Selective synthesis of bis[1,2]dithiolo[1,4]thiazines from 4-isopropylamino-5-chloro-1,2-dithiole-3-ones

Reaction of 4-isopropylamino-5-chloro-1,2-dithiole-3-ones 3 and S₂Cl₂ in acetonitrile gave selectively 3-oxo-bis[1,2]dithiolo[1,4]thiazine-5-thiones 1 by the addition of triethylamine and bis[1,2]dithiolo[1,4]thiazine-3,5-diones 5 under the action of formic acid. 3,5-Diones 5 were also obtained by intramolecular cyclization of N,N-bis(5-chloro-3-oxo[1,2]dithiol-4-yl)amines 6 with S₂Cl₂ in the presence of Et₃N.     

Nitro derivatives of cyclic sulfoximides of the 1,2-benzoisothiazole series

Nitro derivatives of 1-R-1,2-benzoisothiazol-3-one 1-oxide were synthesized by the reactions of 2-alkyl(phenyl)thio-4-nitro- and 4,6-dinitro-2-(phenylthio)benzamides with chlorine in 60% acetic acid. Analogous reactions of 2-(n-butylthio)-4-nitro- and 2-(tert-butylthio)-4-nitrobenzamides with chlorine afforded 2-butyl- and 2-H-1,2-benzoisothiazol-3-one 1-oxides, respectively. The proposed reaction mechanism includes the formation and subsequent transformations of S-alkyl-S-aryl- and S,S-diarylchlorosulfonium chlorides.     

Novel and Stereospecific Synthesis of (2S)‐3‐(2,4,5‐Trifluorophenyl)propane‐1,2‐diol from D‐Mannitol

A stereospecific synthesis of (2S)‐3‐(2,4,5‐trifluorophenyl)propane‐1,2‐diol from D ‐mannitol has been developed. The reaction of 2,3‐O‐isopropylidene‐D ‐glyceraldehyde with 2,4,5‐trifluorophenylmagnesium bromide gave [(4R)‐2,2‐dimethyl‐1,3‐dioxolan‐4‐yl](2,4,5‐trifluorophenyl)methanol in 65% yield as a mixture of diastereoisomers (1 : 1). The Ph₃P catalyzed reaction of the latter with C₂Cl₆ followed by reduction with Pd/C‐catalyzed hydrogenation gave (2S)‐3‐(2,4,5‐trifluorophenyl)propane‐1,2‐diol with >99% ee and 65% yield.     

1,2-Thiazole durch Ringtransformation von 2H-Thiopyran-2-thionen

Summary Aminolyses of 4-dialkylamino-2-methylthiothiopyranes halides with ammonia leads to 4-amino-2-dialkylaminothiopyranylium halides. On treatment with alkali these products are hydrolyzed to N,N-dialkyl-3-amino-2,4-hexadienthioamides, which react with peroxide under oxidative cyclization to 5-dialkylamino-1,2-thiazoles. In order to determine the structures of the unsaturated thioamides and isothiazoles¹³C-NMR-spectroscopic analysis and a single crystal X-ray structure analysis of 5-dimethylamino-3-(2-methyl-1-propenyl)-1,2-thiazole (6 a) at 100K were carried out: C₉H₁₄N₂S,M _r=182.28, monoclinic, P 2₁/a,a=11.622(2),b=6.303 (1),c=13.678(2), =104.49(3)°,V=970.1(3)ų,Z=4,d _x=1.248 g/cm³, =27.0 mm^–1,R=4.93%,R _w=4.84% (1 672 observations, 157 parameters).

Herrn Prof. Dr. G. Zigeuner zum 70. Geburtstag gewidmet     

Reactions of 3-hydroxy-1,2-dihydroquinazolin-4-ones with acid chlorides

The reactions of 3-hydroxy-1,2-dihydroquinazolin-4-ones with acid chlorides can afford compounds of different types. The structures of the products depend on the type of acid chloride used and on the nature of the substituent at position 2 of the 3-hydroxy-1,2-dihydroquinazolin-4-one. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1346–1349, July, 1999.     

