3603-99-4Relevant academic research and scientific papers
Synthesis of bridged nicotinates having [n](2,5)pyridinophane skeletons (n=8-14)
Kanomata, Nobuhiro,Yamada, Shinsuke,Ohhama, Takayuki,Fusano, Akira,Ochiai, Yoshiharu,Oikawa, Jun,Yamaguchi, Masahiro,Sudo, Fumio
, p. 4128 - 4138 (2006)
Synthesis of various bridged nicotinates 6 having [n](2,5)pyridinophane skeletons (n=8-14) was accomplished by the unique pyridine-formation reaction of methyl propiolate with a series of formyl-substituted (vinylimino)phosphoranes 5, which were prepared from the corresponding cycloalkanones 1 via Vilsmeier-Haack formylation giving chloro-substituted cycloalkenals 2, their thermal and photochemical transformation to formyl azirines 4, and the following ring-opening reactions with triphenylphosphine. The HPLC analysis of [11](2,5)pyridinophane derivatives, (Sp,S)-14 and (Rp,S)-14, showed that these diastereomers rapidly epimerize themselves at room temperature and that their planar-chirality was thermodynamically less stable as compared to the corresponding [11](2,5)cyclophane systems.
Cyclopentadecanon preparation method
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Paragraph 0012; 0074-0075, (2018/03/26)
The invention discloses a cyclopentadecanon preparation method. Specifically, the method comprises the following steps: (a) in an inert solvent, reacting formula IV compound with diazomethane to formformula III compound; (b) in the inert solvent, reacting the formula III compound with the diazomethane to form formula II compound; (c) in the inert solvent, reacting the formula II compound with thediazomethane to form formula I compound. The method disclosed by the invention has the characteristics of ability in accurately controlling pressure and material feeding, ability in greatly improvingreaction speed, stable reaction yield, high product purity and low technological cost; thus, the method has a wide application prospect.
Exaltone (=Cyclopentadecanone) from Isomuscone (=Cyclohexadecanone), a one-C-atom ring-contraction methodology via a stereospecific favorskii rearrangement: Regioselective application to (-)-(R)-muscone
Chapuis, Christian,Robvieux, Fabrice,Cantatore, Carole,Saint-Leger, Christine,Maggi, Laurent
, p. 428 - 447 (2012/05/07)
Treatment of cyclohexadecanone (1g; with I2 (2.2 mol-euqiv.) and KOH in MeOH) furnished the unsaturated (Z)-ester 2g in 83% yield, via a stereospecific Favorskii rearrangement (Scheme 1). Further treatment with 3-chloroperbenzoic acid (m-CPBA) afforded the unreported epoxy ester 3g (88% yield), which was cleaved in 33% yield to Exaltone (=cyclopentadecanone; 1f) with NaOH in MeOH/H2O and then HCl at 65°. This methodology was similarly extended to higher (C17) and lower (C15 to C11) cyclic ketone analogues, as well as regioselectively to (-)-(R)-muscone (5c) and homomuscone (5f) (Scheme 2). Olfactive properties of the corresponding macrocyclic 1-oxaspiro[2,n]alkanes and -alkenes 4 and 8, resulting from a Coreyi-Chaykovsky oxiranylation, are also presented. Copyright
A novel, short and repeatable two-carbon ring expansion reaction by thermo-isomerization: Easy synthesis of macrocyclic ketones
Nagel, Matthias,Hansen, Hans-Ju?rgen,Fra?ter, Georg
, p. 275 - 279 (2007/10/03)
A novel two-carbon ring enlargement procedure, in which medium- and large-ring 1-vinylcycloalkanols are thermoisomerized in a flow reactor system at temperatures of 600°C to about 650°C, produces the isomeric ring-expanded cycloalkanones directly and efficiently. This two-step ring expansion protocol can easily be applied several times successively. For e.g., the musk odorant cyclopentadecanone (Exaltone?) is prepared from cycloundecanone in two repetitive cycles. Thermo-isomerization of the corresponding ethynylic cycloalkanols gives in moderate yields the bishomologous α,β-unsaturated macrocyclic (E)-2-cycloalkenones. A reaction mechanism via alkyl hydroxyallyl biradical intermediates is proposed.
