p-Terphenyl as unexpected by-product in the synthesis of 2,5-diphenylpyrrole from acetophenone oxime and phenylacetylene

Russian Journal of Organic Chemistry -     

The synthesis of lactone-bridged 1,3,5-triphenylbenzene derivatives as pi-expanded coumarin triskelions

Two triply lactone-bridged 1,3,5-triphenylbenzene derivatives with solubilizing moieties have been synthesized in five and six steps from commercially available starting materials. Compounds containing the 1,3,5-triphenylbenzene core with two atom bridges are relatively unknown. This new class of pi-expanded coumarins contain triskelion architectures and X-ray crystallographic studies of one of the triskelions indicates that the 1,3,5-triphenylbenzene core adopts a near-planar geometry. This is the only known example of a two atom-bridged 1,3,5-triphenylbenzene derivative to adopt a planar structure.     

Thermodynamic study of 1,2,3-triphenylbenzene and 1,3,5-triphenylbenzene

The energetic study of 1,2,3-triphenylbenzene (1,2,3-TPhB) and 1,3,5-triphenylbenzene (1,3,5-TPhB) isomers was carried out by making use of the mini-bomb combustion calorimetry and Knudsen mass-loss effusion techniques. The mini-bomb combustion calorimetry technique was used to derive the standard (p° = 0.1 MPa) molar enthalpies of formation in the crystalline state from the measured standard molar energies of combustion for both isomers. The Knudsen mass-loss effusion technique was used to measure the dependence with the temperature of the vapour pressure of crystalline 1,2,3-TPhB, which allowed the derivation of the standard molar enthalpy of sublimation, by application of the Clausius–Clapeyron equation. The sublimation study of 1,3,5-TPhB had been performed previously. From the combination of data obtained by both techniques, the standard molar enthalpies of formation in the gaseous state, for both isomers, at T = 298.15 K, were calculated. The results indicate a higher stability of the 1,3,5-TPhB isomer relative to 1,2,3-TPhB, similarly to the terphenyls. Nevertheless, the 1,2,3-TPhB isomer is not as energetically destabilized as one might expect, supporting the existence of a π–π displacive stacking interaction between both pairs of outer phenyl rings. The volatility difference between the two isomers is ruled by the enthalpy of sublimation. The volatility of the 1,2,3-TPhB is two orders of magnitude higher than the 1,3,5-TPhB isomer, at T = 298.15 K.     

5.

Unsymmetrical bifunctional trithiocarbonate as unexpected by-product in the synthesis of a dithioester RAFT agent     

André Laschewsky  Gwenaelle Pound  Katja Skrabania  Hans-Jürgen Holdt  Joachim Teller 《Colloid and polymer science》2007,285(8):947-952

The trithiocarbonate 2-(benzylsulfanylthiocarbonylsulfanyl) propanoic acid is formed as minor by-product in the synthesis of the dithioester 2-((2-phenylthioacetyl)sulfanyl) propanoic acid via the Grignard route. The mechanism for this side reaction is not clear. The isolated trithiocarbonate may act as unsymmetrical but bifunctional RAFT agent in the aqueous polymerization of N,N-dimethyl acrylamide. Therefore, it is important to separate it completely from the dithioester before engaging the latter in controlled free radical polymerization to guarantee a maximum control.     

6.

2-Phenylpyrrole: one-pot selective synthesis from acetophenone oxime and acetylene by a Trofimov reaction*     

A. I. Mikhaleva  O. V. Petrova  L. N. Sobenina 《Chemistry of Heterocyclic Compounds》2012,47(11):1367-1371

We have developed a technologically orientated, one-pot way of synthesis of high purity 2-phenylpyrrole in 74% yield by treatment of acetophenone oxime with acetylene in the KOH–DMSO system. The reaction is carried out at 135-150°C under an acetylene atmospheric pressure. The synthesis was performed in laboratory (glass apparatus) and in a large scale (10 l reaction vessel).     

7.

Azo coupling and aminomethylation of 2,5-diphenylpyrrole and its derivatives     

A. N. Grinev  M. V. Mezentseva  E. F. Kuleshova  L. M. Alekseeva 《Chemistry of Heterocyclic Compounds》1986,22(5):499-503

The azo coupling of 2,5-diphenylpyrrole with arenediazonium chlorides has given previously unknown 3-arylazopyrroles and 4-phenylazo-3-phenylhydrazono-3H-pyrrole. The methylation and reductive acetylation of the anylazo derivatives have led to N-methylarylazo and acetylamino derivatives of 2,5-diphenylpyrrole. 3-Amino-2, 5-diphenylpyrrole has been obtained by the reduction of 3-p-chlorophenylazo-2,5-diphenylpyrrole. The aminomethylation of 2,5-diphenylpyrrole and its derivatives with bis(dialkylamino)methanes had led to aminomethyl derivatives.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5. pp. 612–615, May, 1986.     

