2‐Amino‐1,4‐naphthochinone und 4‐Amino‐1,2‐naphthochinone als Nucleophile ‐ ein Vergleich

Abstract

Vor einiger Bit') konnten wir zeigen, daD 4-Amino-1,2-naphthochinon (1; Schema 3) entsprechend seiner Funktion als Quasi-Enamin unter Aminoalkylierungsbedingungen zu Salzen von C-Munnich-Basen fuhrt.Beim Einsatz der vergleichsweise fomal inversen Enamin-Struktur im 2-Amino-1.4-naphthochinon (2) ergab der Umsatz mit Methyleniminiumsalzen in Acetonitril ein unerwartetes Ergebnis. Bei genauer Reaktionskontrolle fie1 hier die rasche Bildung von primiiren Aminoalkylierungsprodukten 3.HX -6.HX auf, wobei je nach Reaktionsdauer, z.T. noch in der Acetonitrilliisung, eine Umlagerung in die

One-Pot Synthesis of Spiro-isobenzofuran Compounds via the Sequential Condensation/Oxidation Reaction of Ninhydrin with 4-Amino-1,2-naphthoquinones/2-Amino-1,4-naphthoquinones under Mild Conditions

“…Mechanistically, based on the well-known chemistry of ninhydrin as a cyclic polyketone 30 and due to the potential 1,3-binucleophilic nature of enaminones such as 4-(alkyl/arylamino)naphthalene-1,2-diones ( 1 ), 31 one would expect the formation of 6b,11b-dihydroxybenzo[ g ]indeno[1,2- b ]indole ( A ) ( Scheme 3 ) from the condensation reaction of ninhydrin with enaminones ( 1 ). To prove this claim, the diol intermediates A for products 2b and 4e were randomly isolated and their structures were characterized based on their spectroscopic data.…”

Aminonaphthoquinones in heterocyclization

“…For instance, the intramolecular N ‐acylation of some aminoquinones has required their prior reduction to the more basic aminonaphthohydroquinone derivatives [48, 49]. Lately, 2‐amino‐1,4‐naphthoquinone (55) has been shown to have some reactivity with some electrophiles such as β‐dielectrophiles [50], and methyleniminium salts (Fig. 5) [50].…”

“…Lately, 2‐amino‐1,4‐naphthoquinone (55) has been shown to have some reactivity with some electrophiles such as β‐dielectrophiles [50], and methyleniminium salts (Fig. 5) [50]. In these reactions, the principal product was found to be that of N ‐alkylation.…”

“…2‐Amino‐1,4‐naphthoquinone ( 55 ) behaves as a bidentate nucleophile with primary amines and formaldehyde to give 3‐substituted 1,2,3,4‐terahydrobenzo[ g ]chinazoline‐5,10‐diones 102 in poor to moderate yields (Scheme ) [50].…”

A new and efficient procedure for the synthesis of hexahydropyrimidine-fused 1,4-naphthoquinones

“…Some of them are restrictive, troublesome and produce the hexahydropyrimidine-1,4-naphthoquinones in low yields. Möhrle and Herbruggen synthesized unsymmetrical hexahydropyrimidine-fused 1,2- and 1,4-naphthoquinones by the reaction of 4-amino-l,2-naphthoquinone and 2-amino-1,4-naphthoquinone with amines and formaldehyde in moderate yields [ 37 ]. Ohta et al studied the nucleophilic addition reaction of methylamine to 2-bromo-3-hydroxymethyl-1,4-naphthoquinone ( 1 ) and obtained hexahydropyrimidine-fused 1,4-naphthoquinone ( 5 ) as side product ( Scheme 1 ) [ 38 – 39 ].…”