Tetrahydro-2-methyl thiophene

Oxidation of thiophene and its derivatives was studied using hydrogen peroxide (H2O2), t-butyl-hydroperoxide and Ti-Beta redox molecular sieve as selective oxidation catalysts. A new reaction pathway was discovered and investigated using C-13 NMR, GC, GC-MS, HPLC, ion chromatography, and XANES. The thiophene oxidized to thiophene-sesquioxide [3a,4,7,7a-tetrahydro-4,7-epithiobenzo[b]-thiophene 1,1.8-trioxide] and the sesquioxide oxidized mostly to sulfate. 2-Methyl-thiophene and 2,5 dimethylthiophene also oxidized to sulfate and sulfone products. The Benzothiophene oxidation product was sulfone. This proposed new reaction pathway is different from prior literature, which reported the formation of thiophene 1,1-dioxide (sulfone ) as a stable oxidation product... 

C8H8O2S2, 6-Acetoxy-l,4-dithiocin, 44B, 319 C8H8Sft, 3-Methyl-1,2,4,5-benzotetrathiepine, 45B, 369 C8H8Se3, 3,4-Trimethylene-6a-selenaselenophthene, 39B, 238 C8H10CIN3S, 2-(2-Chloro-4-methyl-thiophene-3-yl-imino)-tetrahydro-imidazole, 45B, 371... 

Thiophene, tetrahydro-2-methyl-synthesis, 4, 901 Thiophene, tetrahydro-2-oxo-reactions, 4, 857 Thiophene, tetrahydro-3-oxo-reactions, 4, 857 synthesis, 4, 876-877 Thiophene, tetrahydro-2-phenyl-synthesis, 4, 865 Thiophene, tetraiodo-synthesis, 4, 934... 

The discovery of junipal focused the attention of Sorensen, who had been investigating the occurrence of polyacetylenes in Com-positae, on the possibility that these acetylenes were accompanied by thiophenes. From Coreopsis grandiflora Hogg ex sweet, 2-phenyl 5-(1-propynyl) thiophene (240) was isolated and its structure confirmed by synthesis of the tetrahydro compound, 2-phenyl-5-n-propyl-thiophene. From the root of tansy, the cis and trans isomers of methyl 5-(l-propynyl)-2-thienylacrylate (241) have been isolated. The total synthesis of trans (241) was achieved by reacting junipal with methylcarbethoxy triphenylphosphonium bromide (Wittig reaction) Several monosubstituted thiophenes, (242), (243), and... 

Because of their inherent penetrating smell, certain organic sulfur compounds are used for odorization. Repellents from the skunk contain compounds such as trans-2-butene-l-thiol and 3-methyl-1-butanethiol. Ethylmercaptan, because of its extremely low odor threshold, is the favorite compound used as an odorant in natural gas and liquid propane for leak detection. Tetrahydro-thiophene is also often used. Common odorization reagents are summarized in Table 15-1 and Figures 15-1 to 15-3. 

CjHjS, Thiophene, tetrahydro-gold complexes, 26 85-87 C4H,NO, 2-Propenamide, 2-methyl-nickel complex, 26 205 C4H1()02, Ethane, 1,2-dimethoxy-solvates of chromium, molybdenum, and tungsten carbonyl cyclopentadienyl complexes, 6 343 tungsten complex, 26 50 ytterbium complex, 26 22 C4H i02.NaC5H5, Ethane, 1,2-dimethoxy-compd. with cyclopentadienylsodium, 26 341... 

Condensation of 5 with methyl tetrahydro-4-oxothiophene-3-carboxyl-ate (64) led to the formation of the ring-closed enamino thiolactone 65. Chemical transformation of 65 with sodium hydride/methyl iodide gave 67, whereas 4H, 10//-thieno[3,4-c][l,5]benzothiazepin-10-one (66) was obtained upon aromatization of the thiophene ring by the action of sulfuryl chloride (Scheme 18) (80JOC497). 

In Table III two additional heterocyclic thioethers are shown which have not been identified as natural products thus far. Their structures were elucidated on the basis of infrared, H-NMR and mass spectrometry to be the 2-methyl-2-(2-methyl-3-th ieny1thio)-tetrahydrothiophene 14 and the 2-methyl-3-(2-methyl-2-tetrahydrothieny1thio)-furan 1J, i.e. in this case the thioethers are substituted with sulfur in the furan or thiophene ring systems at the 8-position while the sulfur in the tetrahydro-part of the structure is at the C-position. 

Friedel-Crafts acetylation of l-methyl-4,5,6,7-tetrahydrobenzo[c]-thiophene is reported10 to give l-acetyl-3-methyl-4,5,6,7-tetrahydro-benzo[c]thiophene. Successive treatment of methyl 4,5,6,7-tetra-hydrobenzo[c]thiophene- 1-carboxylate with /V-bromosuccinimide and sodium methoxide gives benzo[c]thiophene-l-carboxylic acid.16,38... 

Methoxycarbonyl-ethyl)-methyl-E13/2, 1325 (S-Oxygenierung) Thiophen 3-Methoxy-tetrahydro- -1,1-dioxid VI/3, 24... 

Thiophen 3-Hydroxyimino-2-methoxycarbonyl-4-methyl-tetrahydro E6a, 379 (Oxo - Oxim)... 

A-(6-Chloronaphthalen-2-)sulfonylpiperazine derivatives 4 and 5 (Figure 15.12) are potent factor Xa inhibitors. Haginoya et al proposed to replace the pyridine-phenyl or the pyridine-piperidine residue by a fused-bicyclic ring which contains an aliphatic amine and a pyridine to yield the compound 6 that has an interesting factor Xa inhibitor activity. The bioisosteric replacement of the pyridine moiety of the 6-methyl-5,6,7,8-tetrahydro-[l,6]naphthyridine by phenyl, thiophene, or thiazole analogs yielded analogs with similar or better antifactor Xa activity, but also to conserve a moderate bioavailability. 

Methoxycarbonylamino-3-athoxycarbonylamino-2-(4-carboxy-butyl)-tetrahydro-durch katal. Hydrierung von 4- Mcthoxycarbonyl-amino-3-athoxycarbonylamino-2-(4-carb-oxy-butyl)-thiophen mit Pd/C 364 2-Methoxycarbonyl-2,5-dihydro- 639 2-Methoxy methyl- 362 2-Methyl- 55... 

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