Collection of Czechoslovak Chemical Communications, 1987
Eleven analogues of chalcones were synthesized; the variously substituted ferrocenyl, ruthenoceny... more Eleven analogues of chalcones were synthesized; the variously substituted ferrocenyl, ruthenocenyl or η5-cyclopentadienyltricarbonylmanganese are attached to the β-carbon of the chalcone double bond. Methyl malonate was added to eight selected chalcones. The effect of an aryl group on the chemical shift difference of diastereotopic -COOCH3 groups is discussed. The Vilsmeier-Haack formylation was employed to prepare 1'-chloro and 1'-bromoferrocenecarbaldehydes. The synthesis of 2-chloroferrocenecarbaldehyde from 2-chloroferrocenylmethyldimethylamine is also described.
Collection of Czechoslovak Chemical Communications, 1987
Diels-Alder addition of acryloylferrocene to 1-phenyl-1,3-butadiene catalysed by homoionic forms ... more Diels-Alder addition of acryloylferrocene to 1-phenyl-1,3-butadiene catalysed by homoionic forms of montmorillonite proceeds with higher selectivity and yields than does the reaction catalysed with aluminium trichloride. The catalytic activity of Mn+-montmorillonites decreases in the sequence: Al3+, Cr3+, Co2+, Fe3+, and Cu2+.
Collection of Czechoslovak Chemical Communications, 2000
Benzoylations of several benzene, naphthalene and thiophene derivatives with benzoyl chloride or ... more Benzoylations of several benzene, naphthalene and thiophene derivatives with benzoyl chloride or benzoic anhydride, catalyzed with EPZG® catalyst and in the absence of solvents were studied under microwave irradiation (MWI). Reasonable to good yields of products were achieved in short times.
Collection of Czechoslovak Chemical Communications, 1982
Two series of disubstituted ferrocenes, 1-acyl-1'-cinnamoylferrocenes and 1-acyl-1'-alken... more Two series of disubstituted ferrocenes, 1-acyl-1'-cinnamoylferrocenes and 1-acyl-1'-alkenoylferrocenes, were prepared and kinetics of their cyclization to [5]ferrocenophane-1,5-dione derivatives has been studied. It was found that substitution on the double bond of the acceptor affects the activation parameters of the reaction less than substitution on the donor of Michael addition. Bulky substituents increase markedly ΔH##f up to 116 kJ mol-1 and ΔS##f up to +44 J mol-1 K-1.
The specific nonpurely thermal effects of microwaves were evidenced according to neutral or charg... more The specific nonpurely thermal effects of microwaves were evidenced according to neutral or charged leaving groups during nucleophilic substitution of benzylic electrophiles with triphenylphosphine and tributylphosphine. Microwave (MW) irradiation considerably enhanced the reactions with charged alkylating agents, especially under solvent-free conditions. Results are interpreted considering the magnitude of MW effects according to the position of the transition state along the reaction coordinates.Key words: microwave irradiation, specific effects, phosphonium salts, leaving group effects.
Research into supported palladium complexes is described. The complexes are immobilised on porous... more Research into supported palladium complexes is described. The complexes are immobilised on porous silica supports using both grafting and templated sol-gel techniques. The resultant complexes are efficient catalysts for various C-C bond forming reactions, including Heck, Suzuki and allylic substitution. The catalysts are stable and can be easily recovered and reused, making them suitable for cleaner processing. Catalysts based on palladium (Pd) have provid- ed some of the most effective and exciting transformations in organic chemistry. A wide range of couplmg reactions are known, including the Heck (1-3), Suzuki (4-6) and Sonagashira reac- tions 0, all of which are efficient and have excellent generality. Other transformations such as hydrogenations and nucleophilic attack on allylic electrophiles are also widely used. Carbonylations represent a further class of reactions where carbon skeletons are elaborated, lea- to a wide range of useful products. Many of these reaction types ha...
Collection of Czechoslovak Chemical Communications, 1986
Page 1. 1112 REACTIVITY OF [m)FERROCENOPHANONES: THE ALDOL CONDENSATION Pavol ELEcKoa, Stefan TOM... more Page 1. 1112 REACTIVITY OF [m)FERROCENOPHANONES: THE ALDOL CONDENSATION Pavol ELEcKoa, Stefan TOMAa, Miroslav VRUBELa and Eva SOLCANIOVAb a Department 0/ Organic Chemistry, Faculty 0/ Natural ...
Collection of Czechoslovak Chemical Communications, 1986
13C NMR spectra of 18 ferrocene analogues of trans stilbenes (1-aryl-2-ferrocenylethylenes) were ... more 13C NMR spectra of 18 ferrocene analogues of trans stilbenes (1-aryl-2-ferrocenylethylenes) were measured. It was found that bridge group weakens the transfer of the substituent electron effects into ferrocene nucleus, especially distinctly into 3',4'positions of cyclopentadienyl ring. The transfer of substituent effects into β-position of the bridge -CH=CH- is greater in derivatives studied by us than in stilbenes. Synthesis of 1-(4-dimethylaminophenyl)-2-ferrocenylethylene is described.
