1.4.5- Thiadiazepine

The 1,3,5-thiadiazepine (559) has been prepared by the thermal rearrangement of the [4 + 2] cycloadduct (558) of the azirine (557) and thiobenzoyl isocyanate (74JOC3763). The benzoyl isocyanate adduct does not rearrange to give an oxadiazepine. 

Triphenyl-4,7-dihydro-l,3,5-thiadiazepin-4-one was prepared in 1974 by the reaction of thiobenzoyl isocyanate with 2,3-diphenyl-l-azirine <74JOC3763>. The second examples of this ring system, 1,3,5-thiadiazepin-6-ones (112), were prepared by the reaction of the isothiocyanate derivatives (110) with methanol or isopropylthiol. The initially formed adducts (111) were readily converted into the final products (112) upon treatment with a base, such as sodiiun methoxide (Scheme 18) <86S817>. 

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