C=C([CH2:6][CH2:7][C:8]1[C:13]([O:14][C:15](=O)[CH3:16])=[C:12]([CH3:18])[C:11]([CH3:19])=[C:10]([O:20]C(=O)C)[C:9]=1[CH3:24])CC#N.[OH-:25].[K+].[CH2:27]([OH:30])[CH2:28]O.Cl>O>[OH:20][C:10]1[C:11]([CH3:19])=[C:12]([CH3:18])[C:13]2[O:14][C:15]([CH2:28][C:27]([OH:30])=[O:25])([CH3:16])[CH2:6][CH2:7][C:8]=2[C:9]=1[CH3:24]A mixture of 623 mg (1.89 mmoles) of the mixture of E- and Z-3-methyl-5-(2,4,5-trimethyl-3,6-diacetyloxyphenyl)-3-pentenenitrile and 3-methylene-5-(2,4,5-trimethyl-3,6-diacetyloxy-phenyl)pentanenitrile, 498 mg (7.70 mmoles) of 85% KOH, 5 ml of ethylene glycol and 0.5 ml of water was stirred and refluxed for 36 hr. The reaction mixture was cooled to room temperature, then poured into water. The pH of the solution was adjusted to 8 with 1 N aqueous HCl and the resulting mixture was extracted with two portions of ether (the extracts were discarded). The aqueous phase was acidified with 3 N aqueous HCl and worked-up with ether in the usual manner giving 421 mg (84%) of rac.-(6-hydroxy-3,4-dihydro-2,5,7,8-tetramethyl-2H-1-benzopyran-2-yl)acetic acid as a tan solid, mp 168°-170°.
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