With the rapid development and complex challenges of chemical substances, new drug synthesis pathways are usually the most effective.13031-04-4,4,4-Dimethyldihydrofuran-2,3-dione,as a common compound, the synthetic route is as follows.
Examples 1-4 [00041] The process of the present invention as set forth in FIG. 1 is typically initiated by dissolving the alpha ketocarbonyl compound and the modifier in vessel (1). The resulting solution contains from about 0.1 wt % to about 100 wt % of the alpha ketocarbonyl compound and from about 1¡Á10-5 wt % to about 0.5 wt % of modifier. [00042] The mass flow is started at the reaction temperature, for example, at 17 C. or 20 C. (Examples 1 and 2, respectively). The above solution containing an alpha ketocarbonyl compound and a modifier is pumped into the fixed bed reactor (2) and contacted with hydrogen to start the hydrogenation reaction. Before catalytic runs, the reactor is flushed with nitrogen. [00043] Subsequently, the content of vessel (1) is continuously pumped into the fixed bed reactor. The solution flow rate is preferably from about 0.1 to about 50 ml/minute, the preferred flow of the alpha ketocarbonyl compound is 2¡Á10-5-2¡Á10-2 mol/gcat/minute. More preferably, the solution flow rate is preferably from about 2.5 to about 10 ml/minute, and the flow of the alpha ketocarbonyl compound is from about 2¡Á10-4-3¡Á10-3 mol/gcat/minute. [00044] The modifier flow rate is preferably from about 2¡Á10-9 to about 2¡Á10-4 mol/gcat/minute, such as, for example, from about 2¡Á10-8 to about 7¡Á10-6 mol/gcat/minute. [00045] Hydrogen is continuously fed into the fixed bed reactor via flow line (3) containing a compressor (4) and a pressure control system (5). The inert gas, e.g. nitrogen, is fed into the reactor (2) via line (7). [00046] The hydrogen flow rate into the reactor is metered and monitored by a rotameter. Suitable hydrogen flow rates are from about 0.0001 mol/minute (2.4 ml/minute) to about 1 mol/minute (24000 ml/minute), for example, from about 5¡Á10-6 to about 10 mol/gcat/minute. [00047] The hydrogenation reaction can be carried out at a relatively low temperature ranging between about -20 C. and about 100 C., the preferred temperature range is from about -10 C. to about 50 C., such as for example from about 0 C. to about 20 C. [00048] The pressure in the reactor is suitably adjusted to between about 2 bar and about 150 bar, preferably from about 40 bar to about 100 bar. [00049] The effluent from the hydrogenation reaction zone is fed over a two-step expansion module (6) to a separator where the alpha hydroxy carbonyl compound is recovered. [00050] The process set forth in FIG. 2 is initiated by dissolving the alpha ketocarbonyl compound and the modifier in vessel (1) or by adding a solution containing the modifier to a liquid alpha ketocarbonyl compound. The resulting solution has the following concentration: [00051] about 0.1 wt % to about 100 wt % of alpha ketocarbonyl compound; and [00052] about 1¡Á10-6 wt % to about 0.5 wt % of modifier. [00053] The reactor vessel (2) is charged with a supercritical solvent via flow line (3) containing a compressor (4) and a pressure control system (5). [00054] The organic flow is started at a reaction temperature of, for example, about 50 C. (Example 3) or 36 C. (Example 4). The solution set forth above is pumped into the fixed bed reactor (2) and contacted with hydrogen to start the hydrogenation reaction. [00055] Subsequently, the content of vessel (1) is continuously pumped into the fixed bed reactor with the same solution flow rate as in the process according to FIG. 1. [00056] The flow rate of the supercritical co-solvent is preferably from about 50 ml/minute to about 5000 ml/minute. [00057] When using a liquid alpha ketocarbonyl compound, the supercritical co-solvent is used with a flow rate of about 50 ml/minute to about 5000 ml/minute. [00058] The modifier flow rate is preferably from about 2¡Á10-11 to about 2¡Á10-4 mol/gcat/min. [00059] Hydrogen is continuously fed into the fixed bed reactor via flow line (7) containing a pressure control system (5). The hydrogen flow rate into the reactor was metered and monitored by a rotameter. [00060] Suitable hydrogen flow rates are from about 0.0001 mol/minute (2.4 ml/minute) to about 1 mol/minute (24000 ml/minute) such as for example from 5¡Á10-6 to about 10 mol/gcat/minute. [00061] The hydrogenation reaction can be carried out at a relatively low temperature ranging between about 20 C. to about 100 C., preferably from about 30 C. to about 60 C., such as for example from about 35 C. to about 50 C. The pressure is suitably adjusted to between about 2 bar to about 150 bar, preferably about 40 bar to about 100 bar.
13031-04-4 4,4-Dimethyldihydrofuran-2,3-dione 39, aTetrahydrofurans compound, is more and more widely used in various.
Reference£º
Patent; Roche Vitamins Inc.; US6646135; (2003); B1;,
Tetrahydrofuran – Wikipedia
Tetrahydrofuran | (CH2)3CH2O – PubChem