Re-examination of the Synthesis of 3,5-Dimethoxy-2-nitrobenzaldehyde

Blanco, M. Mar; Avendaño, Carmen; Cabezas, Nieves; Menéndez, J. Carlos

doi:10.1080/00397919308011222

Cited by 5 publications

(4 citation statements)

References 6 publications

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“…[5] except for a broad absorption at δ 5.40, which was not found in the material described in this work. Furthermore, the 13 C NMR spectrum also matched well with that described, but the reported absorption for the aldehyde carbon (δ 191.73) was not observed in our material. An absorption at δ 152.58, not reported by Blanco, et.…”

Section: Resultssupporting

confidence: 90%

“…The δ 9.09 absorption is assignable to H-3, and is found in all of the 3-unsubstituted anthranils (δ 8.8-9.2) that we and others [8] have studied. In addition, the δ 152.58 absorption is due to C-3 and is also present in the 13 C spectra of the 3-unsubstituted anthranil derivaties (δ 152.0-155.2) that we and Kim, et. al.…”

Section: Resultssupporting

confidence: 60%

“…Whereas 9a also exists predominantly in the cyclic form ( > 95 %) in solution and in the solid state, the 1 H NMR (DMSO) spectrum of the dimethoxy compound 9b shows that it is a 2:3 mixture of the cyclic and open chain forms 9b and 10, respectively. Both forms are also clearly recognizable in the 13 C NMR spectrum (see experimental section). In CD 3 CN solution, equal amounts of the two forms are present at room temperature, but the aldehyde form is favored over the cyclic form (3:2) at 330 ºK.…”

Section: Resultsmentioning

confidence: 78%

“…al. [13] was complicated by the formation of polynitration products such as 18. In contrast, when this nitration was effected at ice-bath temperature, the reaction was essentially complete in 10 min, gave a 6:1 mixture of 4b and 17 from which 4b could be isolated in nearly 70 % yield (Entry 7).…”

Section: Resultsmentioning

confidence: 99%

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o-Hydroxylaminobenzaldehydes and the N-Acylated Derivatives Thereof

Muchowski,

Maddox

2020

J. Mex. Chem. Soc.

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Abstract. Ethyl acetate solutions of o-hydroxylaminobenzaldehydes (1a, 8c, 8d) can be generated by reduction of the corresponding nitrocompounds with zinc and ammonium chloride in a two phase ethylacetate-water system at room temperature, but 2-nitro-3,6 dimethoxybenzaldeyhde (4b) is converted into the anthranil 11 under these conditions. The N-acylated compounds derived from 1a and 8c exist exclusively as the cyclic tautomers (6a-c and 9a) in solution and inthe solid state, whereas the N-acetyl compound 9b is in equilibriumwith the open chain form 10 in solution, but only the cyclic form ispresent in the solid state. The N-acylated-o-hydroxylaminobenzaldehydes undergo a novel internal redox reaction on thermolysis generating o-acylaminobenzoic acids which are converted into 2-substituted-4H-3,1-benzoxazin-4-ones (e.g., 6b→12b→13b) to a greater or lesser extent under the reaction conditions.Resumen. Soluciones de o-hidroxilaminobenzaldehídos (1a, 8c, 8d)en acetato de etilo se pueden generar por medio de la reducción delcorrespondiente compuesto nitro con zinc y cloruro de amonio en unsistema bifásico de acetato de etilo-agua a temperatura ambiente, sinembargo, el 2-nitro-3,6-dimetoxibenz-aldehido (4b) se convierte en elantralino 11 bajo estas condiciones. Los compuestos N-aciladosderivados de 1a y 8c existen exclusivamente como los tautómeroscíclicos (6a-c y 9a) en solución y en el estado sólido, mientras que elcompuesto N-acetilo 9b esta en equilibrio con la forma abierta 10 ensolución, pero solo la forma cíclica está presente en el estado sólido.Los N-acilados o-hidroxil- aminobenzaldehídos sufren una nuevareacción oxidoreductiva interna bajo termólisis generando ácidos oacilaminobenzóicos los cuales son convertidos en 2-substituidos-4H-3,1-benzoxazin-4-onas (e.g., 6b→12b→13b) en mayor o menorgrado, bajo las condiciones de reacción.

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Section: Resultssupporting

confidence: 90%

Section: Resultssupporting

confidence: 60%

Section: Resultsmentioning

confidence: 78%

Section: Resultsmentioning

confidence: 99%

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o-Hydroxylaminobenzaldehydes and the N-Acylated Derivatives Thereof

Muchowski,

Maddox

2020

J. Mex. Chem. Soc.

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ChemInform Abstract: Re‐Examination of the Synthesis of 3,6‐Dimethoxy‐2‐nitrobenzaldehyde.

et al. 1994

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Highly Soluble and Green Indigo Dyes: 4,4′,7,7′‐Tetraalkoxy‐5,5′‐diaminoindigotins

Voß

Gradzielski²,

Heınze

et al. 2003

Helvetica Chimica Acta

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Dedicated to the 70th birthday of Prof. Dr. emeritus Hans GerlachTwo new types of 4,4',7,7'-tetraalkoxyindigotins, 1a ± f and 2a ± f along with the new N-substituted indigotins 4e ± f, were synthesized from dinitrobenzaldehydes 5a ± f, which were prepared from 2-hydroxy-5-methoxybenzaldehyde (7) via dialkoxybenzaldehydes 6a ± f (Scheme). The new dialkoxyindigotin 3g was obtained from dialkoxybenzaldehyde 6g via nitrobenzaldehyde 8g. The 1,4-dialkoxy-2,3-dinitrobenzenes 9 were isolated as byproducts. The 4,4',7,7'-tetraalkoxy-5,5'-diaminoindigotins 1 are soluble in organic solvents, and their solutions are green, which is highly uncommon for indigotins and is primarily caused by electronic effects of substituents, steric effects playing a minor role. The indigotins 1 produce a strong red shift of the longest-wavelength absorption and negative solvatochromism indicating the predominance of polar resonance structures in the ground state. Tautomeric structures were excluded. These indigotins are valuable compounds for technical applications, for synthetic purposes, and for analytical studies. SANS (Small-angle neutron scattering) experiments showed that certain 4,4',7,7'-tetraalkoxy-5,5'-diaminoindigotins 1 form rod-like aggregates in solution. The similarly substituted 4,4',7,7'-tetraalkoxy-5,5'-dinitroindigotins 2 are far less soluble. They produce red monoanions (preferably dimers) and bluish-purple dianions in organic solvents.

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Re-examination of the Synthesis of 3,5-Dimethoxy-2-nitrobenzaldehyde

Cited by 5 publications

References 6 publications

o-Hydroxylaminobenzaldehydes and the N-Acylated Derivatives Thereof

o-Hydroxylaminobenzaldehydes and the N-Acylated Derivatives Thereof

ChemInform Abstract: Re‐Examination of the Synthesis of 3,6‐Dimethoxy‐2‐nitrobenzaldehyde.

Highly Soluble and Green Indigo Dyes: 4,4′,7,7′‐Tetraalkoxy‐5,5′‐diaminoindigotins

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