8.

Synthesis and photophysical properties of triphenylamine-based dendrimers with 1,3,5-triphenylbenzene cores     

Haijian Xia 《Tetrahedron letters》2007,48(33):5877-5881

Two new conjugated dendrimers bearing a triphenylamine moiety as dendrons and 1,3,5-triphenylbenzene as a core have been synthesized through a convergent synthetic strategy. These conjugated dendrimers have high fluorescence quantum yields and exhibit similar absorption and emission behaviors in solutions and in solid films, which demonstrate that these dendrimers form good amorphous states.     

9.

Synthesis of liquid crystalline materials based on 1,3,5-triphenylbenzene and 2,4,6-triphenyl-1,3,5-s-triazine     

Sambasivarao Kotha  Dhurke Kashinath 《Tetrahedron letters》2008,49(37):5419-5423

C₃-symmetric alkyloxy/aryloxy polyether dendrimers have been synthesized from 1,3,5-triphenylbenzene and 2,4,6-triphenyl-1,3,5-s-triazine and their liquid crystalline properties have been studied. C₃-symmetric derivatives with n-hexyl and n-dodecyl chains at the periphery show mesophase properties when they are complexed with trinitrofluorenone at different temperatures.     

10.

The synthesis and three-dimensional structure of 2,5-diphenyl-2-bora-1,3,5-dioxaphosphorinane     

B. A. Arbuzov  O. A. Erastov  G. N. Nikonov  T. A. Zyablikova  R. P. Arshinova  R. A. Kadyrov 《Russian Chemical Bulletin》1979,28(10):2170-2174

Conclusions Hydroxymethyldiphenylboryloxymethylphenylphosphine and 2,5-diphenyl-2-bora-1,3,5-di-oxaphosphorinane, in which the phenyl group at the phosphorus atom is predominantly found in the axial position, are formed in the reaction of di(hydroxymethyl)phenylphosphine with isobutyl diphenylborate.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2349–2352, October, 1979.     

11.

Preparation and thermal studies of self-crosslinked terpolymer derived from 4-acetylpyridine oxime, formaldehyde and acetophenone     

Narendra P.S. Chauhan  Suresh C. Ameta 《Polymer Degradation and Stability》2011,96(8):1420-1429

Terpolymer (4-APOFA) has been synthesized using the monomer 4-acetylpyridine oxime, formaldehyde and acetophenone in 1:5:1 molar proportion. The structure of 4-APOFA terpolymer has been elucidated based on various physicochemical techniques, i.e., FT-IR, ¹H NMR, Pyrolyis GC/MS and viscosity average molecular weight. The glass transition temperature (T_g) and thermal stability of terpolymer have been determined by DSC. The activation energy of the thermal reaction has been determined with differential scanning calorimetry using Kissinger method. The apparent activation energies (E_a) of each step during thermodegradation have been determined using Flynn-Wall-Ozawa method. The type of solid-state mechanism has been established by Craido method. From the calculation, the solid-state thermal mechanism is proposed to be D₃ (three-dimensional diffusion) at initial decomposition state and F₁ (random nucleation with one nucleus on the individual particle) at second decomposition state for 4-APOFA. It has also been shown to possess excellent antimicrobial activities as compared to other cationic resins.     

12.

An efficient synthesis of flavans from salicylaldehyde and acetophenone derivatives     

Ofentse MazimbaIshmael B. Masesane  Runner R. Majinda 《Tetrahedron letters》2011,52(50):6716-6718

An efficient total synthesis of flavans from the reactions of salicylaldehyde and acetophenone derivatives is reported. The synthesis involves preparation of chalcones through an aldol reaction followed by reduction of both the double bond and the ketone using NaBH₄ and an acetic acid mediated cyclization. Methoxy groups on the aromatic rings did not affect significantly the yields of the procedure.     

13.

