Benzene → 4,4-Dimethylthiochroman
Reaction equation
C1([CH:7]([S:12]C(C2C=CC=CC=2)C=C(C)C)[CH:8]=[C:9]([CH3:11])[CH3:10])C=CC=CC=1.O=P12OP3(OP(OP(O3)(O1)=O)(=O)O2)=O.P(=O)(O)(O)O.[CH:43]1[CH:48]=[CH:47][CH:46]=[CH:45][CH:44]=1>>[CH3:10][C:9]1([CH3:11])[C:48]2[C:43](=[CH:44][CH:45]=[CH:46][CH:47]=2)[S:12][CH2:7][CH2:8]1Participants
5
Procedure
To a solution of 15.48 g (86.824 mmol) of phenyl-3-methylbut-2-enylsulfide (Compound 60) in 160 ml benzene were added successively 12.6 g (88.767 mmol) of phosphorus pentoxide and 11 ml of 85% phosphoric acid. This solution was refluxed with vigorous stirring under argon for 20 hours, then cooled to room temperature. The supernatant organic layer was decanted and the syrupy residue extracted with 3×50 ml ether. Organic fractions were combined and washed with water, saturated NaHCO3 and saturated NaCl solutions and then dried (MgSO4). Solvent was removed in vacuo and the residue purified by kugelrohr distillation (80 degrees C, 0.5 mm) to give the title compound as a pale yellow oil. PMR (CDCl3) :& 1.30 (6H, s), 1.90-1.95 (2H, m), 2.95-3.00 (2H, m), 6.96-7.00 (2H, m), 7.04-7.07 (1H, m), 7.30-7.33 (1H, m).