Intermediate compounds for the preparation of
View Patent ↗Disclosed are novel amino acid derivatives of formula (I) and (II) processes for the preparation thereof, and their use in the preparation of trans-5-chloro-2-methyl-2,3,3a,12b-tetrahydro-1H-dibenz[2,3:6,7]oxepino-[4,5-c]pyrrole.
1. A process for preparing asenapine of formula A,
or a salt thereof, from a mixture of isomers without the use of post reaction isomer separation techniques the process comprising:
(a) Stereoselectively preparing a trans-amino acid derivative which is Formula I, Formula II, or a mixture of Formula I and Formula II:
or a salt thereof, by reacting with a base in the presence of an alcohol a lactam mixture which is:
(i) a mixture of lactams of Formula IV and Formula V:
(ii) a mixture of lactams of Formula VII and Formula VIII:
(iii) a mixture of the mixtures of lactams of (i) and (ii),
said reaction thereby stereoselectively opening the trans isomer in said mixture, and isolating said trans-amino acid derivative product from the reaction mixture by: (A) neutralization of the reaction mixture; or (B) treating the corresponding hydrochloride salt of the ring-opened product with ammonia or sodium hydroxide solution;
(b) cyclizing said ring-opened products isolated from Step (a) thereby yielding: (1) the lactam of Formula IV if the lactam mixture used in Step (a) was a mixture of Formula IV and Formula V: (2) the lactam of Formula VII if the lactam mixture used in Step (a) was a mixture of Formula VII and Formula VIII; or (3) a mixture of lactams of Formula VII and IV if the lactam mixture (iii) was provided in Step (a);
(c) reducing the carbonyl moiety of the lactam or lactam mixture prepared in Step (b) to give the compound of Formula A; and
(d) optionally converting the compound of Formula A from step (c) to a salt.
2. The process of claim 1 , wherein said cyclizing Step (b) comprises heating the trans-amino acid derivative prepared in Step (a) in a solvent.
3. The process of claim 2 wherein said heating is carried out in the presence of sodium acetate.
4. The process of claim 1 wherein said cyclizing Step (b) is carried out by converting said amino acid derivative prepared in Step (a) into an activated form and treating the activated form of the amino acid derivative with a base.