Photoisomerization of cis‐1,2‐di(1‐Methyl‐2‐naphthyl)ethene at 77 K in Glassy Media

cis‐1,2‐Di(1‐methyl‐2‐naphthyl)ethene, c‐ 1,1 , undergoes photoisomerization in methylcyclohexane, isopentane and diethyl ether/isopentane/ethanol glasses at 77 K. On 313 nm excitation the fluorescence of c‐ 1,1 is replaced by fluorescence from t‐ 1,1 . Singular value decomposition reveals that the spectral matrices behave as two component systems suggesting conversion of a stable c‐ 1,1 conformer to a stable t‐ 1,1 conformer. However, the fluorescence spectra are λ_exc dependent. Analysis of global spectral matrices shows that c‐ 1,1 is a mixture of two conformers, each of which gives one of four known t‐ 1,1 conformers. The λ_exc dependence of the c‐ 1,1 fluorescence spectrum is barely discernible. Structure assignments to the resolved fluorescence spectra are based on the principle of least motion and on calculated geometries, energy differences and spectra of the conformers. The relative shift of the c‐ 1,1 conformer spectra is consistent with the shift of the calculated absorption spectra. The calculated structure of the most stable conformer of c‐ 1,1 agrees well with the X‐ray crystal structure. Due to large deviations of the naphthyl groups from the ethenic plane in the conformers of both c‐ and t‐ 1,1 isomers, minimal motion of these bulky substituents accomplishes cis → trans interconversion by rotation about the central bond.     

Beiträge zur Chemie schwefelhaltiger Heterocyclen, 2. Mitt.

Zusammenfassung 6-Nitro-benzo[b]thiophen-1,1-dioxid wurde unter verschiedenen Bedingungen hydriert. Das durchSkraupsche Synthese aus 2,3-Dihydro-6-amino-benzo[b]thiophen-1,1-dioxid gewonnene Produkt konnte auf Grund des NMR-Spektrums als 2,3-Dihydrothieno[2,3-f]chinolin-1,1-dioxid identifiziert werden.

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6-Nitro-benzo[b]thiophene-1,1-dioxide was hydrogenated under various conditions. The product prepared from 2,3-dihydro-6-amino-benzo[b]thiophene-1,1-dioxide by theSkraup synthesis was identified by nmr as 2,3-dihydro-thieno[2,3-f]quinoline-1,1-dioxide.

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1. Mitt.:F. Sauter, Mh. Chem.99, 1507 (1968).     

Synthesis of carbosilane block copolymers by means of a living anionic polymerization of 1,1-diethylsilacyclobutane

Block polymerization of 1,1-diethylsilacyclobutane with styrene derivatives and methacrylate derivatives was investigated. Sequential addition of styrene to a living poly(1,1-diethylsilabutane), which was prepared from phenyllithium and 1,1-diethylsilacyclobutane in THF–hexane at −48°C, gave poly(1,1-diethylsilabutane)-b-polystyrene. Similarly, addition of 4-(tert-butyldimethylsiloxy)styrene to the living poly(1,1-diethylsilabutane) provided poly(1,1-diethylsilabutane)-b-poly(4-(tert-butyldimethylsiloxy)styrene). Poly(1,1-diethylsilabutane)-b-poly(methyl methacrylate) was obtained by treatment of living poly(1,1-diethylsilabutane) with 1,1-diphenylethylene followed by an addition of methyl methacrylate. Poly(1,1-diethylsilabutane)-b-poly(2-(tert-butyldimethylsiloxy)ethyl methacrylate) was also synthesized by adding 2-(tert-butyldimethylsiloxy)ethyl methacrylate to the living poly(1,1-diethylsilabutane) which was end-capped with 1,1-diphenylethylene in the presence of lithium chloride. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2699–2706, 1998     

Elektrophile Substitutionsreaktionen des 1,1-Difluoro-1H-cyclopropabenzols

Electrophilic Substitution Reactions of 1,1-;Difluoro-1H-cyclopropabenzene 1,1-Difluoro-1H-cyclopropabenzene ( 1 ) can be deprotonated with strong bases at C( 2 ). The resulting 1,1-di-fluoro-2-lithio-1H-cyclopropabenzene ( 2 ) reacts with electrophiles to form C( 2 )-substituted derivatives of 1 . The Diels-Alder reactions with electron-poor dienes, characteristic for 1H-cyclopropabenzene, do not occur with the 1,1-difluoro analogue 1.     

