Showing papers on "Aryl radical published in 1994"

Mechanism of dediazoniation of arenediazonium salts with triphenylphosphine and trialkyl phosphites. Generation of cation radicals from trivalent phosphorus compounds and their reactions

Abstract: 4-Nitro-, 4-methyl-, and 4-methoxy-benzenediazonium fluoroborates are readily dediazoniated with triphenylphosphine or trialkyl phosphites (alkyl = methyl or ethyl) in alcoholic solvents at room temperature in the dark under a nitrogen atmosphere to give the corresponding arenes and the corresponding oxidation product from the phosphine or the phosphites, triphenylphosphine oxide or trialkyl phosphates, respectively, along with a small amount of biaryls. In the reaction with the phosphite, dialkyl arylphosphonate is also formed. The stoichiometry of the reactions and the results of the reactions in deuteriated methanols, together with other evidence, indicate that the reactions proceed by a radial-chain mechanism initiated by single-electron transfer from the trivalent phosphorus compound to the diazonium salt, during which the cation radical is generated from the former. The product distribution shows that this cation radical reacts with the solvent alcohol to give a phosphoranyl radical, which eventually affords the final product, the phosphine oxide or the phosphate, from the phosphine or the phosphite, respectively. The cation radical from the phosphite also undergoes radical coupling with the aryl radical Ar˙ generated during the reaction to yield dialkyl arylphosphonate via a phosphonium intermediate, whereas no radical coupling of the cation radical from the phosphine with Ar˙ takes place.

Indoline formation by regioselective aryl radical cyclization to azomethine bond

Abstract: Aryl radical-initiated cyclization of the ketimines derived from acetophenone and benzophenone occurred exclusively at the nitrogen end of the azomethine bond in an exo-5 mode to yield the corresponding indoline derivatives

Optically aktive 2-imidazolin-5-one and 2-imidazolin-5-thione derivatives as fungicides.

Abstract: Optically active derivatives of 2-imidazolin-5-ones and 2-imidazoline-5-thiones of general formula (I), wherein M = O, S or optionally halogenated CH2, W = O, S or S=O, p = 0 or 1, R1, R2 and R4 are a hydrocarbon radical, especially an aryl radical, which is optionally substituted, especially by halogen atoms, R3 is H or optionally halogenated C1-C2 alkyl, R5 is a hydrocarbon radical. Disclosed is also process for their production, intermediates for their production, and their use as agricultural fungicides.

Regioselective Aryl Radical Cyclization. 1. Stereocontrolled Synthesis of Linearly Condensed Hydroaromatic Carbocyclic Systems through 6-endo-Ring Closures

Abstract: The stereocontrolled synthesis of trans-octahydroanthracenes (3), (11a- c), and (14a-c) and trans-octahydro-5aH-cyclohepta[b] naphthalene (27) through implementation of an efficient and highly regioselective 6-endo -trig-aryl radical cyclization of the respective 2-(o-bromoaryl)-1-me- thylenecyclohexanes (2), (10a-c), and (13a-c) and 2-(o-bromobenzyl)-1- methylenecycloheptane (41) with tri-n-butyltin hydride is described. The radical cyclization of 2-(o-bromobenzyl)-1-methylenecyclopentane (43), in contrast, produced a mixture of the cis- and trans-hexahydro- 1H-benz[f]indenes (38) and (37)

The mechanism of titanium complex-catalyzed reduction of aryl halides by sodium borohydride is strongly solvent dependent

Abstract: The titanium complex-catalyzed reduction of aryl halides by sodium borohydride in dimethylacetamide (DMA) or ethers proceeds by electron transfer from a reduced titanium species, yielding an intermediate aryl radical

