Notes

Abstract

C,HI4 requires C, 87.3; H, 12.7%). (b) 4,5-cisand aZl-trans-2,3-dimethyZocta-2,4,6-triene (I11 ; n = 1). [19G4]Notes. 2467and after 4 hr. in diffuse daylight the solution showed an absorption spectrum similar to that of the all-trans-triene, Amax. 276, 287 mp (G 39,300, 30,700). The condensation of the phosphorane (I) and hexa-2,4-dienal (11; n = 2) was carried out as in (a), and, after refluxing of the mixture on a waterbath for 4 hr., the cis-and trans-iomers (111; n = 2) (74%), b. p. 61-74"/0.01 mm., were isolated and isomerised as in (a), to yield the all-trans-tetraene (111; n = 2), b. p. 71-72"/0.03 mm., A , =