Facile one pot multicomponent synthesis of novel 4-(benzofuran-2-yl)-2-(3-(aryl/heteryl)-5-(aryl/heteryl)-4,5-dihydro-1H-pyrazol-1yl)thiazole derivatives

An efficient base catalyzed one pot multicomponent reaction of aryl/hetryl chalcones, thiosemicarbazide and 1-(benzofuran-2-yl)-2-bromoethan-1-one was developed to synthesize the novel 4-(benzofuran-2-yl)-2-(3-(aryl/heteryl)-5-(aryl/heteryl)-4,5-dihydro-1H-pyrazol-1yl)thiazole derivatives.     

Structural, spectral and thermal studies of N-2-(4-picolyl)- and N-2-(6-picolyl)-N′-(2-chlorophenyl)thioureas and N-2-(6-picolyl)-N′-(2-bromophenyl)thiourea

N-2-(4-picolyl)-N′-2-chlorophenylthiourea, 4PicTu2Cl, monoclinic, P2₁/c, a=10.068(5), b=11.715(2), β=96.88(4)°, and Z=4; N-2-(6-picolyl)-N′-2-chlorophenylthiourea, 6PicTu2Cl, triclinic, P-1, a=7.4250(8), b=7.5690(16), c=12.664(3) Å, =105.706(17), β=103.181(13), γ=90.063(13)°, V=665.6(2) ų and Z=2 and N-2-(6-picolyl)-N′-2-bromophenylthiourea, 6PicTu2Br, triclinic, P-1, a=7.512(4), b=7.535(6), c=12.575(4) Å, a=103.14(3), β=105.67(3), γ=90.28(4)°, V=665.7(2) ų and Z=2. The intramolecular hydrogen bonding between N′H and the pyridine nitrogen and intermolecular hydrogen bonding involving the thione sulfur and the NH hydrogen, as well as the planarity of the molecules, are affected by the position of the methyl substituent on the pyridine ring. The enthalpies of fusion and melting points of these thioureas are also affected. ¹H NMR studies in CDCl₃ show the NH′ hydrogen resonance considerably downfield from other resonances in their spectra.     

铜配合物[CuL2(ClO4)2]的合成、晶体结构及热稳定性(L=3-对溴苯基-4-对甲苯基-5-(2-吡啶基)-1，2，4-三氮唑)

以3-对溴苯基-4-对甲苯基-5-(2-吡啶基)-1,2,4-三氮唑(L)作为配体,合成了1个铜配合物trans-[CuL2(ClO4)2],对其进行了红外、电喷雾质谱、热重分析和单晶结构表征,该配合物属于三斜晶系,空间群P1,a=0.829 29(15)nm,b=0.854 48(16)nm,c=1.502 7(3)nm,α=83.517(2)°,β=89.200(2)°,γ=73.064(2)°,V=1.011 9(3)nm3,Z=1,R1=0.041 2。单晶结构表明,铜离子处于1个扭曲的八面体配位环境中,2个高氯酸根离子呈反式配位,每个配体L通过三氮唑上的1个氮原子和吡啶氮原子参与配位。热重分析表明该配合物在310℃开始发生分解。     

Chiral synthesis of (R)-( -)-mellein and (3R,4aS)-( + )-ramulosin

By employing an intramolecular Diels-Alder reaction as the key-step, (R)-(—)-mellein 1a (a metabolite of Aspergittus melleus) and (3R,4aS)-( +)-ramulosin 2 (a metabolite of Pestalotia ramulosa) were synthesised from ethyl (R)-3-hydroxybutanoate 3a.     

Structural and spectral studies of N-2-(pyridyl)-, N-2-(3-, 4-, 5-, and 6-picolyl)- and N-2-(4,6-lutidyl)-N′-2-thiomethoxyphenylthioureas

