The chemistry of isothiazoles (original) (raw)
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The preparation of some fused isothiazole derivatives
Canadian Journal of Chemistry, 1985
The treatment of di(2-amino-5-methylphenyl)methane with N-sulfinylmethanesulfonamide gives two materials, 3-(2-amino-5-methylphenyl)-5-methyl-2,1-benzisothiazole and what appears to be its tautomer, a 2,1-benzisothiazolo[2,3-b]-2,1-benzisothiazole derivative. Reaction of the former with methyl iodide gives mono-, di-, and trimethyl derivatives. The second of these also possesses the symmetrical 2,1-benzisothiazolo[2,3-b]-2,1-benztsothiazole structure. The structure of the other methylation product and of the acetylation products are discussed. Some 1,2-dithiol-3-ylidene-2-pyridylmethanes were made by condensation of 3-alkylthio-1,2-dithiolium salts with methyl 2-pyridylacetate. These demonstrate little sulphur–nitrogen interaction. 3-Methylthio-4-phenyl-1,2-dithiolium iodide reacts anomalously with methyl 2-pyridylacetate to form a quinolizinethione. 1,2-Benzisothiazolo[2,3-a]pyridintum triiodide was made by iodine oxidation of 2-(2-mercaptophenylpyridine).
Crystal structures of an isomeric pair of 3-methylthio-5-amino-1,2,4-triazoles
Journal of Molecular Structure, 1984
The structures of an isomeric pair: l-[2-(2,6-dichlorophenoxy)-ethyl]-3-methylthio-5-amino-m-1,2,4-triazole (IV) and 2-[ 2-( 2,6-dichlorophenoxy)-ethyl] -3-methylthio-5-amino=-1,2,4-triazole (V) have been established by X-ray crystallography from diffractometer data. Crystals of IV are monoclinic, space group P2,/c with a = 11.220(l), b = 10.005(3), c = 12.784(3) A, p = 91.99(l)', 2 = 4, D, = 1.478 g cm-'. CrystalsofV are orthorhombic, space group Pbca with a = 'i-618(2), b = 14.289(4), c = 26.494(7) A, Z = 8, D, = 1.470 g cm-. The structures determined by direct methods were refined to R = 0.060 for 1931 reflections of IV and R = 0.061 for 1315 reflections of V. The X-ray analysis corroborated the structures assigned to the isomeric pair on the basis of proton coupled 13C-NMR spectra The features (i.e. the sequence of the endocyclic bond angle magnitudes) of the planar s-triazole rings are governed by the same rules reported recently by Kalman and Argay [J. Mol. Struct., 102 (1983) 3911 discussing the structures of the related I, II and III compounds. In contrast to I, II, III and IV the S(6 j C(7) bond of V is almost perpendicular to the best plane of the s-triazole ring C(7)-S(6)-C(3)-N(4) = -79.0(7)". This unusual orientation of the S-methyl bond is created by the steric hindrance of the very same uicinal P-ethyl (C(S)H,-C(lO)H,)
S-Methyl-(-N-aryl and -N-alkyl)isothioureas derived from 2-aminobenzothiazole
Arkivoc, 2007
S-Methylisothioureas, 2-N-H,-N-alkyl and-N-aryl are synthesized from the reaction of ammonia or the corresponding aromatic amines with benzothiazole dithiomethylcarboimidate. The reaction with pyrrolidine and piperazine are reported. Compounds were characterized by 1 H and 13 C NMR spectroscopy and the X-ray molecular structure of S-methy-Nbenzothiazolelisothiourea derivative is reported.
2005
Chemistry Department, Faculty of Science, Cairo University, El-Faiyum Branch, El-Faiyum, Egypt<br> <em>E-mail</em> : hamohammed@yahoo.com<br> Chemistry Department, Faculty of Science, Ain Shams University, Cairo, Egypt<br> <em>Manuscript received 6 December 2004, revised 18 April 2005, accepted 21 June 2005</em> Interaction of 2-aminothiazole (AT) base with 3,5-dinitrobenzoic acid (DNB) and 3,5-dinitrosalicylic acid (DNS) gave<br> 1 : 1 molecular species. The salts were investigated using IR, NMR and UV-Vis spectroscopic techniques. Proton transfer<br> occurred from the acid to the hetero nitrogen atom of the aminothiazole to form a Lewis Salt. The crystal structure<br> of AT-DNB (1) and AT-DNS (2) were determined by single crystal X-ray diffraction. Both two compounds crystallize<br> in a monoclinic cell, (space group P2<sub>1</sub>/c ). The structures were determined by direct methods and refined to R = ...
New regiospecific isothiazole C-C coupling chemistry
Organic & Biomolecular Chemistry, 2006
Regioselective palladium catalysed coupling reactions are achieved in good to high yields, starting from either 3,5-dichloro-or 3,5-dibromoisothiazole-4-carbonitriles 1 and 2, providing 3-halo-5-(hetero/aryl, alkenyl and alkynyl)isothiazoles 3, 4, 6-9 from Stille couplings, 3-halo-5-(hetero/arylethynyl)isothiazoles 14-19 from Sonogashira and 5,5 -bi(3-chloroisothiazole-4-carbonitrile) (13) from an Ullmann type coupling. 3,5-Dibromoisothiazole-4-carbonitrile 2 is more reactive than the dichloroisothiazole-4-carbonitrile 1 and effective enough for Stille, Negishi and Sonogashira couplings. 5,5-Bi(3-chloroisothiazole-4-carbonitrile) (13) is prepared by a palladium catalysed Ullmann coupling from 3-chloro-5-iodoisothiazole-4-carbonitrile (11). A variety of 3-substituted isothiazoles (3-substituents = Cl, Br, OMs, OTs and OTf) are less reactive and fail to give successful Suzuki couplings at the isothiazole C-3 position. The 3-iodo-5-phenyl-isothiazole-4-carbonitrile (28), prepared via Sandmeyer iodination, participates successfully in Suzuki, Ullmann type, Stille, Negishi and Sonogashira coupling reactions. All products are fully characterized.
European Journal of Medicinal Chemistry, 2006
5-Sulfanyl-3-alkylaminoisothiazole dioxide derivatives have been identified as a new class of potent inhibitors of rat aortic myocite proliferation. They were prepared by applying a simple methodology able to introduce a heteroatom on C-5 of the 3-alkylaminoisothiazole dioxide system. 3-Aminosubstituted-5-chloroisothiazole dioxides react smoothly not only with S-nucleophiles but also with N-and O-nucleophiles affording the corresponding 5-heterosubstituted isothiazole dioxides through an addition-elimination reaction. The behavior of 3-alkylamino-4bromo-isothiazole 1,1-dioxide with S-, N-and O-nucleophiles affording the same products has also been described. On the contrary, the 3amino-4,5-unsubstituted isothiazole dioxide system reacts easily only with sulfur nucleophiles affording the corresponding 4,5-dihydro-5-sulfanylderivatives through a simple Michael addition reaction.