Bärbel Schulze

Triphenyltin derivatives of isothiazol-3(2H)-one 1,1-dioxides. Synthesis, Mössbauer spectra, some fungitoxicity data, and crystal structure of triphenylstannyl 1,2-benziosthiazol-3-(2H)-one 1,1-dioxide·N,N-dimethylformamide

The syntheses and tin-119m Mossbauer spectroscopic data are reported for two series of stannylimides, 2-triphenylstannyl 1,2-benziosithiazol-3(2H)-one 1,1-dioxide·L (L = O-donor ligand) and 2-triphenylstannyl 4,5-substituted isothiazol-3(2H)-one 1,1-dioxides, and for the stannylester, triphenyltin 1,2-benzisothiazol-3(2H-onyl-2-acetate 1,1-dioxide. The observed quadrupole splitting (QS) values (3.12–3.25 mm s−1) are interpreted in terms of trans-C3SnNo trigonal bipyramidal structures for the (C6H5)3SnNC(O)C6H4SO2·L [ L = (C6H5)2C2CO, (CH3)2NCHO, C9H7NO, (C6H5CH2)2SO, (C6H53PO, (C6H5)3AsO] adducts. A crystal structure determination of the N,N-dimethylformamide adduct confirms the Mossbauer assignment. The ipso-carbons [Sn-C 2.120(4), 2.120(5), 2.122(5) A] comprise the equatorial girdle of the trigonal bipyramid, the apical positions being occupied by the imido nitrogen [Sn−N 2.242(5) A] and amido oxygen [Sn–O 2.402(5) A] atoms. A similar five-coordinate structure is assigned to (C6H5)3SnNC(O)C(R′)C(R″)SO2 [Qs 2.95–3.32 mm s−1; R′ = R″ = CH3; R′ = H, R″ = C6H5; = −(CH2)4−; R′R″ = −(CH2)5−], but for the R′ = CH3, R″ = C6H5 derivative, the lower QS value (2.54 mm s−1) is more consistent with a four-coordinated tetrahedral structure. A trans-C3SnO2 trigonal bipyramidal structure for the (C6H5)3SnO2CCH2NC(O)C6H4SO2 stannylester is indicated by its large QS (3.53 mm s−1). Results on fungitoxicity tests on some of the triphenyltin compounds are presented.

2,4,5-Triphenylisothiazol-3(2H)-one 1,1-dioxides as inhibitors of human leukocyte elastase

A series of substituted 2,4,5-triphenylisothiazol-3(2H)-one 1,1-dioxides 9 was synthesized and investigated as inhibitors of human leukocyte elastase (HLE). All compounds were found to inhibit HLE in a time-dependent manner and most of them exhibited kobs/[I] values > 300 M− 1s− 1. The most potent 3-oxosultam of this series was 9l (kobs/[I] = 2440 M− 1s− 1). Kinetic investigations performed with 9g and different substrate concentrations did not allow to clearly distinguish between a competitive or noncompetitive mode of inhibition. A more complex interaction is supported by the failure of a linear dependency of kobs values on the inhibitor concentration.

Synthesis of stable hydroperoxides of sultams by oxidation of isothiazolium salts

Abstract In this paper the first synthesis of stable 3-hydroperoxy-sultams 3a-d as well as the corresponding isothiazol-3(2H)-one, 1,1-dioxides 8a-e by oxidation of isothiazolium salts 6a-e is reported. The 3-hydroxy-sultams 7b-d are obtained by reduction of hydroperoxides 3b-d .

Synthesis and elastase-inhibiting activity of 2-pyridinyl-isothiazol-3(2H)-one 1,1-dioxides.

The synthesis of a series of new isothiazol-3(2H)-one 1,1-dioxides with halogenated (mostly fluorinated) pyridinyl and pentafluorophenyl substituents at 2-position is reported. These compounds (18-24) became easily accessible from 2-thiocyanato-1-carboxaldehydes and aminopyridines, pentafluoroaniline, respectively, by an isothiazolium cyclization-oxidation route. Compound 21 exhibited an IC(50) value of 3.1 microM toward human leukocyte elastase. The proteases cathepsin G, trypsin, cathepsin L, and angiotensin-converting enzyme, and the serine esterases acetylcholinesterase and cholesterol esterase were not inhibited by 21.

