EP3560929A2 — Crystalline 6,7-unsaturated-7-carbamoyl morphinane derivative, and method for producing same

USPTO Abstract

The present invention relates to a process for preparing a compound of the formula (II):wherein R<sup>1b</sup>is a hydroxy-protecting group, R<sup>2</sup>is optionally substituted lower alkyl, and R<sup>3</sup>is optionally substituted lower alkyl, optionally substituted cycloalkyl, substituted or non-substituted aryl or substituted or non-substituted heteroaryl, characterized by reacting a compound of the formula (III):wherein R<sup>1b</sup>and R<sup>2</sup>are the same as defined above, in the presence or absence of an acid with a compound of the formula: R<sup>3</sup>-N=C=O , wherein R<sup>3</sup>is the same as defined above, or with a compound of the formula: R<sup>3</sup>-NH-C(=O)-X, wherein R<sup>3</sup>is the same as defined above and X is a leaving group.