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Biomimetic Synthesis of a Twofold N N-Bridged Porphyrinogen.

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of the solvent provide chemical means for tuning the t c -
catalyst system.
Received: August 19, 1986;
revised: October 2, 1986 [Z 1906 IE]
German version: Angew. Chem. 99 (1987) 76
11.1 K. A. Ostoja Starzewski, J. Witte, Angew. Chem.
97 (1985) 610; Angew.
Chem. Inr. Ed. Engl. 24 (1985) 599.
I21 The polymers with a molecular weight M of ca. lo' g/mole are PE waxes.
Higher molecular weight types are hard waxes ( M S lo4 g/mole), HDPE
( M = 10' g/mole), and UHMW-PE ( M = 10' g/mol).
[3] a) A. Schonberg, A. F. A. Ismail, J. Chem. SOC.1940, 1374; b) R. F. Hudson, P. A. Chopard, Helu. Chim. Acra 46 (1963) 2178; c) G. Aksnes, Acra
Chem. Scand. 15 (1961) 692.
(41 a) D. L. Beach, J . J . Harrison, US-Pat. 4293727 (October 6, 1981), Gulf
Research and Development Company. b) Y. V. Kissin, D. L. Beach, J .
Po1.vm. Sci. Polym. Chem. Ed. 22 (1984) 333.
[5] P. Haussle, DOS 2923206 (December I I , 1980), Chemische Werke Huls
[6] HDPE molecular weights are usually catalyst-specifically regulated down
to the desired level. This is usually achieved by increasing the temperature or by use of hydrogen, comonomers, or a second metal component,
i.e. generally by termination or transfer agents. Cf., e.g., a) K.-Y. Choi, W.
H. Ray, J . Macromol. Sci. Rev. Macromol. Chem. Phys. C25 (1985) I ; b)
W. Kaminsky, K. Kulper, S. Niedoba, Makromol. Chem.. Macromol.
Symp. 3 (1986) 377; c) J. Boor: Ziegler-Narra-Catalysts and Polymerizarions, Academic Press, New York 1979, Chap. 10.
171 We obtain modified catalysts with organoaluminum compounds.
181 For a comparison of the electronic structure of R,PCH2 ligands with
R3PNX ligands and R3P0 ligands, cf. also K. A. Ostoja Starzewski, H.
tom Dieck, Inorg. Chem. 18 (1979) 3307, and references cited therein.
[9] R. Kuhn, H. Kromer, G. Rossmanith, Angew. Makromol. Chem. 40/4/
(1974) 361.
4 a , n = 0 , R = CH -CO H
4b, n = 1 , R = Et
reactive dialcohol 7, which was allowed to react in situ
(see Scheme 1) at - 60°C. Work-up and chromatographic
purification furnished the 21,24 :22,23-bis-trimethylene2,3,7,8,12,13,17,18-octaethylporphyrinogen8 as the tetrahydrate in the form of fine needles that are stable on drying (m.p. 109oC)."ol According to spectroscopic data, especially MS and 'H-NMR data, 8 is a dimeric condensation
product of 7.
Biomimetic Synthesis of
a Twofold N,N'-Bridged Porphyrinogen**
By Rarf Timmermann. Rainer Mattes, and
Burchard Franck*
Among the reactions of heme biosynthesis,l','l the cyclizing condensation of four molecules of the monopyrrole
precursor porphobilinogen 1 is of particular significance
for the development of biomimetic syntheses. 1 and structurally related pyrrole derivatives undergo highly selective
acid-catalyzed condensation to give the porphyrinogens,
the cyclic tetrapyrrole precursors of the p ~ r p h y r i n s . ' ~In
continuation of our studies on the practicability of this
biomimetids1cyclotetramerization we were able to synthesize novel, non-planar and fourfold expanded porphyrinogens 4aIb1and 4b"I by acid-catalyzed condensation of
the monopyrroles 2 and 3, respectively, and to convert
them into the corresponding porphyrins. We now report
on the use of this biomimetic principle for the synthesis of
the twofold N. "-bridged porphyrinogens 8 from the trimethylenedipyrrole 7, which can be regarded as a simplified N , "-bridged dimer of porphobilinogen 1.
