Tetralin formylation

Azido-5-formyl-l,3-dimethyluracil is cyclized with hydrazines to afford pyrazolo[3,4-reaction with triphenylphosphine in benzene result in the formation of isoxazolo[3,4-c/]pyrimidine and pyrimido[4,5-[Pg.182]

Formylation and Carboj lation. Formylatlon of aromatic compounds such as benzene, toluene, xylenes, mesltylene, Indan, tetralin, and halobenzenes Is achieved In HSOsF-SbFs under atmospheric CO pressure at 0 °C (eq 19). However, In the cases of alkylbenzenes, both formylatlon and sulfonation took place under these reaction conditions to give alkylbenzaldehydes and formylalkylbenzenesulfonyl fluorides, as well as small amounts of alkylbenzenesulfonyl fluorides and bis (alkyIphenyl) sulfones. With benzene and halobenzenes, because of their lower reactivity only aldehydes were produced. 

Investigation of the decomposition of 2-azidophenazine 97a in various hydrocarbon solvents showed that the main product in all the solvents at 130-131 °C is 2-aminophenazine 98 (Scheme 3.32). The same compound is readily obtained at room temperature in tetraline and decaline. In other solvents (hexane, cyclohexane, benzene, and xylene) saturated with oxygen, 2-nitrophenazine 99, 3-[2-(3-formylquinoxalinyl)] acrylonitrile 100, and 4-formyl-l-nitrosopyrrolo[l,2-a] quinoxaline 101 are formed, while in the absence of oxygen resinification occurs (Bettinetti et al. 1978). 

In the di-substituted benzene series o- and m-xylene give the expected products. However, p-xylene undergoes isomerisation to furnish 2,4-dimethylbenzaldehyde. The tri-substituted benzene series i.e. mesitylene and pseudo-cumene yield normal formylation products. Tetralin and di-isopropyltetralin in the naphthalene series are reported to undergo Gattermann-Koch formylation whereas naphthalene itself is formylated in the modified reaction using HF and BF3 as catalyst. 

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