7- -cinnolinone

On reduction with LAH, cinnolines generally yield di- and tetrahydro derivatives. The LAH reduction of 5,6,7,8-tetrahydro-3-cinnolinones (304) in THF leads to mixtures of the dihydrocinnolines 305, the decahydro cinnolines 306 and the deoxygenated tetrahydrocinnolines 307. The ratio of products is dependent on the substituents and the amount of LAH used. ... [Pg.51]

There is a discrepancy in the literature concerning 4-hydroxy-cinnoline. Whereas two measurements of pKa values indicate that the cinnolinone structure predominates by a large factor in aqueous solution (see Table III), comparison of the ultraviolet spectra of 4-hy-... [Pg.365]

Quinolin-4-one forms a 3-bromo derivative, but coumarin gives the addition compound (116) which is easily re-aromatized (116 — 117). 4-Thiopyrones are halogenated in position 3. Pyridazinones and cinnolinones are also readily halogenated in the expected position. [Pg.191]

Cinnolinone, 763 Cyclohepta[6]furan-5-one, 1107 Cyclohepia(/>]furan-8-one, 899 Cyclohepta[c)pyrazole, 807 Cyclohepta[c)pyrazol-8-one, 1268 Cycloheptale pyrazolo 1,5-a Ipyrimidine,... [Pg.769]

Alkylation of 3-ethoxycarbonyl-4( 1//)-cinnolinones by alkyl iodides or dialkyl sulfates with potassium carbonate in DMF gives a mixture of the 3-ethoxycarbonyl-l-alkyl-4(l//)-cinnolinones along with the anhydro bases formed by alkylation of N-2. The latter compounds undergo hydrolysis and decarboxylation in acid <89CPB93). [Pg.27]

The role of carbonyl compounds is dominant in the chemistry of dihydro derivatives of pyridazines. Dihydro-3 (2/ -pyridazinone derivatives are more stable than the corresponding simple dihydropyridazine derivatives and constitute the majority of dihydro compounds reported. The analogous derivatives are of course not possible in the phthalazine and cinnoline series, though 1,4-dihydro-3 (2/ -cinnolinones are known. [Pg.35]

When reviewed in CHEC-I some examples of cyclization y to the heteroatom had been described for the synthesis of pyridazines, but the method was of most importance in the synthesis of cinnolines. Examples of pyridazine syntheses included cyclization of ketazines with EDA, and intramolecular Wittig reactions of phosphoranes derived from phosphacumuleneneylides and the hydrazones produced from 1,3-dicarbonyl compounds and aryldiazonium salts. Synthetically useful approaches to cinnolines given include the intramolecular Friedel-Crafts acylation of the diacid chlorides derived from the condensation products of aryldiazonium salts and diethyl malonate to give 4(l//)-cinnolinones, and thermal cyclization of iminium hydrazones obtained from enamine esters and aryldiazonium salts. [Pg.65]

This approach was described in CHEC-I as of importance only for the synthesis of cinnolines <84CHEC-i(3B)i>. Most of the examples given involve the insertion of nitrogen as the sixth atom by diazotization of o-aminophenyl derivatives, in which the ortho substituent is generally an alkene, alkyne, or enolisable ketone. Another example is the synthesis of 3-substituted-4(l//)-cinnolinones via diazotisation of o-aminophenylalkynes (Scheme 90) the precursor is readily made by palladium and copper iodide catalysis <89H(29)1255>. [Pg.66]

Ethyl-1 -methoxycarbonylmethyl-2-(o-propylphenylhydrazono)cyclohexane (23) (prepared in situ) gave 4a-ethyl-2-(o-propylphenylhydrazono)-4,4a,5, 6,7,8-hexahydro-3(2f/)-cinnolinone (24) (20% H2SO4, reflux, 30 min 26% after separation from another product) analogs likewise. ... [Pg.5]

In contrast, the same substrate (93) under less gentle conditions gave only 3-phenyl-4(lH)-cinnolinone (95), presumably via the initial product (94, X = Cl) (36% HCl, NaNOji slowly, 0°C, 2h then reflux, 1 h 82%). l-(o-Aminophenyl)-2-trimethylsilylacatylene (96) gave 4(l//)-cinnolinone (97) (6M HCl, NaN02i slowly, <0°C, 30 min then reflux, 3h 73%). ... [Pg.15]

