摘要:

68 J. CHEM. RESEARCH (S) 1997 Synthesis and Structure of Macrocyclic Diaza-bis-enediynes b Burkhard K�onig,*a Tom Fricke,a Ina Dixb and Peter G. Jonesb a ur Organische Chemie der Technischen Universit Institut f� at Braunschweig Hagenring 30 � D-38106 Braunschweig Germany Institut f�ur Analytische und Anorganische Chemie der Technischen Universit�at Braunschweig Hagenring 30 D-38106 Braunschweig Germany Scheme 1 The reaction of 1,8-dibromooct-4-ene-2,6-diyne (1) with secondary amines such as n-butylamine (2a) yields macrocyclic 2:2 substitution products 3; the structure of 3a was investigated by X-ray crystallography. We recently reported the synthesis of 1 and its facile reaction with malonates to yield macrocyclic bis-enediynes.1 Heteroatom nucleophiles of weak basicity such as phenolates or carboxylates are also suitable reactants for replacing the two prop-2-ynylic bromine substituents of 1.2 In this paper we report our attempts at using nitrogen nucleophiles in the ring-closing reaction with 1.Equimolar amounts of 1 and n-butylamine (2a) were allowed to react in CH3CN in the presence of K2CO3 as base at room temperature. Compound 3a was isolated as the only product by column chromatography. The isolated yields are low because of the competing decomposition of the starting material 1 and the product 3a under the reaction conditions and during isolation. However neither smaller (1:1) nor larger alkylation products could be detected in the reaction mixture. The absence of nine-membered 1:1 alkylation products is to be attributed to the insufficient driving force of the nucleophilic displacement reaction for the synthesis of a highly strained compound.The reaction of 1 with aniline (2b) yielded small amounts of the labile compound 3b. The compound is not stable and decomposes rapidly. The rapid decomposition of all the synthesized diaza-bisenediynes may be rationalized by a baseinduced prop-2-ynyl–allene isomerisation. The resulting ene-yne-allene is not stable at room temperature because of the facile Myers–Saito3 cyclisation. The reaction of 1 with NH3 gave 3c in 25% yield. The possible reaction of 3c with a third molar equivalent of 1 was not observed. Crystal data for 3a.† C Single crystals of 3a were obtained by slow evaporation of a chloroform solution.The X-ray structure shows a twisted conformation for the macrocyclic bis-enediyne. The distances between the acetylenic enediyne carbons C(10)·C(15) and C(2)·C(7) are 420.8 and 421.5 pm respectively. 24H30N2 Mr=346 F(000)=1504 orthorhombic a=1023.8(3) b=1716.4(7) c=2455.4(4) pm V=4.315(2) nm2 space group Pbca Z=8 Dx=1.067 Mg mµ3 T=143 K. A pale yellow prism ca. 0.8Å0.7Å0.5 mm was mounted on a glass fibre in an inert oil and transferred to the cold gas stream of a Stoe STADI-4 diffractometer with a Siemens LT-2 low-temperature attachment. A *To receive any correspondence (e-mail B.Koenig@tu-bs.de). †Atomic coordinates thermal parameters and bond lengths and angles are given in the full text and have also been deposited at the Cambridge Crystallographic Data Centre (CCDC).Any request to the CCDC for this material should quote the full literature citation and the reference number 423/2. total of 5313 intensities (3799 unique Rint=0.0431) were measured to 2y 50°. The structure was solved by direct methods and refined anisotropically on F2 (program SHELXL-93 G. M. Sheldrick University of G�ottingen). The final wR(F2) for all reflections was 0.19 with a conventional R(F) of 0.086 for 236 parameters. The high R values may be attributed to the appreciable thermal motion (or slight disorder) of the n-butyl side chains. In summary a one step procedure for the synthesis of very labile 18-membered macrocyclic diaza-bisenediynes via twofold N-alkylation of amines has been described.Techniques used 1H NMR 13C NMR IR UV MS elemental analysis X-ray diffraction References 4 Table 2 Atomic coordinates and equivalent isotropic displacement parameters for 3a Table 3 Intramolecular bond distances and angles for 3a Appendix packing diagram for 3a and Fig. 1 with thermal ellipsoids Received 25th September 1996; Accepted 5th November 1996 Paper E/5/06583J J. Chem. Research (S) 1997 68 J. Chem. Research (M) 1997 0385–0394 Fig. 1 Molecular structure of 1,10-dibutyl-1,10-diazacycloocta- 5,14-diene-3,7,12,16-tetrayne (3a) References cited in this synopsis 1 B. K�onig W. Pitsch I. Dix and P. G. Jones Synthesis 1996 446. 2 B. K�onig H. Hollnagel B. Ahrens and P. G. Jones Angew. Chem. 1995 107 2763; Angew.Chem. Int. Ed. Engl. 1995 34 2538. 