Showing papers on "Cyclopropane published in 1971"
TL;DR: X-ray-diffraction methods show that the structures formed in water by phosphatidylethanolamine, isolated from organisms grown at 5 degrees C and 22 degrees C, are identical when compared at the respective growth temperatures, which points to a control mechanism of the physical state of the lipids that is sensitive to the operating temperature of the organism.
Abstract: 1. Pseudomonas fluorescens was grown at various temperatures between 5°C and 33°C. The extractable lipids from organisms at various stages of growth and grown at different temperatures were examined. 2. The extractable lipids contained phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, and an ornithine-containing lipid. The relative amounts of these lipids did not vary significantly during growth or with the changes in growth temperature. 3. The major fatty acids were hexadecanoic, hexadecenoic and octadecenoic acids and the cyclopropane acids methylene-hexadecanoic and methylene-octadecanoic acids. The relative amount of unsaturated acids (including cyclopropane acids) did not change significantly during growth, but increased with decreasing temperature. 4. Phosphatidylethanolamines with different degrees of unsaturation and containing different amounts of cyclopropane acids were isolated from organisms grown at 5°C and 22°C and their surface and phase behaviour in water was investigated. Thermodynamic parameters for fusion and monolayer results for cyclopropane and other fatty acids were examined. 5. The surface pressure–area isotherms of phosphatidylethanolamines containing different amounts of unsaturated fatty acids show small differences but the individual isotherms remain essentially unchanged over the temperature range 5–22°C. X-ray-diffraction methods show that the structures (lamellar+hexagonal) formed in water by phosphatidylethanolamine, isolated from organisms grown at 5°C and 22°C, are identical when compared at the respective growth temperatures. This points to a control mechanism of the physical state of the lipids that is sensitive to the operating temperature of the organism. 6. The molecular packing of cyclopropane acids is intermediate between that of the corresponding cis- and trans-monoenoic acids. However, substitution of a cyclopropane acid for a cis-unsaturated acid has insignificant effects on the molecular packing of phospholipids containing these acids.
122 citations
93 citations
77 citations
TL;DR: The N.M.R. data for cyclopropane dissolved in a liquid crystal are treated with allowance for vibrational motion and a substantial improvement in the consistency of the data is obtained as mentioned in this paper.
Abstract: The N.M.R. data for cyclopropane dissolved in a liquid crystal are treated with allowance for vibrational motion and a substantial improvement in the consistency of the data is obtained. Furthermor...
66 citations
TL;DR: In this paper, the rate constants and products from the interaction of the first triplet state of nitrogen, N2(A 3Σu+), with C2H4 and cis−C4H8 have been measured in a discharge flow apparatus.
Abstract: The rate constants and products from the interaction of the first triplet state of nitrogen, N2(A 3Σu+), with C2H4 and cis‐C4H8 have been measured in a discharge flow apparatus The reactions are fast with rate constants near 1014 cc mole−1·sec−1 and give products which are typical of other triplet—triplet donor reactions with olefins The product yields were used to measure the concentration of N2(A 3Σu+) molecules This concentration was combined with the absolute emission intensity from the N2(A 3Σu+−X 1Σg+) transition to estimate the radiative lifetime of (N2A 3Σu+; v′=0, 1) The data support the recently published low lifetime value reported by Shemansky and Carleton Rate constants were measured for quenching of N2(A 3Σu+) by acetylene, cyanogen, propene, benzene, 1,4‐butadiene, cyclopropane, oxygen, sulfur dioxide, carbon monoxide, nitrous oxide, and ammonia The first‐order removal of N2(A 3Σu+) by the quartz surface also was characterized
62 citations
TL;DR: The mode of bonding of cyclopropane to platinum is described through a crystal structure determination of the complex [PtCI2(C5H5N)2C3H6] as discussed by the authors.