Trimethyl-6-phenacyl-l,4-benzoquinone (98) gave 5,7,8-trimethyl-3-phenyl-6(2//)-cinnolinone (99) (H2NNH2 H2O, trace AcOH, PhMe, 20°C,... [Pg.15]

Ethoxycarbonylmethyl)cyclohexane (100) gave 4,4a,5,6,7,8-hexahydro-3 (27/)-cmnolinone (101) (H2NNH2 H2O, EtOH, reflux, 1 h 72%) and thence 5,6,7,8-tetrahydro-3(2f/)-cinnolinone (102) (CuCl2, MeCN, reflux, 1 h 87%) minor variations in the foregoing reaction produced lower yields. ... [Pg.16]

In contrast, 2-(a-carboxy-a-morpholinomethyl)cyclohexanone, as its morpholi-nium salt (103), gave 5,6,7,8-tetrahydro-3(2/i)-cinnolinone (102) directly oxidation was provided by spontaneous loss of morpholine (H2NNH2 H2O,... [Pg.16]

Phenacyl-l,3-cyclohexanedione (106) gave 3-phenyl-4,6,7,8-tetrahydro-5(lfl)-cinnolinone (107 unisolated) and thence 3-phenyl-5,6,7,8-tetrahydro-5-cin-nolinone (108) by oxidation (H2NNH2, EtOH, 20°C, 30 min then dichloro-... [Pg.16]

Carboxymethyl-5-phenylcyclohex-5-enone (109) gave 7-phenyl-4,4a,5,6-tet-rahydro-3(2//)-cinnolmone (110, R = H) (neat H2NNH2-H20, reflux, 4h 92%) or 2-methyl-7-phenyl-4,4a,5,6-tetrahydro-3(27/)-cinnolinone (110, R = Me) (H2NNHMe, EtOH, reflux, 16 h 65%) analogs likewise. ... [Pg.17]

Dimethyl-l,3-cyclohexanedione (dimidone, 145) and ethyl 2-(/7-tolylhydra-zono)acetoacetate (146) gave ethyl 4,7,7-trimethyl-5-oxo-l-p-tolyl-l,5,6,7-tetrahydro-3-cinnohnecarboxylate (147) (neat AcONEU, 170°C, 30 min 80%) " the same substrate (145) and benzil monohydrazone (148) gave 7,7-dimethyl-3,4-diphenyl-6,7-dihydro-5(l//)-cinnolinone (149) (or tauto-... [Pg.22]

Acetyl-1,4,4-triphenyl-l,2-diazetidin-3-one (162) rearranged into 2-acetyl-4,4-diphenyl-l,4-dihydro-3(2ff)-cinnolinone (163) (neat F3CCO2H >95% ... [Pg.24]

Tetrahydro-l-benzazocine-2,6(l/i)-dione (168) gave 3-(2-carboxyethyl)-4(l//)-cinnolinone (169) (MeOCHzCHzOMe, trace HjO, BuONO, HCl gasi, 25 C, 5 min then stirred, 25°C, 12 h then suspension of crude diazonium intermediate, lOO C, 5 min 61%) a dozen analogs, substimted in the phenyl... [Pg.25]

Acetoxy-2-methyl-2,3,4,5,6,7-hexahydrobenzofuran-3-one (170) with hydrazine gave 3-methyl-5,6,7,8-tetrahydro-4(l//)-cinnolinone (171) (EtOH, 20°C, 12 h 85%) or with methylhydrazine gave a separable mixture of 1,3-dimethyl-5,6,7,8-tetrahydro-4(17/)-cinnolinone (172) and 2,3-dimethyl-5,6, 7,8-tetrahydrocinnolin-2-ium-4-olate (173) (EtOH, 0°C 20°C, 12 h 67% and 15%, respectively) the related substrate, 2-methoxy-2-methyl-... [Pg.25]

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