Anionic ring-opening polymerization of silacyclobutane derivatives

Anionic polymerizations of 1,1-dimethylsilacyclobutane, 1,1-diethylsilacyclobutane and 1-methyl-1-phenylsilacyclobutane were investigated. Addition of 5 mol % of butyllithium to a solution of 1,1-dimethylsilacyclobutane in THF-hexane (1 : 1) at −48°C provided poly(1,1-dimethylsilabutane) in 99% yield. M_n and M_w/M_n of the obtained polymer were 2400 and 1.10. This polymerization proceeded with a living nature. M_n increased in proportion as the yield of polymer increased. Addition of the second fresh feed of the monomer to the reaction mixture restarted polymerization of the second monomer at the same rate as in the initial stage. Addition of styrene to the living poly(1,1-dimethylsilabutane) provided a poly(1,1-dimethylsilabutane-b-styrene) block copolymer. It was also found that a polymerization of 1,1-diethylsilacyclobutane in THF-hexane at −48°C showed a living nature. In contrast, a polymerization of 1-methyl-1-phenylsilacyclobutane in THF at −78°C did not show a living nature. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3207–3216, 1997     

High-energy kinetic study of chemically activated 1,1-dichlorocyclopropane

1,1-Dichlorocyclopropane has been produced by addition of CH₂(¹A₁) to 1,1-dichloroethylene. CH₂(¹A₁) was generated by the photolysis of ketene at 277–334 nm. The 1,1-dichlorocyclopropane was formed in a chemically activated state, had an energy content between 386 and 400 kJ/mol, and reacted in two parallel channels to 2,3-dichloropropene and 1,1-dichloropropene. 1,1-Dichloropropene was also formed directly by insertion of CH₂(¹A₁) into the CH bond of 1,1-dichloroethylene. As secondary reactions elimination of HCl from chemically activated 2,3-dichloropropene occurred with 3-chloropropyne and chloroallene as products. In some of the experiments perfluoropropane was added as an inert gas. The apparent rate constants for the isomerization and elimination reactions are reported. The results of RRKM calculations including distribution functions for the activated 1,1-dichlorocyclopropane and a step-ladder model for the deactivation verify the proposed reaction scheme.     

Syntheses of pyrimidine and purine analogs derived from 1,2,6-thiadiazine 1,1-dioxide

5-Amino-3-oxo-2H, 4H-1,2,6-thiadiazine 1,1-dioxide and the monopotassium salt of 3,5-dioxo-2H, 4H,6H-1,2,6-thiadiazine 1,1-dioxide was obtained by condensation of sulfamide and ethyl cyanacetate and diethyl malonate, respectively. 7-Oxo-1H,4H,6H-imidazo[2,3-c]-1,2,6-thia-diazine 5,5-dioxide was prepared by a multi-step reaction sequence from 5-amino-3-oxo-2H, 4H-1,2,6-thiadiazine 1,1-dioxide.     

Synthesis and chemical properties of cyclic β-keto sulfones (review)

Published data on the synthesis and chemical properties of dihydrothiophen-3(2H)-one 1,1-dioxide, dihydro-2H-thiopyran-3(4H)-one 1,1-dioxide, 1-benzothiophen-3(2H)-one 1,1-dioxide, and 1H-isothio-chromen-4(3H)-one 2,2-dioxide are reviewed. The choice of subjects was based on the presence of identical structural fragments, carbonyl, active methylene, and sulfonyl groups.     