62 citations
TL;DR: The spectra of the endo- and exo-cyclopropano-norbornene were analyzed in this article, and it was shown that a significant homoconjugation exists between the π-orbital of the double bond and the symmetric Walsh-esorbital in the cyclopropane ring in the exoisomer.
Abstract: Photoelectron spectra of endo- and exo-cyclopropano-norbornene ( = endo- and exo-tricyclo[3.2.1.02.4]octa-6-ene) show that a significant homoconjugation exists between the π-orbital of the double bond and the symmetric Walsh-es-orbital of the cyclopropane ring in the exo-isomer, whereas the interaction is negligeable in the endo-derivative.
48 citations
TL;DR: In this article, the cyclopropane resulting from trapping of a siloxy carbene by the alkene was shown to be cycloprocessor of cyclohexanone in diethyl fumarate.
Abstract: Photolysis of diphenylsilacyclohexanone in diethyl fumarate yields a product shown to be the cyclopropane resulting from trapping of a siloxycarbene by the alkene.
42 citations
34 citations
TL;DR: Methyl 12-mesyloxyoleate is readily converted into methyl 9-methoxy (acetoxy, hydroxy)-10,11-methyleneheptadecanoate by reaction with methanol (acetic acid, or water) in a suitably buffered solution as discussed by the authors.
31 citations
TL;DR: In this paper, the photolysis of 3-diazo-1,1,2,2-tetrafluoropropane gives the corresponding carbene in which migration of the difluoromethyl group is the major reaction; other minor products are believed to arise from a cyclopropANE in an excited state, formed by insertion into the γ-CH bond.
Abstract: Photolysis of 4-diazo-1,1,1,2,2,3,3-heptafluoropentane gives heptafluoropropyl(methyl)carbene, in which migration of hydrogen takes place to give 3,3,4,4,5,5,5-heptafluoropent-1-ene in high yield. Migration of fluorine or of the pentafluoroethyl group is not observed. The photolysis of 3-diazo-1,1,2,2-tetrafluoropropane gives the corresponding carbene in which migration of the difluoromethyl group is the major reaction; other minor products are believed to arise from a cyclopropane in an excited state, formed by insertion into the γ-CH bond.The exploration of routes to 2-diazo-1,1-difluoroethane and 2-diazo-1-fluoropropane, and the n.m.r. spectra of a number of compounds containing the CHF2·CF2· group are also reported.
TL;DR: A surprisingly strong specificity of the cyclopropane synthetase for the (n-7) series of monoenoic fatty acids is revealed.
TL;DR: In this article, photolysis of 5-diazo[a,d]cycloheptene (10 ) and 9-diazotribenzo [a,c,e]cyclopropane (23 ) in cis and trans -2-butene led stereospecifically to the formation of cyclopropanes derivatives.
TL;DR: In this paper, the formation of [CH2OH]+ by fragmentation of [C3H7O]+ ions in the electron-impact mass spectra of 2-methyl-2-propanol and 2-Propanol has been investigated using 13C labeling, deuterium labeling and metastable studies.
Abstract: The formation of [CH2OH]+. by fragmentation of [C3H7O]+. ions in the electron-impact mass spectra of 2-methyl-2-propanol and 2-propanol has been investigated using 13C labeling, deuterium labeling and metastable studies. The similar fragmentation reaction in the chemical ionization mass spectrum of acetone has been studied. It is concluded that the fragmentation reaction does not involve complete randomization of the carbon atoms and therefore does not proceed through formation of a hydroxylated cyclopropane intermediate. Alternative mechanisms are discussed.
TL;DR: In this paper, the pyrolysis of cyclopropane + argon mixtures was studied in a single-pulse shock tube over the temperature range 1060-1870 K. At a total pressure of 500 mmHg and temperatures below 1300 K, an apparent first-order rate constant of 1011.9 exp ( −230 kJ/RT) s−1 was obtained.
