Dibenzo-l,4-oxathiine

Dibenzo-l,4-oxathiine 2,8-Dinitro-E9a, 58f. [2-(4-ND2-phcnoxy) 5-N02 -1 -S02H - benzene/H +]... 

Dibenzo-l,4-oxathiine 8-Methyl-2-nitro- E9a, 58 [2-(4-CH3-phenoxy) — 5-N02 — 1 -S02H -benzene/11+]... 

Annulation with oxathiin (synthesis of dibenzo-l,4-oxathiin)... 

The central ring of both dibenzo[l,4]- dithiins and -oxathiins is cleaved on treatment with Li and a catalytic amount of 4,4"-di-rert-butylbiphenyl (DTBB) to afford thiols after reaction of the dilithio intermediate with electrophiles. In certain instances, the initial product can be cyclised to the dibenzo- dithiepine and -oxathiepine <02CL726>. The dilithio salt from thianthrene reacts sequentially with two different carbonyl compounds to give a l,2-di(hydroxyalkyl)benzene. When C02 is used as the second electrophile, a phthalan results <02TL7205>. 

Benzo- and Dibenzo-1,4-dithiins.—An improved synthesis of benzo-l,4-dithiin and -oxathiin is based on a novel intramolecular sulphenylation of the thiol-sulphonates PhY(CHa)2SSOaMe (Y = S or O) in the presence of aluminium chloride. Phenyl-lithium reacts with bromobenzene and carbon disulphide to give 2,3-diphenyl-l,4-benzodithiin via a benzyne intermediate. ... 

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