Structures of the following compounds have been obtained: N-(2-pyridyl)-N′-2-thiomethoxyphenylthiourea, PyTu2SMe, monoclinic, P2₁/c, a=11.905(3), b=4.7660(8), c=23,532(6) Å, β=95.993(8)°, V=1327.9(5) ų and Z=4; N-2-(3-picolyl)-N′-2-thiomethoxyphenyl-thiourea, 3PicTu2SeMe, monoclinic, C2/c, a=22.870(5), b=7.564(1), c=16.941(4) Å, β=98.300(6)°, V=2899.9(9) ų and Z=8; N-2-(4-picolyl)-N′-2-thiomethoxyphenylthiourea, 4PicTu2SMe, monoclinic P2₁/a, a=9.44(5), b=18.18(7), c=8.376(12) Å, β=91.62(5)°, V=1437(1) ų and Z=4; N-2-(5-picolyl)-N′-2-thiomethoxyphenylthiourea, 5PicTu2SMe, monoclinic, C2/c, a=21.807(2), b=7.5940(9), c=17.500(2) Å, β=93.267(6)°, V=2893.3(5) ų and Z=8; N-2-(6-picolyl)-N′-2-thiomethoxyphenylthiourea, 6PicTu2SMe, monoclinic, P2₁/c, a=8.499(4), b=7.819(2), c=22.291(8) Å, β=90.73(3)°, V=1481.2(9) ų and Z=4 and N-2-(4,6-lutidyl)-N′-2-thiomethoxyphenyl-thiourea, 4,6LutTu2SMe, monoclinic, P2₁/c, a=11.621(1), b=9.324(1), c=14.604(1) Å, β=96.378(4)°, V=1572.4(2) ų and Z=4. Comparisons with other N-2-pyridyl-N′-arylthioureas having substituents in the 2-position of the aryl ring are included.     

Novel (E)- and (Z)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles from (E)- and (Z)-3-styrylchromones: the unexpected case of (E)-3(5)-(2-hydroxyphenyl)-4-(4-nitrostyryl)pyrazoles

An efficient synthetic method for the preparation of (E)- and (Z)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles has been developed. The reaction of (E)- and (Z)-3-styrylchromones with hydrazine hydrate afforded the corresponding (E)- and (Z)-4-styrylpyrazoles, respectively, saved 4′-nitro-derivatives where both (E)- and (Z)-4′-nitro-3-styrylchromones afforded (E)-3(5)-(2-hydroxyphenyl)-4-(4-nitrostyryl)pyrazoles. The reaction mechanism for these transformations was discussed and the stereochemistry of all products was assigned by NMR experiments.     

Synthesis of (E)- and (Z)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles

Abstract  

An efficient synthesis method for the preparation of a series of new (Z)- and (E)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles was developed. The reaction of (Z)- and (E)-3-styrylchromones with hydrazine hydrate afforded the corresponding (Z)- and (E)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles, except for nitro derivatives, where both (Z)- and (E)-4′-nitro-3-styrylchromones afforded (E)-3(5)-(2-hydroxyphenyl)-4-(4-nitrostyryl)pyrazoles. The reaction mechanism for these transformations is discussed and the stereochemistries of all products were established by NMR experiments.     

Efficient synthesis of new 1-alkyl(aryl)-5-(3,3,3-trihalo-2-oxopropylidene)-1H-pyrrol-2(5H)-ones

The synthesis of 1-alkyl(aryl)-5-(3,3,3-trihalo-2-oxopropylidene)-1H-pyrrol-2(5H)-ones 5, 6a-d from 1-alkyl(aryl)-4-bromo-5-(3,3,3-trihalo-2-oxopropylidene)-1H-pyrrolidin-2-ones 3, 4a-d is reported. The 1-alkyl(aryl)-4-bromo-5-(3,3,3-trihalo-2-oxopropylidene)-1H-pyrrolidin-2-ones 3, 4a-d were obtained from regiospecific bromination of 1-alkyl(aryl)-5-(3,3,3-trihalo-2-oxopropylidene)-1H-pyrrolidin-2-ones 1, 2a-d with molecular bromine. The NMR and X-ray diffraction data showed that 1-alkyl(aryl)-5-(3,3,3-trihalo-2-oxopropylidene)-1H-pyrrolidin-2-ones were brominated at 4-position in the pyrrolidin-2-one ring.     

Efficient synthesis of (Z)- and (E)-methyl 2-(methoxyimino)-2-phenylacetate

Direct oximation of 2-oxo-2-phenylacetate (3) gave the (Z)-methyl 2-(methoxyimino)-2-phenylacetate (1) in 71% yield, while the E oxime 2 was prepared from 3 in 65% yield via oxime isomerization of 2-(methoxyimino)-2-phenylacetic acid (5). Computational studies suggest that the isomerization of 5 is thermodynamically driven, while the direct oximation of ketoester 3 is kinetically controlled.     