Eine neue Synthese von Tetrachlordiphosphan sowie Untersuchungen zur 1,2-Addition an Cycloalkene

A New Synthesis of Tetrachlorodiphosphane and Investigations Concerning the 1,2-Addition to Cycloalkenes . The phosphorus subhalide P₂Cl₄ has been synthesized by co-condensation of PCl₃ and Cu vapour in 14% yield. The ³¹P-NMR chemical shift of P₂Cl₄ has the value of δ=155. P₂Cl₄ decomposes during several hours at 0°C in a N₂ atmosphere by a disproportionation process to yield PCl₃ and a yellow polymeric compound of the approximately composition (PCl)_x. P₂Cl₄ is flammable in air to give POCl₃ and (PCl)_x. Investigations regarding the addition of P₂Cl₄ to cyclooctyne, cyclohexene, and cyclohexa-1,4-diene has been carried out. Surprisingly, cyclooctyne does not react with P₂Cl₄ but cyclohexene as well as cyclohexa-1,4-diene undergo 1,2-addition to yield the trans-1,2-bis(dichlorophosphino) substituted carbonhydrides. By derivatization with Me₃Si—NMe₂ the corresponding trans-1,2-bis[bis(dimethylamino)phosphino] compounds are synthesized.     

Synthese und Kristallstruktur von Bis(1,2-dimethyl-5-nitro-imidazol)dichlorocobalt(II)

Synthesis and Crystal Structure of Bis(1,2-dimetyl-5-nitro-imidazole)dichlorocobalt(II) Bis(1,2-dimethyl-5-nitro-imidazol)dichlorocobalt(II) was obtained by reaction of CoCl₂ · 6 H₂O with 1,2-dimethyl-5-nitro-imidazole in methanol. The compound forms blue crystals which were characterized by IR and UV-vis spectroscopy and by an X-ray crystal structure determination. Co(C₅H₇N₃O₂)₂Cl₂: tetragonal, space group I4 2d, Z = 8, a = 1142.1(1) pm, c = 2577.3(2) pm. R = 0.036 for 670 independent reflexions. The Co atom is tetrahedrally surrounded by two chlorine and two N atoms at distances of 222.8(2) and 203.5(4) pm.     

Synthesis of substituted 1,2-di(alkylsulfonyl)indolizines. Molecular and crystal structure of 3-(4-fluorobenzoyl)-6-methyl-1,2-di(propylsulfonyl)indolizine

The reactions of substituted pyridinium salts with E-1,2-di(alkylsulfonyl)-1,2-dichloroethenes proceed regiospecifically. Heating of these reagents in chloroform in the presence of a threefold excess of Et₃N affords substituted 1,2-di(alkylsulfonyl)indolizines in high yields. The structures of the reaction products were confirmed by physicochemical methods, including X-ray diffraction. Dedicated to Academician N. K. Kochetkov on the occasion of his 90th birthday. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1205–1209, May, 2005.     

Reactions of 3-hydroxy-1,2-dihydroquinazolin-4-ones with aldehydes

The reactions of 3-hydroxy-2-(2-hydroxyalkyl)- [or (2-hydroxyaryl)]-1,2-dihydro-quinazolin-4-ones with formaldehyde or acetaldehyde afford 1,3-oxazino[3,4-a]quinazolin-4-one derivatives. The reactions with other aldehydes RCHO and 3-hydroxy-2-R′-1,2-dihydroquinazolin-4-ones can give 3-hydroxy-2-R-1,2-dihydroquinazolin-4-ones, 2-substituted quinazolin-4-ones, or dianthranilide. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2523–2526, December, 1998.     

Synthesis of aliphatic 1,2-bishydroxylamines from 1,3- dihydroxyimidazolidines.

Reduction of l-hydroxy-3-imidazoline-3-oxides with NaBH₄ gives 1,3-dihydroxyimidazolidines. The latter on subsequent treatment with NH₂OH · HCl in EtOH or in hydrochloric acid afford 1,2-bishydroxylamines. An X-ray study of 1,2-bishydroxylaminocycloalkanes has shown them to becis-configurated.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 896–901, May, 1993.     

