The present invention relates to a method of production of 4-boronophenylalanine (BPA) from 4-iodophenylalanine, in which all the functional groups of the amino acid are protected by benzyl protection method, and which uses isopropyl magnesium halogenide stabilized by a complexation base, and subsequent condensation of the resulting Grignard reagent with a boric acid ester. The final reaction step, catalytic hydrogenolysis or transfer hydrogenolysis of protecting groups on the amino acid, occurs after hydrolysis of the boronate ester groups.

An integrated process for maximizing recovery of aromatics is provided. The process comprises passing at least a portion of a xylene column bottoms stream to a heavy aromatics column to provide a heavy aromatics column bottoms stream comprising C.sub.9+ aromatics and a heavy aromatics column overhead stream. The heavy aromatics column bottoms stream is passed to a second stage hydrocracking reactor of a two-stage hydrocracking reactor. In the second stage hydrocracking reactor, the heavy aromatics column bottoms stream is hydrocracked in the presence of a hydrocracking catalyst and hydrogen to provide a hydrocracked effluent stream.

An integrated process for maximizing recovery of aromatics is provided. The process comprises passing at least a portion of a xylene column bottoms stream to a heavy aromatics column to provide a heavy aromatics column bottoms stream comprising C.sub.9+ aromatics and a heavy aromatics column overhead stream. The heavy aromatics column bottoms stream is passed to a second stage hydrocracking reactor of a two-stage hydrocracking reactor. In the second stage hydrocracking reactor, the heavy aromatics column bottoms stream is hydrocracked in the presence of a hydrocracking catalyst and hydrogen to provide a hydrocracked effluent stream.

The present invention provides a novel and improved process for the preparation of Crisaborole of Formula (I) and its pharmaceutically acceptable salts. The present invention also provides novel intermediates and process for the preparation of intermediates used in the preparation of Crisaborole. The present invention also provides an improved process for the preparation of Crisaborole and pharmaceutically acceptable salts thereof, that is commercially and industrially scalable.

The invention addresses the problem of providing a method for producing 2-acetyl-4H,9H-naphtho[2,3-b]furan-4,9-dione that is suited to industrial production. The invention provides a method for producing 2-acetyl-4H,9H-naphtho[2,3-b]furan-4,9-dione by reacting 3-bromo-3-buten-2-one and 2-hydroxy-1,4-naphthoquinone in the presence of a solvent, then obtaining crystals of 2-acetyl-4H,9H-naphtho[2,3-b]furan-4,9-dione by adding an alcohol-based solvent and/or water to the reaction system, and treating the crystals by using a specific adsorbent in the presence of a solvent.

The invention addresses the problem of providing a method for producing 2-acetyl-4H,9H-naphtho[2,3-b]furan-4,9-dione that is suited to industrial production. The invention provides a method for producing 2-acetyl-4H,9H-naphtho[2,3-b]furan-4,9-dione by reacting 3-bromo-3-buten-2-one and 2-hydroxy-1,4-naphthoquinone in the presence of a solvent, then obtaining crystals of 2-acetyl-4H,9H-naphtho[2,3-b]furan-4,9-dione by adding an alcohol-based solvent and/or water to the reaction system, and treating the crystals by using a specific adsorbent in the presence of a solvent.

The present invention provides a novel and improved process for the preparation of Crisaborole of Formula (I) and its pharmaceutically acceptable salts. The present invention also provides novel intermediates and process for the preparation of intermediates used in the preparation of Crisaborole. The present invention also provides an improved process for the preparation of Crisaborole and pharmaceutically acceptable salts thereof, that is commercially and industrially scalable.

An integrated process for maximizing recovery of aromatics is provided. The process comprises passing at least a portion of a xylene column bottoms stream to a heavy aromatics column to provide a heavy aromatics column bottoms stream comprising C.sub.9+ aromatics and a heavy aromatics column overhead stream. The heavy aromatics column bottoms stream is passed to a second stage hydrocracking reactor of a two-stage hydrocracking reactor. In the second stage hydrocracking reactor, the heavy aromatics column bottoms stream is hydrocracked in the presence of a hydrocracking catalyst and hydrogen to provide a hydrocracked effluent stream.

An integrated process for maximizing recovery of aromatics is provided. The process comprises passing at least a portion of a xylene column bottoms stream to a heavy aromatics column to provide a heavy aromatics column bottoms stream comprising C.sub.9+ aromatics and a heavy aromatics column overhead stream. The heavy aromatics column bottoms stream is passed to a second stage hydrocracking reactor of a two-stage hydrocracking reactor. In the second stage hydrocracking reactor, the heavy aromatics column bottoms stream is hydrocracked in the presence of a hydrocracking catalyst and hydrogen to provide a hydrocracked effluent stream.

A purification method of desflurane (difluoromethyl-1,2,2,2-tetrafluoroethyl ether of the formula (1)) includes bringing a mixture containing desflurane and a trihalomethane into contact with a base in the presence of a phase transfer catalyst, thereby decomposing the trihalomethane. By this method, only the trihalometane contained as a by-product in the desflurane is decomposed without causing decomposition of the desflurane, whereby the desflurane is obtained with high purity. ##STR00001##