A new approach to the synthesis of heteroannulated 3,1-oxazin-4-ones from β-enamino esters and phosgeneiminium salts
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...
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| Main Authors: | , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
2000
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| In: |
Synthesis
Year: 2000, Issue: 2, Pages: 255-258 |
| ISSN: | 1437-210X |
| DOI: | 10.1055/s-2000-6249 |
| Online Access: | Verlag, kostenfrei registrierungspflichtig, Volltext: http://dx.doi.org/10.1055/s-2000-6249 Verlag, kostenfrei registrierungspflichtig, Volltext: https://www.thieme-connect.de/products/ejournals/abstract/10.1055/s-2000-6249 
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| Author Notes: | Zhijun Wang, Richard Neidlein, Claus Krieger |
| Summary: | 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. |
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| Item Description: | Gesehen am 28.04.2017 |
| Physical Description: | Online Resource |
| ISSN: | 1437-210X |
| DOI: | 10.1055/s-2000-6249 |