- New Synthesis and Spectroscopic Studies of Thialene (Cyclopentathiapyran)
-
A new five-step synthesis of thialene, cyclopentathiapyran (2c), an intensely blue-violet pseudoazulene, is described.The critical final step in the reaction sequence gave 35percent yield of the title compound via rapid sequential thermolysis and dehydrogenation of cyclopentano-2,4-dihydro-3-(N,N-dimethyl(thiocarbamoyl)thiapyran (8), an intermediate which allowed transient formation of the highly unstable tetrahydro derivative(s).Theoretical and spectroscopic studies of 2c indicate extensive ?-delocalization.The 600.6-MHz 1H NMRspectrum displays peaks from 6.78 to 7.84 ppm, confirming a sustained ring current and establishing the molecule as aromatic based on a diatropic definition.The 1H-decoupled 75.47-MHz 13C NMR spectrum displays peaks from 110.01 to 132.09 ppm.The 70-eV EI-MS is startlingly similar to benzothiophene, indicating probable rearrangement to the benzenoid heterocycle prior to fragmentation.The molecule displays weak emission from S2; λmax = 338 nm.The IR, (+) and (-) chemical ionization MS, and solvatochromic shifts are reported.The conflict between aromaticity and chemical reactivity is discussed.
- Klein, Robert F. X.,Horak, Vaclav
-
-
Read Online
- Bioorthogonal Ligation and Cleavage by Reactions of Chloroquinoxalines with ortho-Dithiophenols
-
A bioorthogonal ligation and cleavage method via reactions of chloroquinoxalines (CQ) and ortho-dithiophenols (DT) is presented. Double nucleophilic substitutions of ortho-dithiophenols to chloroquinoxalines provide conjugates containing tetracyclic benzo[5,6][1,4]dithiino[2,3-b]quinoxaline with strong built-in fluorescence together with release of the other functional molecules. Three cleavable linkers were designed and successfully used in release of the molecules containing biotin from the protein conjugates. The CQ-DT bioorthogonal reactions can be applied for the bioorthogonal ligations, bioorthogonal cleavages, and trans-tagging of proteins, and show advantages of readily accessible unnatural orthogonal groups, appealing reaction kinetics (k2≈1.3 m?1 s?1), excellent biocompatibility of orthogonal groups, and high stability of conjugates. This complements previous bioorthogonal reactions and is a new route for protein-fishing applications and in-gel fluorescence analysis.
- Fu, Hua,Li, Hongyun,Li, Youshan,Lou, Zhenbang,Yang, Haijun,Zhao, Yufen
-
supporting information
p. 3671 - 3677
(2020/02/04)
-
- Synthesis of dithiocarbamates and selenothiocarbamates
-
Several dithiocarbamates and selenothiocarbamates were synthesized by the reaction of N,N-dimethylthiocarbamoyl chloride with the corresponding thiolates and selenolates.
- Koketsu, Mamoru,Otsuka, Toshihiro,Ishihara, Hideharu
-
p. 443 - 448
(2007/10/03)
-
- 4-(3-cyclohexyl-4-hydroxy or-methoxy phenylsulfonyl) 3,5 dibromo phenyl acetic thyromimetic cholesterol-lowering agents
-
Compounds of general formula (I) STR1 wherein R 1 is (CH 2) n ((CHNR 7 R 8) m C(O)R 9 ; n=1-3; and m=0 or 1;R 3 and R 5 are independently Cl, Br, I, or CH 3 ;R 7 and R 8 are independently H or (C 1 -C 4)alkyl;R 9 is OH, (C 1 -C 4)alkoxy, or NR 7 R 8 ;R 31 is H, Cl, Br, I, (C 1 -C 4)alkyl, (C 4 -C 6)cycloalkyl, (C 1 -C 4)haloalkyl, (C 4 -C 6)halocycloalkyl, or --CH(R 10)Ar where Ar is selected from 5-hydroxypyrid-2-yl, 6-hydroxypyrid-3-yl, 6-hydroxypyridazin-3-yl, 6-methoxypyridazin-3-yl, 6-hydroxypyridazin-3-yl N-oxide, and 6-methoxypyridazin-3-yl N-oxide and R 10 is H or (C 1 -C 4)alkyl;R 41 is OH or a bioprecursor thereof; and the pharmaceutically acceptable salts thereof; are structural analogs of the thyroid hormones T 3 and T 4 and exhibit selective thyromimetic activity. Pharmaceutical compositions of the novel compounds and their use for the treatment of mammalian cholesteremia are provided.
- -
-
-
- Novel β-D-phenylthioxylosides, their method of preparation and their use as pharmaceuticals
-
The present invention relates to β-D-phenylthioxyloside compounds selected from the group consisting of: (i) the β-D-phenylthioxylosides of the formula: STR1 in which: R1 and R2, which can be identical or different, which represent a hydrogen atom or a trifluoromethy or cyano group, A represents CHOH or CO and Y represents a hydrogen atom or an acyl group; and (ii) epimers thereof when A is CHOH. The said β-D-phenylthioxyloside compounds are useful in therapy as antithrombotics.
- -
-
-
- A Convenient Laboratory Preparation of N,N-Dimethyldichloro-methylene-iminium Chloride (Phosgene-iminium Chloride)
-
A method of preparation of the title compound 1a avoiding the use of gaseous chlorine is described.Tetramethylthiuram disulfide 4 is oxidized with sulfuryl chloride to dimethylthiocarbamoyl chloride 5, which is converted to 1a by means of phosphorus pentachloride.
- Vilkas, Michel,Qasmi, Driss
-
p. 2769 - 2773
(2007/10/02)
-
- Improved Synthesis of Aromatic Diselenides
-
The reaction of aromatic and heterocyclic lithio derivatives with elemental selenium, followed by dimethylthiocarbamyl chloride, gives highly crystalline and readily purified Se-aryl N,N-dimethylselenothiocarbamates.Alkaline hydrolysis of the latter, followed by ferricyanide oxidation, affords diselenides.Overall yields and purity of the diselenides are superior to those obtained by the standard direct selenation-oxidation method.
- Jen, Kwan-Yue,Cava, Michael P.
-
p. 1449 - 1451
(2007/10/02)
-
