The introduction of a hydroxyl function into phenol to give hydroquinone and catechol can be achieved in high yields by the reaction of hydrogen peroxide with alkenylphenols. These alkenylphenols are obtained by thermolysis of bisphenol A, alkylation of phenol with cyclopentadiene followed by isomerization, and alkylation of phenol with mesityl oxide followed by thermolysis to give 4-isopropenylphenol, 2-and 4-(cyclopenten-l-yl)phenol, and 2,2,4-trimethyl-l,2-chromene, respectively.

No abstract

cyanogen in 35 ml of ethyl acetate was prepared in the usual manner in the dark at 0°. To this cold solution was added 7.2 mmol of I in 20 ml of ethyl acetate over at 15-min period. At this point tic indicated that no thiol remained. The appropriate thioether (7.2 mmol) was dissolved in 25 ml of ethyl acetate and added in one portion to the reaction mixture. The solution was stirred in the dark for 2 hr at 0°, allowed to warm to room temperature, and stirred for an additional period of time (3-33 hr depending on the reaction progress as demonstrated by tic). After reaction was complete the solution was diluted to 200 ml with ethyl acetate and washed with 5% sodium bicarbonate solution, water, and saturated brine. The organic extract was dried and evaporated in vacuo, and the residue was triturated with hexane to remove the trityl thiocyanate. The resulting powder was purified by recrystallization or chromatography followed by recrystallization. The reported yields (Table I) are based on the amount of purified product.B. Acidic Solvents.-To a cold, stirred solution containing 9 mmol of thio cyanogen in 35 ml of ethyl acetate was added 7.2 mmol of I in 20 ml of trifluoroacetic acid (TEA). After 10 min,

dified with concentrated HC1 to precipitate 1.1 g (5%) of 3b, mp 133-135°( reported3 mp 134°).B. From Base Rearrangement of lb. A mixture of 1.0 g (0.005 mol) of lb and 100 ml of 1 TV NaOH was warmed on the steam bath for 5 min or until complete solution took place. The cooled solution was acidified with concentrated HC1 to precipitate 3b: 0.80 g (86%); mp 133-135°; ir (Nujol) 1730 (acetyl C=0), 1615 cm-1 (2-pyrone C=0); uv max (95% EtOH) 212 nm (e 23,000), 300 (14,000), 320 sh (9600); mass spectrum m/e (rel intensity) 204 (60), 189 (40), 162 (20), 121 (60), 120 (60), 105 (10), 93 (15), 92 (50), 77 (25), 43 (100).4-Hydroxy-3-(l-oxopropyl)-2H-l-benzopyran-2-one (3c). A mixture of 5.5 g (0.028 mol) of methyl salicyloylacetate, 150 ml of xylene, 19.5 g (0.15 mol) of propionic anhydride, and 30 g of powdered potassium carbonate was heated with stirring at 135°for 0.5 hr. Ether (300 ml) was added to the cooled mixture and the solids were filtered and washed with ether. The filter cake was stirred with 500 njl of water, the insoluble portion was filtered, and the filtrate was acidified with concentrated HC1 to precipiate 4.8 g (78%) of 3c: mp 122-124°(reported8 mp 123°); ir (Nujol) 1720 (acyl C=0), 1610 cm"1 (2-pyrone C=0); uv max (95% EtOH) 226 nm sh (e 15,200), 301 (13,300); mass spectrum m/e (rel intensity) 218 (50), 200 (15), 189 (100), 162 (17), 121 (50), 120 (25), 105 (12), 93 (12), 92 (25), 77 (25), 43 (5).

No abstract