Selective dichlorocyclopropanation of dicyclopentadiene under controlled phase transfer catalysis conditions

Jayachandran, Joseph Paul; Wang, Maw‐Ling

doi:10.1016/s0926-860x(00)00591-3

Cited by 16 publications

(7 citation statements)

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“…By subsequent treatment of that fraction with a 5% solution of potassium hydroxide in methanol we obtained RUSSIAN a mixture of diol II and chloride IV, and each product was isolated in the pure state by column chromatography. The formation of dichlorocyclopropane ring is confirmed by the absence in the 1 H and 13 C NMR spectra of II-IV of downfield signals from protons and carbon atoms at the double bond and the presence in the 13 C NMR spectrum of a singlet at δ C 69.43 ppm, which is typical of a carbon atom attached to two chlorine atoms in cyclopropane ring fragment [13]. The C 28 signal in the 13 C NMR spectra of II and IV (Table 1).…”

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confidence: 84%

“…Pentane, 4 ml, was added to the oily residue, the solution was separated from the precipitate by decanting, and the precipitate was washed with pentane (3 × 1.5 ml) and dried under reduced pressure to obtain 0.10 g (86%) of diacetate Va. The filtrate was evaporated, pentane was added to the oily residue, the solution was separated from the precipitate by decanting, and the solvent was removed to obtain 0.01 g (9%) of a mixture of diastereoisomers Va and Vb at a ratio of 1 : 1 (according to the 13 Hydrolysis of diacetate Va. A mixture of 0.05 g (0.082 mmol) of compound Va and 8 ml of a 5% solution of potassium hydroxide in methanol was stirred for 7 h at 20°C. The mixture was left overnight, 5% hydrochloric acid was added to pH 6, the mixture was filtered, methanol was distilled off from the filtrate, the residue was extracted with chloroform, and the extract was dried over MgSO 4 and evaporated.…”

Section: Methodsmentioning

confidence: 99%

“…13 C and 1 H chemical shifts (δ, δ C , ppm) and coupling constants (J HH ) in the NMR spectra of compounds II-IVTable 2 13. C and 1 H chemical shifts (δ, δ C , ppm) and coupling constants (J HH ) in the NMR spectra of compounds Va, Vb, VI, VII, and IX…”

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Cyclopropanation of betulin and its diacetate with dihalocarbenes

et al. 2004

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Reactions of betulin, its diacetate, and 17-acetoxy-28-norlupan-3-one with dichlorocarbene generated from chloroform follow the [1 + 2]-cycloaddition pattern leading to the corresponding adducts in moderate to quantitative yield. In the reaction with betulin, [1 + 2]-cycloaddition is accompanied by dichlorocarbene attack on the primary hydroxy group to give the corresponding halogen derivative and formate. The addition of dichlorocarbene to betulin is strictly stereoselective, while the reaction with betulin diacetate affords a mixture of two diastereoisomers at a ratio of 95 : 5. The reaction of betulin diacetate with dibromocarbene yields dibromocyclopropane derivative which can be converted into the the corresponding diol.Compounds containing a cyclopropane fragment were found among various naturally occurring biologically active substances, including steroids and terpenoids. The synthetic and biological potentials of these compounds are difficult to overestimate [1,2]. The presence of an isopropenyl group in molecules of lupane triterpenoids makes it possible to introduce a functionalized cyclopropane moiety into the side chain, thus opening wide prospects in modifying the lupane skeleton at C 20 and giving rise to new approaches to design of complex molecules on the basis of accessible lupane triterpenoids and to search for new kinds of biological activity in the series of these compounds. Among lupane derivatives containing a cyclopropane fragment, esters derived from betulin (Ia) and tetramethylcyclopropanecarboxylic and permetrinic acids have been reported [3].The double bond in compound Ia and its derivatives can be involved in isomerization, oxidation, reduction, and allylic bromination [4][5][6][7][8]. However, despite wide synthetic potential, cyclopropanation of betulin (Ia) was not studied. In particular, such experimentally simple and convenient procedure as dihalocyclopropanation of double bond under conditions of phase-transfer catalysis was not applied to betulin [9].While performing the present study, a publication appeared [10], where a high antituberculous activity was predicted by computer simulation for 20,29-dichloromethanolupane-3β,28-diol and a procedure was proposed for the synthesis of this compound in 35% yield from betulin (Ia) in one step under conditions of phase-transfer catalysis. However, no spectral data were given, and the melting point reported therein, 293-294°C, considerably differed from the melting point of a sample prepared by us.We have found that the reaction of betulin (Ia) with dichlorocarbene generated from CHCl 3 by the action of 50% aqueous sodium hydroxide in the presence of benzyltriethylammonium chloride at room temperature gives a mixture of dichlorocyclopropanated diol II, formate III, and chloride IV (Scheme 1). The reaction follows the [1 + 2]-cycloaddition pattern and is accompanied by dichlorocarbene attack on unshared electron pair on the oxygen atom of the primary hydroxy group [11,12]. Diol II was isolated in 55% yield by column chromatography. Formate...

