Wolfgang Hanefeld

Branched-Chain Sugars as Push-Pull Butadienes

Abstract Treatment of methyl 4,6-O-benzylidene-2-(dicyanomethylene)-2,3-dideoxy-α-D-erythro-hexopyranoside (2) with 3-benzyl-2-methylthio-2-thiazolinium iodide (3), 4,5-dihydro-3-methyl-2-methylthio-1,3-thiazinium iodide (5) and 3-benzyl-4,5-dihydro-2-methylthio-1,3-thiazinium iodide (6), respectively, gave methyl 4,6-O-benzylidene-3-[(2Z)-3-benzyl-2-thiazolidinylidene, 3-methyl-1,3-thiazinan-2-ylidene and 3-benzyl-1,3-thiazinan-2-ylidene]-2-(dicyanomethylene)-2,3-dideoxy-α-D-erythro-hexopyranoside (4), (7), (8), respectively.

Strukturvariationen durch Reaktionen der Thiocarbonylgruppe

Structural Variations by Reactions of the Thiocarbonyl GroupThe 2,3-dihydrothiazol-2-thiones 1a—c have been methylated to the 2-methylsulfanylthiazolium iodides 2a—c, which could be reacted with double activated CH-acidic compounds like 4-nitrophenylacetonitrile (3) to yield 5 and 6a,b, with malonic acid derivatives 7a—c to yield the push pull substituted ketene-S,N-acetales 8a—c or with 3-aminorhoda-nine derivatives to yield 12a,b. Vinylogous CH-acidic compounds like 9a—d reacted with 2b to the push-pull substituted butadienes 10a—d. With p-phenethidine 2b formed depending on the reaction conditions either the rare structure of an ortho-dithiocarbonic diester diamide (14) or the isothiourea 15. With hydrazino compounds, 16a—c with hydrazono partial structure resulted. Efforts to acylate the unsubstituted nitrogen of 17 with carbonic acid ester derivatives always yielded the S-acylated products 18 and 20a,b.

Synthesis of pentacyclic retinoids

Abstract Two pentacyclic analogues of the retinoid temarotene (1) have been prepared. We describe the first palladium-catalyzed coupling of a stannylated pyridine with an aromatic triflate and a novel way for the preparation of the benzo-[c]-1,8-naphthyridine skeleton.

Oxidationen an Thiourethanen. 16 [1]; Elektrochemische Oxidationen. 2 [2]: Elektrochemische Oxidationen von cyclischen Dithiourethanen, analytische Peakpotentialermittlung

Oxidations on Carbamothioates. 16 [1]; Electrochemical Oxidations. 2 [2]: Electrochemical Oxidations of Carbamodithioates, Analytical Evaluation of Peak Potentials It is possible to oxidize carbamodithioates of type I to the related carbamothioates of type II by electrochemical anodic oxidation. As analytical methods have been applied direct current voltammetry, differential pulse polarography and cyclic voltammetry. Each of these methods could be applied to the carbamodithioates 1-11 resulting in values for well defined oxidation-potentials.