| 摘要 |
<p>2-Amino-3-cyano-5-dialkoxymethylpyrazine derivatives of the general formula III <IMAGE> (III) where R1 and R2 are each hydrogen or a protective group usually employed for amino groups and R5 and R6 are each alkyl of 1 to 4 carbon atoms, or together form an ethylene or propylene radical which is unsubstituted or substituted by methyl, are prepared starting from a novel 3-halomethyl-5-dihalomethyl-2-aminopyrazine derivative of the formula IV <IMAGE> (IV) where X is Cl or Br, via a novel intermediate of the general formula I <IMAGE> (I) where R3 is -CH2-O-CO-CH3 (a), -CH2OH (b), <IMAGE> (c) or -C 3BOND N (d) and R4 is -CHCl2 or -CHBr2 or, where R1 and R2 are each a protective group, R4 may furthermore be <IMAGE> The compounds according to the invention are useful intermediates for the preparation of folic acid and active compounds derived from this.</p> |
