4481-35-0Relevant academic research and scientific papers
An efficient preparation of 2H-cyclohepta[b]furan-2-ones
Morita, Noboru,Kudo, Masao,Yokoyama, Ryuji,Ito, Shunji
, p. 679 - 689 (2007/10/03)
2H-cyclohepta[b]furan-2-one (3) was prepared in high yield from a [2+2] cycloadduct between cycloheptatriene and dichloroketene by Baeyer-Villiger oxidation followed by dehydrochlorination. 3-Chloro- (8) and 6-chloro-2H-cyclohepta[b]furan-2-one (9) were obtained from the [2+2] cycloadduct by adding an epoxidation step to the above synthetic way in moderate yields.
Synthesis of polyalkylphenyl prop-2-ynoates and their flash vacuum pyrolysis to polyalkylcyclohepta[b]furan-2(2H)-ones
Nagel, Matthias,Hansen, Hans-Juergen
, p. 1022 - 1048 (2007/10/03)
A new method for the smooth and highly efficient preparation of polyalkylated aryl propiolates has been developed. It is based on the formation of the corresponding aryl carbonochloridates (cf Scheme 1 and Table 1) that react with sodium (or lithium) propiolate in THF at 25-65°, with intermediate generation of the mixed anhydrides of the arylcarbonic acids and prop-2-ynoic acid, which then decompose almost quantitatively into CO2 and the aryl propiolates (cf. Scheme 11). This procedure is superior to the transformation of propynoic acid into its difficult-to-handle acid chloride, which is then reacted with sodium (or lithium) arenolates. A number of the polyalkylated aryl propiolates were subjected to flash vacuum pyrolysis (FVP) at 600-650°and 10-2 Torr which led to the formation of the corresponding cyclohepta[b]furan-2(2H)-ones in average yields of 25-45% (cf. Scheme 14). It has further been found in pilot experiments that the polyalkylated cyclohepta[b]furan-2(2H)-ones react with 1-(pyrrolidin-1-yl)cyclohexene in toluene at 120-130°to yield the corresponding 1,2,3,4- tetrahydrobenz[a]azulenes, which become, with the growing number of Me groups at the seven-membered ring, more and more sensitive to oxidative destruction by air (cf. Scheme 15).
Reaction of 2,2,2-Triphenyl-2H-6,11-methanocycloundec-1,2λ5-oxaphosphole (2-Triphenylphosphoranylidenemethyl-5,10-methanoannulenone) and Its Related Compounds with Heterocumulenes
Nitta, Makoto,Naya, Shin-ichi
, p. 2363 - 2380 (2007/10/03)
Reactions of 2,2,2-triphenyl-2H-6,11-methanocycloundec-1,2λ5-oxaphosphole annulenone> 8 and 2-(triphenyl-phosphoranylidenemethyl)tropones 9a-c with heterocumulenes have been studied to provide evidence for a P---O bonding betaine and to explore a preparative method for annulated heterocycles. The reaction of 8 with phenyl isocyanate 2 afforded N-phenyl-2H-6,11-methanocycloundecapyrrol-2-one in good yield, while that with phenyl isothiocyanate 4 afforded N-phenyl-2H-6,11-methanocycloundecapyrrol-2-thione and 2-(N-phenylamino)-4H-6,11-methanocycloundecathiophen-4-one in good combined yield. On the other hand, the reaction of 2-triphenylphosphoranylidenemethyltropone 9a, its ethoxycarbonyl- and cyano-substituted derivatives 9b,c with the isocyanate 2 gave 2H-cycloheptafuran-2-ones along with N-phenyl-2H-cycloheptafuran-2-imines, which are obtained by the reaction of compounds 9a,b with diphenylcarbodiimide 3. On the other hand, the reaction of compound 9a with the isothiocyanate 4 afforded 2-(N-phenylamino)-4H-cycloheptathiophen-4-one in addition to N-phenyl-2H-cycloheptafuran-2-imine, while compounds 9b,c reacted with the isothiocyanate 4 to give 2H-cycloheptafuran-2-thiones along with N-phenyl-2H-cycloheptafuran-2-imines. The reaction pathways and the important behavior of a P---O bonding structure for 8, as compared to that for 9a-c, are discussed on the basis of the 31P NMR spectral data and product analyses.
Synthesis and analysis of positive inotropic effects of 3-substituted-2H-cyclohepta[b]furan-2-one derivatives
Yokota,Yanagisawa,Kosakai,Wakabayashi,Tomiyama,Yasunami
, p. 865 - 871 (2007/10/02)
Several 3-substituted-2H-cyclohepta[h]furan-2-one derivatives were prepared and tested in vitro for positive inotropic character. Introduction of an isopropyl group at the 5-position of compound 8a caused an increase of PIC50 (negative logarithm of the dosage which increases the contractile force by 50%) from 4.48 to 5.10. Among the 5-isopropyl-8-alkoxy compounds, the isopropoxy compound 12f had the most potent activity with a PIC50 value of 5.99. Conversion of the ester group at the 3-position to a methylene group and of the alkoxy group at the 8-position to a substituted amino group caused a decrease in activity. The most active compound, 12f, was also found to bave a weaker heart rate (HR)-increasing effect compared to milrinone and amrinone.
Cycloadditions of Methanoannulenones with Dichloro- and Chloro-ketenes. Preparation of 2H-Methanocycloundecafuran-2-one Ring Systems
Nitta, Makoto,Tomioka, Hiroki,Akaogi, Akira,Takahashi, Kensuke,Saito, Katsuhiro,Ito, Kazuaki
, p. 2625 - 2630 (2007/10/02)
Cycloaddition of dichloroketene with 3,8-methanoannulenone 5 proceeded smoothly to give 3-chloro-2H-4,9-methano- and 3-chloro-2H-6,11-methano-cycloundecafuran-2-ones 4a and 7a in good combined yield, while that with 4,9-methanoannulenone 6, gave 3-chloro-2H-5,10-methanocycloundecafuran-2-one 11a in modest yield.Reductive elimination of the 3-chlorosubstituent of 4a, 7a and 11a was successfully accomplished to give the corresponding parent 2H-methanocycloundecafuran-2-ones 4b, 7b, and 11b, respectively.In a similar reaction using chloroketene, compound 5 gave unsubstituted-, 3-chloroacetyl- and 3-(1-chloroacetoxy-2-chloro)vinyl-2H-4,9-methanocycloundecafuran-2-ones 4b, 19 and 20 in good combined yield, while with 6, only 3-chloroacetyl-2H-5,10-methanocycloundecafuran-2-one 21 was obtained in modest yield.The reactivity and/or regioselectivity of the cycloadditions were rationalized on the basis of AM1 calculations.An X-ray crystallographic determination of compound 4a was also carried out.
