Source: https://patents.justia.com/patent/7339081
Timestamp: 2020-06-06 08:55:59
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US Patent for Route to prepare 4-bromo-1-oxypentafluorosulfanylbenzene Patent (Patent # 7,339,081 issued March 4, 2008) - Justia Patents Search
Justia Patents Sulfur ContainingUS Patent for Route to prepare 4-bromo-1-oxypentafluorosulfanylbenzene Patent (Patent # 7,339,081)
Jul 10, 2006 - Air Products and Chemicals, Inc.
A process for preparing bromo-1-oxypentafluorosulfanylbenzene is provided, the process including the step of brominating pentafluorosulfanyloxybenzene with a bromination agent to provide the bromo-1-oxypentafluorosulfanylbenzene. The process is more effective than prior art processes for preparing such compounds.
The present invention pertains to processes for preparing 4-bromo-1-oxypentafluorosulfanylbenzene.
Aryl-OSF5 compounds are useful for preparing many other useful compounds including, but not limited to, agricultural compounds, pharmaceuticals, monomers and polymers.
For example, DE 100 58 472 A1 to Kirsch et al. discloses derivatives of 4-((hetero)cyclyl)-pentafluorosulfuranyloxybenzene, which are used in liquid crystal media for LCDs and other electro-optical devices. This reference discloses that 4-bromo-l-oxypentafluorosulfanylbenzene can be prepared by reacting bromobenzene with SF5OOSF5 at 150° C. for 18 hours in a nickel-lined autoclave. The product is recovered by fractional distillation.
Case et al., “Preparation and Properties of Some Pentafluorosulphuroxyaryl Compounds, ArO-SF5.” J. Am. Chem. Soc. 2107 (1962), discloses that bispentafluorosulphur compounds react with benzene, toluene or chlorobenzene to yield compounds in which the pentafluorosulphuroxy group is substituted on the aromatic ring.
Despite the foregoing developments, it is desired to provide other routes to prepare pentafluorosulfuroxyaryl compounds, and particularly 4-bromo-1- oxypentafluorosulfanylbenzene.
Accordingly, a process for preparing bromo-1-oxypentafluorosulfanylbenzene is provided, said process comprising brominating pentafluorosulfanyloxybenzene with a bromination agent to provide the bromo-1-oxypentafluorosulfanylbenzene.
The invention provides a process for preparing bromo-1 -oxypentafluorosulfanylbenzene, which is much more effective than prior art processes for preparing such compounds. The most preferred product of the process is 4-bromo-1-oxypentafluorosulfanylbenzene, which has the following formula:
Other, less preferred, isomers of this product can also be produced in the inventive process, including 2-bromo-1-oxypentafluorosulfanylbenzene and 3-bromo-1-oxypentafluorosulfanylbenzene. In preferred embodiments of the invention, the yield of the para (i.e., 4-bromo) isomer is maximized relative to the yield of the other isomer(s). In certain embodiments of the invention, the products include the para and ortho isomers, wherein the para isomer is greater than 50% of the total amount of bromo-1 -oxypentafluorosulfanylbenzene isomers. Preferably, the product mixture obtained by the process of the invention comprises more 4 bromo-1-oxypentafluorosulfanylbenzene than 2-bromo-1-oxypentafluorosulfanylbenzene. In certain embodiments, the product mixture comprises at least 51 wt% 4-bromo-1-oxypentafluorosulfanylbenzene and 0 to 49 wt% 2-bromo-1 -oxypentafluorosulfanylbenzene.
The inventive process uses pentafluorosulfanyloxybenzene as a reagent. Pentafluorosulfanyloxybenzene, has the following formula:
Means for providing pentafluorosulfanyloxybenzene for use in the process are not particularly limited. For example, it can be provided by the process described in Case et al., cited above. Thus, a bispentafluorosulphur compound can be reacted with benzene to yield pentafluorosulfanyloxybenzene. Suitable bispentafluorosulphur compounds may include, but are not limited to, SF5OOSF5, SF5OOCF3, SF5OOTeF5, SF5OOSO2F, SF5OSF5, S2F10, or SF5OX (where X =F or CI).
The pentafluorosulfanyloxybenzene forming reaction is optionally conducted in a radical-tolerant solvent, such as, e.g., FREON F-113 or CCl4.
In certain embodiments of the pentafluorosulfanyloxybenzene-providing reaction, the reaction mixture is heated to about 50 to 150° C. (preferably about 125° C.) and stirred at temperature for 10-25 hours, preferably about 18 hours. After the specified time, the reaction product is cooled, and combined with a basic aqueous solution (preferably cold 20% aqueous KOH) such that the immiscible denser liquid portion (product) can be separated by decantation.
The reactants in the preferred pentafluorosulfanyloxybenzene-providing reaction (i.e., the bispentafluorosulphur compound and benzene) can be provided in amounts that are stoichiometrically equivalent, or substantially stoichiometrically equivalent (i.e., ±10% of precise stoichiometric equivalence). Alternatively, benzene can be provided in stoichiometric excess of the bispentafluorosulphur compound, or vice versa.