Preparation,molecular structures,and characteristic properties of (E)-1-(2-furyl)- and (E)-1-(2-thienyl)-2-(3-guaiazulenyl)ethylenes and (E)-1-(3-furyl)- and (E)-1-(3-thienyl)-2-(3-guaiazulenyl)ethylenes

Wittig reactions of 2-furaldehyde (20) [and thiophene-2-carbaldehyde (21)] with (3-guaiazulenylmethyl)triphenylphosphonium bromide (19) in ethanol containing NaOEt at 25 °C for 24 h under argon give (E)-1-(2-furyl)-2-(3-guaiazulenyl)ethylene (22E) and (E)-1-(2-thienyl)-2-(3-guaiazulenyl)ethylene (23E) in 53 and 36% yields. Similarly, Wittig reactions of 3-furaldehyde (29) [and thiophene-3-carbaldehyde (30)] with 19 under the same reaction conditions as for 20 and 21 afford (E)-1-(3-furyl)-2-(3-guaiazulenyl)ethylene (31E) and (E)-1-(3-thienyl)-2-(3-guaiazulenyl)ethylene (32E) in 32 and 46% yields. Molecular structures and characteristic properties as well as preparation of the title E (i.e., one of the geometrical isomers) forms, with a view to comparative study, are reported. Moreover, reactions of those conjugated π-electron systems with TCNE (=tetracyanoethylene) in benzene [and in DMF (=N,N-dimethylformamide)] at 25 °C for 24 h under argon yield unique products, possessing interesting molecular structures, respectively, whose characteristic properties and crystal structures are documented, also.     

Synthesis of 5-polyfluoroalkyl-4-( p -tolyl-sulfonyl)pyrazoles and 4-polyfluoroalkyl-5-( p -tolylsulfonyl)pyrimidines from 1-dimethylamino-2-( p -tolylsulfonyl)-polyfluoro-1-alken-3-ones

1-Dimethylamino-2-(p-tolylsulfonyl)polyfluoro-1-alken-3-ones were obtained from hydrates of 3,3,3-trifluoro-1-(p-tolylsulfonyl)-2-propanone and 3,3,4,4,5,5-hexafluoro-1-(p-tolylsulfonyl)-2-pentanone under conditions of the Vilsmeier-Haack-Arnold reaction. The analogous reaction of 3,3-difluoro-1-(p-tolylsulfonyl)-2-propanone hydrate leads to 3-chloro-1-dimethylamino-4,4-difluoro-2-(p-tolylsulfonyl)-1,3-butadiene. The feasibility of using 1-dimethylamino-2-(p-tolylsulfonyl)-polyfluoro-1-alken-3-ones in reactions with nitrogen binucleophiles has been demonstrated for the regioselective synthesis of pyrazoles and pyrimidines. The structure of 1-phenyl-4-(p-tolylsulfonyl)-5-trifluoromethyl-1H-pyrazole was confirmed by X-ray diffraction structural analysis. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1052–1058, July, 2007.     

Regioselective synthesis of cytotoxic 4-(1-alkynyl)-substituted 2-(5H)-furanones

4-(1-Alkynyl)-3-bromo- and 4-(1-alkynyl)-3-chloro-2(5H)-furanones have been regioselectively synthesized in moderate to good yields by a new version of the Pd/Cu-catalyzed Sonogashira reaction involving treatment of 1-alkynes with 3,4-dibromo- and 3,4-dichloro-2(5H)-furanone, respectively, in the presence of KF as a base. 4-(1-Alkynyl)-3-bromo-2(5H)-furanones have been found to be able to undergo Stille-type and Suzuki-type reactions with aryl(tributyl)tins and arylboronic acids, respectively, to give 4-(1-alkynyl)-3-aryl-2(5H)-furanones in modest to satisfactory yields. Some 4-(1-alkynyl)-substituted 2(5H)-furanones so prepared have been found to exhibit significant cytotoxic activities, especially against human leukemia cell lines.     

Total synthesis of (S)-(+)-curcudiol, and (S)-(+)- and (R)-(-)-curcuphenol.

A highly enantioselective synthesis of the versatile chiral synthons possessing one stereogenic center, (S)- and (R)-4-aryl-5-hydroxy-(2E)-pentenoate (3) was achieved based on the enzymatic reaction of (+/-)-3 with commercially available lipases MY-30 or OF-360 from Candida rugosa. Application of (S)-3 and (R)-3 to the total syntheses of(S)-curcuphenol (1), (S)-curcudiol (2), and (R)-curcuphenol (1), respectively, is described.     

