Study of the reaction of cis- and trans-4-acylamino-3-hydroxythiophans with thionyl chloride

The reaction of cis- and trans-4-acylamino-3-hydroxythiophans with thionyl chloride was studied. It was found that chlorosulfites are initially formed with retention of the configuration of the starting compound. 2-Substituted 3a,4,6,6a-tetrahydrothieno[3,4-d]oxazoline is formed from trans-4-acylamino-3-chlorosulfitothiophans by thermal reaction or in the presence of pyridine, whereas trans-4-acylamino-3-chlorothiophans are obtained from cis-4-acylamino-3-chlorosulfitothiophans; both reactions proceed with inversion of configuration.     

Study of the formation of 2-substituted 3a,4,6,6a-tetrahydrothieno[3,4-d]oxazolines from cis- and trans-4-amino-3-hydroxythiophans

The formation of 2-substituted 3a,4,6,6a-tetrahydrothieno[3,4-d]oxazolines from N-acyl-substituted cis-and trans-4-amino-3-hydroxythiophans in deuteroacetic acid and by the action of thionyl chloride was studied. Only the derivatives of cis-4-amino-3-hydroxythiophans are cyclized in deuteroacetic acid. The formation of an oxazoline ring from 4-amino-3-hydroxythiophan by the action of thionyl chloride depends both on the relative position of the hydroxy and amino groups and on the character of the acyl substituent attached to the amino group.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 913–917, July, 1974.     

Synthesis,configuration, and conformation of 3-acyl derivatives of 3a,4,6,6a-tetrahydrothieno[3,4-d][1,2,3]oxathiazoline 2-oxide

3-Benzoyl-3a,4,6,6a-tetrahydrothieno[3,4-d][1,2,3]oxathiazoline 2-oxide is formed as a result of intramolecular cyclization of cis-4-benzamido-3-chlorosulfitothiophan. Only one sulfur atom — that of the sulfoxide group — is removed from the cyclization product and the analogous 3-methoxycarbonyl-3a,4,6,6a-tetrahydrothieno[3,4-d][1,2,3]oxathiazoline 2-oxide by the action of Raney nickel; the products in this case are, respectively, cis-4-benzamido-3-hydroxythiophan and 3a,4,6,6a-tetrahydrothieno]3,4-d]oxazolidone. The three-dimensional structure of 3-acyl-3a,4,4,6a-tetrahydrothieno[3,4-d][1,2,3]oxathiazoline 2-oxide was determined by ¹H and ¹³C NMR spectroscopy. A difference between the conformational state of 3-substituted 3a,4,6,6a-tetrahydrothieno[3,4-d][1,2,3]oxathiazoline 2-oxides and 3-substituted 3a,4,6,6a-tetrahydrothieno[3,4-d]oxazolidones was established.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 191–197, February, 1977.     

Huisgen reaction of nitrile oxides and nitrile imines leading to isoxazoline and pyrazole-4,6-diones

Huisgen reaction of nitrile oxides and nitrile imines generated in situ in the presence of N-benzylmaleimide afforded regiospecifically the corresponding cis-3-aryl-5-benzyl-3a,4,6,6atetrahydro-4H, 6H-pyrrolo[3,4-d]isoxazoline-4,6-diones and cis-3-aryl-5-benzyl-1-(2′,4′-dibromophenyl)-3a, 4,6,6a-tetrahydro-1H,5H-pyrrolo[3,4-c]pyrazole-4,6-diones in good yield. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 935–939, June, 2006.     

Study of the stereospecificity of the reaction of r-4-benzamido-t-3-hydroxy-c(or t)-2-(4-methoxycarbonylbutyl)thiophan with thionyl chloride

It has been established that the presence of a substituent in the 2 position in trans-4-benza-mido-3-hydroxythiophan changes the mechanism of the reaction with thionyl chloride from S_N2 to S_N1. r-4 Benzamido-t-3-chloro-c(or t)-2- (4-methoxycarbonylbutyl)thiophan and 2-phenyl-cis (or trans)-6-(4-methoxycarbonylbutyl)-cis-3a,4,6,6a-tetrahydrothieno[3,4-d]oxazoline are formed simultaneously from r-4-benzamido-t-3-hydroxy-c(or t)-2-(4-methoxy-carbonylbutyl) thiophans on reaction with thionyl chloride. The configurations of the products were established by PMR spectroscopy by means of the temperature dependence of the vicinal spin-spin coupling constants and the angular dependence of these constants.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 331–337, March, 1976.     

