N-Alkylation and Aminohydroxylation of 2-Azidobenzenesulfonamide Gives a Pyrrolobenzothiadiazepine Precursor Whereas Attempted N-Alkylation of 2-Azidobenzamide Gives Benzotriazinones and Quinazolinones

Abstract

N-Alkylation of 2-azidobenzenesulfonamide with 5-bromopent-1-ene gave an N -pentenyl sulfonamide, which underwent intramolecular aminohydroxylation to give an N -(2-azidoaryl)sulfonyl prolinol, a precursor for the synthesis of a pyrrolobenzothiadiazepine. The attempted N-alkylation of 2-azidobenzamide gave a separable mixture (∼1:1) of a benzotriazinone and a quinazolinone in a 72% combined yield. Other primary alkyl halides (3 examples) gave similar mixtures of benzotriazinones and quinazolinones. Benzylic, allylic, and secondary and tertiary alkyl halides (5 examples) gave only benzotriazinones in moderate yields. The results of mechanistic studies show the likely involvement of nitrene intermediates in the quinazolinone pathway and a second pathway involving a dimethylsulfoxide or dimethylsulfide-mediated conversion of 2-azidobenzamide into benzotriazinones.

The PIFA-initiated oxidative cyclization of 2-(3-butenyl)quinazolin-4(3H)-ones – an efficient approach to 1-(hydroxymethyl)-2,3-dihydropyrrolo[1,2-a]quinazolin-5(1H)-ones

“…2-(But-3-en-1-yl)quinazolin-4(3 H )-one (7a) [ 59 ]: Prepared using amide 10a (218 mg, 1 mmol, 1 equiv). Light brown powder (142 mg, 0.71 mmol, 71%).…”

Visible‐Light‐Enabled Selective Oxidation of Primary Alcohols through Hydrogen‐Atom Transfer and its Application in the Synthesis of Quinazolinones

“…When the reaction was completed, The crude reaction mixture was purified by flash chromatography on silica gel, employing N-hexane/EtOAc (10 : 1) as the eluent gel to afford the product 4 h' in 65% yield (1.408 g). [28] Toluene (1 mL) were addedto the mixture of 3 I (0.2 mmol), 2 c (0.2 mmol), eosin Y (0.002 mmol) and PTSA (0.08 mmol), in a 25 mL sealed quartz tube with an N 2 balloon, then the reaction mixture was stirred for 24 h at room temperature (~25°C) under visible light irradiation from a Xe lamp with a 400 nm of cut-off filter (400-780 nm). When the reaction was completed, the crude reaction mixture was purified by flash chromatography on silica gel, employing n-hexane/ethyl acetate (8 : 1) as the eluent gel to afford the product M-4-1.…”

Alkaloids with Nitric Oxide Inhibitory Activities from the Roots of Isatis tinctoria

“…As our ongoing phytochemical and pharmacological research project on this plant [8,9,10,11,12], four new alkaloids and four new natural products, along with 15 known analogues, were obtained, and their structures and absolute configurations were determined by extensive spectroscopic data analysis, including one-dimensional and two-dimensional-NMR, HRESIMS, and IR, specific rotation data, and electronic circular dichroism (ECD) experiments. The known compounds ( 4 – 22 , Figure 1) were identified by comparison of their spectroscopic and optical rotation data with those in the reported literature as 4- p -hydroxyphenyl-2(1 H )-quinolinone ( 4 ) [13], 2-(1 H -indol-2-yl)-6-methoxy-4(3 H )-quinazolinone ( 5 ) [14], 2-(2-hydroxyphenyl)-4(3 H )-quinazolinone ( 6 ) [15], 2-(but-3-en-1-yl)-4(3 H )-quinazolinone ( 7 ) [16], 2-(1 H -indol-2-yl)-4(3 H )-quinolinone ( 8 ) [17], tryptanthrin ( 9 ) [18], 3-(2,4-dioxo-1,2- dihydroquinazolin-3(4 H )-yl)propanoic acid ( 10 ) [19], indiforine C ( 11 ) [3], 4-(2,4-dioxo-1,2- dihydroquinazolin-3(4 H )-yl)butanoic acid ( 12 ) [20], methyl 4-(2,4-dioxo-1,2-dihydroquinazolin- 3(4 H )-yl)butanoate ( 13 ) [21], 3-(2-hydroxyphenyl)-4(3 H )-quinazolinone ( 14 ) [22], 3-(2-carboxyphenyl)-4(3 H )-quinazolinone ( 15 ) [23], 4-methyl-1,2-dihydro-2-oxoquinazoline ( 16 ) [24], 2-methyl-4(3 H )-quinazolinone ( 17 ) [25], 4-hydroxy-3-methyl-2(1 H )-quinolinone ( 18 ) [26], 2-amino-4-quinolinecarboxylic acid ( 19 ) [27], 4(1 H )-quinolinone ( 20 ) [28], 4(1 H )-quinolone-3- carboxylic acid ( 21 ) [29], and 1,2,3,4-tetrahydro-4-hydroxy-quinolinecarboxylic acid ( 22 ) [30]. The NO inhibitory activities of the isolates ( 1 – 23 ) were also evaluated against the LPS-stimulated RAW264.7 macrophages.…”