Synthesis and characterization of novel polyarylates from 2,5-bis(4-hydroxyphenyl)-3,4-diphenylpyrrole and various aromatic dicarboxylic acids     

Hwa-Jin Jeong  Masa-Aki Kakimoto  Yoshio Imai 《Journal of polymer science. Part A, Polymer chemistry》1994,32(6):1057-1062

A new tetraphenylated heterocylic diol, 2,5-bis(4-hydroxyphenyl)-3,4-diphenylpyrrole, was synthesized in three steps starting from 4-methoxydeoxybenzoin. The tetraphenylpyrrole-containing polyarylates having inherent viscosities of 0.28–0.88 dL/g were prepared from the diol and various aromatic dicarboxylic acid chlorides by both phase transfer catalyzed two-phase polycondensation and high temperature solution polymerization methods. All the polyarylates were semi-crystalline, and were readily soluble in a variety of solvents including N-methyl-2-pyrrolidone, m cresol, pyridine, and 1,4-dioxane. These polymers had glass transition temperatures in the range of 223–279°C, with no weight loss below 400°C in both air and nitrogen atmospheres. © 1994 John Wiley & Sons, Inc.     

14.

The ultraviolet photochemistry of phenylacetylene and the enthalpy of formation of 1,3,5-hexatriyne.   总被引：1，自引：0，他引：1  

O Sorkhabi  F Qi  A H Rizvi  A G Suits 《Journal of the American Chemical Society》2001,123(4):671-676

The ultraviolet photochemistry of phenylacetylene was studied in a molecular beam at 193 nm. The only primary photofragments observed were HCCH (acetylene) and C(6)H(4). Some of the C(6)H(4) molecules were found to decompose to 1,3,5-hexatriyne and molecular hydrogen. An enthalpy of formation of DeltaH(f) < or = 160 +/- 4 kcal mol(-1) was determined for 1,3,5-hexatriyne from the energetic threshold for this process. This experimentally determined value agrees well with our ab initio calculations performed at the G2 level of theory. Angular distribution measurements for the HCCH + C(6)H(4) channel yielded an isotropic distribution and were attributed to a long-lived intermediate and ground-state dissociation. An exhaustive search yielded no evidence for the phenyl + ethynyl or the atomic hydrogen elimination channels even though these were observed in the pyrolytic studies of phenylacetylene [Hofmann, J.; Zimmermann, G.; Guthier, K.; Hebgen, P.; Homann, K. H. Liebigs Ann. 1995, 631, 1995. Guthier, K.; Hebgen, P.; Hofmann, K. H.; Zimmermann, G. Liebigs Ann. 1995, 637, 1995].     

15.

Synthesis and characterization of new soluble aromatic polyimides from 3,4-bis(4-aminophenyl)-2,5-diphenylpyrrole and aromatic tetracarboxylic dianhydrides     

Hwa-Jin Jeong  Masa-Aki Kakimoto  Yoshio Imai 《Journal of polymer science. Part A, Polymer chemistry》1991,29(12):1691-1695

Novel aromatic polyimides containing tetraphenylpyrrole unit were synthesized from 3,4-bis(4-aminophenyl)-2,5-diphenylpyrrole and various aromatic tetracarboxylic dianhydrides by the usual two-step procedure that included ring-opening polyaddition and subsequent thermal cyclodehydration. These polymers had inherent viscosities in the 0.20–0.65 dL/g range and were practically amorphous as shown by the X-ray diffraction studies. All the polyimides except for polypyromellitimide were easily soluble in a wide range of organic solvents such as o-chlorophenol, pyridine, 1,3-dimethyl-2-imidazolidone, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone at room temperature. These polyimides had high glass transition temperatures of 302–359°C and exhibited 10% weight loss at temperatures above 510°C in nitrogen.     

16.

Synthesis and characterization of novel aromatic polyamides from 3,4-bis(4-aminophenyl)-2,5-diphenylpyrrole and aromatic diacid chlorides     

Hwa-Jin Jeong  Masa-Aki Kakimoto  Yoshio Imai 《Journal of polymer science. Part A, Polymer chemistry》1991,29(5):767-772

A new polymer-forming monomer, 3,4-bis(4-aminophenyl)-2,5-diphenylpyrrole, was synthesized in three steps starting from 4′-nitrodeoxybenzoin. Tetraphenylpyrrole-containing aromatic polyamides and copolyamides were prepared from the diamine with various aromatic diacid chlorides and from a mixture of the diamine and 4,4′-oxydianiline with terephthaloyl chloride, respectively. The resultant polymers had inherent viscosities in the 0.3–1.8 dL/g range and were generally soluble in various organic solvents including N,N-dimethylacetamide and m-cresol. They have glass transition temperatures in the range of 306–333°C and showed no weight loss below 380°C in both air and nitrogen atmospheres.     

