共查询到20条相似文献,搜索用时 15 毫秒
1.
James Burdon Saleh T. Ezmirly Thomas N. Huckerby 《Journal of fluorine chemistry》1988,40(2-3):283-318
The fluorination of butane over cobalt trifluoride has given a complex mixture of partially fluorinated compounds: 51 of these have been identified, comprising over 99% of the products. Most were polyfluorobutanes but 1-2% were polyfluoro-2-methylpropanes. The reaction has no synthetic utility. There was some selectivity in the fluorination: secondary C-H was converted into C-F more easily then primary, and the ease of replacement of a particular H was reduced by geminal and vicinal fluorines. A computer of the fluorination was only partially successful, perhaps because the fluorination proceeded in part by simple F for H replacement and in part via alkenes: the model only allowed for the former. 相似文献
2.
2-Methylpropane has been fluorinated over cobalt trifluoride at 140-200°C to give a mixture of at least 30 components, of which 22 have been identified with some certainty and five, more tentatively; this represents well over 95% of the reaction mixture. About 95% of the identified products were polyfluoro(2-methylpropanes); the rest were polyfluorobutanes. The fluorination was not completely random; there was a clear preference (by some 10 times greater than chance) for compounds in which the tertiary hydrogen had been replaced by fluorine. A scheme for the fluorination pathway is proposed. Attempts to dehydrofluorinate 1
,3
-pentafluoro-2-fluoromethylpropane failed. 相似文献
3.
Flourination of benzene, in the vapour phase, over manganic fluoride at 300° has given undecafluorocylohexane (3.5%); 1H-, 3H- and 4H-nonafluorocyclohexene (3.3, 0.2 and 1.6%, respectively); 1H/2H- and 1H/4H-decafluorocyclohexane (1.1 and 6.2%, respectively); 1H,4H-hexafluorocyclohexa-1:4-diene (4.0%); 1H,2H- and 1H,4H-octafluorocyclohexene (0.04 and 15.8%, respectively); floruo- (3.9%), p-difluoro- and 1,2,4-trifluoro-benzene; 1H4H/2H, 1H/2H,4H- and 1H,2H/4H-nonafluorocyclohexane; and 1H,3H/4H-, 1H,4H/5H- and 1H, 2H,4H- (8.0%) heptafluorocyclohexene. 相似文献
4.
Fluorination of ethane and ethene with KCoF4 and CoF3 over a range of temperatures gave, in all cases, mixtures of polyfluoroethanes, C2H6-nFn n = 1–6, with very little CC bond cleavage. Apart from an initial easy saturation of ethene to CH2FCH2F, both substrates had a similar reactivity. Hydrogen appeared to be replaced by fluorine almost randomly in all fluorinations. CH2FCH2F is a stable compound, contrary to literature reports. 相似文献
5.
《Tetrahedron letters》2004,45(24):4657-4660
Synthesis of 1,4-diazabicyclo[4,4,0]decanes and 1,4-diazabicyclo[4,3,0]nonanes was achieved by using 4-formyl spiro β-lactams as easily available starting materials. Furthermore, the application of this protocol to the preparation of conformationally restricted σ-receptor ligands was also performed. Theoretical calculations were carried out on a model reaction, in order to give some understanding of the reaction mechanism. 相似文献
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Fluorobicyclo[2,2,2]octanes as follows were made by fluorination with cobaltic fluoride :- 1H- and 2H- tridecafluoro- ; 1H,2H-, 1H,3H-, 2H,2H-, 2H,3H-, and 1H,4H- dodecafluoro-; 1H,2H,3H-, 1H,2H,4H-, and 1H,3H,3H- undecafluoro-; 2H,2H,3H,3H- decafluoro-. These afforded, by the appropriate dehydrofluorinations, dodecafluoro-; 1H- and 2H- undecafluoro-; 1H,2H-, 1H,3H-, and 1H,4H- decafluoro- bicyclo[2,2,2]oct-2-ene. Self-consistent nmr data confirmed all structures. 1H-Trideca- and 1H,4H-dodeca- fluorobicyclo[2,2,2]octanes possess acidic bridgehead hydrogens, which are reactive under basic conditions, and may be replaced by various functional groups. 1-Lithiotridecafluorobicyclo[2,2,2]octane, a remarkably stable perfluoroalkyl lithium derivative, survived many hours in refluxing ether, but slowly decomposed to 1- substituted undecafluorobicyclo[2,2,2]oct- 2-enes, via a transient intermediate, a bridgehead ‘olefin’ ‘violating’ Bredt's rule. 相似文献
10.
Hong-Xia Jin 《Tetrahedron letters》2005,46(34):5767-5769
As potential antimalarial agents, four novel spiro-peroxides were designed and synthesized with the peroxy bond introduced employing the Kobayashi’s methodology (with modifications). The results showed that by using cyclic hemiketal as substrates the incorporation of the hydroperoxyl group could be achieved in high yields without recourse to the expensive Sc(OTf)3 catalyst. 相似文献
11.