Abstract: The pyrolysis of cyclopropane + argon mixtures has been studied in a single-pulse shock tube over the temperature range 1060–1870 K. At a total pressure of 500 mmHg and temperatures below 1300 K, an apparent first-order rate constant of 1011.9 exp (–230 kJ/RT) s–1 was obtained. This is in agreement with extrapolations from low temperature data provided allowance is made for the deviation from limiting first-order behaviour with increasing temperature. Above 1300 K, radical chain decomposition of the cyclopropane and/or the propylene product was observed but the overall loss of cyclopropane, which is best fitted by the expression 104.75 exp(–48.5 kJ/RT) s–1, was much lower than predicted by current unimolecular reaction rate theory. Various alternative mechanisms are examined but no acceptable explanation can yet be offered.
Patent•
02 Aug 1971
TL;DR: In this article, a cyclopropanecarboxylic acid and esters of the formula "STR1" are selected from the group consisting of hydrogen, alkyl, aralkyl, aryl, alkenyl, and alkenynyl, with the proviso that when Z1 and Z2 are methyl and R1 is other than methyl and their preparation.
Abstract: Novel cyclopropanecarboxylic acids and esters of the formula ##STR1## wherein Z1 and Z2 are selected from the group consisting of hydrogen, alkyl, aralkyl, aryl, alkenyl non-conjugated with the cyclopropane ring, alkynyl non-conjugated with the cyclopropane ring, cycloalkyl, cycloalkenyl and heterocyclic; R is selected from the group consisting of OH and OR' in which R' is selected from the group consisting of lower alkyl which may be substituted, benzyl which may be substituted on the phenyl or methylene portion, N-methylene-dicarboximide, (5-benzyl-furyl-3) methyl, and a cyclopentene of the formula ##STR2## wherein R" is selected from the group consisting of alkyl, alkynyl, alkenyl, aryl, aralkyl, cycloalkyl, cycloalkenyl and heterocyclic; A is a bivalent alkyl radical selected from the group consisting of ##STR3## wherein R1 is selected from the group consisting of hydrogen and lower alkyl, R2 and R3 are selected from the group consisting of alkyl, alkynyl, alkenyl, aryl, aralkyl, cycloalkyl, cycloalkenyl and heterocyclic and taken together with the carbon atom to which they are attached form a ring selected from the group consisting of carbon homo rings and unsaturated carbon homo rings of 3 to 7 carbon atoms and heterocyclic rings which may be substitued with lower alkyl or lower alkoxy and R2 and R3 may together form a polycyclic aromatic radical, R4 is lower alkyl, R5 is selected from the group consisting of hydrogen and lower alkyl and R4 and R5 together with the carbon atoms to which they are attached may form a saturated or unsaturated carbon homo ring or a heterocyclic ring, Y is selected from the group consisting of methylene and a saturated or unsaturated carbon chain and Y' is selected from the group consisting of methine and a saturated or unsaturated carbon chain with the proviso that when Z1 and Z2 are methyl and R1 is hydrogen, R2 is other than methyl and their preparation.
TL;DR: In this paper, the cycloaddition of cycloheptatriene to maleic anhydride was re-examined and found to produce, in addition to the reported main product anti-tricyclo[3.2.2]nona-2,6-diene-endo-8,endo-9-dicarboxylic anhydrase (5), the exo, exo isomer of this compound (4) and bicyclo[1.02,4]non-6-endriene-
Abstract: Cycloaddition of cycloheptatriene to maleic anhydride was re-examined and found to produce, in addition to the reported main product anti-tricyclo[3.2.2.02,4]non-6-endo-8,endo-9-dicarboxylic anhydride (1), the exo, exo isomer of this compound (4) and bicyclo[3.2.2]nona-2,6-diene-endo-8,endo-9-dicarboxylic anhydride (5). Evidence for these structures involving the orientation of the cyclopropane ring in 1 and 4 and the configuration of the carboxylic anhydride was provided by PMR spectroscopy using the intramolecular nuclear Overhauser effect and paramagnetic induced shift due to tris(dipivalomethanato)europium(III). The structure assignment by Alder and Jacobs for 1 was found to be correct, but not the one by Schenk et al The difference in free energies of activation leading to 1 and 4 was determined.