Oxyfunctionalization of novel diaryl- and triaryl-isothiazolium salts: the first isolable crystalline 3-hydroperoxyisothiazole

The synthesis of novel monocyclic di- and triphenyl-substituted hydroperoxysultims rac-cis 7 and 8 and sultams 11 and 12, as well as the 3-oxosultams 15 and 16, by oxidation of corresponding salts 1 and 2 with H2O2 in acetic acid is described. For the first time, it was possible to isolate a 3-hydroperoxide (3a) and also to determine the position of the primary oxidizing attack on the C-3 atom of isothiazolium salts 1, which have generally a much lower oxidation reactivity. Novel 3-hydroxysultams 13 and 14 were obtained by oxidation reaction of salts 1 and 2 with magnesium monoperoxyphthalate (MMPP) in acetonitrile in the ultrasound bath. Dedicated to Professor Dr. Jürgen Liebscher on the occasion of his 60th birthday.

Isothiazol-3(2H)-Ones, Part I: Synthesis, Reactions and Biological Activity

Abstract This review deals with methods for the synthesis, reactions and biological activity of isothiazol-3(2H)-ones. Monocyclic isothiazol-3(2H)-ones have been reported by oxidative cyclization of thiomalonamide derivatives, amides of 3-thionocarboxylic acids and 4,5-dithiaoctanediamides; by cyclocondensation of β-thiosubstituted propenamides and ring contraction of 1,4-thiazepines. Isothiazol-3(2H)-ones and their tautomer OH-forms have been investigated. Isothiazol-3(2H)-ones and their metal salt complexes are potent industrial microbiocides because of antifungal and antibacterial properties.

Synthesis of novel N-aroyl- and N-arylsulfonylisothiazole-2-imines by cyclization of thiocyanatovinylaldehyde hydrazones

Abstract The synthesis of N-aroyl- and N-arylsulfonylisothiazole-2-imines 7c - f as well as the corresponding acceptor-substituted 2-aminoisothiazolium sa

Stereochemical aspect of the intramolecular diaza-wittig reaction

Reactions of fluoroalkyl-substituted vinyl diazo carbonyl compounds with triphenylphosphine are accompanied by spontaneous intramolecular cyclization of the initially formed phosphazene, and pyridazines are formed as a result of tandem process [1–3]. However, no analogous transformations occur with fluorine-free vinyl diazo carbonyl compounds. Taking into account that fluoroalkyl-containing vinyl diazo carbonyl compounds are usually characterized by cis configuration* of the double bond [1, 4] and that their fluorine-free analogs are trans isomers [5, 6], the most probable reason for their different reactivities is different arrangement of functional groups (CO2Alk, CN2) at the double C=C bond. The goal of the present work was to compare chemical transformations of diastereoisomeric fluoroalkyl-containing and fluorinefree phosphazenes derived from vinyl diazo carbonyl compounds.

3,3,6,6-Tetramethyl-1,2,4,5-tetroxane: a twinned crystal structure.

The title compound, C6H12O4, also known as dimeric acetone peroxide, Me2(C2O4)Me2, has crystallographically imposed inversion symmetry and adopts a chair conformation in the solid state. This structure contrasts with that of the sulfur homologue Me2(C2S4)Me2, which has crystallographically imposed -4 symmetry and crystallizes in a twist-boat conformation. Crystals of the title compound are twinned along the reciprocal c* axis.

Oxidation of Acceptor‐substituted Isothiazolium‐2‐imines to Stable Cyclic Sulfin‐ and Sulfonamides with 3‐Hydroperoxy Function

The oxidation of isothiazolium 2-imines 3,5 and their salts 4 to stable 3-hydroperoxy-2,3,4,5,6,7-hexahydro-1,2-benzisothiazole 1-oxides 7 and 1,1-dioxides 8 and 9 as a new class of cyclic sultims and sultams is described. The formation of 3-hydroxysultams 10 and isothiazol-3(2H)one 1,1-dioxides 11 is presented.