Cinnoline complexation

To investigate the influence of different diazeno ligands on these reactions, the diazanorbomene and benzo [c] cinnoline complexes 27 and 29 were also reacted with a variety of alkynes. The reactivity of 27 (Fig. 17) is similar to that of 28. The... 

The NMR spectra of cinnoline and its derivatives are complex. The unequivocal assignments are based on the complete iterative analysis of the spectra of a large number... 

Pyrido[2,3-c]cinnolines synthesis, 3, 242, 245 Pyrido[3,2-c]cinnolines synthesis, 3, 242, 245 Pyrido[3,4-c]cinnolines synthesis, 3, 242, 244, 245 Pyrido[4,3-c]cinnolines synthesis, 3, 242, 245 Py rido[ 18]crown-6 t-butylammonium complex... 

The 8-ester group of 7-oxopyrido[3,2,l-t/]cinnoline-8-carboxylates (68, R- + H) was hydrolyzed under basic or acidic conditions. The carboxyl group of68(R = H) was esterified and the carboxyl group was converted to a boron complex (70) by treatment with the boron trifluoride-ether complex (92EUP470578). 

Figure 26 1,2,3,6,7,8-Hexahydrocinnolino[5,4,3-cc/e]cinnoline-based metal complexes.

Iron cyclopentadienyl complexes of 3-(2-chlorophenyl)propanones are cyclized with hydrazine into 1,4-dihydrocinnoline complexes, demetalated with sodium amide to give 3- or 3,4-disubstituted cinnolines (70-80%) (Scheme 29) (88JHC1107). 

As in the case of (cis-diazene)Fe(C0)4 complexes the diazeno ligand disturbs the local symmetry (C4v) in L-M(CO)s and gives rise to four or five v(CO) bands instead of three. The low-energy absorption band of (benzo[c]cinnoline) M(CO)s (M=Cr, Mo, W) was assigned to an rt- -n transition5 ). However, in view of the assignments made for the spectra of LCr(CO)s compounds (L = amines, phosphines)52) this transition may be rather of "d-d" or CTML character. 

In contrast to the pyrazoline and diazanorbornene-Fe2(CO)6 complexes (27,28), the benzo[c]cinnoline compound 29 yields only the cycloadducts 40 and no diazafer-role or double-addition products (Fig. 19). 

Figure 5. CD within the near-UV region of azanaphthalenes after formation of inclusion complexes with B-cyclodextrin. Spectra are shown for (a) quinoline, (b) phthalazine, (c) isoquinoline, and (d) cinnoline (data adapted from reference [38]).

Chloroperoxidase catalysis by, 58, 302 in chlorination of pyrazoles, 57, 337 Chlorophyll, thioaldehyde synthetic intermediate to, 55, 3 Chlorosulfonyl isocyanate, reaction with 2-arylhydrazono-3-oxobutanoate, 59, 148 Chromatography, of [l,2,4]triazolo[l,5-a]-pyrimidines, 57, 106 Chrom-3-enes, see 2//-l-Benzopyrans Chromium tricarbonyl complexes of 3,5-diphenyl-l-(alkyl- or oxido-)-thiabenzenes, 59, 206, 227 indoles, lithiation of, 56, 181, 184 of pyridine, 58, 160 pyridines, lithiation of, 56, 230, 239 of 2f/-thiopyrans, 59, 227 Chromones, see l-Benzopyran-4-ones Cinnamonitrile, a-cyano-, condensations with thio-, seleno-amides, 59, 184, 186 Cinnoline, nitration, MO calculation, 59, 302... 

Related complexes having N—N-bonded bridging groups were isolated from the reactions of iron carbonyls with rigid cw-azo compounds, such as benzo[c]cinnolines (XXXVII) (177), dibenzo-l,4,5-oxadiazepine, 2,3-diazabicyclo[2.2.1]-hept-2-ene, and 4,5,9,10-tetrazapyrene. The latter compound gave a tetranuclear complex [C,2H6N4(Fe(CO)3)4] presumed to... 