Leonard M. Rice Bhagvandas S. Sheth James W. Wheeler 《Journal of heterocyclic chemistry》1973,10(5):737-741
N-(2-Dimethylaminopropyl)-8,8-dimethyl-8-sila-2-azaspiro[4.5]decane ( 1 ) and N-(3-dimethyl-aminopropyl)-9,9-dimethyl-9-sila-3-azaspiro[5.5]undecane ( 2 ) have been synthesized from 4,4-dimethyl-4-silacyclohexanone ( 5 ). Biological evaluation of 1 and 2 indicated cytotoxic action against human cancer cells grown in tissue culture. 相似文献
12.
Diels-Alder reactions between ethylene and octa-, 1-hepta-, and 1H, 4H-hexa-fluorocyclohexa-1,3-diene gave, respectively, 1,2,3,4,5,5,6,6-octa-, 1,2,3,5,5,6,6-hepta-, and 2,3,5,5,6,6-hexa-fluorobicyclo[2, 2, 2]oct-2-ene, each characterised by oxidation to the corresponding polyfluorocyclohexane-1,4-dicarboxylic acid. 相似文献
13.
Leonard M. Rice Bhagvandas S. Sheth James W. Wheeler 《Journal of heterocyclic chemistry》1973,10(5):731-735
N-(2-Dimethylaminopropyl)-8,8-dimethyl-2-azaspiro[4.5]decane ( 1 ), N-(2-dimethylaminopropyl)-8,8-diethyl-2-azaspiro[4.5]decane ( 2 ), N-(3-dimethylaminopropyl)-9,9-dimethyl-3-azaspiro[5.5]undecane ( 3 ), and N-(3-dimethylaminopropyl)-9,9-diethyl-3-azaspiro[5.5]undecane ( 4 ) have been synthesized from 4,4-dimethylcyclohexanone ( 5 ) and 4,4-diethylcyclohexanone ( 6 ). Biological evaluation of these amines showed significant inhibition of cancer cell growth in human cancer cells grown in tissue culture. 相似文献
14.
The thiazolidine, 1-thia-4-azaspiro[4,5] decane (Ia), which is derived from cyclohexanone and 2-aminoethanethiol (X), forms a thiazolidone (VIII) with mercaptoacetic acid more slowly and in lower yield than with 2-phenylthiazolidine, a case reported previously. A thiazolidine which is related to a non-conjugate chain tautomer such as Ic, might be expected to behave in this way. Alkylation, as another possible example of tautomer chemistry, was studied, and N-, S-, and C-alkylation were all observed under varying circumstances. Thus, thiazolidine la undergoes alkylation with methyl iodide in ethanol to form the N-methylthiazolidine (IIa), and in sodium-liquid ammonia to give the S-methyl derivative (III). In the latter case, alkylation occurs with reductive cleavage. Although no trace of other tautomer derivatives (IV, V) was to be found in the methyl iodide alkylation, I with acrylonitrile did in fact give C-alkylation. An analytically pure mixture of tautomers was obtained, from which 2-oxocyclohexanepropionitrile (VI) was isolated on hydrolysis. In a manner similar to the formation of III, IIa was S-alkylated by treatment with sodium-liquid ammonia followed by benzyl chloride to give a saturated product (XVII). Although such a process might be identified with a chain tautomer (IIb), the evidence is to the contrary, since the intermediate (XIV), which might be involved in such a process, fails to undergo a similar reduction with sodium-liquid ammonia. A greatly improved procedure for the preparation of thiazolidine (XI, 86% yield) is also reported. 相似文献
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An efficient synthesis of the optically active spiro[4.5]decane sesquiterpene acorenone is described. The key carbon-carbon bonds are formed by a (2+2) photochemical cycloaddition between 2,2-dimethyl-3(2H)-furanone and an alkene derived from limonene. 相似文献
16.
[reactions: see text] Fragmentation of the cyclobutane-containing adducts generated from intramolecular cycloadditions of cyclobutadiene with olefins provides rapid entry into bicyclo[5.3.0]decane and bicyclo[4.3.0]nonane ring systems. Whereas earlier studies featured thermal methods to achieve the desired rearrangements, a mild, Lewis acid-mediated fragmentation has been identified for substrates with appropriate functionality adjacent to the strained ring system. The substrate scope and stereochemical outcome of the acid-mediated fragmentation are complementary to the thermal ring expansions, particularly in the case of the bicyclo[5.3.0]decanes. 相似文献
17.
Elena Stanoeva 《Tetrahedron》2004,60(23):5077-5084
A series of 1-alkyl- and 1-alkenyl-2,9,10-trioxatricyclo[4.3.1.03,8]decanes, models for the core orthoester structural moiety of resiniferatoxin and synaptolepis factors, was prepared by a transetherification reaction of (±)-all-cis-cyclohexane-1,2,4-triol and trimethyl orthocarboxylates. The synthesis of the starting trimethyl orthocarboxylates is also given in detail. 相似文献
18.
3,4-Dihydro-2H-pyrano[2,3-b]quinolines 5a-e and 2H-pyrano[2,3- b ]quinolines 10a-c were synthesised starting from the appropriate ω-chloro-n-valeroylanilides 2a-e . Compounds 10a-c were transformed to analogs of the novel antihypertensive agent Cromakalim ( 1 ). 相似文献
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3-Acetylpyrrolidines are prepared from 5-methyl-5-vinyloxazolidines in a reaction which involves a directed 2-azonia-[3,3]-sigmatropic rearrangement. 相似文献