TL;DR: In this article, the thermal decarbonylation of cyclopropane containing carbonyl bridge compounds has been investigated in solution and the rate constants have been determined as well as the derived activation parameters.
TL;DR: In this article, the removal of two bromine atoms from erythro - and threo -2,3-dibromo-4-methylpentane by bis(trimethylgermyl)- mercury is stereospecifically cis, suggesting a one stage molecular mechanism for this elimination.
TL;DR: Phenyl(1,1-dichloroethyl)mercury has been prepared via 1, 1,1dichlormyloethyllithium and evaluated as a potential CH 3 CCl transfer agent as discussed by the authors.
Patent•
16 Sep 1971
TL;DR: In this paper, the authors discuss the use of Lactone lekone alkones in pre-positioning the cyclopropane ring in order to pre-prepare countries for having PHARMACEUTICAL UTILITY.
Abstract: TRICYCLIC LACTONE ALKENES OR ALKENYNES OF THE FORMULA: 2-(O=),4-(Y-CH=CH-)PERHYDROCYCLOPROPA(3,4)CYCLOPENTA(1,2-B)FURAN WHEREIN Y IS 1-PENTYL OR PENTYL-2-YNYL, AND $ INDICATES ATTACHMENT OF THE MOIETY TO THE CYCLOPROPANE RING IN EXOOR ENDO CONFIGURATION ARE USEFUL AS INTERMEDICATES IN PREPARING PROSTAGLANDINS HAVING PHARMACEUTICAL UTILITY.
Patent•
21 Oct 1971
TL;DR: A 3-SUBSTITUTED-BENZYL CYCLOPROPANECARBOXYLATE REPRESENTED by the FORMULA, 1-R1,1-R2,2, 2-DI(H3C)-CYCLOP-3-YL-COO-CH2-(1,3- PHENYLENE)-CH2-R3 WHEREIN R1 IS A HYDROGEN ATom OR A METHYL Group; R2 IS METHyl, 2 -METHyl-
Abstract: 1. A 3-SUBSTITUTED-BENZYL CYCLOPROPANECARBOXYLATE REPRESENTED BY THE FORMULA, 1-R1,1-R2,2,2-DI(H3C-)-CYCLOPROP-3-YL-COO-CH2-(1,3- PHENYLENE)-CH2-R3 WHEREIN R1 IS A HYDROGEN ATOM OR A METHYL GROUP; R2 IS METHYL, 2-METHYL-1-PROPENYL, 2-METHOXYCARBONYL-1-PROPENYL OR PHENYL WHEN R1 IS A HYDROGEN, OR METHYL GROUP WHEN R1 IS A METHYL GROUP; AND R3 IS A PHENYL GROUP WHICH MAY BE SUBSTITUTED BY A CHLORINE ATOM OR A METHYL GROUP.
TL;DR: In this paper, the reduction of gem-dibromocyclopropane(I) with CrII acetate in DMSO gives monobromocycyclopropanes (II and III) exclusively, whereas the same components in aq DMF afford cyclopropyl acetates(IV and V) as the major products in addition to II and III.
Abstract: The reduction of gem-dibromocyclopropane(I) with CrII acetate in DMSO gives monobromocyclopropanes (II and III) exclusively, whereas the same components in aq DMF afford cyclopropyl acetates(IV and V) as the major products in addition to II and III. A similar substitution on cyclopropane carbon is observed in the reduction of I with K3Co(CN)5 in DMSO, furnishing cyclopropyl cyanides (IX and X) mainly. The stereochemistry of II, III, IV, and V is determined by the NMR coupling constants and chemical shifts, and that of IX and X, by transformation to the corresponding cyclopropyl methyl ketones derived from cyclopropanecarboxylic acids of known configurations. The reaction of II or III with K3Co(CN)5 is also described.