Tin(II) Halide Insertion or Halogen Exchange in the Reactions of Dihaloplatinum(II) Complexes with Tin(II) Halide

Reactions of SnCl₂ with the complexes cis‐[PtCl₂(P₂)] (P₂=dppf (1,1′‐bis(diphenylphosphino)ferrocene), dppp (1,3‐bis(diphenylphosphino)propane=1,1′‐(propane‐1,3‐diyl)bis[1,1‐diphenylphosphine]), dppb (1,4‐bis(diphenylphosphino)butane=1,1′‐(butane‐1,4‐diyl)bis[1,1‐diphenylphosphine]), and dpppe (1,5‐bis(diphenylphosphino)pentane=1,1′‐(pentane‐1,5‐diyl)bis[1,1‐diphenylphosphine])) resulted in the insertion of SnCl₂ into the Pt? Cl bond to afford the cis‐[PtCl(SnCl₃)(P₂)] complexes. However, the reaction of the complexes cis‐[PtCl₂(P₂)] (P₂=dppf, dppm (bis(diphenylphosphino)methane=1,1′‐methylenebis[1,1‐diphenylphosphine]), dppe (1,2‐bis(diphenylphosphino)ethane=1,1′‐(ethane‐1,2‐diyl)bis[1,1‐diphenylphosphine]), dppp, dppb, and dpppe; P=Ph₃P and (MeO)₃P) with SnX₂ (X=Br or I) resulted in the halogen exchange to yield the complexes [PtX₂(P₂)]. In contrast, treatment of cis‐[PtBr₂(dppm)] with SnBr₂ resulted in the insertion of SnBr₂ into the Pt? Br bond to form cis‐[Pt(SnBr₃)₂(dppm)], and this product was in equilibrium with the starting complex cis‐[PtBr₂(dppm)]. Moreover, the reaction of cis‐[PtCl₂(dppb)] with a mixture SnCl₂/SnI₂ in a 2 : 1 mol ratio resulted in the formation of cis‐[PtI₂(dppb)] as a consequence of the selective halogen‐exchange reaction. ³¹P‐NMR Data for all complexes are reported, and a correlation between the chemical shifts and the coupling constants was established for mono‐ and bis(trichlorostannyl)platinum complexes. The effect of the alkane chain length of the ligand and Sn^II halide is described.     

1,2,4-benzothiadiazine 1,1-dioxides 3. Reactions of 2-aminobenzenesulfonamide with chloroalkyl isocyanates

Reactions of 2-aminobenzenesulfonamide ( 1 ) with allyl, methyl, 2-chloroethyl aor 3-chloropropyl isocyanates gave 2-(methylureido)-, 2-(allylureido)-, 2-(2′-chloroethylureido)- and 2-(3′-chloropropylureido)-benzene sulfonamides 3a,b and 7a,b in excellent yields. Treatment of 3a,b at refluxing temperature of DMF afforded 2H-1,2,4-benzothiadiazin-3(4H)-one 1,1-dioxide ( 4 ) in good yield. However, when compounds 7a,b were refluxed in 2-propanol, 3-(2′-aminoethoxy)-2H-1,2,4-benzothiadiazine 1,1-dioxide ( 11a ) and 3-(3′-aminopropoxy)-2H-1,2,4-benzothiadiazine 1,1-dioxide ( 11b ) were obtained in a form of the hydrochloride salts 10a,b in 87% and 78% yields respectively. Heating 11b in ethanol gave a dimeric form of 2H-1,2,4-benzothiadiazin-3(4H)-one 1,1-dioxide and 3-(3′-aminopropoxy)-2H-1,2,4-benzothiadiazine 1,1-dioxide ( 12 ) in 55% yield. Treating of 7a,b or 11a,b with triethylamine at the refluxing temperature of 2-propanol afforded 3-(2′-hydroxyethylamino)-2H-1,2,4-benzothiadiazine 1,1-dioxide ( 2a ) and 3-(3′-hydroxypropylamine)-2H-1,2,4-benzothiadiazine 1,1-dioxide ( 2b ) via a Smiles rearrangement.     

