Quinazolines

Tricyclic Quinazoline Alkaloids Conjugated to Ferrocene: Synthesis, Structure, and Redox Behavior of Ferrocenylmethylene‐Substituted 7H‐Deoxyvasicinones

“…[32] Subsequent treatment with ferrocenecarbaldehyde (7) under basic reaction conditions afforded (E)-3-(ferrocenylmethylene)deoxyvasicinone (8) as the first representative of its class in 74 % yield as a dark-red solid. Intermediate 9 was not observed (Scheme 2).…”

“…Deoxyvasicinone [1; 2,3-trimethylene-4-quinazolone, 2,3-dihydropyrrolo[2,1-b]quinazolin-9(1H)-one; Scheme 1] is a tricyclic quinazoline alkaloid [30][31][32] with a five-membered ring annellated at the quinazoline entity, which has been isolated from the roots of the Indian species Adhatoda vasica [33] and from the seeds of Peganum harmala. [34] Its biosynthesis as well as some chemical syntheses start from anthranilic acid.…”

“…The crude product was purified by column chromatography ( Crystal Structure Analysis of 15: [37] Single crystals of 15 were obtained by slow evaporation of ethanol. C 25 [32] (1; 0.372 g, 2.0 mmol) were added to sodium hydroxide (0.040 g, 1.0 mmol) in ethanol (5 mL). The mixture was heated at reflux for 7 h and then allowed to stand at 25°C for 1 h. After addition of water (10 mL), the mixture was stirred at 25°C for 1 h and the formed precipitate was filtered off, washed with water (3 × 10 mL), and dried at 25°C in air.…”

“…After recrystallization from ethanol, 6 (0.460 g, 1. [32] (1; 0.372 g, 2.0 mmol) and ferrocenecarbaldehyde (7; 0.428 g, 2.0 mmol) were added to sodium hydroxide (0.080 g, 2.0 mmol) in ethanol (5 mL). After stirring at reflux for 6 h and standing for 14 h at 25°C, water (15 mL) was added and the mixture was stirred at 25°C for 1 h. The formed precipitate was filtered off, washed with water (3 × 10 mL) and dried at 25°C in air.…”

(E)-3-Propoxymethylidene-2,3-dihydro-1H-pyrrolo[2,1-b]quinazolin-9-one monohydrate

“…For the synthesis of the title compound and its derivatives, see: Spä th & Platzer, (1935); Shakhidoyatov et al (1976); Oripov et al (1979); Elmuradov et al (2006) ;Elmuradov & Shakhidoyatov (2004); Jahng et al (2008). For the physiological activity of the title compound and its derivatives, see: Amin & Mehta (1959); Chatterjee & Ganguly (1968); Yakhontov et al (1977); Yunusov et al (1978); Johne (1981) ;Shakhidoyatov (1988).…”