CPC C07D 407/12 (2013.01) [C07B 2200/13 (2013.01)] | 17 Claims |
1. A process for preparing a compound of formula (2), or a salt thereof, or solvate thereof, or an enantiomer thereof, or a diastereomer thereof comprising:
(a) contacting a compound of formula (1):
or an enantiomer thereof, or a diastereomer thereof, with 1-{[(p-nitrobenzyl)oxy]carbonyl}-1H-benzotriazole (PNZ-Bt) to form the compound of formula (2):
or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof;
wherein - - - is a single bond or a double bond;
R1 is H or C1-C3 alkyl;
R2 is H or C1-C3 alkyl; and
R3 is H or C1-C3 alkyl.
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