The buta-1,3-diene-1,4-sultone (pysultone) ring, a non-aromatic 6π-electron system: X-ray structural determination

Cycloaddition of sulfene to N,N‐disubstituted (E)5‐aminomethylene‐6,7‐dihydrobenzo[b]furan‐4(5H)ones I gave, only in the case of aliphatic N‐substitution and generally in satisfactory yields, N,N‐disubstituted 4‐amino‐3,4,5,6‐tetrahydrofuro[2,3‐h]‐1,2‐benzoxathiin 2,2‐dioxides II, which are derivatives of the new heterocyclic system furo[2,3‐h]‐1,2‐benzoxathiin. The 4‐dimethylamino and 4‐piperidino cycloadducts IIa,e were dehydrogenated with DDQ to the corresponding 4‐dialkylamino‐3,4‐dihydrofuro[2,3‐h]‐1,2‐benzoxathiin 2,2‐dioxides IIIa,e in low yield. Compounds IIIa,e were tested for photobiological activity and found to be inactive.

Reaction of sulfene with heterocyclic N,N‐disubstituted α‐aminomethyleneketones. VIII. Synthesis of furo[2,3‐h]‐1,2‐benzoxathiin derivatives

Mosti¹,

Schenone²,

Menozzi³

et al. 1982

Reaction of substituted sulfenes with N,N‐disubstituted α‐amino‐methyleneketones. II. Synthesis of N,N‐disubstituted cis and trans 4‐amino‐3‐chloro‐3,4,5,6,7,8‐hexahydro‐1,2‐benzoxathiin 2,2‐dioxides, and 4‐amino‐5,6,7,8‐tetrahydro‐1,2‐benzoxathiin 2,2‐dioxides

Bargagna

Schenone

Bignardi

et al. 1983

The polar 1,4‐cycloaddition of chlorosulfene (generated in situ from chloromethanesulfonyl chloride and triethylamine) to N,N‐disubstituted (E)‐2‐aminomethylenecyclohexanones I gave mixtures of N,N‐disubstituted cis and trans 4‐amino‐3‐chloro‐3,4,5,6,7,8‐hexahydro‐1,2‐benzoxathiin 2,2‐dioxides III and IV, except for N,N‐diphenyl enaminone which did not react. Only compounds IV could be separated from these mixtures by silica gel chromatography, with the exception of the piperidino adducts (III + IV)d, from which also IIId could be obtained pure. Compounds IV or mixtures III + IV were dehydrochlorinated with DBN in refluxing benzene to afford N,N‐disubstituted 4‐amino‐5,6,7,8‐tetrahydro‐1,2‐benzoxathiin 2,2‐dioxides V in satisfactory yields. Structural and conformational features of compounds III, IV and V were determined from uv, ir and nmr spectral data.

Reaction of sulfenes with heterocyclic N,N‐disubstituted α‐aminomethyleneketones. XIII. Synthesis of 1,2‐oxathiino[6,5‐f]quinazoline derivatives

Menozzi

Bargagna

Mosti

et al. 1987

The 1,4‐cycloaddition of sulfene to N,N‐disubstituted (E)‐6‐aminomethylene‐7,8‐dihydro‐(2‐methyl)‐(2‐phenyl)quinazolin‐5(6H)‐ones I gave N,N‐disubstituted 4‐amino‐3,4,5,6‐tetrahydro‐(8‐methyl) (8‐phenyl)‐1,2‐oxathiino[6,5‐f]quinazoline 2,2‐dioxides II, which are derivatives of the new heterocyclic system 1,2‐oxathiino[6,5‐f]quinazoline. With 2‐phenylenaminones Id‐h, the cycloaddition occurred, generally in satisfactory yields, both in the case of aliphatic N,N‐disubstitution and aromatic N‐monosubstitution, whereas with 2‐methyl enaminones Ia‐c the reaction took place in low yields only in the case of aliphatic N,N‐disubstitution. Also the reaction of 2‐phenyl enaminones Id‐g with chlorosulfene occurred as with sulfene, giving a mixture of cycloadducts which were dehydrochlorinated in situ with DBN to afford N,N‐di‐substituted 4‐amino‐5,6‐dihydro‐8‐phenyl‐1,2‐oxathiino[6,5‐f]quinazoline 2,2‐dioxides III generally in satisfactory yields. Compounds III could not be dehydrogenated either by DDQ in boiling benzene or by palladium on carbon in boiling p‐cymene.