Photoelectrochemical reduction of p-halonitrobenzenes

Abstract: A detailed and comparative mechanistic study of the photoelectrochemical dehalogenation of the four p-halonitrobenzenes, X-C6H4-NO2(X = F, Cl, Br or I) in acetonitrile solution is reported. In the case of p-iodonitrobenzene, iodide loss is accomplished by electrochemical reduction alone. The formation of I– is shown to take place via an ECE process with the ultimate generation of the radical anion of nitrobenzene. Dual photo- and electro-chemical activation of p-chloronitrobenzene and p-bromonitrobenzene leads to halide loss through a photo-ECE mechanism. This proceeds via absorption of light by the radical anions, [X-C6H4-NO2]˙–, which is followed by fragmentation forming the ˙C6H4NO2 aryl radical. The latter is shown to react with the solvent system forming nitrobenzene which is further reduced at the electrode with the generation of [C6H4-NO2]˙–. The aryl radical is demonstrated to be able to undergo (partial) recombination with added Br– or Cl–. The effectiveness of different electronic transitions in the radical ions, [X-C6H4-NO2]˙–(X = Br, Cl) towards dehalogenation are compared; both radical anions-exhibit transitions centred near 330 and 470 nm in the near UV–VIS part of the spectrum. For the chloro-compound only the former band is effective in stimulating chloride release, whereas for the bromo-compound the excitation of either band causes bromide loss. The long wavelength band of the latter is quantified as being some 5.6 times more effective towards fragmentation on a per photon absorbed basis and this is rationalised using spin selection rules. No loss of fluoride from [F-C6N4-NO2]˙– was observed at any wavelength in the visible region of the spectrum.

Taxoids, their preparation and the pharmaceutical compositions which contain them

Abstract: This invention relates to a process for preparing taxoid derivatives of formulae II and XI: ##STR1## in which Ar represents an aryl radical; R 1 represents a benzoyl radical or a radical R 2 --O--CO-- in which R 2 represents an unsubstituted or substituted alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, bicycloalkyl, phenyl, or saturated or unsaturated heterocyclic radical; R 3 represents an unsubstituted or substituted alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, bicycloalkyl, saturated or unsaturated heterocyclic, or aryl radial, but not a phenyl radical; R 4 represents a hydrogen atom and R 5 represents a hydroxyl-protecting group or R 4 and R 5 together form a heterocyclic group; G 1 represents a hydroxyl-protecting group; and G 2 represents an acetyl radical or hydroxyl-protecting group; by electrolytically reducing a protected taxoid compound in an electrolyte comprising a quaternary ammonium salt which is soluble in an organic solvent or in an aqueous/organic mixture at a controlled potential.

Cobalt(II) Chloride–Grignard reagent: an alternative to tin hydride in aryl radical cyclisations

Abstract: Reaction of N-methyl, N-acryloyl-2-haloanilines with anhydrous cobalt(II) chloride and a Grignard reagent leads to formation of indol-2(3H)-ones via a reductive aryl radical cyclisation.

Highly regioselective 8-endo-aryl radical cyclisation: a new synthetic route to decahydrodibenzo-[a,d]- and -[a,e]-cyclooctenols

Abstract: A highly regioselective 8-endo-trig-aryl radical cyclisation of the vinylcyclohexanols 2a-c and allylcyclohexanols 6a-c with tri-n-butyltin hydride provides decahydrodibenzo-[a,e]- and -[a,d]-cyclooctenols 3a-c and 7a-c respectively, in moderate to good yields.

Preparation of polymers of C2 -C10 -alk-1-enes using racemic metal-locene complexes as catalysts