Study of the inversion of 4-benzamido-3-hydroxythiophane

Inversion during the acid hydrolysis of trans-4-benzamido-3-hydroxythiophane is accomplished through the intermediate formation of cis-2-phenyltetrahydrothieno[3,4-d]oxazoline. The latter has cis ring fusion, and the oxazoline ring is planar. Opening of the oxazoline ring is not accompanied by inversion and leads to cis-3,4-substituted thiophanes. Migration of the acyl group from the nitrogen to the oxygen atom was detected in substituted thiophanes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No.10, pp. 1339–1344, October, 1971.     

Mechanism of the

Stereochemical studies on [2 + 2] photoaddition of cis-/trans-4-propenylanisole (cis-1 and trans-1) and cis-1-(p-methoxyphenyl)ethylene-2-d(1) (cis-3-d(1)) to C(60) exhibit stereospecificity in favor of the trans-2 cycloadduct in the former case and nonstereoselectivity in the latter. The observed stereoselectivity in favor of the cis-6-d(3) [2 + 2] diastereomer by 12% in the case of the photochemical addition of (E)-1-(p-methoxyphenyl)-2-methyl-prop-1-ene-3,3,3-d(3) (trans-5-d(3)) to C(60) is attributed to a steric kinetic isotope effect (k(H)/k(D) = 0.78). The loss of stereochemistry in the cyclobutane ring excludes a concerted addition and is consistent with a stepwise mechanism. Intermolecular secondary kinetic isotope effects of the [2 + 2] photocycloaddition of 3-d(0) vs 3-d(1), and 3-d(6) as well as 5-d(0) vs 5-d(1), and 5-d(6) to C(60) were also measured. The intermolecular competition due to deuterium substitution of both vinylic hydrogens at the beta-carbon of 3 exhibits a substantial inverse alpha-secondary isotope effect k(H)/k(D) = 0.83 (per deuterium). Substitution with deuterium at both vinylic methyl groups of 5 yields a small inverse k(H)/k(D) = 0. 94. These results are consistent with the formation of an open intermediate in the rate-determining step.     

Condensed thiolane 1,1-dioxide systems. 3. Two modes of cyclization of N-substituted trans-3-chloro-4-thioureidothiolane 1,1-dioxides

Reaction of trans-3-chloro-A-aminothiolane 1,1-dioxide hydrochloride with aryl isothiocyanates gives, according to the base involved, cis-perhydrothieno[3,4-d]imidazole-2-thione 5,5-dioxides or the hitherto undescribed cis-2-aryliminoperhydrothieno 3,4-d] thiazole 5,5-dioxides.For Part 2, see [1].Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1420–1423, October, 1988.     

Sulfur-containing derivatives of five-membered cyclic sulfones. 2. Intramolecular cyclization of isothioureidothiolene 1,1-dioxide salts

cis-2-Imino-4,6,7,8-tetrahydrothieno[3,4-d]thiazole 5,5-dioxides were obtained by intramolecular cyclization of 4-isothioureido-2-thiolene 1,1-dioxide salts. The reaction of N-substituted thioureas with 4-bromo-2-thiolene 1,1-dioxide leads to 3-substituted cis-2-imino-4,6,7,8-tetrahydrothieno[3,4-d]thiazole 5,5-dioxides.See [1] for Communication 1.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 110–113, January, 1988.     

Condensed thiolane 1,1-dioxide system

Alkylation of trans-N-alkyl(or aryl)-N'-(3-hydroxy-1,1-dioxothiolan-4-yl) thioureas with ethyl p-toluenesulfonate, and the reaction of cyanogen bromide wiht an ethyl p-toluenesulfonate, and the reaction of cyanogen bromide with trans-3-hydroxy-4-aminothiolan-1,1-dioxides have given salts of trans-2-iminoperhydrothieno[3,4-d]-oxazole 5,5-dioxides. Rearrangement of these oxazolidines in the presence of bases afford perhydrothieno[3,4-d]imidazole-2-one 5,5-dioxides.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 268–271, February, 1988.     

