RESEARCHES ON QUINAZOLINES (THIRTIETH PAPER). A STUDY OF THE BROMINATION AND NITRATION OF 4-QUINAZOLONES; THE CORRESPONDING AMINOQUINAZOLONES, AND CERTAIN OTHER NEW 4-QUINAZOLONES.¹

Abstract

The 4-quinazoloaes (4-hydroxpquinazolines) are not easily brominated by the action of bromine in aqueous potassium bromide solution, in glacial acetic acid or in acetic anhydride solution. By employing the Juvalta* process, however, the halogen may be introduced. I n this way, monobromo derivatives have been obtained of 4-quinazolone and of 2-methyl-4-quinazolone. Griess,3 in 1869, showed that benzoylene urea could be nitrated, but did not prove the position of the nitro group. In 1890, Dehoff4 nitrated a-methyl and a,3-dimethyl-4-quinazolone, and his products were subsequently shown to be the 6-nitro derivatives by the investigations of Thieme3 and of Bogert and Cook.B According to our experience, the satisfactory nitration of 4-quinazolones requires a high temperature and the use of a mixture of fuming nitric and concentrated sulfuric acids, and but one nitro group can thus be introduced on the 4-quinazolone nucleus. Position 6 seems to be the point where the nitro group enters most readily. Of course, aryl Nor are the quinazolones readily nitrated.

Synthesis and fastness properties of styryl and azo disperse dyes derived from 6‐nitro substituted 3‐aryl‐2‐methyl‐4(3H)‐quinazolinone

“…The introduction of the nitro group into 3-aryl-2-methyl-4(3H)-quinazolinones inevitably involves a nitration reaction. According to the literature, however, nitration of the aryl ring of 3-aryl-2-methyl-4(3H)-quinazolinones is also a possibility [25]. For convenience, 5-nitroanthranilic acid 3 was therefore our preferred starting point (Scheme 2).…”

Combinatorial synthesis of labelled drugs and PET tracers: synthesis of a focused library of 11C‐carbonyl‐labelled acrylamides as potential biomarkers of EGFR expression

“…The syntheses of the precursors were performed by previously described procedures with minor modifications. Briefly, the 4‐anilino‐6‐amino‐quinazolines 5a–c were synthesised starting from anthranilic acid and formamide to give the quinazolinone 1 (Scheme ), which was nitrated in the 6‐position to form 2 . Deoxychlorination was accomplished using thionyl chloride, and different anilines were reacted with 3 to give the 4‐anilino‐6‐nitro‐quinazolines 4a–c .…”

“…Briefly, the 4-anilino-6-amino-quinazolines 5a-c were synthesised starting from anthranilic acid and formamide to give the quinazolinone 1 (Scheme 1), which was nitrated in the 6-position to form 2. 41 Deoxychlorination was accomplished using thionyl chloride, and different anilines were reacted with 3 to give the 4-anilino-6-nitroquinazolines 4a-c. Finally, the nitro group was reduced using iron and acetic acid to yield the nucleophile precursors 4-anilino-6amino-quinazolines 5a-c (Scheme 1).…”

Access to Original Vinylic Chlorides in the Quinazoline Series via a Monoelectronic Transfer Reaction Approach

“…TLC was performed on 5 cm × 10 cm aluminium plates coated with silica gel 60F-254 (Merck) in appropriate solvent. The following substrates or subproducts were prepared and described previously: 4-chloro-2-trichloromethyl-quinazoline ( 1 ) [9,12], N -butyl-2-trichloromethylquinazolin-4-amine ( 3 ) [13], 2,3-dimethyl-2,3-dinitrobutane ( 7 ) [14], 1-nitro-1-(1-nitrocyclopentyl)cyclopentane ( 9 ) [15], 1-nitro-1-(1-nitrocyclo-hexyl)cyclohexane ( 11 ) [16], 2-methyl-6-nitroquinazolin-4(3 H )one ( 16 ) [17], 4-chloro-6-nitro-2-trichloromethylquinazoline ( 17 ) [18], and 6-nitro-2-trichloromethylquinazolin-4( 3H )-one ( 20 ) [18]. …”