A one-pot synthesis and 1,3-dipolar cycloaddition of [1,2]dithiolo[4,3-b]indole-3(4H)-thiones

Treatment of N-substituted 2-methyl-1H-indoles 1 with S₂Cl₂ and DABCO in chloroform gave the corresponding [1,2]dithiolo[4,3-b]indole-3(4H)-thiones 5 by the addition of triethylamine in high yield. 1,2-Dithiole-3-thiones 5 underwent cycloaddition with one or two DMAD equivalents to afford either 2-(3-thioxo-1,3-dihydro-2H-indol-2-ylidene)-1,3-dithioles 10 or fused 4,5-dihydrothiopyrano[3,2-b]indoles 9.     

Reactions of 3-amino-1-phenyl- and 3-amino-1-(thien-2-yl)-4,4,4-trifluorobut-2-en-1-ones with 1,2-diaminopropane and 1,2-diamino-3,3,3-trifluoropropane

The reactions of 3-amino-1-phenyl-and 3-amino-1-(thien-2-yl)-4,4,4-trifluorobut-2-en-1-ones with 1,2-diaminopropane under kinetically controlled conditions afford mixtures ofcis andtrans isomers of 2-aroylmethyl-4-methyl-2-trifluoromethylimidazolidines. Analogous reactions with 1,2-diamino-3,3,3-trifluoropropane yieldcis-2-aroylmethyl-2,4-bis(trifluoro-methyl)imidazolidines. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2135–2139, November, 1999.     

Zur Synthese von (±)-cis-1,2-Epoxy-3-oxo-alkyl-phosphonsäureestern—Phosphonomycinanaloga

Treatment of dialkyl-3-oxo-1-alkenylphosphonates1 with OsO₄-H₂O₂ affords the (±)-threo-glycols2, which were characterised as their corresponding diacetates3. The derivatives2 were transformed into the mono-(tert-butyl-dimethylsilylether)-compounds4 and5. Subsequent treatment withp-toluene-sulfonyl chloride yields6 and7, which can be converted to (±)-cis-1,2-epoxy-3-oxoalkylphosphonates8 with tetrabutylammonium fluoride (TBAF). Sometimes thetrans-derivatives9 can be found just as the tosyloxyphosphonates11 and12 as by-products. In two cases the 1,2-dicarbonyl compounds10 were obtained.

Herrn Kollegen Prof. Dr.E. Ziegler zum 70. Geburtstag gewidmet.     

1,2-Bis(dimethylamino)-3,4,5-triphenyl-3,4,5-triphospha-1,2-diborolan und 1,2-Bis(dimethylamino)-3,4,5,6-tetra-tbutyl-3,4,5,6-tetraphospha-1,2-diborin: Synthese und Struktur sowie Berechnungen zur Molekülstruktur

1,2-Bis(dimethylamino)-3,4,5-triphenyl-3,4,5-triphospha-1,2-diborolane and 1,2-Bis(dimethylamino)-3,4,5,6-tetra-tbutyl-3,4,5,6-tetraphospha-1,2-diborine: Synthesis and Structure as well as Calculations on the Molecular Structure The diphosphides K₂[(C₆H₅)P? (C₆H₅)P? P(C₆H₅)], 4 or K₂[(tBuP)? (tBuP)₂? P(tBu)], 5 , react with (ClBNMe₂)₂ to form the binary 5-membered ring system 1,2-bis(dimethylamino)-3,4,5-triphenyl-3,4,5-triphospha-1,2-diborolane (C₆H₅P)₃(BNMe₂)₂, 2a , and the 6-membered ring system 1,2-bis(dimethylamino)-3,4,5,6-tetra-tbutyl-3,4,5,6-tetraphospha-1,2-diborine, (tBuP)₄(BNMe₂)₂, 3a , respectively. 2a and 3a could be obtained in a pure form and characterized NMR spectroscopically and by X-ray structure analyses. The two ring systems are folded; 2a exists in the ?envelope”?- 3a in the ?boat”?-conformation. Ab initio computations for 3,4,5-triphospha-1,2-diborolane M5 show that the global minimum is characterized by one B? P double bond. The parent compound geometry M6 is characterized by transannular bonding in the PH? BH? BH? PH moiety which differs in character from those in the four- and five-membered rings (BH)₂(PH)₂ and (BH)₂(PH)₃ M5 d , respectively. Explicit calculation of the influence of amino substituents on boron improved agreement of the bond length between computed and X-ray data.     