The pentafluorosulfanyloxybenzene is brominated with a bromination agent to provide the desired bromo-1-oxypentafluorosulfanylbenzene. Suitable bromination agents include but are not limited to 1,3-dibromo-5,5-dimethylhydantoin, N-bromosuccinimide, N-bromoacetamide, and bromine. The most preferred bromination agents are 1,3-dibromo-5,5-dimethylhydantoin and N-bromosuccinimide.
In its simplest form, the brominating step comprises combining the pentafluorosulfanyloxybenzene and the bromination agent. In a preferred embodiment, the brominating step comprises the sequential steps of: (a) adding the bromination agent to a vessel; (b) adding to the vessel a solution comprising the pentafluorosulfanyloxybenzene in a solvent; and (c) adding a catalyst to the vessel.
The reactants (i.e., the pentafluorosulfanyloxybenzene and the bromination agent) can be provided in amounts that are stoichiometrically equivalent, or substantially stoichiometrically equivalent (i.e., ±10% of precise stoichiometric equivalence). Alternatively, pentafluorosulfanyloxybenzene can be provided in stoichiometric excess of the bromination agent, or vice versa.
In certain embodiments, the molar ratio of the pentafluorosulfanyloxybenzene to bromine of the bromination agent is from 1:2 to 2:1 or 1:1.05 to 1.05:1.
The solvent is preferably an organic solvent, more preferably a non-polar organic solvent, and most preferably methylene chloride. Other solvents suitable for use in the brominating step include but are not limited to CHCI3, CCI4, CH3CN, THF, and other hydrocarbon solvents.
The catalyst for the brominating step is preferably triflic acid. Other suitable catalysts include but are not limited to acetic, trifluoroacetic, sulfuric, and fluorosulfonic (fluorosulfuric) acids. The catalyst is preferably provided in an amount of 5 mol% to 100 mol % relative to the brominating agent.
The yield of bromo-1-oxypentafluorosulfanylbenzene from the inventive process is preferably at least 75% of a theoretical yield, more preferably at least 90%, and still more preferably at least 95%.
Example 1 Preparation of C6H5OSF5 (Excess C6H6, no solvent)
Into a 50-cc stirred reactor (Parr Instrument Co.) were loaded 21.75 g (76.0 mmol) SF5OOSF5 and 11.95 g C6H6 (153 mmol). The mixture was heated to 125° C. and stirred at temperature for about 18 hours. After the specified time, the reactor and contents were cooled and vented. The reaction product was poured into a beaker containing cold 20% aqueous KOH and the immiscible denser liquid portion (product) was separated by decantation. Analysis of the product by GC-MS revealed a product distribution (normalized) containing residual benzene (C6H6 =37.5%), fluorobenzene (C6H5F =9.2 %), oxypentafluorosulfanyl benzene (C6H5OSF5=50.1%), oxypentafluorosulfanylfluorobenzene (C6H4FOSF5 =0.9 %), bis(oxypentafluorosulfanyl)benzene (C6H4(OSF5)2 =2.3%) as well as other minor products.
Example 2 Preparation of C6H5OSF5(Near-stoichiometric C6H6, no solvent)
Into a 50-cc stirred reactor (Parr Instrument Co.) were loaded 23.02 g (80.5 mmol) SF5OOSF5 and 6.41 g C6H6 (82.1 mmol). The mixture was heated to 124° C. and stirred at temperature for about 4 hours. After the specified time, the reactor and contents were cooled and vented. The reaction product was poured into a beaker containing cold water and subsequently neutralized with aqueous bicarbonate. The product was extracted into CH2Cl2 and separated by decantation. Analysis of the product by GC-MS revealed a product distribution (normalized) containing residual benzene (C6H6 =29.8%), fluorobenzene (C6H5F =6.4%), oxypentafluorosulfanyl benzene (C6H5OSF5 =57.7%), oxypentafluorosulfanylfluorobenzene (C6H4FOSF5 =3.6 %), bis(oxypentafluorosulfanyl)benzene (C6H4(OSF5)2 =2.5%) as well as other minor products.
Example 3 Preparation of C6H5OSF5 (Stoichiometric C6H6, no solvent)
The method of Example 2 was repeated, with 25.07 g (87.6 mmol) SF50OSF5 and 6.85 g (87.7 mmol) C6H6 heated to 125° C. for 5 hours. Analysis by GC-MS after workup revealed a product distribution (normalized) containing residual benzene (C6H6 =25.0%), fluorobenzene (C6H5F =10.3%), oxypentafluorosulfanyl benzene (C6H5OSF5 =50.0 %), oxypentafluorosulfanylfluorobenzene (C6H4FOSF5 =9.5 %), bis(oxypentafluorosulfanyl)benzene (C6H4(OSF5)2 =5.3 %) as well as other minor products.
