Octane, 1-bromo

Octane, 1-bromo-, 55,111 Octane, 1-chloro-, 55,111 Octane, 1-iodo-, 55, 105, 111 Octane, 2-methyl-, 112 Octane, 1 tosyl- [Octane, l-(4-methylphenyl-sulfonyl) ], 55,111... 

Polymerization of 4-bromo-6,8-dioxabicyclo[3.2.1 ]octane 2 7 in dichloromethane solution at —78 °C with phosphorus pentafluoride as initiator gave a 60% yield of polymer having an inherent viscosity of 0.10 dl/g1. Although it is not described explicitly, the monomer used seems to be a mixture of the stereoisomers, 7 7a and 17b, in which the bromine atom is oriented trans and cis, respectively, to the five-membered ring of the bicyclic structure. Recently, the present authors found that pure 17b was very reluctant to polymerize under similar conditions. This is understandable in terms of a smaller enthalpy change from 17b to its polymer compared with that for 17a. In the monomeric states, 17b is less strained than 17a on account of the equatorial orientation of the bromine atom in the former, whereas in the polymeric states, the polymer from 17b is energetically less stable than that from 17a, because the former takes a conformation in which the bromine atom occupies the axial positioa Its flipped conformation would be even more unstable, because the stabilization by the anomeric effect is lost, in addition to the axial orientation of the methylene group. 

Betzemeier et al. (1998) have used f-BuOOH, in the presence of a Pd(II) catalyst bearing perfluorinated ligands using a biphasic system of benzene and bromo perfluoro octane to convert a variety of olefins, such as styrene, p-substituted styrenes, vinyl naphthalene, 1-decene etc. to the corresponding ketone via a Wacker type process. Xia and Fell (1997) have used the Li salt of triphenylphosphine monosulphonic acid, which can be solubilized with methanol. A hydroformylation reaction is conducted and catalyst recovery is facilitated by removal of methanol when filtration or extraction with water can be practised. The aqueous solution can be evaporated and the solid salt can be dissolved in methanol and recycled. 

Tjandra et al. (1998) have proposed an interfacial reaction model for the kinetics of the reaction between 1-bromo octane and sodium phenoxide to give 1-phenoxyoctane in a nonionic microemulsion. In this model the microemulsion is assumed to consist of the aqueous phase and the interface is covered by a monolayer of surfactant molecules. It is thus possible to assess the interfacial area from the concentration of the surfactant in the microemulsion medium. 

Nucleophilic substitution reactions of halide anions in aprotic solvents are often accompanied by elimination reactions. For instance, reactions of secondary alkyl halides with potassium fluoride solubilized in acetonitrile with the aid of 18-crown-6 [3] give olefins as the main reaction product (Liotta and Harris, 1974). Similarly, the dicyclohexyl-18-crown-6 complex of potassium iodide acted exclusively as a base in its reaction with 2-bromo-octane in DMF (Sam and Simmons, 1974). The strongly basic character of weakly solvated fluoride has been exploited in peptide synthesis (Klausner and Chorev, 1977 Chorev and Klausner, 1976). It was shown that potassium fluoride solubilized... 

Example The mass spectra of both acetone and butanone show typical acyiium ion peaks at m/z 43, whereas the signals in the spectra of isopropyl ethyl thioether (Fig. 6.9), of 1-bromo-octane, (Fig. 6.10), and of isomeric decanes (Fig. 6.18) may serve as examples for carbenium ion signals. The superimposition of both classes of ions causes signals representing an average pattern. The properties of larger carbenium ions are discussed in the section on alkanes (Chaps. 6.6.1 and 6.6.3). 

Fig. 6.10. El mass spectrum of 1-bromo-octane. The product of the a-cleavage, m/z 91, 93 is of minor intensity, whereas the cyclic bromonium ion, m/z 135 and 137, dominates the spectrum. Spectmm used by permission of NIST. NIST 2002.

Korneev and Kaufmann successfully lithiated 2-bromo-l,l-diphenylethylene (46) by bromide-lithium exchange to form 2-lithio-l,l-diphenylethylene (47). A second lithia-tion could be effected in four hours at room temperature by deprotonation of the aromatic ring with w-butyllithium in the presence of TMEDA (Scheme 17). Like in the synthesis of compound 23, the first lithiation activates the ortho-hydrogen atom of the Z-phenyl substituent to give 1,4-dilithium compound 48. In total, three equivalents of the alkyl-lithium base are required the third equivalent is consumed in the trapping reaction of w-bromobutane with generation of octane. 

Table 1. Physical characteristics of LPFC perfluorocyclohexan (PFE), perfluorotributylamine (PFBA), perfluoro-n-octan (PFO), perfluorodecaline (PFD) bromo perfluoro-n-octan (PFOB), perfluorophenanthren (PFPN)...

Neighboring-group participation reactions by sulfur and nitrogen functions have also been observed for deoxyhalogeno sugars. An example is the formation of the anhydride 146, which possesses an oxathiabicyclo[2.2.2]octane ring-system constrained in a boat-like conformation, on treatment of methyl 4-0-benzoyl-2-S-benzoyl-6-bromo-6-deoxy-2-thio-Q -D-altropyranoside (145) with methanolic... 

Substantial variations of the organic solvent used in triphase catalysis with polystyrene-bound onium ions have been reported only for the reactions of 1-bromo-octane with iodide ion (Eq. (4))74) and with cyanide ion (Eq. (3)) 73). In both cases observed rate constants increased with increasing solvent polarity from decane to toluene to o-dichlorobenzene or chlorobenzene. Since the swelling of the catalysts increased in the same order, and the experiments were performed under conditions of partial intraparticle diffusional control, it is not possible to determine how the solvents affected intrinsic reactivity. 

Fig. 10. Dependence of on mean particle size of 2% CL catalyst for reaction of 1-bromo-octane in toluene with 10 molar equiv of KI in water and 0.02 molar equiv of catalyst at 90 °C 16% RS catalyst 34 (A), 17% RS catalyst 35 ( ), 14% RS catalyst 41 (O) stirring speed 550-600 rpm...

The dimer 29 of the dihydronaphthylmethylidenecyclopropane 30 was formed at a surprisingly low temperature (— 90 °C), when the bromo derivative 28 was treated with terf-butyllithi-um in tetrahydrofuran.62 The E configuration of the dispiro[2.0.2.2]octane derivative was proved by X-ray crystal structure analysis. Similar dimerizations of 1-donor-substituted allyli-dcnccyclopropanes have been observed at + 50 C.63... 

Magnesium-mediated elimination of bromine monofluoride has been reported in the reaction of 2-bromo-2-chloro-l,l,l-trifluoroethane with ketones, e.g. reaction of 5 with octan-2-one. 

Carbohydrate analogs that have been produced by direct photobromination reactions are the nucleoside derivative l,A-dibenzoyl-2, 3, 5 -tri-0-benzoyl-4 -bromoadenosine38 (98) (compare Section II,3b) and the cyclohexane derivative (15,25,37 ,45,55,7/ )- l-acetoxy-2,3,4-tetra- >-benzoyl-oxy-7-bromo-6-oxabicyclo[3.2.1]octane (99) (compare Section II,4a). 

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