Showing papers on "Cyclopropane published in 1968"
64 citations
TL;DR: In this article, the stereochemistry of the following ring opening reactions are discussed: 1. Homoallylic rearrangement of secondary and tertiary cyclopropyl alcohols in the presence of electrophilic reagents, 2. The addition of carboxylic acids to vinylcyclopropanes, 3. The thermal rearrangements of vinylcyclopric compounds into cyclopentenes.
Abstract: This review article deals with the stereochemistry of the following ring opening reactions: 1. Homoallylic rearrangement of secondary and tertiary cyclopropyl alcohols in the presence of electrophilic reagents, 2. The addition of carboxylic acids to vinylcyclopropanes, 3. The thermal rearrangement of vinylcyclopropanes into cyclopentenes. An account is also given of the NMR spectroscopic determination of the conformations of substituted vinylcyclopropanes.
57 citations
56 citations
TL;DR: In this paper, the electronic structure of cyclopropane, ethylene oxide and ethylenimine was investigated using the Pople-Segal Complete Neglect of Differential Overlap self consistent field molecular orbital method, including all valence electrons.
Abstract: The electronic structure of cyclopropane, ethylene oxide and ethylenimine, have been investigated using the Pople-Segal Complete Neglect of Differential Overlap self consistent field molecular orbital method, including all valence electrons. The theory gives a good account of the ground state charge distributions and dipole moments and a reasonable interpretation of the electronic spectra of the three molecules.
42 citations
40 citations
TL;DR: In this article, the cis octadecenoic esters have been converted to cyclopropane compounds by reaction with zinc-copper couple and di-iodomethane.
38 citations
TL;DR: In this article, the photolysis of cyclocamphanone to cyclopropane ring to give cyclopentadiene and ketene has been shown to yield cyclic acetal.
Abstract: ion from the solvent by the excited cyclocamphanone to give (XXV), cleavage of the cyclopropane ring to give (XXXVI), and hydrogen atom transfer and ketonization. This postulated route for the isomerization of cyclocamphanone to (XXXIV) is based on the proposal by Srinivasan for the route of isomerization of camphor to the ketone (XIV)'°. The photolysis of (XXXIV) to give (XVI) finds close analogy in work on the photolysis of dehydronorcamphor (XXXVII a) which has shown that cleavage occurs to give cyclopentadiene and ketene'5. A similar reaction has also been observed in the case of dehydrocamphor with a 5-aryl substituent (XXXVII b) which gives a 3-aryl-1 ,5,5-trimethylcyclopentadiene (XXXVIII b)'6. Formation of cyclic acetals by irradiation of other cyclic ketones Since our original preliminary report on the novel photochemical ring expansion of cyclic ketones to cyclic acetals'7 many other examples have come to light. Hostettler18 found that irradiation of the bicyclic ketone (XXXIX) gave two major products. One of these is the cyclic acetal (XL), which is the analogue of the acetals obtained from cyclocamphanone and nortricyclanone. The other is the ester (XLI), which is considered to be formed from the corresponding ketene, itself formed by photocleavage of the four-membered ring in a well-known fashion that was first observed in the vapour phase photolysis of cyclobutanone itself19. Hostettler20 has also observed cyclic acetal formation in the photochemical reactions of a series of 3-substituted-2,2,4,4-tetramethylcyclobutanones (XLII). Irradiation in alcohols gave a mixture of the corresponding ring-expanded cyclic acetal
37 citations
TL;DR: Perfluorobutadiene and tris(triphenylphosphine)chlororhodium(I) gave a complex with a diolefinic heterocycle formed through loss of two fluorine atoms and of constitution (C4F4)RhCl(PPh3)2 as mentioned in this paper.
Abstract: The interaction of dicarbonylchlororhodium(I) dimer with cyclopropane produces a dimeric complex, [(C3H6CO)RhCl(CO)]2, which involves rhodium(III) in a five-membered ketonic heterocycle together with bridging halogens. The bridge can be cleaved by aromatic amines or triphenylphosphine (L) to give either a monomeric complex, (C3HC6O)RhCIL2, or the salt [(C3H6CO)Rh(CO)L2]Cl, where the heterocyclic ring is retained.Perfluorobutadiene and [RhCl(CO)2]2 give again a rhodium(III) complex, [(C4F6)Rh(CO)2Cl]2, with the metal atom in an unsaturated perfluoroheterocycle.Perfluorobutadiene and tris(triphenylphosphine)chlororhodium(I) also give a complex with a diolefinic heterocycle formed through loss of two fluorine atoms and of constitution (C4F4)RhCl(PPh3)2. By contrast buta-1,3-diene gives a chelating diolefin complex of rhodium(I), (C4H6)RhCl(PPh3)2.The complexes are characterised inter alia by i.r. and n.m.r. spectroscopy.