Umsetzungen von Halbsandwich-Rhenium(V)-Oligochalkogenidkomplexen mit Acetylen-dicarbonsäuredimethylester. Molekülstrukturen der neuen 1,2-Dicarbomethoxy-ethen-1,2-dichalkogenat-Chelatverbindungen Cp*Re[S2C2(COOMe)2]2 und Cp*Re(NtBu)[Se2C2(COOMe)2]

Reactions of Halfsandwich Rhenium(V) Oligochalcogenide Complexes with Dimethyl Acetylene Dicarboxylate. Molecular Structures of the New 1,2-Dicarbomethoxy-ethene-1,2-dichalcogenate Chelate Compounds Cp*Re[S₂C₂(COOMe)₂]₂ and Cp*Re(N^tBu)[Se₂C₂(COOMe)₂] The reaction of Cp*Re(S₃)(S₄) ( 1a ) with dimethyl acetylene dicarboxylate (dmad) leads through the blue intermediate Cp*Re(S₄)[S₂C₂(COOMe)₂] ( 2a ) to the red bis(ethene-1,2-dithiolato) complex Cp*Re[S₂C₂(COOMe)₂]₂ ( 3a ). The product 3a is also formed in the reactions of dmad with the tetrasulfidorhenium complexes Cp*Re(L)(S₄) (L = O ( 4a ), N^tBu ( 5a )) while the analogous tetraselenidorhenium compounds Cp*Re(L)(Se₄) ( 4b and 5b ) are only transformed to Cp*Re(L)[Se₂C₂(COOMe)₂] (L = O ( 6b ), N^tBu ( 7b )). According to the X-ray crystal structure analyses, the (ethene-1,2-dithiolato)rhenium chelate rings in 3a are folded along the S …? S vector towards the Cp* ligand (angle between the planes ReS₂/S₂C₂ 159.2°), whereas the ReSe₂C₂ chelate ring in 7b is planar.     

Intercalation of 1,2-Alkanediols into α-Zirconium Hydrogenphosphate

Intercalation compounds of α-Zr(HPO₄)₂ · H₂O with 1,2-alkanediols (from C3 to C16) have been prepared by replacing 1-propanol in α-Zr(HPO₄)₂ · 2C₃H₇OH with the desired 1,2-alkanediols by a treatment in a microwave field. It was found that the intercalates contain 1.5 molecules of diol per formula unit. The diol molecules are placed between the host layers in a bimolecular way with their aliphatic chains tilted at an angle of 51°. The diol molecules are anchored in the interlayer space by H-bonds. A mixed intercalate, containing 1,2-butanediol and 1,2-decanediol in a roughly equimolar ratio, is formed when the α-Zr(HPO₄)₂ · 2C₃H₇OH intercalate, suspended in a mixture of 1,2-butanediol and 1,2-decanediol, is exposed to microwave radiation. No new phase containing both types of the guest molecules was observed when the 1-propanol intercalate, suspended in a mixture of 1-propanol and 1,2-octanediol, is exposed to microwave radiation.     

A Stereoselective Glycosylation Approach to the Construction of 1,2-trans-β-d-Glycosidic Linkages and Convergent Synthesis of Saponins

Conventional syntheses of 1,2-trans-β-d - or α-l -glycosidic linkages rely mainly on neighboring group participation in the glycosylation reactions. The requirement for a neighboring participation group (NPG) excludes direct glycosylation with (1→2)-linked glycan donors, thus only allowing stepwise assembly of glycans and glycoconjugates containing this type of common motif. Here, a robust glycosylation protocol for the synthesis of 1,2-trans-β-d - or α-l -glycosidic linkages without resorting to NPG is disclosed; it employs an optimal combination of glycosyl N-phenyltrifluroacetimidates as donors, FeCl₃ as promoter, and CH₂Cl₂/nitrile as solvent. A broad substrate scope has been demonstrated by glycosylations with 12 (1→2)-linked di- and trisaccharide donors and 13 alcoholic acceptors including eight complex triterpene derivatives. Most of the glycosylation reactions are high yielding and exclusively 1,2-trans selective. Ten representative, naturally occurring triterpene saponins were thus synthesized in a convergent manner after deprotection of the coupled glycosides. Intensive mechanistic studies indicated that this glycosylation proceeds by S_N2-type substitution of the glycosyl α-nitrilium intermediates. Importantly, FeCl₃ dissociates and coordinates with nitrile into [Fe(RCN)_nCl₂]⁺ and [FeCl₄]⁻, and the ferric cationic species coordinates with the alcoholic acceptor to provide a protic species that activates the imidate, meanwhile the poor nucleophilicity of [FeCl₄]⁻ ensures an uninterruptive role for the glycosidation.     

