The Production Process of [2R-(2a,3b,11bb)]-1,3,4,6,7,11b-Hexahydro-9,10-dimethoxy-3-(2-methylpropyl)-2H-benzo[a]quinolizin-2-ol

The production process of [2R-(2a,3b,11bb)]-1,3,4,6,7,11b-Hexahydro-9,10-dimethoxy-3-(2-methylpropyl)-2H-benzo[a]quinolizin-2-ol, also known as 2H-1,3-oxazepin-10-one, is a complex and multi-step process that involves several synthetic techniques and purification methods to obtain a pure and crystalline product.

The synthesis of 2H-1,3-oxazepin-10-one can be achieved through several methods, including chemical synthesis, biotechnological synthesis, and synthesis using natural sources.
In this article, we will discuss the chemical synthesis of 2H-1,3-oxazepin-10-one, which is the most common method used in the chemical industry.

Step 1: Preparation of 2-chloro-1,3-oxazepin-4-one
The first step in the synthesis of 2H-1,3-oxazepin-10-one is the preparation of 2-chloro-1,3-oxazepin-4-one, which is a key intermediate in the synthesis of 2H-1,3-oxazepin-10-one.
To prepare 2-chloro-1,3-oxazepin-4-one, 2-chloro-1,3-oxazepine is reacted with an appropriate acid catalyst in the presence of a solvent such as dichloromethane or acetonitrile.
The reaction is exothermic and requires careful temperature control to avoid unwanted side reactions.

Step 2: Preparation of 2-(2-methylpropyl)-2H-1,3-oxazepin-4-one
The next step in the synthesis of 2H-1,3-oxazepin-10-one is the preparation of 2-(2-methylpropyl)-2H-1,3-oxazepin-4-one, which is another key intermediate in the synthesis of 2H-1,3-oxazepin-10-one.
To prepare 2-(2-methylpropyl)-2H-1,3-oxazepin-4-one, 2-chloro-1,3-oxazepin-4-one is treated with a Grignard reagent or a metal alkoxide in the presence of a solvent such as ether or THF.
The reaction is typically carried out at low temperatures, and the product is isolated by precipitation with a solvent such as ether or hexane.

Step 3: Preparation of [2R-(2a,3b,11bb)]-1,3,4,6,7,11b-Hexahydro-9,10-dimethoxy-3-(2-methylpropyl)-2H-benzo[a]quinolizin-2-ol
The final step in the synthesis of 2H-1,3-oxazepin-10-one is the preparation of the final product, [2R-(2a,3b,11bb)]-1,3,4,6,7,11b-Hexahydro-9,10-dimethoxy-3-(2-methylpropyl)-2H-benzo[a]quinolizin-2-ol.
This step involves the completion of the synthesis of the intermediate 2-(2-methylpropyl)-2H-1,3-oxazepin-4-one, followed by a series of chemical transformations such as Suzuki-Miyaura coupling, Pd-catalyzed cross-coupling, and selective oxidation to introduce the desired functionalities in the molecule.

The preparation of [2R-(2a,3b,11bb)]-1,3,4,6,7,11b-Hexahydro-9,10-dimethoxy-3-(2-methylpropyl)-2H-benzo[a]quinolizin-2-ol requires strict control of reaction conditions and purification