Synthesis and Asymmetric Enantioselective Addition of Chiral Polybinaphthyl and Polybinaphthol I.igands

Four chiral polymers P-1, P-2, P-3 and P-4 were synthesized by the polymerization of （S）-2,2＇-dioctoxy-1,1＇- binaphthyl-6,6＇-boronic acid （S-M-3） with （S）-6,6＇-dibromo-1,1＇-binaphthol （S-M-1）, （R）-6,6＇-dibromo-1,1＇- binaphthol （R-M-1）, （S）-3,3＇-diiodo-1,1＇-binaphthol （S-M-2） and （R）-3,3＇-diiodo-1,1＇-binaphthol （R-M-2） under Pd-catalyzed Suzuki reaction, respectively. All four polymers can show good solubility in some common solvents due to the nonplanarity of the polymers in the main chain backbone and flexible alkyl groups in the side chain. The analysis results indicate that specific rotation and circular dichroism （CD） spectral signals of the alternative S-S chiral polymers P-1 and P-3 are larger than those of S-R chiral polymers P-2 and P-4, but their UV-Vis and fluorescence spectra are almost similar. The results of asymmetric enantioselectivity of four polymers for diethylzinc addition to benzaldehyde indicate that catalytically active center is （R） or （S）-1, 1＇-binaphthol moieties.     

Synthesis of isomeric N-substituted 5-methyl-2H-1,2,6-thiadiazin-3(6H)one 1,1-dioxides from sulfamides and diketene

The reaction of N-n-butyl and N-benzylsulfamides with diketene in acetic acid solution in the presence of mercuric cyanide as a catalyst, afforded the corresponding 5-methyl-2-substituted-2H-1,2,6-thiadiazin-3(6H)one 1,1-dioxides. The reaction of the above mentioned sulfamides with diketene in an aqueous alkaline medium resulted in the isolation of the corresponding N-aceto-acetyl-N' -substituted-sulfamides, which were then converted into 5-methyl-6-substituted-2H-1,2,6-thiadiazin-3(6H)one 1,1-dioxides. Catalytic hydrogenation of the 5-methyl-2- and 6-n-butyl-2H-1,2,6-thiadiazin-3(6H)one 1,1-dioxides furnished the corresponding dihydro-derivatives. The structures of the isomeric 1,2,6-thiadiazine 1,1-dioxide derivatives obtained were assigned on the basis of nmr spectroscopic studies.     

Reaction of esters,ortho esters,acetals, thioacetals and epoxides with 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide (Lawesson reagent)

2,4-Bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide,LR, reacted with ethyl formate, triethoxymethane, 1,1,1-triethoxyethane and tetraethoxymethane to give2a and3. 1,1-diethoxymethylbenzene when treated withLR produced2a,3,7,8, and9b. Triethoxymethylbenzene when heated withLR gave2a,8 and11. The reaction of benzyl formate, tris(benzyloxy)methane and 1,1-dibenzyloxy-N,N-dimethylmethanamine withLR afforded2b. Bis(methylthio)methane, tris(ethylthio)methane and 1,1-bis(butylthio)ethane withLR gave9. 1,1-Bis(2,2-dimethylpropoxy)-N,N-dimethylmethanamine withLR yielded2c and17. The reaction of 1,2-epoxyethylbenzene withLR gave20, while 1,2-epoxypropane or 1,2-epoxybutane withLR afforded23 a,b.

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Reaktionen von Estern, Orthoestern, Acetalen, Thioacetalen und Epoxiden mit 2,4-Bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetan-2,4-disulfid (Lawesson Reagens)

Zusammenfassung Lawesson-Reagens (LR) reagiert mit einer Vielzahl von Verbindungen zu entsprechenden Derivaten. Es wurden folgende Reaktionspartner fürLR eingesetzt: Ethylformiat, Triethoxymethan, 1,1,1-Triethoxyethan, Tetraethoxymethan, 1,1-Diethoxymethylbenzol, Triethoxymethylbenzol, Benzylformiat, Tris(benzyloxy)methan, 1,1-Dibenzyloxy-N,N-dimethylmethanamin, Bis(methylthio)methan, Tris(ethylthio)methan, 1,1-Bis(butylthio)ethan, 1,1-Bis(2,2-dimethylpropoxy)-N,N-dimethylmethanamin, 1,2-epoxyethylbenzol, 1,2-epoxypropan und 1,2-Epoxybutan. Die entstandenen Produkte wurden mittels MS und¹³C- bzw.¹H-Spektroskopie charakterisiert.