Collection of Czechoslovak Chemical Communications, 1987
Eleven analogues of chalcones were synthesized; the variously substituted ferrocenyl, ruthenoceny... more Eleven analogues of chalcones were synthesized; the variously substituted ferrocenyl, ruthenocenyl or η5-cyclopentadienyltricarbonylmanganese are attached to the β-carbon of the chalcone double bond. Methyl malonate was added to eight selected chalcones. The effect of an aryl group on the chemical shift difference of diastereotopic -COOCH3 groups is discussed. The Vilsmeier-Haack formylation was employed to prepare 1'-chloro and 1'-bromoferrocenecarbaldehydes. The synthesis of 2-chloroferrocenecarbaldehyde from 2-chloroferrocenylmethyldimethylamine is also described.
Collection of Czechoslovak Chemical Communications, 1987
Diels-Alder addition of acryloylferrocene to 1-phenyl-1,3-butadiene catalysed by homoionic forms ... more Diels-Alder addition of acryloylferrocene to 1-phenyl-1,3-butadiene catalysed by homoionic forms of montmorillonite proceeds with higher selectivity and yields than does the reaction catalysed with aluminium trichloride. The catalytic activity of Mn+-montmorillonites decreases in the sequence: Al3+, Cr3+, Co2+, Fe3+, and Cu2+.
Collection of Czechoslovak Chemical Communications, 2000
Benzoylations of several benzene, naphthalene and thiophene derivatives with benzoyl chloride or ... more Benzoylations of several benzene, naphthalene and thiophene derivatives with benzoyl chloride or benzoic anhydride, catalyzed with EPZG® catalyst and in the absence of solvents were studied under microwave irradiation (MWI). Reasonable to good yields of products were achieved in short times.
Collection of Czechoslovak Chemical Communications, 1982
Two series of disubstituted ferrocenes, 1-acyl-1'-cinnamoylferrocenes and 1-acyl-1'-alken... more Two series of disubstituted ferrocenes, 1-acyl-1'-cinnamoylferrocenes and 1-acyl-1'-alkenoylferrocenes, were prepared and kinetics of their cyclization to [5]ferrocenophane-1,5-dione derivatives has been studied. It was found that substitution on the double bond of the acceptor affects the activation parameters of the reaction less than substitution on the donor of Michael addition. Bulky substituents increase markedly ΔH##f up to 116 kJ mol-1 and ΔS##f up to +44 J mol-1 K-1.
The specific nonpurely thermal effects of microwaves were evidenced according to neutral or charg... more The specific nonpurely thermal effects of microwaves were evidenced according to neutral or charged leaving groups during nucleophilic substitution of benzylic electrophiles with triphenylphosphine and tributylphosphine. Microwave (MW) irradiation considerably enhanced the reactions with charged alkylating agents, especially under solvent-free conditions. Results are interpreted considering the magnitude of MW effects according to the position of the transition state along the reaction coordinates.Key words: microwave irradiation, specific effects, phosphonium salts, leaving group effects.
Research into supported palladium complexes is described. The complexes are immobilised on porous... more Research into supported palladium complexes is described. The complexes are immobilised on porous silica supports using both grafting and templated sol-gel techniques. The resultant complexes are efficient catalysts for various C-C bond forming reactions, including Heck, Suzuki and allylic substitution. The catalysts are stable and can be easily recovered and reused, making them suitable for cleaner processing. Catalysts based on palladium (Pd) have provid- ed some of the most effective and exciting transformations in organic chemistry. A wide range of couplmg reactions are known, including the Heck (1-3), Suzuki (4-6) and Sonagashira reac- tions 0, all of which are efficient and have excellent generality. Other transformations such as hydrogenations and nucleophilic attack on allylic electrophiles are also widely used. Carbonylations represent a further class of reactions where carbon skeletons are elaborated, lea- to a wide range of useful products. Many of these reaction types ha...
Collection of Czechoslovak Chemical Communications, 1986
Page 1. 1112 REACTIVITY OF [m)FERROCENOPHANONES: THE ALDOL CONDENSATION Pavol ELEcKoa, Stefan TOM... more Page 1. 1112 REACTIVITY OF [m)FERROCENOPHANONES: THE ALDOL CONDENSATION Pavol ELEcKoa, Stefan TOMAa, Miroslav VRUBELa and Eva SOLCANIOVAb a Department 0/ Organic Chemistry, Faculty 0/ Natural ...
Collection of Czechoslovak Chemical Communications, 1986
13C NMR spectra of 18 ferrocene analogues of trans stilbenes (1-aryl-2-ferrocenylethylenes) were ... more 13C NMR spectra of 18 ferrocene analogues of trans stilbenes (1-aryl-2-ferrocenylethylenes) were measured. It was found that bridge group weakens the transfer of the substituent electron effects into ferrocene nucleus, especially distinctly into 3',4'positions of cyclopentadienyl ring. The transfer of substituent effects into β-position of the bridge -CH=CH- is greater in derivatives studied by us than in stilbenes. Synthesis of 1-(4-dimethylaminophenyl)-2-ferrocenylethylene is described.
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