The benzannelated dihydropyrenes 3 and 4 were synthesized from l,3-bis(bromomethyl)naphthalene ( 16) and l,3-bis(bromomethyl)-2-methylnaphthalene (22) (the latter obtained in 18% yield in seven steps from 2,3-dimethylnaphthalene) in 7.4% and 4.8% overall yields, respectively, using Stevens or Wittig rearrangement-Hofmann elimination sequences on the dithiacyclophanes 13 and 14, followed by valence tautomerization of the resulting cyclophanedienes 11 and 12. The dihydrobenzopyrene 3 rapidly dehydrogenates to benzo[a]pyrene (21), whereas the dimethyl derivative 4 is relatively stable.

No abstract

Durch Kondensation des Dibromids (I) mit Bis‐ (mercaptomethyl)‐aromaten wie z.B. (II) in großer Verdünnung entstehen das Dithiacyclophan (III) sowie die Analogen (IV) und (V).

INTERMOLECULAR adducts of aromatic amines and quinones form one of the best known classes of donor-acceptor complexes.1 Crystalline adducts Table . have been isolated293 and, depending on the electron affinity of the quinone, the complexes are reversible bleaching of the solutions upon acidification. Representative data are given in the TABLE Charge transfer spectra of compowtds (Ia-e) either completely covalent, or completely ionic as a result of electron transfer from amine to quinone. The compounds (I a -e ) were available from CH,OH solvent CH,Cl, solvent studies on the reactivity of quinone methides4 and has brn) Amax brn) 'maX 506 220 614 306 50 1 294 513 363 475 214 480 232 crystalline state. 485 194 495 232 466 348 470 303

Straining Strained Molecules.