Synthesis and molecular structure of the optically active organoaluminium dimer (S)-(—)-(S)-(—)- [(C6H5)CH(CH3)NHA1(CH3)2]2

Reaction of the optically active primary amine (S)-(—)--methylbenzylamine with trimethylaluminium in heptane affords the crystalline organoaluminium dimer (S)-(—)-(S)-(—)-[(C₆H₅)CH(CH₃)NHA1(CH₃)₂]₂. Isolated as large, colourless, extremely air-sensitive prismatic crystals, the title compound crystallizes in the orthorhombic space group P2₁2₁2₁ with unit cell parameters a = 8.406(3), b = 15.505(4), c = 17.547(5) Å, V = 2287 ų and p = 1.03 g cm⁻³ for Z = 4. Least-squares refinement based on 1477 observed reflections converged at R = 0.056, R_w = 0.058. Methane was eliminated during the course of the reaction due to cleavage of A1---C and N---H bonds resulting in an asymmetric A1₂N₂ fragment at the core of the organoaluminium dimer. The mean A1---C bond distance in the dimethylaluminium units is 1.930(8), while the mean A1---N bond distance is 1.950(5) Å. Specific rotation ([]_D²⁵ in CH₂C1₂)of the dimer is determined to be - 20.6°.     

Total syntheses of beta-carboline alkaloids, (R)-(-)-pyridindolol K1, (R)-(-)-pyridindolol K2, and (R)-(-)-pyridindolol.

The total syntheses of beta-carboline alkaloids, (R)-(-)-pyridindolols (1, 5, and 6) are described. The two key steps involved are (1) a thermal electrocyclic reaction of the 3-alkenylindole-2-aldoxime 10 and (2) a thermal cyclization of 3-alkynylindole-2-aldoxime 11 to construct the beta-carboline N-oxides 8, which upon heating with acetic anhydride and sequential treatment with trifluoromethanesulfonic anhydride gave the triflates 18. The Stille coupling reaction of 18 with vinylstannane, followed by cleavage of MOM ether, afforded the 1-ethenyl-3-hydroxymethyl-beta-carboline (7a). Subsequent acetylation of 7a yielded the acetate 7b, which was subjected to the Sharpless asymmetric 1,2-dihydroxylation by AD-mix-beta to produce (R)-(-)-pyridindolol K2 (6). Selective acetylation of 6 was effected by Ac(2)O and collidine to form (R)-(-)-pyridindolol K1 (5). By contrast, hydrolysis of 6 provided (R)-(-)-pyridindolol (1).     

Stereoselective synthesis of (R)-(+)-1-methoxyspirobrassinin, (2R,3R)-(−)-1-methoxyspirobrassinol methyl ether and their enantiomers or diastereoisomers

Stereoselective synthesis of cruciferous indole phytoalexin (R)-(+)-1-methoxyspirobrassinin and its unnatural (S)-(−)-enantiomer was achieved by spirocyclization of 1-methoxybrassinin in the presence of (+)- and (−)-menthol and subsequent oxidation of the obtained menthyl ethers. Methanolysis of menthyl ethers in the presence of TFA afforded (2R,3R)-(−)-1-methoxyspirobrassinol methyl ether as well its unnatural (2S,3S)-, (2R,3S)-, and (2S,3R)-isomers.     

Synthesis of conjugated (1E,3E)- and (1Z,3Z)-1,4-di(n-pyridyl) (or n-quinolyl)-1,3-butadienes from n-(2′-chloroethenyl)pyridine (or quinoline)

The homocoupling reaction between the conjugated n-(2-chloroethenyl)pyridine; n, 2-, 3- and 4- (or quinoline; n, 2- and 4-) mediated by zero-valent nickel complexes at room temperature affords to the corresponding 1,4-diaryl-1,3-butadiene, always as the 1E,3E stereoisomer. The yield in 1,4-diaryl-1,3-butadiene increases with the nickel catalyst and hence, the active zero-valent nickel catalyst is not regenerated during the homocoupling reaction.The stereospecific synthesis of (1Z,3Z)-1,4-di(4′-pyridyl)-1,3-butadiene stereoisomer was efficiently carried out by partial hydrogenation of the appropriate 1,4-di(4′-pyridyl)-1,3-butadiyne.     

Synthesis of novel 6-(substituted amino)-4-(4-ethoxyphenyl)-1-phenyl-2(1H)-pyridinones via azo coupling

Abstract  

6-(Substituted amino)-4-(4-ethoxyphenyl)-1-phenyl-2(1H)-pyridinones were prepared from β-aryl glutaconic acid, which, on fusion with aniline, results in 4-(4-ethoxyphenyl)-1-phenylpyridine-2,6(1H,5H)-dione. This, on further treatment with phosphorus oxychloride gave 6-chloro-4-(4-ethoxyphenyl)-1-phenyl-2(1H)-pyridinone, and further treatment with secondary amines yielded 6-(substituted amino)-4-(4-ethoxyphenyl)-1-phenyl-2(1H)-pyridinones. These were subjected to azo coupling with different aryldiazonium chlorides furnishing two isomers, which were separated by column chromatography. All compounds were characterized by elemental analysis, and use of IR and NMR spectral data, and were evaluated for antimicrobial activity.     