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confidence: 84%

Section: Methodsmentioning

confidence: 99%

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Cyclopropanation of betulin and its diacetate with dihalocarbenes

et al. 2004

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“…The primary advantages of using phase-transfer catalysis are to obtain a large conversion, high reaction rate and selectivity at moderate reaction conditions. [8][9][10] It is interesting to note that powdered KOH or NaOH/BTEAC/CHCl 3 has been suggested as a very effective CCl 2 precursor. 11 A comparison with the original Makosza method showed similar yields, but the process with solid base was proved to be faster.…”

Section: Methodsmentioning

confidence: 99%

Convenient synthesis of new functionalized cyclopropanes from monoterpenic olefines

Ziyat¹,

Itto²,

Ali³

et al. 2006

Arkivoc

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“…Phase transfer catalysis (PTC) is now established as a versatile and important synthetic technique in organic synthesis chemistry 1–4. It involves simple experimental operations, mild reaction conditions, and inexpensive and environmentally benign reagents and solvents,5–7 so it has been widely used in industrial and organic chemistry.…”

Section: Introductionmentioning

confidence: 99%

Preparation of polymer‐supported polyethylene glycol and phase‐transfer catalytic activity in benzoate synthesis

2009

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The crosslinked polymeric microspheres (GMA/MMA) of glycyl methacrylate (GMA) and methyl methacrylate (MMA) were prepared by suspension polymerization. Polyethylene glycol (PEG) was grafted on GMA/MMA microsphers via the ring‐opening reaction of the epoxy groups on the surfaces of GMA/MMA microspheres, forming a polymer‐supported triphase catalyst, PEG‐GMA/MMA. The Phase‐transfer catalytic activity of PEG‐GMA/MMA microspheres was evaluated using the esterification reaction of n‐chlorobutane in organic phase and benzoic acid in water phase as a model system. The effects of various factors on the phase transfer catalysis reaction of liquid–solid–liquid were investigated. The experimental results show that the PEG‐GMA/MMA microspheres are an effective and stable triphase catalyst for the esterification reaction carried out between oil phase and water phase. The polarity of the organic solvent, the ratio of oil phase volume to water phase volume and the density of the grafted PEG on PEG‐GMA/MMA microspheres affect the reaction rate greatly. For this investigated system, the solvent with high polarity is appropriate, an adequate volume ratio of oil phase to water phase is 2:1, and the optimal PEG density on the polymeric microspheres is 15 g/100 g. Triphase catalysts offer many advantages associated with heterogeneous catalysts such as easy separation from the reaction mixture and reusability. The activity of PEG‐GMA/MMA microspheres is not nearly decreased after reusing of 10 recycles. © 2009 American Institute of Chemical Engineers AIChE J, 2010

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Selective dichlorocyclopropanation of dicyclopentadiene under controlled phase transfer catalysis conditions

Cited by 16 publications

References 29 publications

Cyclopropanation of betulin and its diacetate with dihalocarbenes

Cyclopropanation of betulin and its diacetate with dihalocarbenes

Convenient synthesis of new functionalized cyclopropanes from monoterpenic olefines

Preparation of polymer‐supported polyethylene glycol and phase‐transfer catalytic activity in benzoate synthesis

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