W-Methoxyacetophenone

Ozone or performic acid readily converts 106 into the aldehyde 107, which then undergoes cyclodehydration to 108 with PPA.201 Thus, 4-allyloxy-2-hydroxy-cu-methoxyacetophenone gives (Claisen) 3-allyl-2,4-dihydroxy-w-methoxyacetophenone, then (with ozone) aldehyde (109) and 4-hydroxy-5(methoxyacetyl)benzofuran (110). 

Armesto and co-workers have reported the photochemical behaviour of the vinylcyclopropane derivatives (98) under w-methoxyacetophenone sensitisation in methylene chloride as the solvent. A variety of products are formed, the nature of which is dependent upon the substituent on the cyclopropyl ring. The key intermediate is believed to be the biradical (99) that is formed following energy transfer. A study of the effect of wavelength on the outcome of the irradiation of (100) has been reported. At short wavelengths (250 and 254 nm), it is thought that the S2 state of (100) is populated and this results in the formation of the three products (101), (102) and (103) in a ratio of 6 1 1. 

Photosensitized decomposition of oxime oxalyl amides proceeded via carbamoyl radicals which underwent A-exo cyclizations forming four-membered /3-lactams as main products. Irradiation of solution of oxime derivative 22 and 4-methoxyacetophenone (MAP) in toluene at 100 °C with a 400 W UV lamp led to azetidinone 23 in 3 1 ratio of diastereoisomers (equation 10) . ... 

The reaction of a-chloro carbonyl compounds with ammonia is not always successful, for example, w-chloro-o-methoxyacetophenone and w-chloro-o,p-dimethoxyacetophenone yield only resinous products (236), but in these cases potassium phthalimide may be used for the ammonation to the a-amino carbonyl compound. This last method was developed by Gabriel (116) and co-workers (187). 

A mixture of 250 mg 3,3-dimethyl-1,5,5-triphenyl-2-aza-l,4-pentadiene (0.80 mmol), 550 mg m-methoxyacetophenone (3.7 mmol) and 450 mL dry -BuOH was put into a quartz immersion well apparatus with a Pyrex filter. The solution was purged with argon for 1 h and was irradiated with a 400-W medium-pressure mercury arc lamp for 6 h. After completion of the irradiation, the solvent and the sensitizer were removed under reduced pressure, the residue was chromatographed with hexane/Et20 (99 1) as an eluent to afford 65.0 mg benzaldehyde, and 13.0 mg of cyclopropylimine as a colorless oil, in a yield of 5%. Further elution with Et20 yielded 25 mg of a highly polar material. Final elution with EtOH afforded 148 mg l,l-dimethyl-3,3-diphenyl-2-propenylamine, in a yield of 81%. 

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