Multifunctional Ligands. Phosphinimine-Substituted Cyanofluoroaromatics Including X-ray Molecular Structures of Three Representative Ligands 4,6-(CN)(2)C(6)F(2)-1,3-(N=PPh(3))(2), 4,6-(CN)(2)C(6)F(2)-1,3-(N=PPh(2)Me)(2) and 4,6-(CN)(2)C(6)F(2)-1-(N=PPh(3))-3-(N=PPh(2)Me). Formation of Rhodium(I) Complexes

Reaction of 1,3-dicyanotetrafluorobenzene with 2 equiv of (trimethylsilyl)iminophosphoranes gave the disubstituted derivatives 4,6-(CN)(2)C(6)F(2)-1,3-AB: 1, A = B = (N=PPh(3)); 2, A = B = (N=PPh(2)Me); and 3, A = (N=PPh(3)), B = (N=PPh(2)Me). Monosubstituted compounds of the type 2,4-(CN)(2)C(6)F(3)-1-A; notably 4, A = (N=PPh(3)), and 5, A = (N=PPh(2)Me), were readily obtained by reaction of 1 molar equiv of the silylated iminophosphorane with the cyanofluoro aromatic. Substitution of the fluorine para to the CN group(s) occurs in all cases. Reactions of 1,2- and 1,4-dicyanotetrafluorobenzene with (trimethylsilyl)iminophosphoranes gave only monosubstituted derivatives 3,4-(CN)(2)C(6)F(3)-1-A (6, A = (N=PPh(3)), and 7, A = (N=PPh(2)Me)) and 2,5-(CN)(2)C(6)F(3)-1-A (8, A = (N=PPh(3)), and 9, A = (N=PPh(2)Me)), respectively, as the result of electronic deactivation of the second substitutional point. 1, 4,6-(CN)(2)C(6)F(2)-1,3-(N=PPh(3)), 2, 4,6-(CN)(2)C(6)F(2)-1,3-(N=PPh(2)Me)(2), and 3, 4,6-(CN)(2)C(6)F(2)-1-(N=PPh(3))-3-(N=PPh(2)Me) have been structurally characterized. For 1 (at 21 degrees C), monoclinic, C2/(c) (No. 15), a = 15.289(2) ?, b = 10.196(1) ?, c = 23.491(6) ?, beta = 91.63(2) degrees, V = 3660(2) ?(3), and Z = 4. The P=N bond length is 1.579(2) ? and the P(V)-N-C(phenyl) angle is 134.0(2) degrees. For 2, (at 21 degrees C) monoclinic, C2/(c) (No. 15), a = 18.694(2) ?, b = 8.576(1) ?, c = 40.084(4) ?, beta = 94.00(1) degrees, V = 6411(2) ?(3), and Z = 8. The P(1)=N(1) bond length is 1.570(4) ?, the P(2)=N(2) bond length is 1.589(3) ?, the P(1)-N(1)-C(14) angle is 131.6(3) degrees, and the P(2)-N(2)-C(16) angle is 131.3(3) degrees. For 3, (at -80 degrees C) monoclinic, P2(1)/c (No. 14), a = 9.210(1) ?, b = 18.113(2) ?, c = 20.015(2) ?, beta = 100.07(1) degrees, V = 3287(2) ?(3), and Z = 4. The P(1)=N(1) bond length (PPh(3) group) is 1.567(4) ?, the P(2)=N(2) bond length (PPh(2)Me group) is 1.581(5) ?, the P(1)-N(1)-C(1) angle is 140.4(4) degrees, and the P(2)-N(2)-C(3) angle is 129.4(4) degrees. These new multifunctional chelating ligands readily react with [Rh(cod)Cl](2) and AgClO(4) to give cationic Rh(I) complexes in which the imine and/or the nitrile groups are coordinated to the Rh center.     

3-对甲氧基苯基-和3-对羟基苯基-1-氨基-3a,4,5,9b-四氢化-9b-羟基-3H-环戊烯并[a]萘-2-甲腈的合成和晶体结构

用低价钛试剂(TiCl₄-Zn)与2-氰基-3-对甲氧基苯基-3-(1-四氢萘酮-2-基)丙腈反应合成了3-对甲氧基苯基-1-氨 基-3a,4,5,9b-四氢化-9b-羟基-3H-环戊烯并[a]萘-2-甲腈和3-对羟基苯基-1-氨基-3a,4,5,9b-四氢化-9b-羟基-3H-环戊烯并[a]萘-2-甲腈, 并用X射线衍射分析确定了这两个产物的结构.