Synthesis of 2-oxohexahydrothieno[3,4-d]imidazole derivatives

Conclusions We synthesized the cis-3- and 4-methyl-2-oxo-6-(-carboxybutyl) hexahydro [3,4-d]-imidazoles by the reduction of the 3- and 4-methyl-2-oxo-2,3-dihydro-6-(carboxybutyl)-1H-thieno [3,4-d] imidazoles with HSiEt₃ in CF₃COOH and subsequent alkaline hydrolysis of the intermediate methyl ethers.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1634–1636, July, 1980.The authors express their gratitude to Prof. A. Mark (France) for supplying the sample of 2-oxo-4-methyl-6-(6-carboxybutyl)hexahydrothieno[3,4-d]imidazole.     

Carbene fragmentation in the bicyclo[3.1.0]hexyl system: disconnecting the trishomocyclopropenyl cation

[structure: see text] Fragmentation of cis-3-bicyclo[3.1.0]hexyloxychlorocarbene (4) affords cis- and trans-3-bicyclo[3.1.0]hexyl chlorides, cis- and trans-2-bicyclo[3.1.0]hexyl chlorides, and 2-bicylo[3.1.0]hexene. The promiscuity of product formation, taken together with kinetics and labeling studies, suggests that the fragmentation of 4 proceeds via a 3-bicyclo[3.1.0]hexyl cation-chloride ion pair but largely bypasses a trishomocyclopropenyl cation intermediate.     

Substituted Butanolides and Butenolides: XVI. Oxidative and Hydrolytic Transformations of Butanolide Fused to Dihydropyrazole Ring

Reactions of 3a,4,6,6a-tetrahydro-3H-furo[3,4-c]pyrazol-6-one with chlorine and bromine give the corresponding 2,6-dihydro-4H-furo[3,4-c]pyrazol-6-one hydrohalides. Hydrolysis of 3a,4,6,6a-tetrahydro-3H-furo[3,4-c]pyrazol-6-one is accompanied by oxidation of the dihydropyrazole ring to pyrazole and opening of the lactone ring.     

Cobalt(III) complexes of monodentate N9-bound adeninate (ade-), [Co(ade-kappaN9)Cl(en)2]+ (en = 1,2-diaminoethane): syntheses, crystal structures, and protonation behaviors of the geometrical isomers

In acidic aqueous solution, a cobalt(III) complex containing monodentate N(9)-bound adeninate (ade(-)), cis-[Co(ade-kappaN(9))Cl(en)(2)]Cl (cis-[1]Cl), underwent protonation to the adeninate moiety without geometrical isomerization or decomposition of the Co(III) coordination sphere, and complexes of cis-[CoCl(Hade)(en)(2)]Cl(2) (cis-[2]Cl(2)) and cis-[Co(H(2)ade)Cl(en)(2)]Cl(3) (cis-[3]Cl(3)) could be isolated. The pK(a) values of the Hade and H(2)ade(+) complexes are 6.03(1) and 2.53(12), respectively, at 20 degrees C in 0.1 M aqueous NaCl. The single-crystal X-ray analyses of cis-[2]Cl(2).0.5H(2)O and cis-[3]Cl(2)(BF(4)).H(2)O revealed that protonation took place first at the adeninate N(7) and then at the N(1) atoms to form adenine tautomer (7H-Hade-kappaN(9)) and cationic adeninium (1H,7H-H(2)ade(+)-kappaN(9)) complexes, respectively. On the other hand, addition of NaOH to an aqueous solution of cis-[1]Cl afforded a mixture of geometrical isomers of the hydroxo-adeninato complex, cis- and trans-[Co(ade-kappaN(9))(OH)(en)(2)](+). The trans-isomer of chloro-adeninato complex trans-[Co(ade-kappaN(9))Cl(en)(2)]BF(4) (trans-[1]BF(4)) was synthesized by a reaction of cis-[2](BF(4))(2) and sodium methoxide in methanol. This isomer in acidic aqueous solution was also stable toward isomerization, affording the corresponding adenine tautomer and adeninium complexes (pK(a) = 5.21(1) and 2.48(9), respectively, at 20 degrees C in 0.1 M aqueous NaCl). The protonated product of trans-[Co(7H-Hade-kappaN(9))Cl(en)(2)](BF(4))(2).H(2)O (trans-[2](BF(4))(2).H(2)O) could also be characterized by X-ray analysis. Furthermore, the hydrogen-bonding interactions of the adeninate/adenine tautomer complexes cis-[1]BF(4), cis-[2](BF(4))(2), and trans-[2](BF(4))(2) with 1-cyclohexyluracil in acetonitrile-d(3) were investigated by (1)H NMR spectroscopy. The crystal structure of trans-[Co(ade)(H(2)O)(en)(2)]HPO(4).3H(2)O, which was obtained by a reaction of trans-[Co(ade)(OH)(en)(2)]BF(4) and NaH(2)PO(4), was also determined.     

