Wyniki wyszukiwania - Biblioteka Nauki

1

Reakcje związków siarko-organicznych z karbenami oraz karbenoidami

100%

Mlostoń G.

LAB Laboratoria, Aparatura, Badania

|

2000

|

tom R. 5, nr 4

14-17

2

Generation and Typical Reactions of Thiocarbonyl Ylides

63%

Mlostoń G. , Heimgartner H.

Polish Journal of Chemistry

|

2000

|

tom Vol. 74, nr 11

1503-1532

EN

In recent years, thiocarbonyl ylides found new application as useful building blocks in syntheses of sulfur containing heterocycles. They were also shown to play an important role as key intermediates in two-step [3+2] cycloaddition reactions. Strategies explored for the generation of thiocarbonyl ylides and their typical reactions including [3+2] cycloadditions,1,3- and 1,5-electrocyclizations, additions of OH, SH, and NH groups, and rearrangements are presented. Reactivities of isolable, push-pull stabilized thiocarbonyl ylides are compared with those proposed as transient species.

3

Quantum chemical calculations on S-centered 1,3-dipoles : 1. Molecular and electronic structures of thiocarbonyl S-imides

63%

Fabian J. , Mlostoń G.

Polish Journal of Chemistry

|

1999

|

tom vol. 73 nr 4

669-681

EN

Results of high level quantum chemical calculations on thiocarbonyl S-imides of type 4 are reported. Structure and properties of thioformaldehyde S-imide (4b) (CH2SNH) and its derivatives were calculated by DFT(B3LYP) in conjunction with 6-31+G(d,p) and 6-31+G(3df,3dp) basis sets. For the sake of comparison conventional ab initio quantum chemical calculations were also performed at MP2 and QCISD(T) levels. The calculated geometry and molecular properties of 4b are compared with those of closely related ylidic structures such as thioformaldehyde S-methylide (1, R1-R4 =H), thioformaldehyde S-oxide (2,R1-R2 =H), and thioformaldehyde S-sulfide (3, R1-R2 = H). Differently substituted thiocarbonyl S-imides 4d-i were calculated to show the effect of substitution on their molecular and electronic structure as well as on some physical properties. The parent compound 4b in the molecular ground state is predicted to be most stable in the planar and bent anti-conformation with geometric parameters and electronic characteristics of a predominantly ylidic structure. The IR and UV absorption maxima of 4b were calculated and discussed with respect to the expected structure of this reactive intermediate.

4

Adamantanethione and diazomethane : dual regiochemistry of cycloadditions [1]

63%

Huisgen R. , Mlostoń G.

Polish Journal of Chemistry

|

1999

|

tom vol. 73 nr 4

635-644

EN

Cycloadditions of diazoalkanes to thiones take place in two directions furnishing 1,3,4-thiadiazolines and/or their 1,2,3-isomers, depending upon the substituents. Adamantanethione and diazomethane give rise to both regioisomers; a literature report on the high solvent dependence of the isomer ratio is confirmed, and the two regioisomers are isolated. The 1,3,4-thiadiazoline 20 eliminates N2 at 800C(t1/2 55s) in a 1,3-dipolar cycloreversion; the thiocarbonyl ylide 22 generated undergoes electrocyclization, forming a thiirane, or is intercepted by reactions with HX (thiols, alcohols) or dipolarophilic multiple bonds. The N2 extrusion from the isomeric 1,2,3-thiadiazoline 21 is at 800C 600 times slower; the formation of the spirothiirane and homoadaadamantane-2-thione is explained by a diazonium thiolate as an intermediate.

5

Quantum chemical calculations on S-centered 1,3-dipoles : 2. Reactivity of thiocarbonyl S-imides in perycyclic reactions

63%

Mlostoń G. , Fabian J.

Polish Journal of Chemistry

|

1999

|

tom vol. 73 nr 4

683-692

EN

Results of high level quantum chemical calculations on thiocarbonyl S-imides 1 are reported. The reactivity of thioformaldehyde S-imide (1a) (CH2S+NH-) in pericyclic reactions was calculated by density functional theory using gradient corrected functionals in conjunction with 6-31+G(d,p) and 6-31+G(3df, 3dp) basis sets. For the sake of comparison, conventional ab initio quantum chemical calculations at correlated levels of theory, such as MP2, QCISD(T) G1 and G2(MP2), were also performed. The predicted reactivity of the parent compound is compared with those of some closely related ylides (S-centered 1,3-dipoles), such as thioformaldehyde S-methylide (2a), thioformaldehyde S- oxide (3a) and thioformaldehyde S-sulfide (4a). To show the effect of substitution on structure and reactivity a series of acyclic and cyclic substituted thiocarbonyl S-imides 1b-k was calculated. The 1,3-electrocyclic ring closure of 1a to form thiaziridines 5 is predicted to be exothermic process by about 10 kcal/mol with activation energies of about 30 kcal/mol. The calculated reaction energies are considerably affected by higher angular momentum polarization functions, such as f-functions. In the case of some substituted thiocarbonyl S-imides, such as thiotropone S-imide (1i) and thiofluorenone S-imide (1j), the exothermicity of the ring closure reaction is lower than that of the parent compound. The concerted prototype [3+2]-cycloaddition of 1a with ethylene is strongly exothermic (about 50 kcal/mol) with the activation energy of about 20 kcal/mol. The energetics of both types of the pericyclic reactions of 1a appears closely related to that of 4a but differs more strongly from that of 3a. The contemporary knowledge on thiocarbonyl S-imides 1 is reviewed and discussed in conjunction with theoretical results.

