Succinic anhydride → 6,7-Diethyl-3,4-dihydronaphthalen-1(2H)-one

Participants

Reaction Conditions

Reaction Steps

3-(3',4'-Diethylbenzoyl) propanoic acid (m.p. 93° C, prepared by the acylation of 1,2-diethyl benzene with succinic anhydride) was catalytically reduced to 4-(3',4'-diethylphenyl) butanoic acid (b.p.0.7 143°-147° C). A mixture of this acid (59g; 0.27 mole) and 85% polyphosphoric acid (450g) was warmed to 80° C with stirring for 30 mins. and worked up as in example 8(a) to yield 48.30g (89%) of 6,7-diethyl-1-tetralone, b.p.0.7 118°-122° C. (Found; C, 82.95; H, 9.21; C14H18O requires; C, 83.12; H, 8.97%). Alternatively 4-(3',4'-diethylphenyl butanoic acid (23.3g; 0.106 mole) may be cyclized by stirring at 100° C with 80% sulphuric acid (115ml) for 1 1/2 hrs. After dilution, extraction into ether and distillation 15.53g (74%) of the tetralone was recovered.

Provenance & Evidence