Ring forming reactions of imines of 2-aminobenzaldehyde and related compounds

Abstract

By addition of organometallic reagents to 2-aminobenzonitriles followed by quenching with suitable electrophiles (acyl halides, aldehydes and ketones), several types of 6-membered benzofused aromatic and non-aromatic nitrogen heterocycles could be obtained. Rearrangements leading to 1,2-dihydro-3H-1,4-benzodiazepin-3-ones and preparation of various quinazolines are described.

An efficient and facile ultrasonic‐accelerated one‐pot synthesis of N‐acetyl‐2‐aryl‐1, 2‐dihydro‐(4H)‐3,1‐benzoxazin‐4‐ones

“…As part of our ongoing research on the application of ultrasonic irradiation technique as a clean and useful protocol in organic synthesis 36 and also regarding the lack of sufficient reports on the synthesis of substituted 1,2‐dihydro‐(4 H )‐3,1‐benzoxazin‐4‐one 31,32, we were encouraged, in this report, to study the hitherto unreported useful application of ultrasound in the synthesis of n ‐acetyl‐2‐aryl‐1,2‐dihydro‐(4 H )‐3,1‐benzoxazin‐4‐one. We preliminarily examined the condensation reaction of 2‐hydroxybenzaldehyde 1c as the test compound with anthranilic acid in the presence of acetic anhydride under sonication and catalyst‐free conditions.…”

“…These compounds are also valuable starting materials in the synthesis of various heterocycles such as 2,3‐disubstituted quinazolin‐4(3 H )‐one 22–29. In contrast to the parent 4 H ‐3,1‐benzoxazin‐4‐one, only very few routes have ever been reported on the synthesis of n ‐substituted‐1,2‐dihydro‐(4 H )‐3,1‐benzoxazin‐4‐ones 30–32. A method was previously reported on the synthesis of n ‐acetyl‐1,2‐dihydro‐4 H ‐3,1‐benzoxazin‐4‐one employing the reaction of N‐acylated anthranilic acids with paraformaldehyde in refluxing AcOH 33.…”

The discovery of new and more potent chloropyramine (C4) analogues for the potential treatment of invasive breast cancer

“…The second series of compounds ( 13a–m ), featuring an additional carbonyl group in the N,N ‐dimethylamino ethyl side chain moiety of C4 , were prepared according to Scheme A. The first step involved a reductive amination reaction between the corresponding aniline derivative ( 9a–l ) and p ‐halobenzaldehyde ( 10a or 10b ) to give the key intermediates ( 11a–l ). The final compounds were obtained by reacting N,N ‐dimethylaminoacetyl chloride hydrochloride 12 with intermediates ( 11a–l ) in tetrahydrofuran at room temperature.…”

Synthesis of 1,4-benzodiazepin-3-ones and 1,5-benzodiazocin-4-ones by addition of Grignard reagents to derivatives of o-aminobenzonitrile

“…98 Furthermore, a number of well-known drugs containing amide moieties have been thionated in the past e.g. diazepam (5, Valium), sildenafil (122,Viagra) and acyclovir (123). 99 Thiosildenafil was recently found as an additive in "natural" supplements, marketed as aphrodisiac for treating erectile dysfunction.…”