Abstract: Polymers of C2 -C10 -alk-1-enes are prepared at from 0.5 to 3000 bar and from -50° to 300° C. using a catalyst system by a process in which the catalyst system used is one which contains, as active components: a) a metallocene complex of the general formula I ##STR1## where M is titanium, zirconium, hafnium, vanadium, niobium or tantalum, X is fluorine, chlorine, bromine, iodine, hydrogen, C1 -C10 -alkyl, C6 -C15 -aryl or --OR7, R7 is C1 -C10 -alkyl, C6 -C15 -aryl, alkylaryl, arylalkyl, fluoroalkyl or fluoraryl, where each alkyl radical is of 1 to 10 carbon atoms and each aryl radical is of 6 to 20 carbon atoms, R1 to R6 are each hydrogen, C1 -C10 -alkyl, 5-membered to 7-membered cycloalkyl, which in turn may carry C1 -C10 -alkyl radicals as substituents, C6 -C15 -aryl or arylalkyl, where two adjacent radicals together may furthermore be a cyclic group of 4 to 15, carbon atoms, or Si(R8)3 R8 is C1 -C10 -alkyl, C6 -C15 -aryl or C3 -C10 -cycloalkyl, is silicon, germanium, tin or carbon, Y1, Y2 are each ##STR2## R9 to R16 are each hydrogen, C1 -C10 -alkyl, 5-membered to 7-membered cycloalkyl, which in turn may carry C1 -C10 -alkyl radicals as substituents, C6 -C15 -aryl or arylalkyl, where two adjacent radicals together may furthermore be a cyclic group of 4 to 15 carbon atoms, or Si(R17)3, R17 is C1 -C10 -alkyl, C6 -C15 -aryl or C3 -C10 -cycloalkyl and u, v, w are each an integer from 0 to 7, with the proviso that the sum is u+v+w≧2, and b) an open-chain or cyclic alumoxane compound of the general formula VI or VII ##STR3## where R18 is C1 -C4 -alkyl and m is an integer from 5 to 30.

Pseudodipeptide product having an imidazole grouping and applications

Abstract: Pseudodipeptide product of general formula (I), wherein A has: a) either the form (a) in which B is an amine whereof the nitrogen atom directly linked to the carbon atom is selected from amines, imines and ammoniums, → R is a fluorine atom, a fluoroalkyl radical, a functional grouping, an acyl radical, a linear alkyl chain or an alkenyl or aryl radical, → R' is a hydrogen atom, a fluorine atom, an alkyl radical, or a fluoroalkyl radical, and Im is an imidazole or N-substituted imidazole ring; b) or the form (b), in which R is a hydrogen atom or a fluoroalkyl, acyl or hydrocarbon radical which can be substituted by one or more functional groupings, and R' is a hydrocarbon radical or an acyl radical.

Electrochemically induced radical cyclization reactions

Abstract: A new route has been devised for intramolecular aryl radical cyclization reactions involving the electrochemical reduction of an ortho-halogenophenyl compound in acetonitrile at a mild steel cathode.

Reaction of silyl enol ethers with arenediazonium salts. Part 1. α-Arylation of ketones

Abstract: α-Arylation of ketones is accomplished by the use of arenediazonium salts as aryl-cation equivalents. The reaction of silyl enol ethers with arenediazonium tetrafluoroborates proceeds in the presence of palladium(0) catalysts and tetraphenylborate anion to give α-aryl ketones in moderate yields. Alternatively, silyl enol ethers smoothly react with arenediazonium tetrafluoroborates in pyridine even without palladium catalysts and tetraphenylborate anion, affording arylated ketones in good yields. A mechanism involving addition of an aryl radical to a silyl enol ether is proposed for the latter process.

New baccatin III and 10-deacetylbaccatin-III derivatives, their preparation and pharmaceutical compositions containing them

Abstract: Novel taxane derivatives of general formula (I), their preparation, and pharmaceutical compositions containing same. In general formula (I), Ar is an aryl radical; R1 is hydrogen or acetyl; R is optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, bicycloalkyl, phenyl or heterocyclyl, with the proviso that when Ar is an aryl radical and R1 is hydrogen or acetyl, R is a tert.butyl or ethyl radical. The novel products of general formula (I) have remarkable antitumoral activity.

Polysubstituted 2-amido thiazoles derivatives, process for their preparation, pharmaceutical compositions and utilization for the preparation of a medicament

