Glycoluril derivative

The vast majority of the reactions of the 5-5 fused systems have been the alkylation of nitrogen atoms by electrophiles and oxidants. Most of the examples have been in the alkylation of glycoluril derivatives and the general methods have been extensively covered in CHEC(1984) and CHEC-II(1996) and as such do not generally require comment here. Some of the alternative and less common methods however are outlined below. 

Nitrosation of glycoluril derivatives has also been reported by simple exposure to nitric acid and sodium nitrite (Equation 11) <1998RJOC34>. 

Reductions of these ring systems are common. Most often, active hydrogen techniques are employed to cleave weak heteroatom-heteroatom bonds. Reductions of the glycoluril derivatives are less common due to the lack of such a weak bond. Some recent examples include reactions by Chan et al. <2003TL395> who employed Raney nickel and hydrogen to effect cleavage of an N-O bond in their synthesis of new heterocyclic compounds via 1,3-dipolar cycloaddition chemistry (Equation 15). 

Harrison et al. have demonstrated that bis-acyl glycoluril derivatives 84 undergo efficient Claisen ester condensation, as exemplified in Equation (18) to yield /3-ketoamide derivatives 85. A kinetic study is also presented which indicates clean, bimolecular kinetics and short half lives for the intermediates <2002CJC517>. 

Glycoluril derivatives, inclusion chemistry, 12, 814 18/3-Glycyrrhetinic acid, with trinuclear Ru and Os clusters, 6, 743... 

What is the scope of glycoluril derivatives that can be used in the CB[n]-forming reaction ... 

Figure 17 Hydrogen-bonded structure in the crystals of glycoluril derivatives (R = H,Me).

Hybrid capsules composed of two glycoluril derivatives incorporating different backbone spacer groups have also been demonstrated to form in solutions containing a mixture of two homo-dimers chosen from the above series. In this... 

To fully explore the seope and limitations of the dimerization reaction we needed to access a range of glycoluril derivatives bearing a variety of substituents on their convex face, on their aromatic rings, and containing either free ureidyl NH compounds or cyclic ether moieties. The following sections outline the synthesis of those compounds. 

C. GLYCOLURIL DERIVATIVES BEARING FREE UREIDYL NH GROUPS... 

For the preparation of a series of glycoluril derivatives bearing a single aromatic sidewall and potentially nucleophilic ureidyl NH groups, we adapted chemistry developed by Nolte and Rebek. Deprotonation of glycoluril 1 with /-BuOK in DMSO followed by the addition of alkylating... 

D. GLYCOLURIL DERIVATIVES BEARING CYCLIC ETHER FUNCTIONAL GROUPS. 

The slow addition of diamines to refluxing solutions of glycoluril derivatives and formaldehyde in methanol yielded novel heterocycles (85)-(91) related to cucurbituril (Equation (20)) <85JOC60>. 

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