Synthesis of 2-acyl-3-methylthiofurans from 3-methylthio-2-pentene-1,5-dione enolates

2-Acyl-3-methylthiofurans 3 are obtained in fair yields from 3-methylthio-2-pentene-1,5-dione enolates 1 by reaction with iodine. In a similar reaction 1-phenyl-3-methylthio-4-nitro-2-buten-1-one gave 3-methylthio-2-nitro-5-phenylfuran 11. In the crystalline state the 2-benzoyl-3-methylthio-5-phenylfuran 3b showed a non-bonded sulfur-oxygen interaction as inferred from an X-ray diffraction determination, with a S····O distance of 2.871(5)Å.     

1-(Organosulfonyloxy)-3(1H)-1,2-benziodoxoles: Preparation and Reactions with Alkynyltrimethylsilanes

Organosulfonyloxy derivatives of 1,2-benziodoxol-3(1H)-one (3a-c) and 3,3-bis(trifluoromethyl)-3(1H)-1,2-benziodoxole (5a-c) can be prepared in high yield by the reaction of 1-hydroxybenziodoxoles 1 or 4 and the corresponding sulfonic acids or Me(3)SiOTf in the form of stable, but moderately hygroscopic, microcrystalline solids. Reaction of the triflate derivatives 3a and 5a with alkynyltrimethylsilanes affords either alkynyliodonium triflates 6, or (E)-beta-(trifluoromethanesulfonyloxy)alkenyliodonium triflates 7, while the same reaction in the presence of pyridine selectively gives the respective 1-alkynylbenziodoxoles 8 and 9 in 82-90% yield.     

Chemistry of the phenoxathiins and isosterically related heterocycles. XXXI. Synthesis of the 1,3-diazaphenoxathiin ring system and the relationship of the 13C-NMR chemical shift of the C-10a resonances to the molecular dihedral angle determined by X-Ray diffraction: A further investigation

Synthesis of the 1,3-diazaphenoxathiin ring system and the confirmation of its structure by ¹³C-nmr spectroscopy and X-ray crystallography are reported. Implications of the ¹³C-nmr chemical shift of the C-10a resonance and its relationship to the molecular dihedral angle are presented. The molecule crystallizes in the Pbca space group and was found to have a dihedral angle of 165.5(9)°, the structure refining to a final R-factor of T = 0.0427.     

Single crystal X-ray structure determinations of the reaction products of cis- and trans-cyclohexanedicarboxylic anhydrides and methylhydrazine

The structures of two of the three isomeric products of the reactions between cis- and trans-cyclohexanedicarboxylic anhydrides and methylhydrazine were determined by single-crystal X-ray methods to ascertain their tautomeric forms and stereochemistries. One product was found to be cis-N-methylamino-1,2-cyclohexanedicarboximide and the other trans-hexahydro-2-methylcyclohexa[d]pyridazine-1,2-dione.     

Benzannelated analogs of phenanthro[1,2-b]- and [2,1-b]thiophene: Synthesis and structural characterization by two-dimensional NMR and X-ray techniques

Syntheses of benzo[3,4]phenanthro[1,2-b]thiophene, benzo[3,4]phenanthro[2,1-b]thiophene and their 1-methyl analogs are reported as potential constituents of solvent refined coal liquids and for mutagenicity testing. The attempted synthesis of the 13-methyl analogs which gave the 11-methyl isomers is also described. Total assignments of the ¹H- and ¹³C-nmr spectra based on long range optimized heteronuclear protoncarbon two-dimensional chemical shift correlation are reported. Carbon assignments obtained for benzo[3,4]-phenanthro[1,2-b]thiophene using this approach were confirmed with a 125 MHz ¹³C–¹³C INADEQUATE spectrum. X-Ray crystal structures were determined for benzo[3,4]phenanthro[1,2-b]thiophene and 1-methyl-benzo[3,4]phenanthro[2,1-b]thiophene. Both molecules were helically distorted from planarity. Close intramolecular contacts between the bay region H1–H13 and ClMe-H13 of 2.03 and 2.28 Å, respectively, were responsible for the distortions. There were no close intermolecular contacts of <3.5Å. both molecules refined to an R value of <0.05.     

Synthesis of some heterocyclic skeletons via organoiron complexes. Crystal and molecular structure of (5a,6,7,8,9,9a-η6-1,4-benzoxathiino[3,2-b]pyridine)(η5-cyclopentadienyl)iron hexafluorophosphate

Synthesis of the heterocyclic skeletons of some biologically active compounds from (η⁶-o-dichlorobenzene)(η⁵-cyclopentadienyrl)iron hexafluorophosphate in a two step procedure is described. Cyclopentadienyliron hexafluorophosphate complexes of 1,4-benzodioxino[2,3-b]pyridine, 1,4-benzoxathiino[3,2-b]pyridine, 10H-pyrido[3,2-b]benzoxazine, benzo[b]naphtho[2,3-e][1,4]dioxin, 4-methylbenzo[b]benzopyran-2-one[7,6-e][1,4]dioxin and benzo[b]anthracen-9,10-diono[1,2-e][1,4]dioxin were isolated and characterized. Upon pyrolytic sublimation of these complexes the free heterocycles were obtained and characterized. (η⁶-1,4-Benzoxathiino[3,2-b]pyridine)(η⁵-cyclopentadienyl)iron hexafluorophosphate crystalizes in the orthothombic system, space group Pbca; the dihedral angle between the planes of outer rings was found to be 176.8 (1).     

1-[Hydroxy(sulfonyloxy)iodo]-1H,1H-perfluoroalkanes: Stable, Fluoroalkyl Analogs of Koser's Reagent

1-[Hydroxy(sulfonyloxy)iodo]-1H,1H-perfluoroalkanes 3 [R(f)CH(2)I(OH)OSO(2)R; R = CH(3), CF(3), p-CH(3)C(6)H(4), R(f) = CF(3), C(2)F(5)] can be prepared in two steps from the appropriate iodofluoroalkanes by oxidation with peroxytrifluoroacetic acid and subsequent reaction with TsOH, MsOH, or Me(3)SiOTf. The tosylate derivative 3a reacts with silyl enol ethers under mild conditions to give the respective alpha-(tosyloxy) ketones. A similar reaction of cyclohexene furnishes cis-1,2-bis(tosyloxy)cyclohexane as the major product. Triflates 3c,f react with (trimethylsilyl)arenes under mild conditions to afford the respective (fluoroalkyl) (aryl)iodonium triflates 7, while the analogous reaction with alkynyltrimethylsilanes leads to novel (fluoroalkyl)(alkynyl)iodonium salts 8.