Synthesis 2019; 51(23): 4463-4472
DOI: 10.1055/s-0039-1690678
paper
© Georg Thieme Verlag Stuttgart · New York

Syntheses of Pyrazine-, Quinoxaline-, and Imidazole-Fused Pyrroline Nitroxides

Mostafa Isbera
a   Institute of Organic and Medicinal Chemistry, Medical School, University of Pécs, Szigeti st. 12, 7624 Pécs, Hungary   Email: tamas.kalai@aok.pte.hu
,
Balázs Bognár
a   Institute of Organic and Medicinal Chemistry, Medical School, University of Pécs, Szigeti st. 12, 7624 Pécs, Hungary   Email: tamas.kalai@aok.pte.hu
,
Gergely Gulyás-Fekete
b   Institute of Biochemistry and Medical Chemistry, Medical School, University of Pécs, Szigeti st. 12, 7624 Pécs, Hungary
,
Krisztina Kish
a   Institute of Organic and Medicinal Chemistry, Medical School, University of Pécs, Szigeti st. 12, 7624 Pécs, Hungary   Email: tamas.kalai@aok.pte.hu
,
Tamás Kálai
a   Institute of Organic and Medicinal Chemistry, Medical School, University of Pécs, Szigeti st. 12, 7624 Pécs, Hungary   Email: tamas.kalai@aok.pte.hu
c   Szentágothai Research Centre, Ifjúság st. 20, 7624 Pécs, Hungary
› Author Affiliations
Financial supports from Hungarian National, Research, Development and Innovation Office (OTKA 124331) and grant GINOP (GINOP-2.3.2-15-2016-00049) are greatly acknowledged.
Further Information

Publication History

Received: 08 August 2019

Accepted after revision: 21 August 2019

Publication Date:
13 September 2019 (online)


Dedicated to the memory of Prof. Kálmán Hideg

Abstract

A synthesis of a new diamagnetic synthon, 1-methoxy-2,2,5,5-tetramethylpyrrolidine-3,4-dione, was developed. Condensation of this compound with aliphatic or aromatic 1,2-diamines followed by deprotection yielded pyrroline nitroxide-fused pyrazines, pteridines, or quinoxalines, demonstrated on 7 examples in 15–39% overall yield over 2 or 3 steps. Reaction of the diamagnetic 1,2-diketone with an aldehyde and ammonium acetate produced a pyrrolo[3,4-d]imidazole scaffold in the Debus–Radziszewski reaction.

Supporting Information