The readily accessible[81 3,4-diethyl-2-formylpyrrole 5
was alkylated in the form of its potassium salt with 1,3dibromopropane to the dialdehyde 6 using a method described by Burger and Dreier."] For activation prior to
acid-catalyzed condensation, 6 was reduced to the very
Prof. Dr. B. Franck, DipLChem. R. Timmermann
Organisch~chemischeslnstitut der Universitat
Orleansring 23, D-4400 Munster (FRG)
Prof. Dr. R Mattes
Anorganisch-chemisches lnstitut der Universitat
Corrensstrasse 36, D-4400 Munster (FRG)
[**I This work was supported by the Deutsche Forschungsgemeinschaft and
the Fonds der Chemischen Industrie.
0 VCH VerlagsgeseilschaJt mbH. 0-6940 Weinheim. 1987
8, 9% based on b
Scheme I . Synthesis of 8 from 5 IS]. Reaction conditions: a) KOH/dimethyl
sulfoxide, 1,3-dibromopropane, room temperature, 14 h; chromatography on
silica gel (Merck 0.063-0.2 mm), petroleum ether/ether 4 : 1. b) NaBH,/
MeOH, room temperature, 20 min; p-TosOH/AcOH/MeOH, -60°C; chromatography on AII03, Activity I11 (Woelm), petroleum ether/ether 95 : 5
An isomeric structure with crossed trimethylene bridges,
the 21,23 :22,24-bis-trimethylene derivative, could be ruled
out on the basis of the MS and 'H-NMR data and by the
isolation and structural elucidation of a condensation intermediate. Thus, as expected for 8, preferred splitting of
the molecule into two
took place in the
spectrometer; in the case of crossed coupling this would re-
057#-#833/87/0101-0064 $ 02.50/0
Angew. Chem. Inr. Ed. Engl. 26 (1987) No. I
quire the very unlikely cleavage of four bonds. A crossed
condensation product is also irreconcilable with the 'HN M R data, because, in contrast to 8, it would be centrosymmetric and would not exhibit splitting of the methyl
and methylene signals of the ethyl side chains into two triplets and quadruplets, respectively. Furthermore, it can be
assumed that the acid-catalyzed condensation of 6 first
leads intramolecularly to 9b, from which only 8 can be
9a, R = H
9b, R
If the condensation is carried out with suppression of
the intermolecular reaction (dilution, high temperature,
and large amounts of catalyst) a crystalline product is obtained as well-formed needles in 12% yield (m.p. 92°C).
From a crystal structure analysis (Fig. 1) it followed that
the product was. the tetrahydrodipyrrolo-l,5-diazocine9a,
formed from the initial hydroxymethylene product 9b by
elimination of formaldehyde.
In contrast to the unbridged N, N', N". N"'-tetramethylporphyrinogen 4a,lb'in the new porphyrinogens 8a and 8b
there are strong steric interactions in the center of the molecule, thus rendering a planarization of the molecule difficult. As a consequence, 8 cannot be dehydrogenated like
4a to the corresponding porphyrin.
Received: September 23, 1986 [Z 1930 IE]
German version: Angew. Chem. 99 (1987) 74
[I] B. Franck, Angew. Chem. 94 (1982) 327; Angew. Chem. Inf. Ed. Engl. 21
(1982) 343.
121 M. Akthar, P. M. Jordan in D. H. R. Barton, W. D. Ollis (Eds.): Cumprehensrue Organic Chemistry, Val. 5. Pergamon, Oxford 1979, p. 1121.
[3] G. H. Cookson, C. Rimington, Biuchem. J . 57 (1954) 476.
[4] B. Franck, G. Bringmann, C. Wegner, U. Spiegel, Liehrgs Ann. Chem.
1980. 263.
151 R. Breslow, Q. Rev. Chem. SOC.I (1972) 553: "Biomirnetic chemistry is
the branch of organic chemistry which attempts to imitate natural reactions and enzymatic processes as a way to improve the power of organic
161 B. Franck, C. Wegner, Angew. Chem. 8 7 (1975) 419; Angew. Chem. I n t .
Ed. Engl. 14 (1975) 424.
[7] M. Gosmann, B. Franck, Angew. Chem. 98 (1986) 1107; Angew. Chem.
Int. Ed. Engl. 25 (1986) 1100.
[S] A. W. Johnson, 1. T. Kay, J . Chem. SOC.1965, 1620: B. Fietzke, Disserfofion, Universitat Miinster 1986.
[9] U. Burger, F. Dreier, Tetrahedron 39 (1983) 2065.
