Heterocyclic linked

The third method that we have used to prepare these diazaboracyclohexane systems is the transamination reaction of 1,3-diaminopropane with the bis(dimethyiamino)boryl compound 8 (eq 8). The solid products 12 and 13, which contain, respectively, two or three of the BN2C3 heterocycles linked by B-N bonds, could not be distilled (or crystallized), but they were thermally stable to at least 200°C. After minor impurities were removed from 12 by vacuum distillation and from 13 by washing with hexane, the structures were confirmed by1H, 13C, and 11B NMR spectroscopy. 

Dihydroisoquinoline reacts with the appropriate heterocycle-linked dimedone derivatives to give thiazolo-quinolizinium salts such as 467 <1995RJ0271, 1995DOC776> or pyrazoloquinolizines like 468 <1995RJC146> (Scheme 105). 

Diaryl heterocycles linked via a fused ring system... 

Heterocyclically Linked Cyclic Ammo nium Groups. Reaction of chloroacetamide with pyridine, followed by condensation with acetoacetic esters in alcoholic sodium hydroxide, leads to a 2,6-dihydroxy-4-methylpyridine that is substituted in the 3-position by a pyridinium moiety. If this is coupled with diazotized aromatic or heterocyclic amines, yellow to red cationic azo dyes (e.g., 15 [92691-25-3]) are obtained [46],... 

If we consider, as examples of the second group, polymers containing aromatic carbon- and/or heterocyclic links in the main chain of the macromolecules, we will notice the following general features of their pyrolysis, thermal properties and chemical structure ... 

Some ring-opening reactions have in common the introduction of certain three-membered side chains in the 4-position. These substituents then cyclize with the N3 atom of the pyrimidine part to give a five-membered heterocycle linked to the 2-position of the remaining pyridine ring. 

There has also been continuing interest in extended TTF analogues and examples of this type include 76 <01TL4191>, the azulene systems 77 <01H(54)377>, redox-active dendralenes such as 78 <00CEJ1955> and the heterocycle linked compounds 79 and 80 <01ZN(B)297>, 81 <01CL514> and 82 <01JAP48881>. 

Enantiospecific synthesis of heterocycles linked to purines Different apoptosis modulation of enantiomers in breast cancer cells 13CMD 4924. 

Piperidines and Reiated Heterocycles.—Linking with the preceding section on pyrrolidine derivatives, an intriguing combination of reactions is worthy of closer examination. Condensation of p-hydroxy-phenyl acetic acid with the carbodi-imides (300) afforded the spiro-fused indolinones (301) in yields of about 60%. 

Identical) heterocycles linked by single bonds are treated like related carbocycles ... 

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