Durr et al. have described some novel complex cinnoline derivatives which show photochromic properties. Albini et al. have provided some new evidence on the mechanism for the photoisomerization of heterocyclic N-oxides. Simple pyridine N-oxides are exceptional. Thus irradiation of pyridine N -oxide in aqueous base affords the ring-opened product (23). Aoyama et al. have described the unprecedented photocyclization of the amide (24) to the lactam (25). The first examples of C2a+2Tr] photoreactions of a three-membered ring and an azo-compound have been described by Hunig and Schmitt. Nicolaou et al. have prepared the first stable example of a 1,2-dithiethane the procedure involves (2i +2Tr) photodimerization of C=S groups. 

In the second step the reaction is less efficient because of quenching of the excited state of the diphenylamine component by the adjacent carbazole. Other cyclisations such as the conversion of (41) into (42) by irradiation in acetic acid have also been reported. As mentioned earlier cw-azobenzene derivatives cyclise under conditions where the nitrogens are protonated or complexed. A series of heavily substituted azobenzenes has been shown to undergo photochemical cyclodehydrogenation on irradiation in methylene dichloride solution with added SnCU- The reaction has been shown to be an efficient path to the heavily methylated cinnolines in good yield. 

However, another study by Emerson and Rees found that benzo[c]-cinnoline (1) was reduced more easily than the oxides 4 and 5 thus all three are probably reduced directly to the dihydro compound 6 under these conditions. They also concluded that 2,2 -dinitrobiphenyl (3), the most easily reduced of all, is converted into 2,2 -bis(hydroxylamino)biphenyl (7) in an eight-electron step and thence into 6 [Eq. (2)]. More recent studies by cyclic voltammetry indicate that some steps may be more complex. " It has also... 

Benzo[c]cinnoline forms molecular complexes with halogens in organic solvents thus attempts to brominate it with molecular bromine have been unsuccessful. Using a source of positive bromine, bromine/silver sulfate in sulfuric acid, Corbett and Holt found that reaction occurred at room temperature to give 27% of a monobromo and 4% of a dibromo derivative. These compounds were at first identified as 1-bromo- and l,4-dibromo-(or l,7-dibromo-)benzo[c]cinnolines, but the former was subsequently shown to be the 4 isomer. A reinvestigation of the reaction has shown that both 1- and 4-bromobenzo[c]cinnolines are primary products, formed in the ratio of ca. 2.3 1 at room temperature. The lower isomer ratio as compared with nitration in sulfuric acid probably reflects the greater steric demand of the attacking species. The dibromo compound formed is the 1,4-isomer. The formation of the octachloro derivative by chlorination of benzo[c]cinnoline in the presence of aluminum chloride has been mentioned,but no details are available. 

Like other cyclic compounds having a cis-azo linkage, benzo[c]cinnoline forms fairly stable complexes with many transition metal salts.These all have a 1 1 ligand metal ratio except in the case of palladium(II) chloride, where a 2 1 complex has been isolated.Benzo[c]cinnoline 5-oxide also gives 2 1 complexes with palladium(ll) chloride and with silver nitrate. " A nickel(O) complex, Ni(PEt3)2(benzo[c]cinnoline)2, has been obtained by reaction with biscyclooctadiene nickel and triethylphosphine in hexane. " ... 

The simple carbonyl complexes 89 have recently been prepared indirectly by reactions of benzo[c]cinnoline with norbornadiene metal complexes... 

Reactions of the chloro compounds with lithium dimethylamide are complicated by the fact that nucleophilic displacement of hydrogen often precedes that of chlorine, giving complex mixtures of products. - The results obtained in reactions of potassium amide with chloro- and iodobenzo[ -]cin-nolines show that elimination-addition processes via arynes 93 and 94 are more important than direct nucleophilic displacement (addition-elimina-tion), Surprisingly, no l-aminobenzo[c]cinnoline is formed from the 1-and 2-halogeno compounds, while 4-chlorobenzo[c]dnnoline gives small amounts of 2-aminobenzo[c]cinnoline by a 1,3-displacement. 

Benzo[c]cinnoline (114) (3%) was separated from a complex mixture of colored products obtained from the oxidation of 9 with active manganese dioxide formation of 114 suggests the stepwise loss of nitrogen, 10- 113-+ 1, and 1,4-dipolar cycloaddition of benzyne to 113.16 Oxidation of 9 with (diacetoxyiodo)benzene gave azobenzene (4%), 1-phenylbenzotriazole (112)... 

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