     

Multiple Enantioselection by an Enzyme-Catalyzed Transacylation Reaction

Multiply enantioselective enzyme-catalyzed transacylation reactions are described. Two instances of triply enantioselective enzyme-catalyzed transacylations are 1) the reaction of rac-1-indanol with rac-1,1′-bi-2-naphthy]-2,2′-dibutyrate to afford (S)-1-indanoL (R)-1-indanylacetate, (S)-1,1′-bi-2-naphthyl-2,2′-diol, and (R)-1,1′-bi-2-naphthyl-2,2′-dibutyrate and 2) the reaction of rac-1-indanol with rac-2,2′-bis(butyroxymethyl)biphenyl to afford (S)-1-indanol, (R)-1-indanylbutyrate, (S)-2,2′-biphenyldimethanol, and (R)-2,2′-bis(butyroxy-methyl)biphenyl. Doubly enantioselective enzyme-catalyzed transacylations are described according to two instances: 1) the reaction of rac-1-indanol with rac-1,1′-bi-2-naphthyl-2-ol-2′-butyrate afforded (S)-1-indanol, (R)-1-indanylacetate, (S)-1,1′-bi-2-naphthyl-2,2′-diol, and (R)-1,1′-bi-2-naphthyl-2-ol-2′-butyrate, and 2) the reaction of rac-1-indanol with 1,3,5-O-methylidne-2,4,6-tri-O-butyrate-myo-inositol to afford (S)-1 -indanol, (R)-l-indanylbutyrate, and 1,3,5-O-methylidne-2,6-di-O-butyrate-myo-inositol. Multiply enantioselective enzyme-catalyzed reactions have a merit of the enhancement of enantiomeric excess over singly enantioselective ones.     

Syntheses of helical polymers through the combination of axially dissymmetric segments

Wholly aromatic polymers with various helical structures were prepared through the combination of two axially dissymmetric bifunctional compounds. The palladium-catalyzed condensation of (R)-2,2-diethoxy-6,6′-dibromo-1,1′-binaphthyl with (R)-1,1′-binaphthyl-2,2′-diamine and the reaction of (S)-2,2-diethoxy-6,6′-dibromo-1,1′-binaphthyl with (S)-1,1′-binaphthyl-2,2′-diamine produced helical polyamines, and the chiral conformation was confirmed by their circular dichroism spectra and large specific rotations. The combination of (R)-2,2-diethoxy-6,6′-dibromo-1,1′-binaphthyl and (S)-1,1′-binaphthyl-2,2′-diamine afforded polyamines with a zigzag conformation. The condensation of (R)-2,2′-dimethylbiphenyl-6,6′-dicarbonyl chloride with (R)-2,2′-diamino-6,6′-dimethylbiphenyl and the reaction of (S)-2,2′-dimethylbiphenyl-6,6′-dicarbonyl chloride with (S)-2,2′-diamino-6,6′-dimethylbiphenyl predominantly yielded cyclic dimers and tetramers because of the steric proximity of the reactive groups of the propagating species. The experimental results indicated that the structures of the obtained polymers depended on the combination of the chirality of the bifunctional atropisomeric compounds and the position of the functional groups on the aromatic rings. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4607–4620, 2004     

Synthesis of a new Class of Chiral β—Mercaptoalcohols from Amino Acids

The syntheses of three new optically active β-mercaptoalcohols,(R)-1,1-diphenyl-2-mercapto-3-methyl-1-butanol,(R)-1,1-diphenyl-2-mercapto-4-methyl-1-pentanol,and (R)-1,1-diphenyl-2-mercapto-1-benzenepropanol from the corresponding amino acids are described.The enantiomeric excesses of these β-mercaptoalcohols were determined by ^1H NMR as their (S)-mandeloyl derivatives.     