1,2-Diphosphaferrocene als Liganden in Übergangsmetallkomplexen. Röntgenstrukturanalyse von [(η5-1,3-tBu2C5H3){η5-1,2-[Co2(CO)6]-3,4-(Me3SiO)2-5-(Me3Si)P2C3}]

1,2-Diphosphaferrocenes as Ligands in Transition Metal Complexes. X-Ray Structure Analysis of [(η⁵-1,3-tBu₂C₅H₃){η⁵-1,2-[Co₂(CO)₆]-3,4-(Me₃SiO)₂-5-(Me₃Si)P₂C₃}] Reaction of metallo-1,2-diphosphapropene (η⁵-tBuC₅H₄)(CO)₂Fe? P(SiMe₃)? P?C(SiMe₃)₂ with (Z-cyclooctene)Cr(CO)₅ afforded the pentacarbonylchromium adduct of a 1,2-diphosphaferrocene [(η⁵-tBuC₅C₅H₄){η⁵-1-[Cr(CO)₅]-3,4-(Me₃SiO)₂-5-(Me₃Si)P₂C₃}Fe] ( 1 c ). Diphosphaferrocene [(η⁵-tBuC₅H₄){η⁵-3,4-(Me₃SiO)₂-5-(Me₃Si)P₂C₃}Fe] ( 2 c ) was formed when (η⁵-tBuC₅H₄)(CO)₂FeBr was treated with (Me₃Si)₂P? P?C(SiMe₃)₂ in toluene at 60°C. Photolysis of molybdenum- and tungsten hexacarbonyl in the presence of [(η⁵-1,3-tBu₂C₅H₃){η⁵-3,4-(Me₃SiO)₂-5-(Me₃Si)P₂C₃}Fe] ( 2 b ) gave the pentacarbonylmetal adducts 8 (M = Mo) and 9 (M = W), respectively. A corresponding manganese derivative resulted from the photochemical reaction of 2 b and (MeC₅H₄)Mn(CO)₃. Treatment of 2 b with Co₂(CO)₈ yielded trinuclear [(η⁵-1,3-tBu₂C₅H₃){η⁵-1,2-[Co₂(CO)₆]-3,4-(Me₃SiO)₂-5-(Me₃Si)P₂C₃}Fe] ( 11 ). Constitution and configuration of compounds 1 c, 2 c, 8 – 11 were determined by elemental analyses and spectra (IR, ¹H-, ¹³C-, ³¹P-NMR, MS). In addition the molecular structure of 11 was established by single crystal X-ray analysis.     

Reaction of Z isomers of alkylaromatic 1,2-hydroxylamino oximes with 1,2-diketones

The reactions of Z isomers of alkylaromatic 1,2-hydroxylamino oximes containing the hydroxylamino group at the primary or secondary carbon atom with diacetyl afford 6-acetyl-5,6-dihydro-4H-1,2,5-oxadiazines. The reactions of these compounds with alkylaromatic 1,2-diketones produce N-substituted α-aroylnitrones or 6-aroyl-5,6-dihydro-4H-1,2,5-oxadiazines or, alternatively, their tautomeric mixtures. Dedicated to the memory of Academician V. A. Koptyug on the occasion of the 75th anniversary of his birth. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1008–1013, June, 2006.     

Investigation of reaction of dimedone and ethyl acetoacetate with 1,2-epoxy-3-chloropropane

Reactions of dimedone and ethyl acetoacetate with 1,2-epoxy-3-chloropropane in the presence of K₂CO₃ in DMSO medium were investigated. The reaction of 1,2-epoxy-3-chloropropane with ethyl acetoacetate afforded ethyl 5-hydroxy-2-methyl-5,6-dihydro-4H-pyran-3-carboxylate, with dimedone, 3-(1′,2′-epoxypropyloxy)-5,5-dimethyl-cyclohex-2-en-1-one.