[lo] The new compounds 6, 8 , and 9a have been completely characterized
by elemental analyses and spectroscopic data.-6: m.p. =69-71 "C, 'HNMR (CDC13): 6 = 1.17 (t, J=7.6 Hz, 6 H , ethyl-CHZ at C-4/C-4'), 1.18
(t. J = 7 . 6 Hz, 6 H , ethyl-CH, at C-3/C-3'), 2.40 (4. J=7.6 Hz, 4 H , ethylCH2 at C-4/C-4'). 2.69 (4. 5 ~ 7 . 6 4, H , ethylLCHz at C-3/C-3'), 9.65 (5,
2H, 2 aldehyde-H).-8: m.p.= 109°C. MS (El). rn/z 620 (52%, Ma), 310
(28, M0/2), 162 (100, diefhyl pyrrole i 3 C H 4 ; 'H-NMR (CDC12):
6 = 1 . 1 0 ( t , J = 7 . 4 H z , 12H,4CHr), 1.17(t,J=7.4Hz, 12H,4CH,),2.27
(m, 4 H , 2 CH2 in the middle of the two bridges), 2.42 (4, J = 7 . 4 Hz, 8 H,
CH2 in 4 ethyl groups), 2.44 (4. J = 7 . 4 Hz, 8 H , C H I in 4 ethyl groups),
3.89 (t, J=6.7 Hz, 8 H, 4 N-CH? groups), 4.45 (s, 8 H, 4 meso-CH&9a: m.p.=92"C, crystallizes in the space group P2,/m, with two formula units per unit cell and has a crystallographic mirror symmetry.
a=924.5(8), b=2236(4), c=468.4(4) pm, B= I16.8(1)"; Syntex P2, diffractometer, 1057 independent reflections with F,,23.92o(F,,), 167 parameters, R =0.0561, R,=0.0522. Further details of the crystal structure
investigation are available on request from the Fachinformationszentrum Energie, Physik, Mathematik GmbH, D-7514 Eggenstein-Leopoldshafen 2 (FRG), on quoting the depository number CSD-52 163, the
names of the authors, and the full citation of the journal.-MS (El): m / z
298 (5S0/o, Ma),269 (100, Ma- Ethyl), 162 (66, diethylpyrrole + 3 C H Z ) ;
'H-NMR (CDCI,): 6 = 1.15 (t. J = 7 . 5 Hz,6 H , 2 CH,), 1.16 (t, J = 7 . 5 Hz,
6 H, 2 CHI), 2.26 (m, 5=6.8 Hz, 2 H, CHI in the middle of the trimethylene bridge), 2.40 (q, J=7.5 Hz, 4H, ethyl-CHz), 2.53 (4, J=7.5 Hz,
ethyl-CH2), 3.86(t, J = 6 . 8 Hz, 4 H , N-CH2), 4.33 (s, 2H, H at C-lO),6.28
(s, 2 H , H at C-3/C-7).
Fig. I. Crystal structure of 9a. Selected bond lengths Iprn]: C(lOa)-N(3a)
137.4(3), N(3a)-C(3) 138.3(3), C(3)-C(2) 135.9(5), C(2)-C(I) 142.4(3), C(1)C(l0a) 138.1(4). lnterplanar angle between the pyrrole rings: 1 1 1 " [lo].
Nickel Complexes with a Propellane Structure**
In 9a the pyrrole rings are tilted at 1 1 1 to each other in
a roof-like fashion. Assuming that 9a is a structural element of 8, only 8a and 8b of the four possible configurations of 8 come into question, of which, according to
model considerations, the cage-like configuration 8a is
sterically favored.
By Harald Schwager, Carl Kriiger. Richard Neidlein. and
Gunther Wiike*
Stable complexes of low-valent transition metals with
fluorine-substituted hydrocarbons have been the subject of
numerous studies over the past 20 years."] Of particular
interest is the nature of the bonding in these complexes
compared to that in non-fluorinated systems. The observa[*I
Angew. Chem. Int. Ed. Engl 26 (1987) No. I
Prof. Dr. G. Wilke, Dr. H. Schwager, Prof. Dr. C. Kriiger ['I
Max-Planck-Institut fur Kohlenforschung
Kaiser-Wilhelm-Platz I , D-4330 Mulheim a. d. Ruhr (FRG)
Prof. Dr. R. Neidlein
Pharmazeutisch-chemisches Institut der Universitat
Im Neuenheimer Feld 364, D-6900 Heidelherg (FRG)
['I X-ray structure analysis.
[**I This work was supported by the Deutsche Forschungsgerneinschaft and
the Fonds der Chemischen Industrie.
0 VCH Verlagsgesellschaft mhH. 0-6940 Weinheim. 1987
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synthesis, bridge, twofold, porphyrinogen, biomimetic
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