Abstract: The subject of the invention is the use of a compound of formula in which Y represents a 3-quinolyl group or a 2-indolyl group of formula: in which: - R is hydrogen, an acetyl group or a CH2COOR' group, R' being hydrogen or a C1-C4 alkyl; - X is a (hetero)aryl radical chosen from 4-chloro-2,6-dimethoxyphenyl, 2,6-dimethoxy-4-methylphenyl, 2,4,5-trimethoxyphenyl, 4-methyl-2,3,6-trimethoxyphenyl, 2,6-dimethoxy-4-ethylphenhyl, 2,4,6-trimethoxy-5-chlorophenyl, 2,4,6-trimethoxy-3-pyridyl, 2,4-dimethoxy-6-methyl-3-pyridyl, 6-chloro-2,4-dimethoxy-5-pyrimidrimyl, 2,4,6-trimethoxy-5-pyinidinyl, 5-chloro-2,4-dimethoxyphenyl, 5-chloro-2-methoxy-4-methylphenyl, 2,5-dimethoxy-4-methylphenyl, 4-trifluoromethyl-2,6-dimethoxyphenyl, 2,4-dimethoxy-5-methylphenyl, 5-ethyl-2,4-dimethoxyphenyl or 2,4-dimethoxyphenyl groups; - Z represents H, a C1-C4 alkyl or a benzyl; with the restriction that Z is necessarily hydrogen when X is a phenyl radical simultaneously substituted in the 2- and 6-positions or when X is a 3-pyridyl radical simultaneously substituted in the 2- and 4-positions or when X is a 5-pyrimidinyl radical simultaneously substituted in the 4- and 6-positions.

Method for the preparation of beta-phenylisoserine derivatives

Abstract: PCT No. PCT/FR94/00339 Sec. 371 Date Sep. 28, 1995 Sec. 102(e) Date Sep. 28, 1995 PCT Filed Mar. 25, 1994 PCT Pub. No. WO94/22813 PCT Pub. Date Oct. 13, 1994Method for the preparation of beta -phenylisoserine derivatives of general formula (I) involving the action of an anhydride and hydrogen with a product of general formula (II). The products of general formula (I) are especially useful in the preparation of taxoids having outstanding antitumour properties. In general formulae (I) and (II), Ar is an aryl radical, Ph is a phenyl radical or an optionally substituted alpha or beta -naphtyl, R is a hydrogen atom or an alkyl radical optionally substituted by a phenyl radical and R1 is an optionally substituted phenyl radical or a R2-O radical wherein R2 is an alkyl, alkenyl, cycloalkyl, phenyl or heterocyclyl. (I) (II)

Alkaline earth metal salts, transition metal salts and transition metal complexes of ketocarboxylic acids as corrosion inhibitors

Abstract: Alkaline earth metal salts. transition metal salts and transition metal complexes of ketocarboxylic acids as corrosion inhibitors Abstract There are described novel alkaline earth metal salts, transition metal salts and transition metal complexes of compounds of the formula I (I) in which R1, R2, R3, R4 and R5 are, independently of one another, hydrogen, halogen, nitro, cyano, CF3, C1-C15alkyl, C5-C12cycloalkyl, C2-C15alkenyl, C1,C12haloalkyl, C1-C12alkoxy, C1-C12alkylthio, C6-C10aryl which is unsubstituted or substituted by C1-C4alkyl; C6-C10aryloxy which is unsubstituted or substituted by C1-C4alkyl; C7-C12 arylalkyl which is unsubstituted or substituted on the aryl radical by from 1 to 3 C1-C4-alkyl groups; -CO2R6, -COR6 or , where at least one of the radicals R1 to R5 is hydrogen, halogen or C1-C15alkyl, in addition the radicals R1 and R2, R2 and R3, R3 and R4 or R4 and R5 form, together with the carbon atoms to which they are bound, a benzo or cyclohexenyl ring, R6 is C1-C20alkyl, C2-C20alkyl interrupted by oxygen, sulfur or ; C7-C12arylalkyl which is unsubstituted or substituted on the aryl radical by from 1 to 3 C1-C4alkyl groups, R7 and R8 are, independently of one another, hydrogen, C1-C24alkyl or C2-C24alkyl inter-rupted by oxygen, sulfur or

Topical process for lightening the skin or treating pigmental blemishes using a composition containing 4-thioresorcin derivatives

