Synthesis and Reactions of 3‐Phenyl‐3,4‐Dihydro‐1, 4‐Quinoxalin‐2 (1H) ‐One and its Heterocyclic Analogues

Abstract

ABSTRACTwere synthesized by reactions o? methyl 2-bromo-2-phmylethanorrte 1 with oFthosubstituted arylaminea 2a -2c. Subsequent reductive alkylationofthe lactams with aodium hydride and-iodobthane afforded only the N-alkylated quinoxalinone 4a and benzothiazinone 4b. Lithium aluminium hydride reduction of the lactams 3 8 -3~ gave the dihydro-aerivatives 5a, 5b and 5c while similar reduction of the A-aIkylated lactams 4a and 4b yieldzd tlie unsafurated quinoxaline 6a and benzothiazine 6b respectively. Lead tetraacetate oxidation of the quinsxalinone 3a furnished-the unsaturated quinoxalinone 9 which was N-alkylated using sodiumborohydride in formic acid to give 10. Treatment of the 1actm.w 3a, 3b and 3c with phosphorus pentasulphide produGd only the quinoxalinethiol f l aEd benzsthiazinethione 12. dium ethoxide t b g i v e the S-al&latedTroducta 2 urd 2 respectively. The lactam quinoxalinone 3a, benzothiazinone 3b and benzothiazinone 3cCompounds 11 and 12 were alkylated with iodomzhane and so-

Chemistry, Biological Properties and SAR Analysis of Quinoxalinones

“…In Fig. (30) are reported some examples: 1,2-diaminobenzene derivative (1) reacts with diethyl dibromomalonate (2) (in methanol at r.t.) to give 2-ethoxycarbonylquinoxalin-3-one (3) [154]; with ethyl 2-bromo-2-methylpropanoate (4) (in DMF and Hunig's base, at 80-100 °C) to give 1H,4H-3,3-dimethylquinoxalin-2-one (5) [155]; with methyl 2-bromo-2-phenylacetate (6) (in refluxing methyl acetate, KI, K 2 CO 3 for 12 h, and then CH 3 ONa and benzene under reflux for 7 h) to give 3-phenylquinoxalin-2-one (7) [156]; with ethyl ethoxycarbonylformamidate (8) (in absolute ethanol at 25 °C) to give 3-aminoquinoxalin-2-one (9) [157][158].…”

Synthesis of Substituted Azepino[3,4‐b]indole‐1,5‐diones

“…Starting materials 1c and 1e were prepared according to reported procedures. [35,36] Compounds 1 were first Nprotected with Boc 2 O in the presence of a catalytic amount of DMAP to afford compounds 2 [37Ϫ40] in 72Ϫ99% yield. The formation of the aminals was achieved by using a super hydride  .…”

Rational Design, Synthesis, and Biological Activity of Benzoxazinones as Novel Factor Xa Inhibitors

“…These ethers were then reduced with hydrogen and Raney nickel in methanol which provided the corresponding aniline that underwent intramolecular cyclization to directly afford the benzoxazinone 8. In some instances, as a slightly modified procedure, the o-aminophenol was treated directly with the R-bromoacetic acid derivative 3 such that the benzoxazinone 8 was generated directly, as shown by step e. 11 This sequence was particularly useful to circumvent undesirable overreduction, which resulted in debenzylation or in some situations dehalogenation, for some of the derivatives of Table 1. While an alternative approach of treating the trichloromethyl carbinol derivative 7 with o-aminophenol benefited from a large variety of aldehydes that could easily be converted to the carbinol, the route suffered from modest yields that were obtained upon formation of the benzoxazinone 8 and hence was not generally employed.…”

“…These ethers were then reduced with hydrogen and Raney nickel in methanol which provided the corresponding aniline that underwent intramolecular cyclization to directly afford the benzoxazinone 8 . In some instances, as a slightly modified procedure, the o -aminophenol was treated directly with the α-bromoacetic acid derivative 3 such that the benzoxazinone 8 was generated directly, as shown by step e . This sequence was particularly useful to circumvent undesirable overreduction, which resulted in debenzylation or in some situations dehalogenation, for some of the derivatives of Table .…”