Disuccinimido carbonate

This ring is formed in high yield from a mercapto-amine and either phosgene or disuccinimido carbonate (see Section 1.3). Ethyl potassium xanthate is also effective [3038]. An aminophenol in which the hydroxy group is masked as its dimethyl aminothiocarbamate cyclizes under conditions which generate the amine from the nitro group. The product is the result of a Newman-Kwart rearrangement [B-40, Vol. 3, p. II). 

Disuccinimido carbonate (DSC) is a useful reagent for the insertion under mild conditions of a carbonyl group in diamines [3019]. A cyclization which leads to imidazo[4,5-c]pyridin-2-one is described in Section III. Carbonyldi imidazole-TEA is another reagent for this type of cyclization [3925]. Potassium ethylxan-thate (potassium ethyidithiocarbonate) is an alternative to carbon disulphide in the synthesis of the tautomeric 2-benzimidazolethiones it was first used many decades ago and usually gives good yields [3259]. The synthesis of an imidazo[4,5 c]pyridin-2-one is described in Section 111.2 [2327]. 

A different strategy for the formation of the cyclic core of the BFC is based on peptide bond formations O Fig. 45.10). The macrocycle is formed by an intermolecular reaction of an activated disuccinimido ester with a diamine under high-dilution conditions with a yield of >40%. Reduction of the carbonyl groups and alkylation lead to a BFC, which possesses an attachment function for biomolecules on the carbon backbone of the macrocycKc core (McMurry et al. 1992). 

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