| 摘要 |
<p>Compounds of the general formula <FORM:1107561/C2/1> (in which R1 and R2 are identical or different and each represent hydrogen, an alkyl or acyl group with 1-6 carbon atoms, a benzoyl, benzyloxycarbonyl or benzyl group, or taken together with the adjacent N-atom form a heterocyclic ring, which further may contain an O-atom, and one or more of the hydrogen atoms in positions 3, 4 and 5 may be replaced by an alkyl or cycloalkyl group with not more than 6 carbon atoms) are prepared by cyclizing a compound of the formula <FORM:1107561/C2/2> (in which X represents halogen or an alkylsulphonyloxy, arylsulphonyloxy or aralkylsulphonyloxy radical and the a ,b and g carbon atoms may be substituted as indicated above) by means of lithium hydroxide.</p> |
