1- uracil methyl ester, preparation

Partly saturated pyrazino[l,2-r-]pyrimidines were prepared by formation of the pyrazine ring. 2-Substituted-8-hydroxy-3,4-dihydro-177,277-pyrazino[l,2-r-]pyrimidin-l-ones were prepared by a [6+0] synthesis involving cyclization of 6-hydroxy-pyrimidine-4-(fV-hydroxyethyl)carboxamides <2005W02005/087766>. The 2/7-pyra-zino[l,2-c]pyrimidine-3-carboxamide 164 (Y = NH) was formed from [5+1] atom fragments via the uracil derivative 163 (Y = NH) and DMF-dimethyl acetal. Compounds 163 were prepared from 6-chloromethyluracil and glycine methyl ester 162 (Y = NH) (Scheme 20) <2004W02004/014354>. 

The DL-serine uracil derivative 580 was prepared from OL-serine methyl ester hydrochloride by V-benzoylation to give 578 chloromethylation gave 579, which then was substituted by the silylated uracil (88ZOB2404). 

Six-membered heterocyclic systems which have been synthesised by similar methods include l,6-methano[10]annulenopyridines (214) from (213), y-carblines (215), lavendamycin methyl ester,a range of functionalised 2,3-dihydropyrido[3 ,2 4,5]thieno[3,2-d]pyrimidines (216), and the quinazolino[3,4-a]perimidine derivatives (e.g. 218) from 1,2-dihydro-properimidine azide (217). The previously unreported 4-methylene-4H-3,l-benzozazine ring (219) has been prepared from o-azidoacetophenone and the zwitterionic heteropolycyclic uracils (220) have been synthesised by a three-component reaction of iminophosphorane, isocyanate, and substituted pyridine. ... 

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