Beilstein J. Org. Chem.2022,18, 286–292, doi:10.3762/bjoc.18.32
/addition/nucleophilic substitution reactions.
Keywords: aza-Wittig reaction; 3,4-dihydroquinazoline; 4H-3,1-benzothiazine; nucleophilic substitution; Passerini reaction; Staudinger reaction; Introduction
The chemistry of 3,4-dihydroquinazolines and 4H-3,1-benzothiazines is of constant interest owing to
protein cleaving enzyme 1 (BACE-1) inhibitive [6], and cholinesterase enzyme inhibitive activities [7]. The 3,4-dihydroquinazoline skeleton also exists in some natural products such as vasicine and vasicoline [8]. Some 4H-3,1-benzothiazine derivatives have also received attention due to their good
biological activities, including anticancer [9], neuroprotective [10], antiproliferative and antifungal activities [11]. Due to the significant bioactive properties of the 3,4-dihydroquinazoline and 4H-3,1-benzothiazine moieties, many preparation procedures have appeared in the literature for the synthesis
PDF
Graphical Abstract
Figure 1:
Some bioactive 3,4-dihydroquinazolines and 4H-3,1-benzothiazines.
Beilstein J. Org. Chem.2013,9, 460–466, doi:10.3762/bjoc.9.49
and efficient method to construct ring-fused 4-alkyl-4H-3,1-benzothiazine-2-thione derivatives has been developed from carbon disulfide and (E)-3-(2-aminoaryl)acrylates or (E)-3-(2-aminoaryl)acrylonitriles under mild conditions, without the need for a metal catalyst. The newly developed method
tolerates a wide range of substrates in moderate to excellent yields. Moreover, this method is advantageous over previous ones for the easy synthesis of reactants.
Keywords: 4H-3,1-benzothiazine-2-thione; carbon disulfide; (E)-3-(2-aminoaryl)acrylate; (E)-3-(2-aminoaryl)acrylonitrile; Michael addition
; Introduction
Molecules containing the 4H-3,1-benzothiazine moiety have received considerable interest from the chemical and medicinal community due to their promising biological activity [1][2][3][4] and the applications in recording and photographic materials [5][6][7][8]. A number of efficient approaches for
PDF
Graphical Abstract
Scheme 1:
AgNO3-catalyzed tandem reaction of 2-alkynylbenzenamines with CS2 and their further transformation.