3 A. G. Myers E. Y. Kuo and N. S. Finney J. Am. Chem. Soc. 1989 111 8057; R. Nagata H. Yamanakata E. Okazaki and I. Saito Tetrahedron Lett. 1989 30 4995, J. Chem. Research (S) 1997 68 J. Chem. Research (M) 1997 0385–0394 Synthesis and Structure of Macrocyclic Diaza-bis-enediynes Burkhard K�onig,*a Tom Fricke,a Ina Dixb and Peter G. Jonesb aInstitut f�ur Organische Chemie der Technischen Universit�at Braunschweig Hagenring 30 D-38106 Braunschweig Germany bInstitut f�ur Analytische und Anorganische Chemie der Technischen Universit�at Braunschweig Hagenring 30 D-38106 Braunschweig Germany The reaction of 1,8-dibromooct-4-ene-2,6-diyne (1) with secondary amines such as n-butylamine (2a) yields macrocyclic 2:2 substitution products 3; the structure of 3a was investigated by X-ray crystallography.We recently reported the synthesis of 1 and its facile reaction with malonates to yield macrocyclic bis-enediynes.1 Heteroatom nucleophiles of weak basicity such as phenolates or carboxylates are also suitable reactants for replacing the two prop-2-ynylic bromine substituents of 1.2 In this paper we report our attempts at using nitrogen nucleophiles in the ring-closing reaction with 1. Equimolar amounts of 1 and n-butylamine (2a) were allowed to react in CH3CN in the presence of K2CO3 as base at room temperature. Compound 3a was isolated as the only product by column chromatography. The isolated yields are low because of the competing decomposition of the starting material 1 and the product 3a under the reaction conditions and during isolation.However neither smaller (1:1) nor larger alkylation products could be detected in the reaction mixture. The absence of nine-membered 1:1 alkylation products is to be attributed to the insufficient driving force of the nucleophilic displacement reaction for the synthesis of a highly strained compound. The reaction of 1 with aniline (2b) yielded small amounts of the labile compound 3b. The compound is not stable and decomposes rapidly. The rapid decomposition of all the synthesized diaza-bisenediynes may be rationalized by a baseinduced prop-2-ynyl–allene isomerisation. The resulting ene-yne-allene is not stable at room temperature because of the facile Myers–Saito3 cyclisation. The reaction of 1 with NH3 gave 3c in 25% yield. The possible reaction of 3c with a third molar equivalent of 1 was not observed.Single crystals of 3a were obtained by slow evaporation of a chloroform solution. The X-ray structure shows a twisted conformation for the macrocyclic bis-enediyne. The distances between the acetylenic enediyne carbons C(10)·C(15) and C(2)·C(7) are 420.8 and 421.5 pm respectively. Crystal data for 3a.† C24H30N2 Mr=346 F(000)=1504 orthorhombic a=1023.8(3) b=1716.4(7) c=2455.4(4) pm V=4.315(2) nm2 space group Pbca Z=8 Dx=1.067 Mg mµ3 T=143 K. A pale yellow prism ca. 0.8Å0.7Å0.5 mm was mounted on a glass fibre in an inert oil and transferred to the cold gas stream of a Stoe STADI-4 diffractometer with a Siemens LT-2 low-temperature attachment. A total of 5313 intensities (3799 unique Rint=0.0431) were measured to 2y 50°.The structure was solved by direct methods and refined anisotropically on F2 (program SHELXL-93 G. M. Sheldrick University of G�ottingen). The final wR(F2) for all reflections was 0.19 with a conventional R(F) of 0.086 for 236 parameters. The high R values may be attributed to the appreciable theder) of the n-butyl side chains. In summary a one step procedure for the synthesis of very labile 18-membered macrocyclic diaza-bisenediynes via twofold N-alkylation of amines has been described. Techniques used 1H NMR 13C NMR IR UV MS elemental analysis X-ray diffraction References 4 Table 2 Atomic coordinates and equivalent isotropic displacement parameters for 3a Table 3 Intramolecular bond distances and angles for 3a Appendix packing diagram for 3a and Fig. 1 with thermal ellipsoids Received 25th September 1996; Accepted 5th November 1996 Paper E/5/06583J References cited in this synopsis 1 B.K�onig W. Pitsch I. Dix and P. G. Jones Synthesis 1996 446. 2 B. K�onig H. Hollnagel B. Ahrens and P. G. Jones Angew. Chem. 1995 107 2763; Angew. Chem. Int. Ed. Engl. 1995 34 2538. 3 A. G. Myers E. Y. Kuo and N. S. Finney J. Am. Chem. Soc. 1989 111 8057; R. Nagata H. Yamanakata E. Okazaki and I. Saito Tetrahedron Lett. 1989 30 4995 68 J. CHEM. RESEARCH (S) 1997 *To receive any correspondence (e-mail B.Koenig@tu-bs.de). †Atomic coordinates thermal parameters and bond lengths and angles are given in the full text and have also been deposited at the Cambridge Crystallographic Data Centre (CCDC). Any request to the CCDC for this material should quote the full literature citation and the reference number 423/2. Scheme 1 Fig. 1 Molecular structure of 1,10-dibutyl-1,10-diazacycloocta- 5,14-diene-3,7,12,16-tetrayne

ISSN:0308-2342    

DOI:10.1039/a606583j

出版商:RSC    

年代:1997

数据来源: RSC