Room-temperature photochromism in cis- and trans-[Ru(bpy)2(dmso)2]2+

We report on phototriggered Ru-S --> Ru-O and thermal Ru-O --> Ru-S intramolecular linkage isomerizations in cis- and trans-[Ru(bpy)2(dmso)2]2+. The cis complex features only S-bonded sulfoxides (cis-[S,S]), whereas the trans isomer is characterized by S- and O-bonded dmso ligands. Both cis-[S,S] and trans-[S,O] exhibit photochromism at room temperature in dmso solution and ionic liquid (IL). Rates of reaction in IL were monitored by UV-visible spectroscopy and are similar to those reported in dmso solution (k(O-->S) ranges from approximately 10(-3) to 10(-4) s(-1)). Cyclic voltammetric measurements of cis-[S,S] and trans-[S,O] are consistent with an electrochemically triggered linkage isomerism mechanism. While both cis-[S,S] and trans-[S,O] are photochromic at room temperature, neither complex is emissive. However, upon cooling to 77 K, cis-[S,S] exhibits LMCT (ligand-to-metal charge transfer) emission typical of many ruthenium polypyridine complexes. In contrast to cis-[S,S], trans-[S,O] does not show any detectable emission even at 77 K.     

A Facile method to transform trans-4-carboxy-3,4-dihydro-3-phenyl- 1(2H)-isoquinolones to indeno[1,2-c]isoquinolines

The indeno[1,2-c]isoquinolines are an important class of topoisomerase I inhibitors with anticancer activity. The condensation of Schiff bases with homophthalic anhydrides provides a mixture of cis- and trans-4-carboxy-3,4-dihydro-3-phenyl-1(2H)isoquinolones. Although the cis products can be readily converted to indeno[1,2-c]isoquinolines with thionyl chloride, the trans products do not afford indeno[1,2-c]isoquinolines using this method. The present report describes a route for conversion of the trans diastereomers to indeno[1,2-c]isoquinolines using selenoxide elimination and Friedel-Crafts cyclization chemistry.     

Synthesis of nitrosylruthenium complexes containing 2,2':6',2"-terpyridine by reactions of alkoxo complexes with acids

Nitrosylruthenium complexes containing 2,2':6',2"-terpyridine (terpy) have been synthesized and characterized. The three alkoxo complexes trans-(NO, OCH3), cis-(Cl, OCH3)-[RuCl(OCH3)(NO)(terpy)]PF6 ([2]PF6), trans-(NO, OC2H5), cis-(Cl, OC2H5)-[RuCl(OC2H5)(NO)(terpy)]PF6 ([3]PF6), and [RuCl(OC3H7)(NO)(terpy)]PF6 ([4]PF6) were synthesized by reactions of trans-(Cl, Cl), cis-(NO, Cl)-[RuCl2(NO)(terpy)]PF6 ([1]PF6) with NaOCH3 in CH3OH, C2H5OH, and C3H7OH, respectively. Reactions of [3]PF6 with an acid such as hydrochloric acid and trifluoromethansulforic acid afford nitrosyl complexes in which the alkoxo ligand is substituted. The geometrical isomer of [1]PF6, trans-(NO, Cl), cis-(Cl, Cl)-[RuCl2(NO)(terpy)]PF6 ([5]PF6), was obtained by the reaction of [3]PF6 in a hydrochloric acid solution. Reaction of [3]PF6 with trifluoromethansulforic acid in CH3CN gave trans-(NO, Cl), cis-(CH3CN, Cl)-[RuCl(CH3CN)(NO)(terpy)]2+ ([6]2+) under refluxing conditions. The structures of [3]PF6, [4]PF6.CH3CN, [5]CF3SO3, and [6](PF6)2 were determined by X-ray crystallograpy.     