Abstract: A topical process for lightening the skin or treating pigmental blemishes consisting in applying to the part of the skin to be treated a composition containing, as active compounds, 4-thioresorcin derivatives corresponding to the following formula: ##STR1## wherein: R represents a C 1 -C 6 alkyl radical, a C 1 -C 6 haloalkyl radical, an aryl radical, an aralkyl radical which is unsubstituted or substituted by a lower alkyl or lower alkoxy radical or a halogen atom, the radical --C n H 2n --COOR' where n is an integer between 1 and 5 and R' represents a C 1 -C 6 alkyl radical, a morpholinoalkyl or piperidinoalkyl radical in which the alkyl radical is C 1 -C 6 , or the radical ##STR2##

Hepoxilin analogs useful as anti-inflammatory agents

Abstract: Compounds of general structure (a) and (b) are disclosed, wherein X is O, Cn, NH, or S, wherein n is 1, 2, 3 or 4; R1 is OH, CH3, CH2OH, N3 or CH2N3; R3 is H or CH3; R5 is Y-R2, wherein Y is a six-carbon chain optionally containing up to three double or triple bonds or a mixture of double and triple bonds up to a maximum of three; R2 is C1-C10 alkyl OH, C1-C10 alkyl N3 or COOR4, wherein R4 is H, a branched or unbranched C1-C10 alkyl (including substituted alkyl radicals), cycloalkyl, preferably C5 OC C6 cycloalkyl, or a five- or six-membered aryl radical (including substituted aryl radicals), i.e. R2 is COOH or an ester of R4; R6 is a seven-carbon chain optionally containing up to three double or triple bonds or a mixture of double and triple bonds up to a maximum or three; and (c) indicates a single, double or triple bond. The compounds are analogs of hepoxilins and are used to modulate hepoxilin activity, for example in the control of inflammation or other processes mediated by intracellular calcium levels.

Process for preparing trifluoroethyl sulfur compounds from thiolates and 1-chloro-2,2,2-trifluoroethane

Abstract: Process for preparing trifluoroethyl sulfur compounds from thiolates and 1-chloro-2,2,2-trifluoroethane The invention relates to the preparation of trifluoro-ethyl sulfur compounds of the formula RSCH2CF3 by reacting 1-chloro-2,2,2-trifluoroethane CH2Cl-CF3 in a polar aprotic solvent with salts of thiols of the formula RSH, where R can be an alkyl or aryl radical or a heterocyclic radical.

Use of 4-thioresorcin derivatives in skin whitening cosmetic or dermopharmaceutical compositions

Abstract: Use, as active compounds, of resorcin derivatives for the preparation of a cosmetic or dermatological composition having a depigmenting action; the said derivatives correspond to the following formula: in which: R represents a C1-C6 alkyl radical, a C1-C6 haloalkyl radical, an aryl radical, an aralkyl radical which may or may not be substituted with a lower alkyl radical, a lower alkoxy radical or a halogen atom, or the radical -CnH2n-COOR' where n is an integer between 1 and 5, and R' represents a C1-C6 alkyl radical, a morpholinoalkyl or piperidinoalkyl radical in which the alkyl radical is C1-C6, or the radical

Imidazole containing pseudodipeptide product and compositions containing the same

Abstract: Product pseudodipeptide of general formula: ##STR1## in which A is: a) under the form: ##STR2## B represent an amine which nitrogen atom which is directly linked to the atom of carbon and chosen among the amines, the imines, the ammoniums, R is an atom of fluorine, a fluoro-alkyl radical, a functional group, an acyl radical, a linear alkyl chain, or an alkenyle or aryl radical, R' is an hydrogen atom, a fluorine atom, an alkyl radical, or fluoro-alkyl radical, and Im is an imidazole or an N-substituted imidazole ring; b) or the form of ##STR3## where R is an atom of hydrogen or a fluoro-alkyl or an acyl radical, or an hydrocarbon radical which can be substituted by one or several functional groups, and R" is a hydrocarbon radical or an acyle radical.