6

Flash vacuum pyrolysis of 1,3-thiazole-5(4H)-thiones

51%

Leśniak S. , Mlostoń G. , Heimgartner H.

Polish Journal of Chemistry

|

1998

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tom Vol. 72, nr 8

1915-1920

EN

Flash vacuum pyrolysis of 2-phenyl-1,3-oxazol-5(4H)-one (5) at 600degree C/1.5x10(-3) torr proceeded via CO2-elimination to give 3-phenyl-2H-azirine (6) as the only detectable product which was isolated in 34% yield. Under similar conditions, 4,4-dimethyl-1,3-thiazole-5(4H)-thiones 7a and 7b yielded isomeric 1,4,2-dithiazole derivatives 8a,b as main products. Desulfurization leads to 2-(2-propylidene)-1,3-thiazetes 9 as minor products, and in the case of 7a, disulfide 10a is formed as a second minor product.

7

Synthesis of N-Unsubstituted 1,3-Thiazollidines by [2+3]-Cycloaddition of an Azomethine Ylide with Thiocarbonyl Compounds

51%

Gebert A. , Linden A. , Mlostoń G. , Heimgartner H.

|

tom Vol. 77 / nr 2

157-167

EN

1,3-Dipolar cycloadditions of azomethine ylides with thiocarbonyl compounds have been used for the preparation of N-unsubstituted 1,3-thiazolidines. The reactive 1- phenyl-N-(trimethylsilyl)azomethine ylide (1c) was generated in situ by treatment of N-(benzylidene)[(trimethylsilyl)methyl]amine (6) with trimethylsilyl triflate and CsF in HMPA. All cycloadditions proceeded non-regioselectively, which led to mixtures of 4-phenyl- and 2-phenyl-substituted 1,3-thiazolidines.

8

Effect of the Electrode Material on the Electrochemical Reduction of Some 2,5-Dihydro-1,3,4-thiadiazoles

51%

Turowska M. , Mlostoń G. , Romański J. , Raczak J.

|

tom Vol. 77 / nr 2

237-250

EN

During cyclic voltammetric studies of the 2,5-dihydro-1,3,4-thiadiazoles (_3-1,3,4- thiadiazolines) (1a-e) onHMDEin 0.1_10-3 mol/dm3 LiClO4 acetonitrile and aqueousacetonitrile or aqueous-ethanol Britton-Robinson's buffer solutions in second polarization cycle, besides peaks equivalent to polarographic waves, an additional new system of peaks was observed. The corresponding analogous system of additional peaks has not been observed during the reduction of these substances on electrodes of other materials, as i.e., platinum, gold or glassy carbon. This study showed that it results from the oxidation and reduction of organo-mercury compounds, formed in reaction of the electrode material (Hg) with an adsorbed product of 2,5-dihydro-1,3,4-thiadiazoles reduction.

9

Synthessi of 3-Benzyl-1,3-thiazolidines by {2+3}-Cycloaddition of Sonochemically Generated Azomethine Ylides with Thiocarbonyl Compounds

51%

Gebert A. , Linden A. , Mlostoń G. , Heimgartner H.

|

tom Vol. 77 / nr 7

867-879

EN

Sonification of N-benzyl-N-(methoxymethyl)-N-[(trimethylsilyl)methyl]amine (5a) in the presence of LiF led to the formation of the reactive azomethine ylide 1d, which was intercepted by cyclic thioketones to give spirocyclic 1,3-thiazolidines. In the case of 2,2,4,4-tetramethylcyclobutane-1,3-dithione (13), the 1:1- and 1:2-cycloadduct, respectively, was formed as the major product depending on the ratio of the starting materials. With 1,3-thiazole-5(4H)-thiones, 1d undergoes stereoselective [2+3]-cycloadditions with the C=S group to yield spirocyclic 1:1-adducts. In the case of the 1,3-dipole generated from N-benzyl-N-(methoxymethyl)-N-[1-(trimethylsilyl)ethyl]amine (5b), the [2+3]-cycloaddition proceeded in a non-regioselective manner leading to a mixture of regio- and diastereoisomers.