33 citations
TL;DR: In this article, the Doering-Hoffmann procedure was used to obtain 17 new gem-dihalocyclopropyl-substituted derivatives of carbon, silicon, germanium and tin.
30 citations
TL;DR: In this paper, the NaH-catalyzed Michael type condensations of (−)-menthyl chloropropionate with methyl methacrylate, conducted in media of varying dielectric constant, unequivocally showed the dependence of stereoselectivity of the reaction on solvent polarity.
22 citations
TL;DR: In this paper, the gas phase photolysis of cyclopropane was investigated at 1470 A (8.4 eV), 1236 A (10 eV) and 1048-67 A (11.6-11.8 eV).
Abstract: The gas‐phase photolysis of c‐C3H6–O2, c‐C3H6–NO, and c‐C3H6–H2S mixtures has been investigated at 1470 A (8.4 eV), 1236 A (10 eV), and at 1048–67 A (11.6–11.8 eV), that is, at photon energies below and above the ionization energy of cyclopropane (I.E. = 10.06 eV). Examination of the products formed in the gas‐phase experiments at 1470 and 1236 A as well as of those formed in a few solid‐phase photolysis experiments indicate that the major primary act of the neutral excited cyclopropane molecule can be written as follows: c‐C3H6 + hv→CH2CH2CH2*. The highly excited trimethylene decomposes by the following two processes; (a) CH2CH2CH2*→C2H4+CH2 and (b) CH2CH2CH2*. There is, however, also evidence for rearrangement CH2CH2CH2*→CH3CHCH2* which, at low densities, is always followed by fragmentation of CH3CHCH2*. The primary process c‐C3H6 + hv→H2+C3H4 is of negligible importance, but detachment of H atoms before or after ring opening does occur, and increases in importance, at higher energies. At 1236 A the qua...
TL;DR: In this article, the synthesis of α-pyrones related to isodehydracetic acid (2,4-dimethyl-6-oxopyran-3-carboxylic acid), their bromination, and the reaction of the bromo-compounds with bases have been reinvestigated and extended.
Abstract: The synthesis of α-pyrones related to isodehydracetic acid (2,4-dimethyl-6-oxopyran-3-carboxylic acid), their bromination, and the reaction of the bromo-compounds with bases have been reinvestigated and extended. The sodium-catalysed condensation of β-keto-esters and related compounds with acetyenic esters provides a satisfactory general method for synthesis of the α-pyrones. The reactions of the bromo-pyrones with alkali depend markedly on the structure of the pyrone, the nature of the alkali, and the reaction conditions, and give, variously, acyclic, cyclopropane, cyclopentane, and furan acids or their decarboxylation products. The formation of alkylidenecyclopropanes like Feist's acid is not a very general reaction.
TL;DR: In this article, the major reaction product is a polymer under static conditions, and the polymer is inhibited by free radical scavengers such as NO, O2, butadiene-1,3, etc.
Abstract: Under static conditions the major reaction product is a polymer. Polymerization is inhibited by free radical scavengers such as NO, O2, butadiene-1,3, etc. with a simultaneous large increase in pro...
TL;DR: In this article, it was shown that the solution contained a labile derivative of the reaction intermediate(s) of I and II on alkaline hydrolysis, which led to the conclusion that both I and I could be derived from a common cyclopropane intermediate.
Patent•
06 Dec 1968
TL;DR: An active ingredient may be used in admixture with a synthetic pyrethroid having a greater toxicity to houseflies, e.g. piperonyl butoxide as discussed by the authors, and these mixtures may be obtained by esterifying a furylmethyl alcohol with a mixture of acids or their derivatives.
Abstract: 1,260,847. Insecticides containing cyclopropane carboxylates. NATIONAL RESEARCH DEVELOPMENT CORP. 2 Dec., 1969 [6 Dec., 1968], No. 58144/68. Heading A5E. [Also in Division C2] An insecticidal composition contains as active ingredient a furylmethyl dialkyl-cyclopropane carboxylate of the formula (I):- wherein one of R 1 and R 2 is a C 1-4 alkyl group and the other is a hydrogen atom, each of R 3 and R 4 is a hydrogen atom or an alkyl, alkenyl or alkadienyl group and Y is an alkyl, alkenyl or alkadienyl group or an aryl or heterocyclic group optionally substituted by an alkyl, alkadienyl, alkenyl or alkoxy group or by halogen atoms. The composition may be in the form of a dust, granular solid, wettable powder, emulsion, emulsifiable concentrate, spray or aerosol or other solid or liquid preparation and may also contain a pyrethrum synergist, e.g. piperonyl butoxide. The active ingredient may be used in admixture with a synthetic pyrethroid having a greater toxicity to houseflies, e.g. furylmethyl esters with chrysanthemumic or pyrethric acids, and these mixtures may be obtained by esterifying a furylmethyl alcohol with a mixture of acids or their derivatives.