Convenient two-step synthesis of 4-(2-imidazolyl)phthalazones from o-phthaloyl dichloride

Johnson, Alexander L.

doi:10.1021/jo00867a019

Cited by 16 publications

(6 citation statements)

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“…Heating (4 h) it in acetic acid solution in the presence of hydrochloric acid led predominantly to oxidation and the formation of the dimer 6, but not to the opening of the isoquinoline ring at the C(11)-N(12), similarly to other condensed derivatives of 3-aminoisoquinolin-1-one [13]. Compound 3 also appears to be unstable to heating (2 h) in the presence of bases (MeONa, i-PrONa), which leads to its destruction.…”

mentioning

confidence: 97%

Condensed isoquinolines 27*. Synthesis and oxidation reactions of 5,13-dihydro-11H-isoquino[3,2-b]quinazolin-11-one

Потиха

Gutsul

Туров

et al. 2008

Chem Heterocycl Comp

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Keywords: 2-aminobenzylamine, [6,6′]bi[isoquino[3,2-b]quinazoline], dibenzo[b,f][1,8]naphthyridine, isoquino[3,2-b]quinazoline, 2-(cyanomethyl)benzoic acid, oxidation, rearrangement.2-(Cyanomethyl)benzoic acid (1) on condensation with benzylamine [2], aniline [3], and substituted anilines [4] behaves as 1,5-dielectrophilic synthon and gives derivatives of 3-aminoisocarbostyrene. On interaction with anthranilic acid or its esters acid 1 behaves as a monofunctional compound to give derivatives of 2-[(3,4-dihydro-4-oxo-2-quinazolinyl)methyl]benzoic acid [5].In the present work we have investigated the condensation of acid 1 with 2-aminobenzylamine (2). This reaction was studied previously [6, 7], but the structure of the condensation product -5,13-dihydro-11H-isoquino[3,2-b]quinazolin-11-one (3) was not shown conclusively.We have found that compound 3 can be obtained in higher yield (82%) by boiling the reagents in butanol for 5 h than by carrying out the reaction in anyl (6 h, 68% yield [6, 7]. Prolongation the reaction is considerably decreased by using DMF (2 h) as the solvent and the reaction product does not require further purification. However, as a result of unexpected oxidation, the yield of compound 3 in the last case was considerably reduced (<50%).The reaction of 2-(cyanomethyl)benzoic acid with 2-aminobenzylamine may lead to condensation products with either an angular structure -5,6-dihydro-12H-isoquino[2,3-a]quinazolin-12-one (4) or a linear structure -5,13-dihydro-11H-isoquino[3,2-b]quinazolin-11-one (3). It is not possible using IR and 1 H NMR spectra to determine unequivocally the structures of 3 and 4, it can only be said that an enamine structure is present: ν NH 3250 cm -1 , δ NH 9.72 (s) and δ =CH 5.85 ppm (s). In addition the absence of coupling between the protons of the amino and methylene groups (5.06 ppm, 2H, s) indicates the formation of compound 3. _______ * For Communication 26 see [1].

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confidence: 97%

Condensed isoquinolines 27*. Synthesis and oxidation reactions of 5,13-dihydro-11H-isoquino[3,2-b]quinazolin-11-one

Потиха

Gutsul

Туров

et al. 2008

Chem Heterocycl Comp

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“…The heterocycle in 3-aminoisocarbostyryl isoquinolines undergoes opening upon heating with base or under acid hydrolysis conditions [17,20,21]. We have found that products 2, 3, and 5 are stable upon heating in 2 N ethanolic NaOH, while heating these products in 2 N hydrochloric acid gives a mixture of homophthalic acid 8 and the hydrochloride of the corresponding alkylamine or hetarylamine as shown by elemental analysis and NMR spectroscopy.…”

Section: A R = Pyrid-2-ylmethyl B R = 3-methyl-1н-pyrazol-5-ylmentioning

confidence: 86%

3-(Hetarylamino)- and 3-[(hetarylmethyl)amino]-isoquinolin-1(2H)-ones

Потиха

Gutsul

Ковтуненко

et al. 2010

Chem Heterocycl Comp

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“…In the present work, 4-(1H-benzimidazol-2-yl)phthalazin-1(2H)-one (1), required as a starting material, was conveniently prepared by the ring opening of benzimidazo[1,2-b]isoquinoline-5,12-dione with hydrazine hydrate. 11 This with POCl 3 /PCl 5 on a steam bath gave 4-(1H-benzimidazol-2-yl)-1-chlorophthalazine (2) in good yield. On heating with ethanolic hydrazine hydrate, 2 gave the [4-(1H-benzimidazol-2-yl)phthalazin-1-yl]hydrazine (3) which was used as a key intermediate for the synthesis of the title compounds (Scheme 1).…”

mentioning

confidence: 99%

Fused Heterocycles. Part I. Synthesis of Some Annelated 1,2,4-Triazole Systems from [4-(1H-Benzimidazol-2-yl)-Phthalazin-1-Yl]Hydrazine

Wasfy

2003

Journal of Chemical Research

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Substituted 6-(1 H-benzimidazol-2-yl)-[1,2,4]triazolo[3,4- a]phthalazine derivatives containing alkyl, aryl, hydroxyl, mercapto, methylthio and formyl substituents at position 3 have been synthesised. Di-[6-(1 H-benzimidazol-2-yl)-3-[1,2,4]triazolo[3,4- a]phthalazin-3-yl]alkanes have been obtained by the use of dicarboxylic acids or their esters in the above condensations. Methylation reactions of the triazolo-phthalazine system are reported.

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Convenient two-step synthesis of 4-(2-imidazolyl)phthalazones from o-phthaloyl dichloride

Cited by 16 publications

References 1 publication

Condensed isoquinolines 27*. Synthesis and oxidation reactions of 5,13-dihydro-11H-isoquino[3,2-b]quinazolin-11-one

Condensed isoquinolines 27*. Synthesis and oxidation reactions of 5,13-dihydro-11H-isoquino[3,2-b]quinazolin-11-one

3-(Hetarylamino)- and 3-[(hetarylmethyl)amino]-isoquinolin-1(2H)-ones

Fused Heterocycles. Part I. Synthesis of Some Annelated 1,2,4-Triazole Systems from [4-(1H-Benzimidazol-2-yl)-Phthalazin-1-Yl]Hydrazine

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