A facile electrochemical approach for the synthesis of macrocyclic alkanones
Singh, Arpita,Singhal, Nishi,Agrawal, Hemlata,Yadav, Ashok K.
, p. 423 - 426 (2007/10/03)
The synthesis of macrocyclic alkanones, viz. cyclotetradecanone 4a, cyclohexadecanone 4b, cyclooctadecanone 4c, cyclopentadecanone 4d and cycloheptadecanone 4e have been carried out by using Kolbe symmetrical/unsymmetrical dimerization followed by cyclization in Na-xylene and subsequent reduction with Zn-HCI in 70-80% yield. The products of anodic cross coupling have been separated by column chromatography over silica gel (60-120 mesh) by eluting with benzene-methanol (95: 5). An effort has been made to optimize the electrochemical step by investigating the effect of different parameters, viz. degree of partial neutralization, current density and electrode material. The products have been characterised by elemental analyses and IR and 1H NMR spectral data.
1-Alkenylcycloalkoxy Radical Chemistry. A Two-Carbon Ring Expansion Methodology
Galatsis, Paul,Millan, Scott D.,Faber, Tim
, p. 1215 - 1220 (2007/10/02)
The exploitation of alkoxy radicals derived from 1-ethenylcycloalkanols for use in a two-carbon ring expansion protocol was proposed.Direct one-pot alkoxy radical-mediated fragmentation-cyclization was not feasible since the reactive intermediate was quenched by iodine in the reaction mixture.However, via the use of iodo epoxides 3, the tandem fragmentation-cyclization sequence could be accomplished.This afforded ring-expanded products via an endo mode of cyclization, although in one example product from an exo mode of cyclization was also isolated.This methodologywas shown to be valid for large ring compounds as well.The intermediary of iodo epoxides 3 also afforded improved yields as compared to the direct cyclization of iodo enones 4.These results are the first examples of radical cyclization to medium-sized carbocycles.
Mesomorphic State of Cyclotetradecane
Drotloff, H.,Rotter, H.,Emeis, D.,Moeller, M.
, p. 7797 - 7803 (2007/10/02)
Cyclotetradecane shows a thermal transition 7 K below the melting point.The high-temperature crystal phase is characterized by high molecular mobility and easy deformation.Thermal analysis, MAS 13C NMR with high-power proton decoupling, X-ray diffraction, and birefringence experiments have been performed and are discussed with respect to the onset of molecular motion and molecular disorder.The NMR experiments clearly show the onset of a conformational interconversion process well below the transition, while the positional, orientational, and conformational order are largly preserved.The same applies to some extent even within the high-temperature crystal phase.It is thus shown that molecular dynamics must be strictly differentiated from molecular and crystal disorder.Disordering of molecules with low symmetry such as cyclotetradecane is shown to result in rather large transition entropies, even when the molecular motins are jumplike and involve only minor disorder in the crystal.The concepts of liquid crystal, plastic crystal, and condis-crystal are discussed with regard to the classification of the mesomorphic character of the high-temperature crystal phase of cyclotetradecane.It is classified as a molecule that shows a mesophase with partial orientational disorder and high conformational mobility.
MACROEXPANSION METHODOLOGY; MEDIUM RING SYNTHESIS BASED ON AN EIGHT UNIT RING EXPANSION PROCESS
Wender, Paul A.,Sieburth McN., Scott,Petraitis, Joseph J.,Singh, Sunil K.
, p. 3967 - 3975 (2007/10/02)
Treatment of 1,2-(E,E)-di(1-buta-1,3-dienyl)cyclohexanol (21) with potassium hydride in tetrahydrofuran at room temperature resulted in the facile formation of a 14-membered ring dienolate which on kinetic protonation provided cyclotetradeca-3,5,7-trien-1-one.This novel rearrangement which provides the basis for an efficient, eight unit ring expansion method was also observed when 5,8-dimethyl-5-hydroxy-1,3,7,9-decapentaene (28), the acyclic analogue of 21, was treatad with potassium hydride in tetrahydrofuran.Methodology for the preparation of 21 and 28 including the preparation of 1-lithio-1,3-butadiene is also described.