10

Trapping of thiocarbonyl ylides with NH-azoles; A novel route to N-substituted azoles

51%

Mlostoń G. , Gendek T. , Heimgartner H.

Polish Journal of Chemistry

|

1998

|

tom Vol. 72, nr 1

66-72

EN

Thermal decomposition of 2,5-dihydro-1,3,4-thiadiazoles (1) in the presence of imidazole, pyrazole, 3-phenylpyrazole, and 1,2,4-triazole, respectively, yielded S,N-acetals of type 4. Interception of initially formed thiocarbonyl ylide 2 by the NH-azole is proposed as the reaction mechanism. Treatment of the S,N-acetals 4 with Raney-Ni gave N-substituted azole 6.

11

Reactions of ethyl diazoacetate with thioketones

51%

Kagi M. , Mlostoń G. , Heimgartner H.

Polish Journal of Chemistry

|

1998

|

tom Vol. 72, nr 4

678-687

EN

The reaction of ethyl diazoacetate (10) with 9H-fluorene-9-thione (2a), thiobenzophenone (2b), and adamantanethione (2c), respectively, in THF yielded 1,3-dithiolane carboxylates (Scheme 2). Whereas in the first two cases the reaction proceeded at room temperature, heating to 60 degree C was necessary when the less reactive 2c was used. The additions with 2a and 2c occured in a regioselective way, yielding 1,3-dithiolane-2-carboxylate 11a and 1,3-dithiolane-4-carboxylate 12c, respectively, with opposite regiochemistry. On the other hand, a mixture of the two regioisomeric cycloadducts 11b and 12b was formed in the case of 2b. The analogous reaction of 10 with the sterically crowded thione 13 gave thiirane 14 as the sole product, and with the corresponding dithione 16, a mixture of the cis- and trans-dithiiranes 17 and 18 was formed (Scheme 3). Desulfurization with tris(dimethylamino)phosphine yielded the alpha, beta -unsaturated esters 15 and 19/20, respectively. The alpha, beta-insaturated ester 22 was the only product in the reaction of 10 with 9H-xanthene-9-thione (21), which had to be carried out at 60 degree C.

12

Synthesis and Structure of Spirocyclic Tetrahydrothiophene Derivatives Bearing a 'Cage' Residue

51%

Romański J. , Mlostoń G. , Linden A. , Heimgartner H.

Polish Journal of Chemistry

|

2005

|

tom Vol. 79 / nr 6

973-979

EN

Trapping of the thiocarbonyl S-methanide 4 with tetracyanoethene and N-methylmaleimide led to the [3+2]-cycloadducts 11 and 12, respectively. The structures of these cycloadducts were established by X-ray crystallography. The 1,3-dipole 4 has been generated by thermal decomposition of the corresponding 2,5-dihydro-1,3,4-thiadiazole 2, which was prepared by the 1,3-dipolar cycloaddition of diazomethane with thioketone 1.

13

Reaction of 2,2,4,4-Tetramethyl-3-thioxocyclobutanone with Dimethyl Diazomalonate Catalyzed by Rh2(OAc)4

51%

Mlostoń G. , Romański J. , Heimgartner H.

Polish Journal of Chemistry

|

2002

|

tom Vol. 76 / nr 4

551-555

EN

The reaction of 2,2,4,4-tetramethyl-3-thioxocyclobutanone (1) with dimethyl diazomalonate in the presence of Rh2(OAc)4 in toluene at 50_C yielded a mixture of three products 10, 11, and 12. Thiocarbonyl ylide 8 is believed to be the common intermediate. The formation of 10 is rationalized by the 1,3-dipolar electrocyclization of 8 to give spirocyclic thiirane 9, which spontaneously eliminated sulfur. On the other hand, the 1,5- dipolar electrocyclization of 8 led to 1,3-oxathiole 11, which is converted into lactone 12 by hydrolysis.

14

Reactions of Thioesters with Organic Azides-A Novel Accesss to Imidates and Thioimidates

51%

Mlostoń G. , Romański J. , Heimgartner H.

Polish Journal of Chemistry

|

2001

|

tom Vol. 75, nr 7

975-982

EN

The reaction of O-methyl thiocarboxylates 8a, b with organic azides at 110_C yielded the corresponding imidates of type 9, which were easily hydrolyzed to give amides 10. The formation of 9 can be rationalized by a 1,3-dipolar cycloaddition of the azide with the C=S group, followed by the "twofold extrusion" ofN2 and S. The analogous reaction with methyl dithiobenzoate (11) led to thioimidates 13. On heating, the latter were transformed into thioamides 12.