Relationship between the configurations of 2-phenyltetrahydrothiophenium 1-methylides and their rearrangement products

trans-2-Phenyltetrahydrothiophenium 1-methylide (trans-3), which is generated by fluoride ion-induced desilylation of trans-2-phenyl-1-[(trimethylsilyl)methyl]tetrahydrothiophenium salt (trans-2), gave a mixture of 1,4,5,10a-tetrahydro-3H-2-benzothiocine (4) ([2,3]sigmatropic rearrangement product) and 4-methylsulfanyl-1-phenyl-1-butene (5) (Hofmann elimination product). Ylide trans-3 cannot undergo [2,3]sigmatropic rearrangement because the ylide-carbon is too far from the phenyl group, and trans-3 would instead isomerize to cis-3. In this paper, we discuss the mechanism of the isomerization of trans-3 to cis-3.     

1H- and 2H-T1 relaxation behavior of the rhodium dihydrogen complex [(triphos)Rh(eta 2-H2)H2]+

Protonation of the classical trihydride [(triphos)RhH3] (2) at 210 K in either THF or CH2Cl2 by either HBF4.OMe2 or CF3SO2OH gives the nonclassical eta 2-H2 complex [(triphos)Rh(eta 2-H2)H2]+ (1) [triphos = MeC(CH2PPh2)3]. Complex 1 is thermally unstable and highly fluxional in solution. In THF above 230 K, 1 transforms into the solvento dihydride complex [(triphos)Rh(eta 1-THF-d8)H2]+ (5) that, at room temperature, quickly converts to the stable dimer trans-[[(triphos)RhH]2(mu-H)2]2+ (trans-6). In CH2Cl2, 1 is stable up to 240 K. Above this temperature, the eta 2-H2 complex begins to convert into a mixture of trans- and cis-6, which, in turn, transform into the bridging-chloride dimers trans- and cis-[[(triphos)RhH]2(mu-Cl)2]2+ at room temperature. Complex 1 contains a fast-spinning H2 ligand with a T1min of 38.9 ms in CD2Cl2 (220 K, 400 MHz). An NMR analysis of the bis-deuterated isotopomer [(triphos)RhH2D2]+ (1-d2) did not provide a J(HD) value. At 190 K, the perdeuterated isotopomers [(triphos)RhD3] (2-d3) and 1-d4 show T1min values of 16.5 and 32.6 ms (76.753 MHz), respectively, for the rapidly exchanging deuterides. An analogous 2-fold elongation of T1min is also observed on going from [(triphos)IrD3] to [(triphos)Ir(eta 2-D2)D2]+. A rationale for the elongation of T1min in nonclassical polyhydrides is proposed on the basis of both the results obtained and recent literature reports.     

Isomerization of trans-[Ru(PTA)4Cl2] to cis-[Ru(PTA)4Cl2] in water and organic solvent: revisiting the chemistry of [Ru(PTA)4Cl2

trans-[Ru(PTA)4Cl2] (trans-1), (PTA = 1,3,5-triaza-7-phosphatricyclo[3.3.1.13,7]decane) has been isolated and structurally characterized by X-ray crystallography. The structure reveals ruthenium in a slightly distorted-octahedral environment bound to two axial chlorides and four equatorial PTA ligands. In organic solvents, trans-1 undergoes a relatively clean isomerization to cis-1. In aqueous environments, trans-1 undergoes a more complicated transformation involving isomerization, protonation, and ligand substitution affording cis-1 and a series of structurally related molecules. From these results, we conclude that the synthesis of [Ru(PTA)4Cl2] (1) affords trans-1, not cis-1, as earlier reports suggest. The water-soluble hydride cis-[Ru(PTA)4H2] (2) has also been synthesized from the reaction of trans-[Ru(PTA)4Cl2] with excess sodium formate. Compound 2 is stable in deoxygenated water and undergoes H/D exchange with D2O (t1/2 approximately equal to 120 min, at 25 degrees C). The solid-state structures of both trans-1 and 2 are described.