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On the Structure of the Optically Active Cumulenes.

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On the Structure of the Optically
Active Cumulenes Ell
By Prof. Dr. Richard Kuhn and Bernhard Schulz
Max-Planck-Institut fur Medizinische Forschung,
Institut fur Chemie, Heidelberg (Germany)
By means of oxidative degradation we have obtained o-trimethylacetylbenzoic acid (I) from the hydrocarbon described
in the literature [2] as 1,5-di(t.-butyl)-1,5-diphenylpentatetraene (m.p. 100-101 "C). The keto-acid (I) (m.p. and mixed
m. p. 119 ' C ; infrared spectrum) can also be prepared in good
yield from phthalic anhydride and t.-butylmagnesium
bromide
The above-named hydrocarbon is therefore an isomer of the
expected cumulene and arises by cyclisation; most probably
it is the indene derivative (11) [3].
II
C
II
For example, 1 mole of acetic anhydride and 0.2 ml of 60 %
perchloric acid are heated to 60 OC and 0.22 moles of trioxane
are added within 10 minutes (vigorous exothermic reaction).
The excess of anhydride is then destroyed by pouring the
reaction mixture into an aqueous suspension of sodium
bicarbonate. The mixture is subsequently extracted with
ether; an oily, yellowish product (62 g.) is obtained after
evaporation. The anhydride content (saponification number,
calculated as acetic anhydride content according to Staudinger
[l]) amounts to 69.7 %, which corresponds exactly to an
equimolar mixture of I and I1 (69.4 % theory); the yield is
94 %. Separation of the products is easily achieved by fractional distillation at atmospheric pressure. The physical
constants for (I) and (11) agree with those reported by Sraudinger [ l , 21. The composition of the product remains constant
within a wide range of experimental temperature and concentration.
Below -2O"C, compound (111) is formed in addition to (I)
and (11) (theoretical'anhydride content 53,12 %). At -65 "C
(111) constitutes 80 % of the reaction product. Its separation
was achieved in the manner described above. Other anhydrides, such as butyric or benzoic anhydride, may be used
instead of acetic anhydride.
Presumably a cationic cleavage of the trioxane ring is taking
place in combination with the acylation of products resulting
from this cleavage.
[Z 220/51E]
Received, January 26th. 1962
(11)
[l] H. Staudinger and M. Liithy, Helv. Chim. Acta 8, 41 (1925).
[2] H. Staudinger, R . Signer, H. Johner, M . Luthy, W. Kern, R .
Russidis, and 0.Schweitzer, Liebigs Ann. Chem. 474, 145 (1929).
Formula (11) is in agreement with the uptake of 3 moles of
hydrogen on catalytic hydrogenation [2] and the strong
infrared band at 1940 cm-1. The existence of stable optical
antipodes of pentatetraenes would have been surprising [4].
The existence of optical antipodes [2] of type (11) cumulenes,
however, corresponds to the situation with the known allenes
and does not signify an experimental realisation of J. H. van't
W o f f s prediction, according to which substituted pentatetraenes should exist in D- and L-forms.
Received, March 20th. 1962
[Z 243/69 IE]
[I] Cumulenes: XIV. XIIIth. communication. R . Kuhn and H.
Fischer, Chem. Ber. 94, 3060 (1961).
[2] M. Nakagawa, K . Shingu, and K . Naemura, Tetrahedron
Letters No. 22, 802 (1961).
[3] See K. Brand et al., Ber. dtsch. chem. Ges. 54, 1987 (1921);
54, 2007 (1921); 57, 846 (1924); J. prakt. Chem. 115, 335 (1927);
115, 351 (1927).
[41 No monomeric pentatetraenes are yet known; see R. Kuhn
and H . Fischer, Chem. Ber. 92, 1849 (1959); R . Kuhn, H. Fischer,
and F. A . Neugebauer, Liebigs Ann. Chem., in the press.
Ring Closures with Acylated Carbodiimides
By Dr. K. Hartke and Quim. Farm. J. Bartulin
Central Institute of Chemistry,
University of Concepci6n (Chile)
Aliphatic carbodiimides easily add carbonyl halides at room
temperature. However, the adducts, which tend to decompose into the starting compounds, can be isolated in the
pure form only in special cases [l]. In solution, acylated
carbodiimides react very readily with nucleophilic reagents
and can be used for the synthesis of heterocyclic compounds.
c
1
By Ing. CSc. J. TomiSka and Ing. E. Spousta
We have found that mono-, di-, and trioxymethylene diacetates (I, 11,111) are formed easily, and almost quantitatively,
by cleavage of trioxane in acetic anhydride solution in the
presence of strong mineral acids, especially perchloric acid :
I
1
Ll
Institute for Research in Macromolecular Chemistry,
Brno (Czechoslovakia)
--
r
Low-Molecular Polyoxymethylene
Diacetates from Trioxane
RZ
N-C-CH3
I
(11) 0
Dioxane
X = -NHz or -OCH3
/\/N\/N-H
6
--- (IV)
R1= R2 = isopropyl; m.p. 140 "C
(IV) a: R1= Rz = isopropyl; m.p. 81 "C
b: R1= R2 = cyclohexyl; m.p. 122°C
c : R1 = t.-butyl; R2 = methyl (also possible RI = methyl,
RZ= t.-butyl); m.p. 1 3 2 T
(11)
(111)
Acetylated aliphatic carbodiimides (e.g. I) react with anthranilamide or methyl anthranilate (11) to form 4-quinazolones (111, 'IV). The yields amount to approximately 65%.
Received, February 5th. 1962
[Z 212!49 IE]
[l] H. D . Stachel, Angew. Chemie 71, 246 (1959); 73, 64 (1961).
Angew. Chem. internat. Edit. 1 VoI. I (1962) No. 4
211
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