Oxime compounds used as crosslinking agents for copolymers

Abstract: A compound of formula (I), (II) or (III), in which R?1 and R2? are independently a C?1?-C10 alkyl, alkoxy C1-C10, C5-C10 cycloalkyl or C5-C10 aryl radical which also contain 1 to 3 non-adjacent nitrogen, oxygen or sulphur atoms as heteroatoms in the carbon chain or ring and may be substituted by 1 to 3 C1-C4 alkyl or alkoxy groups, R?1 or R1? may be a hydrogen atom, or R?1 and R2? together form a bridge of 2 to 24 carbon atoms, wherein some of the carbon atoms may also be a component of an aromatic ring system, A and B are n or m-valent organic radical, X is a linear or branched hydrocarbon chain of 2 to 12 carbon atoms, which may be interrupted by 1 to 3 non-adjacent oxygen, sulphur or nitrogen atoms or a C?5?-C10 cycloalkylene or a C5-C10 arylene ring, and n or m is a whole number greater than 1; said compound in dispersion or solution and its use as a cross-linking agent for polymers.

Cosmetic compositions containing hydrofluorocarbon compounds

Abstract: The present invention concerns the use in a cosmetic composition of a hydrofluorocarbon compound with formula (I): RsubF --(CHsub2)subn --X-- Csub3 Hsub5 (OH)!--Y--RsubH(I) where C 3 H 5 (OH) represents the structures: ##STR1## R F represents a perfluorinated C 4 -C 20 alkyl radical or a mixture of perfluorinated C 4 -C 20 alkyl radicals; R H represents a linear or branched C 1 -C 22 alkyl radical or a mixture of linear or branched C 1 -C 22 alkyl radicals, an aryl radical or an aralkyl radical; n is between 0 and 4; X and Y represent ##STR2## It also concerns certain sulfoxide and sulfone compounds and cosmetic compositions including the compounds of the invention

Method of preparing taxoids

Abstract: Method of preparing taxoids of general formula (I) by electrochemical reduction of a taxan derivative of general formula (III). The products of general formula (I) in which R1 is a radical of general formula (II) have remarkable anti-tumor and anti-leukemia properties. In general formulae (I) and (II), R is a hydrogen atom or the radical acetyl, alkoxyacetyl, alkyl or alkylcarbonyl, R1 is a hydrogen atom or a radical of general formula (II) in which Ar is an aryl radical, and R2 is an optionally substituted benzoyl radical, furoyl or thenoyl or an R3-O-CO- radical in which R3 is an alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkynyl, bicycloalkyl, phenyl or heterocyclyl radical.

Light-sensitive mixture containing an 0-naphthoquinonediazide-sulfonic acid ester and recording material produced therewith wherein the 0-naphthoquinone diazides are partial esters

Abstract: A light-sensitive mixture which contains a resinous binder which is insoluble in water but soluble or at least swellable in aqueous-alkaline solutions, and an o-naphthoquinonediazide-sulfonic acid ester, the o-naphthoquinonediazide-sulfonic acid ester being of the formula I ##STR1## in which R is hydrogen or an alkyl or aryl radical and R1 is hydrogen or a 1,2-naphthoquinone-2-diazide-4-sulfonyl, 1,2-naphthoquinone-2-diazide-5-sulfonyl or 7-methoxy-1,2-naphthoquinone-2-diazide-4-sulfonyl radical, and the number of the identical or different naphthoquinonediazide-sulfonyl radicals, defined as R1, in the molecule being 1 to 5; is useful in the preparation of light-sensitive resist materials. The resist material produced using the light-sensitive mixture has a high light sensitivity and very good developer resistance to alkaline developers and can be developed without any problems with aqueous, weakly alkaline solutions.

Preparation of N-alkyl-arylamines

Abstract: Preparation of an N-alkyl-arylamine of the formula ##STR1## in which Ar represents an aryl radical which is optionally monosubstituted or polysubstituted by at least one of halogen and in each case optionally substituted alkyl, alkoxy or alkoxycarbonyl, R 1 represents hydrogen or alkyl and R 2 represents in each case optionally substituted alkyl or aryl, or, together with R 1 , represents alkanediyl, by reacting a nitroarene of the formula Ar--NO.sub.2 (II) with a carbonyl compound of the formula R.sup.1 --CO--R.sup.2 (III) in the presence of hydrogen and in the presence of a catalyst at a temperature between 0° C. and 200° C.