34950-38-4

Upstream product

• 1888-37-5 markiertes 3.4-Dibrom-1.2.3.4-tetraphenyl-cyclobuten 
• 5344-88-7 benzil monohydrazone 
• 941-55-9 4-toluenesulfonyl azide 
• 938-10-3 phenylsulfonyl azide 
• 501-65-5 diphenyl acetylene 
• 7510-34-1 (Z)-1,2,3,4-tetraphenyl-2-butene-1,4-dione 
• 6830-78-0 3,6-diphenyl-1,2,4,5-tetrazine 

Relevant academic research and scientific papers

Purported synthesis of 3,4,7,8-tetraphenyl-1,2,5,6-tetraazocine from benzil and hydrazine: Competing cyclization and carbon-carbon σ-bond scission

The claims that 3,4,7,8-tetraphenyl-1,2,5,6-tetraazocine can be prepared by the thermal condensation of two moles of benzil monohydrazone or of an equimolar mixture of benzil and benzil dihydrazone have been thoroughly reinvestigated. When such thermolyses were conducted in moist air, neither the claimed 3,4,7,8-tetraphenyl-1,2,5,6-tetraazocine nor the precedented isomeric tetraazapentalene derivative was detected. The following products were unambiguously formed from the heating of molten benzil monohydrazone (%): benzil (10), benzaldehyde (10), benzamide (22), benzyl phenyl ketone (19), benzil bis(ketazine) (11), 3,4,5,6-tetraphenylpyridazine (9), benzil benzaldehyde azine (10), and, after column chromatography, 2,4,5-triphenylimidazole (2). This last component had a melting point and the fluorescent properties in UV light attributed by the original investigator to the mistakenly presumed 3,4,7,8-tetraphenyl-1,2,5,6-tetraazocine. Thus, the original claims for the synthesis of such a novel tetraazocine ring or even for the synthesis of the precedented isomeric zwitterionic tetraazapentalene have now been repudiated. The formation of 2,4,5-triphenylimidazole as a side reaction in the thermolysis of benzil monohydrazone can readily be rationalized as arising from benzil, benzaldehyde, and a source of ammonia, namely, benzamide, in the long-known Radziszewski reaction. Corroborating evidence was provided by data from the thermolysis of benzil dihydrazone. In addition, the origin of other side products is explained in terms of other possible condensations. Finally, preliminary experiments on using irreversible dehydrating agents such as titanium(IV) isopropoxide with benzil monohydrazone indicate that 3,4,7,8-tetraphenyl-1,2,5,6-tetraazocine is formed at room temperature as a transitory intermediate, which eliminates dinitrogen to produce 3,4,5,6-tetraphenylpyridazine. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.

Experimental and theoretical characterization of the valence isomerization of Bi-2H-azirin-2-yls to diazabenzenes

3,4-Diazidocyclobutenes 16 were prepared from the corresponding dihalides. Some of these diazides, such as parent compound 16 d and phenyl-substituted derivatives 16c,f, underwent spontaneous stereoselective electrocyclic ring opening below room temperature, whereas the tetraalkyl derivatives of 16 had to be heated to force the same reaction. In most cases, the resulting 1,4-diazidobuta-1,3-dienes 8 were isolated to study their photochemical transformation into bi-2Hazirin-2-yls 9 via intermediate monoazirines 17. Except for starting materials with a low number of substituents such as 9d and 9f, title compounds 9 underwent a thermal valence isomerization which led exclusively to pyridazines 18 at surprisingly low temperatures. Based on quantum-chemical calculations for the parent bi-2H-azirinyl 2-yl 9d at the UB3LYP/6-31+G(d) and MR-MP2/TZV(2df,2p) levels, the valence isomerization process is best explained by simultaneous homolytic cleavage of both C-N single bonds of 9 to generate energetically favorable N,N′ diradicals 26, which cyclize to 18. The theoretical studies indicate also that one stereoisomer of 9, namely, the rac compound, should undergo valence isomerization more easily than the other, which is in conformity with different rates of these rearrangement reactions found experimentally. For the tetramethyl-bi-2H-azirin-2-yls 9g, which are better models for the experimentally studied compounds, simultaneous homolytic cleavage of both C-N single bonds is also predicted by the calculations, although the intermediate diradicals 26 g are significantly higher in energy than those of the parent system 9d.

Oxidation of Aromatic Compounds. IV. Oxidation of Symmetrical Diarylacetylenes in the CF3COOH-CH2Cl2-PbO2 System. A New One-Pot Synthesis of 1,2,3,4-Tetraaryl-2-butene-1,4-diones

Oxidation of symmetrical diarylacetylenes in the CF3COOH-CH2Cl2-PbO2 system (0-20 deg C, 1-3 h) yields 1,2,3,4-tetraaryl-2-butene-1,4-diones.According to (1)H NMR and GC-MS data the compounds synthesized have Z configuration.

Reactions of cobaltacyclopentadiene complexes with organic azides directed toward synthesis of highly substituted pyrroles

The reactions of the cobaltacyclopentadiene complexes (η5-C5H5)(PPH3)-Co(-CR1=CR2-CR3=CR4)- (I) with organic azides were investigated.The complex Ia (R1)=R2=R3=R4=Ph) reacts with phenyl azide at 80 degC to give 1,2,3,4,5-pentaphenylpyrrole in 73percent yeld.Similarly, the reactions of Ia with benzoyl and t-butoxycarbonyl azides give 1-benzoyl- and 1-(t-butoxycarbonyl)-2,3,4,5-tetraphenylpyrroles in 41 and 64percent yields, respectively, but reaction with p-toluenesulfonyl azide gives 2,3,4,5-tetraphenylpyrrole and 3,4,5,6-tetraphenylpyridazine in 35 and 45percent yields, respectively, in place of the expected 1-(p-toluenesulfonyl)-2,3,4,5-tetraphenylpyrrole.The reaction of Ic (R1=R4=Ph, R2=R3=CO2CH3) with phenyl azide at 130 degC gives 1,2,5-triphenyl-3,4-bis(methoxycarbonyl)pyrrole (IIc)and 2,5-diphenyl-3,4-bis(methoxcarbonylpyrrole (Vb) in 22 and 15percent yields, respectively.The reaction of Ic with benzenesulfonyl azide gives only Vb in 57percent yield.In the reaction of Id (R1=R3=Ph, R2=R4=CO2CH3) with benzenesulfonyl azide, Vb was unexpectedly obtained in 26percent yield, together with 2,4-diphenyl-3,5-bis(methoxycarbonyl)pyrrole (Vc, 30percent), which suggests that a skeletal rearrangement of the metallacycle IXd to IXc occurs during the reaction.The reaction of Ic or Id with benzoyl azide at 130 degC gives the 2(1H)-pyridinone derivatives VIIIa (82percent) and VIIIb (53percent), which are the products of the reaction of the corresponding cobaltacyclpentadiene with phenyl isocyanate generated by the rearrangement of benzoyl nitrene, in place of the expected, corresponding pyrrole.