New p-MeOC6H4CH(CH2COOH)CH=CHMe acid (I) (m.p. 81-83 degrees C) was synthesized by condensation of p-MeOC6H4CHO with AcMe to p-MeOC6H4CH=CHCOMe after following redn. with NaBH4 to p-MeOC6H4CH=CHCH(OH)Me, condensation with Me3C(OEt)(3) at 137 degrees C and hydrolysis with aq. soln. of KOH (yield 63%) and then converted to resp. lactones II and III (X = I, Br or Cl). Acid I was reacted with I-2/KI in Et2O to a mixt. of cis-II (X = I) (m.p. 92-95 degrees C, yield 42%) and trans-II (X = I) (oil, yield 2%), with (CH2CO)(2)NBr in tetrahydrofurane to a mixt. of cis-II (X = Br) (m.p. 106-108 degrees C, yield 32%), trans-II (X = Br) (oil, yield 5%) and III (X = Br) (m.p. 74-77 degrees C, yield 10%), and with (CH2CO)(2)NCI in tetrahydrofurane to a mixt. of cis-II (X = Cl) (m.p. 115-118 degrees C, yield 14%), trans-II (X = Cl) (oil, yield 8%), and III (X = Cl) (m.p. 87-89 degrees C, yield 18%). The individual lactones II and III were sepd. by column chromatog. The (HNMR)-H-1, C-13-NMR and IR data available for all products and intermediates. Biol. activity of lactones II and Ill was assumed. [GRAPHICS] .