17.

Complexes of 2,5-diphenyl-1,3,2,5-dioxaboraphosphorinane and 1,3,5-triphenyl-1,3,5-diazaphosphorinane with molybdenum hexacarbonyl     

A. A. Karasik  G. N. Nikonov  R. Z. Musin  Yu. Ya. Efremov 《Russian Chemical Bulletin》1992,41(1):167-169

The reaction of 2,5-diphenyl-1,3,2,5-dioxaboraphosphorinane (L) and 1,3,5-triphenyl-1,3,5-diazaphosphorinane (L) with molybdenum hexacarbonyl gave, respectively, Mo(CO)₄L₂ and Mo(CO)₅L complexes.A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Science Center, Russian Academy of Sciences, 420083 Kazan. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 201–203, January, 1992.     

18.

2,5-Dibromopyridine as a key building block in the synthesis of 2,5-disubstituted pyridine-based liquid crystals     

Y. A. Getmanenko  R. J. Twieg  B. D. Ellman 《Liquid crystals》2006,33(3):267-288

Fifteen 2,5-disubstituted pyridine based liquid crystals were synthesized exploiting the different reactivities of the bromine atoms in 2,5-dibromopyridine under Negishi coupling conditions. Convenient approaches to both 2-iodo-5-alkyl-pyridines and 2-alkyl-5-bromopyridines were also developed. The liquid crystalline behaviour of the synthesized materials was investigated using DSC and polarizing microscopy. The charge mobility of 2-(4-heptyloxyphenyl)-5-heptylpyridine was measured using the time of flight technique.     

19.

New synthesis of 1,3,5-hexatriene from piperylene and formaldehyde     

M. G. Safarov  R. M. Bikkulov  O. M. Nefedov  I. E. Dolgii 《Russian Chemical Bulletin》1978,27(3):632-634

     

20.

Ring-closing metathesis toward the synthesis of 2,5-dihydrofuran and 2,5-dihydropyrrole skeletons from Baylis-Hillman adducts     

Jeong Mi Kim  Sangku Lee 《Tetrahedron letters》2004,45(13):2805-2808

We have developed an efficient method for the synthesis of 2,5-dihydrofuran and 2,5-dihydropyrrole skeletons from the simply modified Baylis-Hillman adducts via RCM reaction.     

Unsymmetrical bifunctional trithiocarbonate as unexpected by-product in the synthesis of a dithioester RAFT agent

The trithiocarbonate 2-(benzylsulfanylthiocarbonylsulfanyl) propanoic acid is formed as minor by-product in the synthesis of the dithioester 2-((2-phenylthioacetyl)sulfanyl) propanoic acid via the Grignard route. The mechanism for this side reaction is not clear. The isolated trithiocarbonate may act as unsymmetrical but bifunctional RAFT agent in the aqueous polymerization of N,N-dimethyl acrylamide. Therefore, it is important to separate it completely from the dithioester before engaging the latter in controlled free radical polymerization to guarantee a maximum control.     

2-Phenylpyrrole: one-pot selective synthesis from acetophenone oxime and acetylene by a Trofimov reaction*

We have developed a technologically orientated, one-pot way of synthesis of high purity 2-phenylpyrrole in 74% yield by treatment of acetophenone oxime with acetylene in the KOH–DMSO system. The reaction is carried out at 135-150°C under an acetylene atmospheric pressure. The synthesis was performed in laboratory (glass apparatus) and in a large scale (10 l reaction vessel).     

Azo coupling and aminomethylation of 2,5-diphenylpyrrole and its derivatives

The azo coupling of 2,5-diphenylpyrrole with arenediazonium chlorides has given previously unknown 3-arylazopyrroles and 4-phenylazo-3-phenylhydrazono-3H-pyrrole. The methylation and reductive acetylation of the anylazo derivatives have led to N-methylarylazo and acetylamino derivatives of 2,5-diphenylpyrrole. 3-Amino-2, 5-diphenylpyrrole has been obtained by the reduction of 3-p-chlorophenylazo-2,5-diphenylpyrrole. The aminomethylation of 2,5-diphenylpyrrole and its derivatives with bis(dialkylamino)methanes had led to aminomethyl derivatives.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5. pp. 612–615, May, 1986.     

