1.6- dihydro annulene

TTAA l,8-dihydro-5,7,12,14-tetramethyldibenso (b,i)-(l, 4,8,1 l-tetraazacyclotetradeca-4,6,11,13-tetraene- 5N4 (tetramethyldibenzo-tetraaza(14)annulene). 

The structures of the dihydro-octa-aza[14]annulene complexes (149) have been reported. The second example of single macrocycles capable of encompassing two metal atoms has been published. The complexes (150) and (151) have been prepared by metal template reactions of acetone and... 

Most of the highly unsaturated monocyclic eight-membered heterocycles contain one or two nitrogen atoms and have been obtained by bond reorganization processes from strained bicyclic or polycyclic precursors. Although several of the less substituted compounds without stabilizing substituents are highly labile substances, 1,4-dihydro-1,4-diazocines qualify as dihetera[8]annulenes and display distinct aromatic properties. 

Dihydro- 1,2-diazocines such as (183) have been referred to as l,2-diaza[8]annulenes (78AHC(23)55), and are of interest in connection with the potential aromaticity of the 107r-electron system provided by these rings (see Section 5.19.4.4). On the basis of UV and NMR data the dibenzodiazocine (183) was suggested to have a partially planar structure there is no direct evidence of aromatic character. 

Aside from the l,4-dihydro-l,4-diazocines (l,4-diaza[8]annulenes) discussed in Section 5.19.4.4.1, completely unsaturated 1,4-diazocines are represented in the literature only by benzo and dibenzo fused systems. 

At the beginning of the 70s Beck and co-workers discovered the electrocatalytic activity of dihydro-dibenzo-tetra-aza-annulene 8>12>, and Binder, Sandstede and co-workers that of tetraphenylporphyrine and its tetramethoxy derivative 9,13-15). 

Parallel to this work, catalysts for the anodic oxidation of several fuels were established 10>. Up to now, however, only one chelate is known to catalyze anodic reactions the cobalt complex of dihydro-dibenzo-tetra-aza-annulene. 

A logical extension of the condensation reactions which yield multidentate nitrogen donors is the formation of macrocyclic ligands. The preference of palladium for square planar coordination makes it an ideal metal for the formation of complexes of these ligands. Thus palladium porphyrins are very stable and resistant to demetallation.281 Both 14- and 16-atom macrocycles have been used to form complexes. The ligand l,8-dihydro-5,7,12,14-tetramethyl-dibenzo[b,i][l,4,8,ll]tetraaza[14]annulene reacts with [PdCl2(PhCN)2] to yield the complex (46). 

While the polymorphic forms of carbamazepine all exhibit an anticarboxamide hydrogen-bond dimer motif, the related compounds oxcarbazepine (10-oxo-10,l l-dihydro-5H-dibenzo[fr,/]azepine-5-carboxamide) and dihy-drocarbamazepine (10,ll-dihydro-5H-dibenzo[fc/]azepine-5-carboxamide) adopt hydrogen-bond chain motifs in their crystal structures [47]. The structures of several cocrystals of the structurally related compound cyten amide (5H-dibenzo[fl,d][7]annulene-5-carboxamide) have been reported, with the details of the hydrogen-bonding patterns being discussed [48-51]. 

The diketothiocane 4-thia-l,7-methano[ll]annulene-2,6-dione 10 has been prepared according to Scheme 11 in a simple reaction sequence <2001H(54)159>. It is the starting material for further syntheses of enlarged diketothio-canes as /(-6,15-epithia-8,13-methanobenzo[e][14]annulene-7,14-dione 4 (Equation 6). Both diketothiocanes 10 and 4 have also been transformed into dihydro thiocines by reaction of keto functions (Section 14.03.7). 

Dihydro-l-chlorostibabenzene, 118-119 Dihydrocrytomerione, 489 Dihydrodibcnzotctrazaj 14] annulene, 414 Dihydrodictamnine, 131 Dihydro-3-furanones, 165 Dihydro-a-ionone, 563 Dihydro-0-ionone, 563 Dihydrojasmone, 472... 

The first N solid-state thermometer was based upon the tautomerism of 1,8-dihydro-5,7,12,14-tetramethyldibenzo(b,i)-l, 4,8,11-tetraazacyclotetradeca-4,6, 1 l,13-tetraene N4(tetramethyldibenzotetraaza(14)annulene) (TTAA). The tautomeric structures of TTAA are shown in Fig. 12. Four lines are observed from the four chemically inequivalent nitrogen atoms. The chemical shift differences between nitrogens a/b and c/d are given by ... 

A number of geometrical and valance isomers of the dihydro-octaza-annulene metal complexes have been isolated and characterized. The findings are summarized in Table III. It is noteworthy that different... 

NfN -di(2-aminoethyl)-l, 2-ethanediamine, 1116 diaminopropane NMR, 1116 polymorphism, 1116 1,3-diatyltriazines, 1118 dicarboxylic acids, 1114 antitumor properties, 1114 dicy anobis(2,9-dimethyl-l, 10-phenanthroline), 1117 1,8-dihydro-5,7,12,14-tetramethyldibenzo [b,i -(1,4,8,1 l]tetraaza[14]annulene, 1120... 

The dihydro-derivative (58) of the unique sesquiterpenoid spiniferin-1 (57), which incorporates the novel l,6-methano[10]annulene skeleton, has been synthesized (Scheme 4) and this confirms beyond doubt its precise structure. ... 

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