Diphenyl azulene

Azulene106) and 4,6,8-trimethyl azulene109 readily undergo electrophilic attack by cation 75 at the five-membered ring leading to l-(l,2-diphenyl-cyclopropenium)-azulenes 143, which are isoelectronic with indolizinium ions 139/140 and represent cyclic vinylogs of the cyclopropenyl heptafulvenylium system 144. 

An azulene (36) having two intramolecularly crossing ethynyl groups was obtained together with its isomer (37) on irradiation of o-diethynylbenzene (35) and no further photochemical reaction was observed . On the other hand, o-bisphenyl-ethynylbenzcne (38) gave an azulenophenalene system, verdene (39), on irradiation . The mechanism of the formation of 39 was considered as a result of further cycloaddition of two triple bonds crossed in an intermediate azulene derivative (40). This photochemical reaction is reminiscent of the Biichi reaction in which diphenyl-acetylene yields an azulene system. 

Bei fast alien photochemischen Uinsetzungen der Acetylene, soweit. sie die Dimerisierung und Cycloaddition bct.rcffen, ist mindestens ein Substituent notwendig, weil er in die Folge-rcaktion mit einbezogen werden muB. So z.B. bei derBildung vonl-Phenyl-azulcn (s. S. 464) und 1,2,3-Triphenyl-azulen (s. u.) aus Phenylacetylen bzw. Diphenyl-acctylen. 

Phenylathinyl-l,2-diphenyl-3- 2-phenyldthinyl-phenyl)-azulen (Verden) 3 1,4,5... 

F F -o 5,6,7,8-Tetrafl,uor-4-phenyldthinyl-l,2- diphenyl-3-(3,4,o,6-tetrafluor-2-phenyl- dthinyl-phenyl)-azulen 4 3... 

Hence, the chemical evidence presented for anthracene was confirmed spectroscopically. Furthermore, Mullen et al. (12) categorized a number of hydrocarbons in Li-NH3 solutions into two classes group 1 hydrocarbons that exist as monoanions in ammonia and group 2 hydrocarbons that exist as dianions in ammonia. Group 1 includes anthracene and its 9-methyl, 9-phenyl, and 9,10-diphenyl derivatives acenaphthylene azulene fluoranthene phenanthrene and pyrene. Group 2 includes aceheptylene, cyclooc-tatetraene, and perylene. 

When S4N4 was heated with phenyl vinyl sulfoxide, no trithiadiazepane was formed the main products were sulfur, diphenyl disulfide and lA 5, 3,5,7A 5 -tetrathia-2,4,6,8-tetraza-2a-azulene (61) (Equation (31)) <85CC1654>. 

Dihydrobenz[a]azulenes. Cyclopropene passed into a soln. of the startg. indanocyclone in methylene diloride until the purple color is discharged 5,9-diphenyl-10-oxo-7,10-dihydrobenz[a]azulene. Y ca. 100%. F. e. s. L. A. Kapicak and M. A. Battiste, Synthesis 1971, 153. 

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