Syntheses of dibenzo[c,e][1,2]diselenin and related novel chalcogenide heterocyclic compounds

Reaction of 2,2′-dilithio-1,1′-binaphthyl with selenium followed by air oxidation gives a mixture of dinaph-thoselenophene and dimer and oligomers of 2,2′-diseleno-1,1′-binaphthyl. 2,2′-Dilithio-1,1′-biphenyl reacts with selenium to afford dibenzo[c,e][1,2]diselenin. Structures of the dimeric 2,2′-diseleno-1,1′-binaphthyl and dibenzo[c,e][1,2]diselenin have been confirmed by X-ray crystallographic analyses. Similar reaction of 2,2′-dilithio-1,1′-binaphthyl with sulfur or tellurium gives a mixture of dinaphthothiophene and dinaphtho[2,1-c:-1′,2′-e][1,2]dithiin or a mixture of dinaphthotellurophene and oligomer of 2,2′-ditelluro-1,1′-binaphthyl, respectively. Dibenzotellurophene and oligomer of 2,2′-ditelluro-1,1′-biphenyl are obtained from reaction of 2,2′-dilithio-1,1′-biphenyl with tellurium.     

Syntheses with nitriles. 60. Preparation of 4-amino-5-cyano-6-phenylpyrimidines from 2-amino-1,1-dicyano-2-phenylethene

The reaction of 2-amino-1,1-dicyanobut-1-ene and 2-amino-1,1-dicyano-2-phenylethene, respectively, with N,N-dimethylformamide dimethylacetal provided the corresponding (N,N-dimethylaminomethylene)amino derivatives. 2-[(N,N-Dimethylaminomethylene)amino]-1,1-dicyano-2-phenylethene was converted into 4-amino-5-cyano-6-phenylpyrimidines by treatment with primary aliphatic and aromatic amines. The structure of the reaction products was confirmed by ¹³C nmr spectroscopy.     

Effektive Synthese von 3,1′-Spiro[3,4-dihydro-2H-[1,3]oxazino[3,2-a]benzimidazol] cyclo- bzw. benzocycloalkanen sowie ihrer Thia-Analogen Über Spirane, 23. Mitt.

Ten new constitutionally unsymmetrical azaspiran systems were synthesized upon condensation of Na-derivatives of 2,3-dihydro-1H-benzimidazol-2-one and 2,3-dihydro-1H-benzimidazol-2-thione, respectively, with 1,1-bis(bromomethyl)-and 1,1-bis(iodomethyl)- and ditosylate of 1,1-bis(hydroxymethyl) cycloalkanes.

Vorgetragen auf dem 28. IUPAC-Kongreß in Vancouver (August 1981).     

Quinolone Analogs 13: Synthesis of Novel 1,1′‐(2‐Methylenepropane‐1,3‐diyl)di(4‐quinolone‐3‐carboxylate) and Related Compounds

The reaction of the 4‐hydroxyquinoline‐3‐carboxylate 6 with pentaerythritol tribromide gave the 1,1′‐(2‐methylenepropane‐1,3‐diyl)di(4‐quinolone‐3‐carboxylate) 11 , whose reaction with bromine afforded the 1,1′‐(2‐bromo‐2‐bromomethylpropane‐1,3‐diyl)di(4‐quinolone‐3‐carboxylate) 12 . Compound 12 was transformed into the (Z)‐1,1′‐(2‐acetoxymethylpropene‐1,3‐diyl)di(4‐quinolone‐3‐carboxylate) 13 or (E)‐1,1′‐[2‐(imidazol‐1‐ylmethyl)propene‐1,3‐diyl]di(4‐quinolone‐3‐carboxylate) 14 . Hydrolysis of the dimer (Z)‐ 13 or (E)‐ 14 with potassium hydroxide provided the (E)‐1,1′‐(2‐hydroxymethylpropene‐1,3‐diyl)di(4‐quinolone‐3‐carboxylic acid) 15 or (Z)‐1,1′‐[2‐(imidazol‐1‐ylmethyl)propene‐1,3‐diyl]di(4‐quinolone‐3‐carboxylic acid) 16 , respectively. The nuclear Overhauser effect (NOE) spectral data supported that those hydrolysis resulted in the geometrical conversion of (Z)‐ 13 into (E)‐ 15 or (E)‐ 14 into (Z)‐ 16 .