Figure shows the bond lengths and bond angles at the
present stage of refinement ( R = 0.16). The figures given are
the mean values of chemically equivalent bonds and angles
and their double standard error (+2a), calculated from the
scatter of the individual values. The bonds in the cyclopropane ring are remarkably short, a fact which is probably
due t o the interaction between the three neighboring double
Received: April 4, 1968
[Z 764 IE]
German version: Angew. Chem. 80,487 (1968)
[*] Dr. H. Dietrich and Dr. H. Dierks
Fritz-Haber-Institut der Max-Planck-Gesellschaft
1 Berlin 33, Faradayweg 4-6 (Germany)
[l] G. Kobrich and H. Heinemann, Angew. Chem. 77,590 (1965);
Angew. Chem. internat. Edit. 4, 594 (1965); G. Kobrich, H .
Heinemann, and W. Zundorj, Tetrahedron 23, 565 (1967).
[ 2 ] J . D. Dunifz and A . Mugnoli, Helv. chim. Acta 49, 1680
Dibenzo [b,dJphosphorin
By P. de Kue, R . van Veen, and F. Bickelhaupt[*l
As part of our studies of aromatic compounds containing
tervalent pzc-hybridized phosphorus as heteroatom we prepared the linearly annelated dibenzo[b,e]phosphorin 11I; we
ROW report the preparation of dibenzo[b,d]phosphorin (= 9phosphaphenanthrene) ( I ) in solution.
As starting material we used 5,6-dihydro-5-hydroxydibenzo[b,d]phosphorin-5-one (2) (21, which was reduced to 5,6-dihydrodibenzo[b,d]phosphorin (3) [41, b.p. 132 "Cj0.01 torr,
in 92 % yield by diphenylsilane[31. 20.15 g of (3) in 350 ml of
methylene chloride was stirred under nitrogen with 7.3 ml of
h at -3OOC and then for l / 2 h at room
phosgene for
temperature [51. The residue obtained o n evaporation under
vacuum gave, on molecular distillation (bath temperature
160 O C , 0.001 torr), 5-chloro-5,6-dihydrodibenzo[b,d]phosphorin ( 4 ) [41, m.p. 58-62 O C , as main fraction in a yield of
35 %.
Crystal Structure of Triisopropylidenecyclopropane
By H. Dietrich and H. Dierks[*l
Triisopropylidenecyclopropane(prepared by Kubrich et al. 111)
crystallizes in the space group P 61 (Ci) with a = 9.39 A, c =
21.36 A, V= 1631 A3, n = 6, and X-ray density 0.9912 g cm-3.
The space group and unit cell were determined previously by
Dunirr and Mugnoli [21 who, however, found different cell
dimensions and a much greater density.
We used three-dimensional X-ray diffraction data (filtered
Cu-K, radiation, multifilm technique), the intensities of
reflections being estimated visually with the aid of comparison scales.
The molecules are arranged in flat sheets perpendicular t o
the c-axis, as concluded previously by Dunitz and Mugnoli
from the high intensity of the (001) reflections. In crystals obtained by recrystallization from ethanol these layers are
apparently stacked irregularly, as can be recognized in the
diffraction diagrams from extension of the reflections along
the length c * . This disorder could be removed, as suggested
by Kobrich, by tempering the crystals for 24 h at 120 OC.
2) HCI
Removal of HC1 was achieved by treating 490.6 mg of the
product (4)in 90 ml of anhydrous, degassed ether at -196 "C
with 394.6 mg of 1,5-diazabicyclo[5.4.0]undec-5-ene (5) 161
(23 % excess) and, after the vessel had been sealed in a vacuum, warming the mixture t o room temperature. A yellow
precipitate was formed [after 3 h, 368.5 mg, of which 291.9
mg was hydrochloride of ( 5 ) (= 73 % yield)]; for determination of the UV spectrum the colorless solution was filtered
from the precipitate into a glass-to-glass sealed 0.1 cm cuvette.
The spectrum obtained (Fig. 1). which we ascribe t o compound (i), reached maximum intensity after 3 hours (extinction E = 0.45 a t A = 372 nm). When compared with the
+ Base
Angew. Chem. internat. Edit.
1 VoI. 7 (1968) f Nu.6
+ Base
- IICl
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crystals, triisopropylidenecyclopropane, structure
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