Synthesis and photophysical properties of triphenylamine-based dendrimers with 1,3,5-triphenylbenzene cores

Two new conjugated dendrimers bearing a triphenylamine moiety as dendrons and 1,3,5-triphenylbenzene as a core have been synthesized through a convergent synthetic strategy. These conjugated dendrimers have high fluorescence quantum yields and exhibit similar absorption and emission behaviors in solutions and in solid films, which demonstrate that these dendrimers form good amorphous states.     

Synthesis of liquid crystalline materials based on 1,3,5-triphenylbenzene and 2,4,6-triphenyl-1,3,5-s-triazine

C₃-symmetric alkyloxy/aryloxy polyether dendrimers have been synthesized from 1,3,5-triphenylbenzene and 2,4,6-triphenyl-1,3,5-s-triazine and their liquid crystalline properties have been studied. C₃-symmetric derivatives with n-hexyl and n-dodecyl chains at the periphery show mesophase properties when they are complexed with trinitrofluorenone at different temperatures.     

The synthesis and three-dimensional structure of 2,5-diphenyl-2-bora-1,3,5-dioxaphosphorinane

Conclusions Hydroxymethyldiphenylboryloxymethylphenylphosphine and 2,5-diphenyl-2-bora-1,3,5-di-oxaphosphorinane, in which the phenyl group at the phosphorus atom is predominantly found in the axial position, are formed in the reaction of di(hydroxymethyl)phenylphosphine with isobutyl diphenylborate.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2349–2352, October, 1979.     

Preparation and thermal studies of self-crosslinked terpolymer derived from 4-acetylpyridine oxime, formaldehyde and acetophenone

Terpolymer (4-APOFA) has been synthesized using the monomer 4-acetylpyridine oxime, formaldehyde and acetophenone in 1:5:1 molar proportion. The structure of 4-APOFA terpolymer has been elucidated based on various physicochemical techniques, i.e., FT-IR, ¹H NMR, Pyrolyis GC/MS and viscosity average molecular weight. The glass transition temperature (T_g) and thermal stability of terpolymer have been determined by DSC. The activation energy of the thermal reaction has been determined with differential scanning calorimetry using Kissinger method. The apparent activation energies (E_a) of each step during thermodegradation have been determined using Flynn-Wall-Ozawa method. The type of solid-state mechanism has been established by Craido method. From the calculation, the solid-state thermal mechanism is proposed to be D₃ (three-dimensional diffusion) at initial decomposition state and F₁ (random nucleation with one nucleus on the individual particle) at second decomposition state for 4-APOFA. It has also been shown to possess excellent antimicrobial activities as compared to other cationic resins.     

An efficient synthesis of flavans from salicylaldehyde and acetophenone derivatives

An efficient total synthesis of flavans from the reactions of salicylaldehyde and acetophenone derivatives is reported. The synthesis involves preparation of chalcones through an aldol reaction followed by reduction of both the double bond and the ketone using NaBH₄ and an acetic acid mediated cyclization. Methoxy groups on the aromatic rings did not affect significantly the yields of the procedure.     

Synthesis and characterization of novel polyarylates from 2,5-bis(4-hydroxyphenyl)-3,4-diphenylpyrrole and various aromatic dicarboxylic acids

A new tetraphenylated heterocylic diol, 2,5-bis(4-hydroxyphenyl)-3,4-diphenylpyrrole, was synthesized in three steps starting from 4-methoxydeoxybenzoin. The tetraphenylpyrrole-containing polyarylates having inherent viscosities of 0.28–0.88 dL/g were prepared from the diol and various aromatic dicarboxylic acid chlorides by both phase transfer catalyzed two-phase polycondensation and high temperature solution polymerization methods. All the polyarylates were semi-crystalline, and were readily soluble in a variety of solvents including N-methyl-2-pyrrolidone, m cresol, pyridine, and 1,4-dioxane. These polymers had glass transition temperatures in the range of 223–279°C, with no weight loss below 400°C in both air and nitrogen atmospheres. © 1994 John Wiley & Sons, Inc.     

The ultraviolet photochemistry of phenylacetylene and the enthalpy of formation of 1,3,5-hexatriyne.