15

Polycyclic [2+3]-Cycloadducts from the Thermal Decomposition of Bis(2,5-dihydro-1,3,4-thiadiazoles) in the Presence of N-Methylmaleimide

51%

Mlostoń G. , Celeda M. , Linden A. , Heimgartner H.

Polish Journal of Chemistry

|

2004

|

tom Vol.78 /nr 11-12

2089-2099

16

A novel type of ring closure of amino-substituted thiocarbonyl ylides

51%

Romański J. , Mlostoń G. , Linden A. , Heimgartner H.

Polish Journal of Chemistry

|

1999

|

tom vol. 73 nr 3

475-485

EN

The reaction of 4,4-dimethyl-1,3-thiazole-5(4H)-thiones 7a-c with dimethyl 2-diazo-3-(phenyloamino)butanoate (2), prepared from dimethyl fumarate and phenyl azide, in toluene at 800C yielded mixtures of dimethyl 2-(4,5-dihydro-4,4-dimethyl-1,3-thiazol-5-ylidene)-3-(N-phenylamino)butanedioates of type 11 and four diastereoisometric 4,4-dimethyl-9-phenyl-1,6-dithia-3,9-diazaspiro[4,4]non-2-ene-7,8-dicarboxylates of type 12. The formation of the products of type 12 is rationalized by a novel cyclization of intermediate thiocarbonyl ylides 9. The structures of cis-12a, cis-12c, and trans-12c were established by X-ray crystallography.

17

New insertion reactions of some carbenoids into amide- and sulfonamide-NH bonds

45%

Mlostoń G. , Celeda M. , Świątek A. , Kaegi M. , Heimgartner H.

Polish Journal of Chemistry

|

1998

|

tom Vol. 72, nr 8

1907-1914

EN

In the presence of catalytic amounts of Rh2(OAc)4 in toluene, dimethyl diazomalonate (1) decomposed with evolution of N2 to form a carbenoid of type 8 which reacted with carboxamides 2 and toluenesulfonamide (4) to,give 2-(acylamino)-and 2-(sulfonylamino)malonates 3 and 5, respectively. In an analogous reaction, alpha-diazo ketone 6 and 4 yielded N-(2-oxo-1, 2-diphenylethyl)toluenesulfonamide (7).

18

Reaction of 1,2-Di(1-adamantyl)-2-thioxoethanone with Diazomethanes; 1,3- versus 1,5-Dipolar Electrocyclization of a Sterically Crowded Thiocarbonyl S-Methylide

45%

Mlostoń G. , Urbaniak K. , Nomura T. , Nakayama J. , Heimgartner H.

Polish Journal of Chemistry

|

2009

|

tom Vol. 83, nr 11

1945-1951

EN

The reaction of 1,2-di(1-adamantyl)-2-thioxoethanone (4c) with diazomethane and 2-diazopropane yielded 2-acylthiiranes 6a and 6b, respectively, and no 1,3-oxathioles of type 7 were formed. The reaction course is explained via [2+3]-cycloaddition, elimination of N2, and 1,3-dipolar electrocyclization of the in ter me di ate acyl-substituted thiocarbonyl ylides of type 1. The fail ure of the competitive 1,5-dipolar electrocyclization is a result of the sterically unfavor able conformation 1a.

19

Addition of Diazomethane to Phosphonodithioformates and Reactions of Phosphonylated Thiocarbonyl S-Methylides

45%

Urbaniak K. , Mlostoń G. , Gulea M. , Masson S. , Heimgartner H.

Polish Journal of Chemistry

|

2005

|

tom Vol. 79 / nr 9

1483-1494

EN

The reaction of phosphonodithioformates 14 with diazomethane at -60 graduate C yielded 2,5-dihydro-1,3,4-thiadiazoles 15 as unstable intermediates. Their structure was evidenced by the base-catalyzed elimination of methylsulfane leading to 1,3,4-thiadiazole- 2-phosphonates. At ca. -35 graduate C, thermal decomposition of 15 by N2-elimination led to reactive thiocarbonyl S-methylides 17. In the absence of trapping reagents, these 1,3-dipoles undergo a head-to-head dimerization leading to 1,4-dithianes 18. An intermediate zwitterionic dimer 19 was detected by 31P NMR spectroscopy. The initially formed thiocarbonyl S-methylide 17 as well as an open-chain zwitterionic dimer 20 was intercepted by methanol. Stable interception products were also obtained with S- and N-nucleophiles.

20

New Thiocarbonyl Ylides Derived from 3,3-Dichloro-2,2,4,4-tetramethylcyclobutanethione; Generation and Reactions

45%

Woźnicka M. , Rutkowska M. , Mlostoń G. , Majchrzak A. , Heimgartner H.

Polish Journal of Chemistry

|

2006

|

tom Vol. 80, nr 10

1683-1693