Phenanthrenes, formation

The catalyst Pd(PPh3)4 favors phenanthrene formation, while Pd2(dba)3 generates primarily the naphthalene product. 

A mild O-acetylation of phenolic aporphines, avoiding phenanthrene formation, utilizes acetyl bromide in trifluoroacetic acid. The diacetate of apomorphine was thus obtained in high yield. 

The addition product, C QHgNa, called naphthalenesodium or sodium naphthalene complex, may be regarded as a resonance hybrid. The ether is more than just a solvent that promotes the reaction. StabiUty of the complex depends on the presence of the ether, and sodium can be Hberated by evaporating the ether or by dilution using an indifferent solvent, such as ethyl ether. A number of ether-type solvents are effective in complex preparation, such as methyl ethyl ether, ethylene glycol dimethyl ether, dioxane, and THF. Trimethyl amine also promotes complex formation. This reaction proceeds with all alkah metals. Other aromatic compounds, eg, diphenyl, anthracene, and phenanthrene, also form sodium complexes (16,20). 

Elimination of sulfur from methyl dibenzo[/),/]thiepin-10-carboxylatcs 15 (R2 = Me) can be achieved in moderate yields (39-55%) upon refluxing in diethyl phthalate in the presence of copper bronze.60 For the dibenzo[A,/]thiepin-10-carboxylic acids 15 (R2 = H), the loss of sulfur is accompanied by decarboxylation. Thus, treatment of these acids with copper bronze in refluxing quinoline for four hours gives the corresponding phenanthrenes 16 (R3 = H) in moderate yield (50%). However, the exposure time to high temperatures influences the product formation. Thus, the decarboxyiated dibenzothiepins are obtained after refluxing for only five minutes.60... 

Hydrazine reacts with biphenyl-2,2 -dicarbaldehyde (3, R = H). under elimination of nitrogen, to give phenanthrene,17 most probably not via the intermediate formation of a diazocine system. With other 2,2 -diacylbiphenyl compounds the expected dibenzo[[Pg.520]

The acid 19 has been dimerized, although in low yield, in the course of a perhydro-phenanthrene synthesis [141]. When the oxidation potential of the double bond is sufficiently lowered by alkyl substituents, lactone formation by oxidation of the couble bond rather than of the carboxyl group occurs (Eq. 7) [142] (see also chap. 15). 

Sutherland JB, JP Freeman, AL Selby, PP Fu, DW Miller CE Cerniglia (1990) Stereoselective formation of a K-region dihydrodiol from phenanthrene by Streptomyces flavovirens. Arch Microbiol 154 260-266. 

C[bicarbonate] and mass spectrometry were used to demonstrate the formation of carboxylic acids during the sulfidogenic mineralization of naphthalene and phenanthrene (Zhang and Young 1997). 

Barnsley EA (1983) Phthalate pathway of phenanthrene metabolism formation of 2 -carboxybenzalpyruvate. J Bacteriol 154 113-117. 

Samanta SK, AK Chakraborti, RK Jain (1999) Degradation of phenanthrene by different bacteria evidence for novel transformation sequences involving the formation of 1-naphthol. Appl Microbiol Biotechnol 53 98-107. 

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