- Dithio and Thiono Esters, 59. - Reactions of Aliphatic Dithio Acid Dianions with Carbon Disulfide
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Dianions 2 of dithioacids 1 and carbon disulfide yield in a kinetically controlled reaction at -78 deg C S-adducts (e.g. 3, 13) or in a thermodynamically controlled reaction at room temperatur C-adducts .Acidification of 10 and subsequent reactions give rise to the tetrathiomalonic acids 18 and its derivatives 19 with 2,6,9,10-tetrathiaadamantane structure.Deprotonation of 10a leads to the tetrathiomalonic acid tetraanion (20) which may be alkylated to yield the tetrakis(alkylthio)allenes 21.By condensation of the dithioacid dianions 2, the tetrathiomalonic acid trianion 10 and the tetrathiomalonic a cid tetraanion (20) with 2,3-dichloro-1,4-naphthoquinone (32) a number of naphtho-1,3-dithiole-4,9-diones (e.g. 33, 35, 37) are obtained. - Key Words: Dithio acid dianions / Tetrathiomalonic acid / Anions / Tetrathiomalonic acid tetraanion / Dithioacrylic esters / Thio acids / Allenes, alkylthio- / Naphtho-1,3-dithiole-4,9-diones / Malonic acid, tetrathio- / Acrylic acid, dithio
- Hartke, Klaus,Rettberg, Norbert,Dutta, Dinah,Gerber, Hans-Dieter
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p. 1081 - 1090
(2007/10/02)
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- NEW ASPECTS OF DITHIO AND THIONO ESTERS
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The field of dithio and thiono esters is expanding rapidly.Therefore emphasis is layed mainly on results obtained by the reasearch group of the author.In agreement with theoretical considerations thiono esters are always more stable than dithio esters.In the preparation of dithio and thiono esters by thiolysis slightly acidic conditions were found to be essential.The CH-acidity at the α-carbon of dithio and thiono esters with pKa values about 12 is comparable to that of classical CH-acidic compounds such as acetoacetic ester.Dithiono and tetrathio malonates do not show the expected chemistry of malonic esters; the electrophile reacts preferentially at the sulfur atom. α,β-Unsaturated dithio and thiono esters have been prepared by Wittig-Horner reactions, by Peterson synthesis, and by aldol condensations. α,β-Acetylenic dithio and thiono esters were obtained for the first time.In the formation of thiopeptide bonds from α-amino dithio esters the racemization observed seems to be of fundamental importance.Dianions of dithio acids were found to condense with different electrophiles.
- Hartke, Klaus
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p. 223 - 253
(2007/10/02)
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- Tetrathiomalonic acid and its anions
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Condensation of ethanedithioic acid with CS2 and 3 Li[HMDS] leads to the trianion 13 which is protonated to give the dimer 17 of tetrathiomalonic acid. Further deprotonation of 13 leads to the tetraanion 19 which is alkylated to form the tetrak
- Hartke,Rettberg
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p. 4679 - 4682
(2007/10/02)
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- The Synthesis of (2S,3R)-2-Hydroxymethylpiperidin-3-ol, a Fragment of the Alakloid Swainsonine
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Methyl α- and β-D-galactopyranoside have been converted into methyl 4,6-di-O-benzyl-2,3-dideoxy-α- and -β-D-threo-hexoside, and subsequent treatment with ethanedithiol gives the same alcohol.Tosylation and azide displacement gives, after hydrolysis, an az
- Mocerino, Mauro,Stick, Robert V.
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p. 1183 - 1193
(2007/10/02)
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- Convenient Synthesis of Alkanediyl Bis(alkyl trithiocarbonate)s from Alkanedithiols with Alkyl Halides and Carbon Disulfide in the Presence of Phase Transfer Catalyst
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Alkanediyl bis(alkyl trithiocarbonate)s were conveniently synthesized by treating alkanedithiols with alkyl halides and carbon disulfide in the presence of a phase transfer catalyst.
- Sugawara, Akira,Hasegawa, Ken,Suzuki, Ken-ichi,Takahashi, Yukio,Sato, Ryu
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p. 435 - 437
(2007/10/02)
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- CHIMIE DES METALLOLES DU GROUPE IV. SYNTHESE DE METHYLSILOLES PAR THERMOLYSE D'ESTERS DE SILACYCLOPENTENE-4 OLS-3 ET COMPLEXES η4-FER TRICARBONYLES
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Thermolysis of esters of silacyclopent-4-ene-3-ols Me2CH=CR-CR'(X)H2 (R,R'=H or Me; X=OC(O)NHPh, OC(S)SMe) leads to 1,1-dimethylsilole (1), 1,1,3-trimethylsilole (2) or 1,1,3,4-tetramethylsilole (3).The thermally unstable S-methylxanthates decompose involving both competitive β-C-H and β-C-Si eliminations.With N-phenylcarbamates a regioselective C-H elimination on an endocyclic carbon, leads to the expected siloles 1-3, is mainly observed.A one pot synthesis of 3, the first methylsilole stable as a monomer, from the corresponding alcohol (X=OH, R=R'=Me) and phenyl isocyanate is described. 1,1,3,4-Tetramethylgermole (4) is similarly obtained.The relative stability of the methylsiloles, their ability to form Diels-Alder dimers and to isomerize into a transoid diene, is discussed.In this respect, the strong influence of C-methyl groups on the stabilization of the tetramethylsilole, as in the case of the 1,1,3,4-tetramethylphospholium ion, is made possible.The principal characteristisc of NMR and mass spectra of methylsiloles 1-3 and those of their stable tricarbonyliron complexes are studied.
- Dubac, Jaques,Laporterie, Andre,Iloughmane, Hafida
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p. 295 - 312
(2007/10/02)
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