The ultraviolet photochemistry of phenylacetylene was studied in a molecular beam at 193 nm. The only primary photofragments observed were HCCH (acetylene) and C(6)H(4). Some of the C(6)H(4) molecules were found to decompose to 1,3,5-hexatriyne and molecular hydrogen. An enthalpy of formation of DeltaH(f) < or = 160 +/- 4 kcal mol(-1) was determined for 1,3,5-hexatriyne from the energetic threshold for this process. This experimentally determined value agrees well with our ab initio calculations performed at the G2 level of theory. Angular distribution measurements for the HCCH + C(6)H(4) channel yielded an isotropic distribution and were attributed to a long-lived intermediate and ground-state dissociation. An exhaustive search yielded no evidence for the phenyl + ethynyl or the atomic hydrogen elimination channels even though these were observed in the pyrolytic studies of phenylacetylene [Hofmann, J.; Zimmermann, G.; Guthier, K.; Hebgen, P.; Homann, K. H. Liebigs Ann. 1995, 631, 1995. Guthier, K.; Hebgen, P.; Hofmann, K. H.; Zimmermann, G. Liebigs Ann. 1995, 637, 1995].     

Synthesis and characterization of new soluble aromatic polyimides from 3,4-bis(4-aminophenyl)-2,5-diphenylpyrrole and aromatic tetracarboxylic dianhydrides

Novel aromatic polyimides containing tetraphenylpyrrole unit were synthesized from 3,4-bis(4-aminophenyl)-2,5-diphenylpyrrole and various aromatic tetracarboxylic dianhydrides by the usual two-step procedure that included ring-opening polyaddition and subsequent thermal cyclodehydration. These polymers had inherent viscosities in the 0.20–0.65 dL/g range and were practically amorphous as shown by the X-ray diffraction studies. All the polyimides except for polypyromellitimide were easily soluble in a wide range of organic solvents such as o-chlorophenol, pyridine, 1,3-dimethyl-2-imidazolidone, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone at room temperature. These polyimides had high glass transition temperatures of 302–359°C and exhibited 10% weight loss at temperatures above 510°C in nitrogen.     

Synthesis and characterization of novel aromatic polyamides from 3,4-bis(4-aminophenyl)-2,5-diphenylpyrrole and aromatic diacid chlorides

A new polymer-forming monomer, 3,4-bis(4-aminophenyl)-2,5-diphenylpyrrole, was synthesized in three steps starting from 4′-nitrodeoxybenzoin. Tetraphenylpyrrole-containing aromatic polyamides and copolyamides were prepared from the diamine with various aromatic diacid chlorides and from a mixture of the diamine and 4,4′-oxydianiline with terephthaloyl chloride, respectively. The resultant polymers had inherent viscosities in the 0.3–1.8 dL/g range and were generally soluble in various organic solvents including N,N-dimethylacetamide and m-cresol. They have glass transition temperatures in the range of 306–333°C and showed no weight loss below 380°C in both air and nitrogen atmospheres.     

Complexes of 2,5-diphenyl-1,3,2,5-dioxaboraphosphorinane and 1,3,5-triphenyl-1,3,5-diazaphosphorinane with molybdenum hexacarbonyl

The reaction of 2,5-diphenyl-1,3,2,5-dioxaboraphosphorinane (L) and 1,3,5-triphenyl-1,3,5-diazaphosphorinane (L) with molybdenum hexacarbonyl gave, respectively, Mo(CO)₄L₂ and Mo(CO)₅L complexes.A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Science Center, Russian Academy of Sciences, 420083 Kazan. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 201–203, January, 1992.     

2,5-Dibromopyridine as a key building block in the synthesis of 2,5-disubstituted pyridine-based liquid crystals

Fifteen 2,5-disubstituted pyridine based liquid crystals were synthesized exploiting the different reactivities of the bromine atoms in 2,5-dibromopyridine under Negishi coupling conditions. Convenient approaches to both 2-iodo-5-alkyl-pyridines and 2-alkyl-5-bromopyridines were also developed. The liquid crystalline behaviour of the synthesized materials was investigated using DSC and polarizing microscopy. The charge mobility of 2-(4-heptyloxyphenyl)-5-heptylpyridine was measured using the time of flight technique.     

Ring-closing metathesis toward the synthesis of 2,5-dihydrofuran and 2,5-dihydropyrrole skeletons from Baylis-Hillman adducts

We have developed an efficient method for the synthesis of 2,5-dihydrofuran and 2,5-dihydropyrrole skeletons from the simply modified Baylis-Hillman adducts via RCM reaction.