A New Approach to the Synthesis of Heteroannulated 3,1-Oxazin-4-ones from β-Enamino Esters and Phosgeneiminium Salts

Zhijun Wang; Richard Neidlein; Claus Krieger

doi:10.1055/s-2000-6249

Synthesis 2000; 2000(2): 255-258
DOI: 10.1055/s-2000-6249

paper

© Georg Thieme Verlag, Rüdigerstr. 14, 70469 Stuttgart, Germany. All rights reserved. This journal, including all individual contributions and illustrations published therein, is legally protected by copyright for the duration of the copyright period. Any use, exploitation or commercialization outside the narrow limits set by copyright legislation, without the publisher's consent, is illegal and liable to criminal prosecution. This applies in particular to photostat reproduction, copying, cyclostyling, mimeographing or duplication of any kind, translating, preparation of microfilms, and electronic data processing and storage.

A New Approach to the Synthesis of Heteroannulated 3,1-Oxazin-4-ones from β-Enamino Esters and Phosgeneiminium Salts

Zhijun Wang^* , Richard Neidlein, Claus Krieger

^*Pharmazeutisch-Chemisches Institut der Universität Heidelberg, Im Neuenheimer Feld 364, D-69120 Heidelberg, Germany; Fax +49 (62 21) 54 64 30; E-mail: richard.neidlein@urz.uni-heidelberg.de

Abstract

als PDF herunterladen Alle Artikel dieser Rubrik

The heterocyclic β-enamino ester, ethyl 3,4-diamino-6-(dimethylamino)thieno[2,3-d]pyrimidine-2-carboxylate (3) was reacted with phosgeneiminium salts 6a,b to yield 4H-pyrimido[5′,4′:4,5]thieno[3,2-d][1,3]oxazin-4-ones 7a,b, respectively. Similarly, the reaction of dichloromethylene dimethylammonium chloride 6a with o-aminothiophenecarboxylates 8 and 10 afforded the thienoxazinones 9 and 11. In the case of the o-aminopyrazolecarboxylate 12, the pyrazoloxazinone 13a was formed in low yield, while the ureidopyrazole 13b was the main product. Reaction of 6a with o-aminopyrazinecarboxylate 14 or o-aminoisoxazolecarboxylate 16 did not afford any bicyclic oxazinones were produced with 6a. Instead, the monocyclic products 15 and 17 were obtained.

heterocyclic β-enamino esters - phosgeneiminium salts - heteroannulated 3,1-oxazin-4-ones - addition reactions - heterocycles

PDF (82 kb)