Example 4 Preparation of C6H5OSF5 (Near-stoichiometric C6H6, F-113 solvent)
Into a 50-cc stirred reactor (Parr Instrument Co.) were loaded 14.9 g (52.1 mmol) SF5OOSF5, 4.5 g C6H6 (57.6 mmol), and 20 mL Freon®-113 (F-113). The mixture was heated to 150 ° C. and stirred at temperature for about 15 hours. After the specified time, the reactor and contents were cooled and vented. The reaction product was poured into a beaker containing cold 20% aqueous KOH and the immiscible denser liquid portion (product) was separated by decantation. Analysis of the product by GC-MS revealed a product distribution (normalized) containing residual benzene (C6H6 =52.5%), fluorobenzene (C6H5F =10.0%), oxypentafluorosulfanyl benzene (C6H50SF5 =33.6%), oxypentafluorosulfanylfluorobenzene (C6H4FOSF5 =2.9%), bis(oxypentafluorosulfanyl)benzene (C6H4(OSF5)2 =1.0%) as well as other minor products.
Example 5 Preparation of bromo-1-oxypentafluorosulfanylbenzene, BrC6H4OSF5
A 50 mL 3-neck round bottom flask equipped with a rubber septum, N2 inlet tube, glass stopper and magnetic stir bar was charged with 1,3-dibromo-5,5- dimethylhydantoin (1.741 g, 6.075 mmol) under N2 and cooled to 0° C. A solution of pentafluorosulfanyloxy benzene, PhOSF5 (2.70g, 12.15 mmol) in CH2Cl2 (27 mL) was added followed by triflic acid (1.08 mL). The reaction was monitored by GC-MS for disappearance of starting material. After 30 min the mixture was treated with saturated NaHCO3. After CO2 evolution ceased, the CH2Cl2 solution was separated, dried (MgSO4), filtered and evaporated in vacuo. The residue was purified by adsorption on a silica gel plug (10 g) and eluting with EtOAc/Hexane (98:2 ratio) to obtain 3.46 g (95% yield) of bromo-1-oxypentafluorosulfanylbenzene. Major isomer: 4-bromo-1-oxypentafluorosulfanylbenzene; GC-MS m/e =300(M+), 1H NMR (CDCI3) δ 7.55 (d, 2H), 7.15 (d, 2H). 19F NMR (CDCl3) δ 72 (q, 1F), 62 (d, 4F). Minor isomer: 2-bromo-1-oxypentafluorosulfanylbenzene: GC-MS m/e =300(M+); ′H NMR (CDCl3) δ 7.65 (d, 1 H), 7.40 (d, 1 H), 7.35 (br. s, 2H); 19F NMR (CDCl3) δ72 (q, 1 F), 64 (d, 4 F).
The procedure of Example 5 was carried out with PhOSF5 (200 mg, 0.9 mmol) and N-bromosuccinimide (160 mg, 0.9 mmol) in CH2Cl2 (2.0 mL) and triflic acid (80 μL) for 30 min at 0° C. Work up as above afforded 251 mg (93% yield) of bromo-1-oxypentafluorosulfanylbenzene with isomer ratio similar to that from the reaction described in Example 5.
A series of Comparative Examples (Examples 7-11) were done to demonstrate the inferiority of reacting bromobenzene with SF5OOSF5 (as suggested by DE 100 58 472 A1) to obtain 4-bromo-phenyl-OSF5.
Comparative Example 7 Reaction of C6H5Br with SF5OOSF5 without solvent at 125 ° C. for 62 hours
Into a 50-cc reactor (Parr Instrument Co.) were loaded 6.6 g (23.1 mmol) SF5OOSF5 and 3.7 g C6H5Br (23.6 mmol). The mixture was heated to 125 ° C. and held at temperature for about 62 hours. After the specified time, the reactor and contents were cooled and vented. The reaction product was poured into a beaker containing cold water and subsequently neutralized with aqueous bicarbonate. The product was extracted into CH2Cl2 and separated by decantation. Analysis of the product by GC-MS revealed a normalized product distribution as follows:
Normalized Area % Results for Example 7.
Product GC Area Normalized Area %
C6H5Br 130317890 23.8% C6H4BrF 11322510 2.1% C6H3Br2F 7151299 1.3% C6H3FBrOSF5 (isomer a) 1908926 0.3% C6H3FBrOSF5 (isomer b) 4963476 0.9% C6H3FBrOSF5 (isomer c) 1483302 0.3% C6H4BrOSF5 (isomer 1) 45896673 8.4% C6H4BrOSF5 (isomer 2) 142391610 26.0% C6H4BrOSF5 (isomer 3) 71123345 13.0% C6H4Br2 61429450 11.2% C6H4Br2 25598132 4.7% C6H4(OSF5)2 42108451 7.7% C6H4(OSF5)2 2031913 0.4%
Comparative Example 8 Reaction of C6H5Br with SF5OOSF5 without solvent at 150° C. for 4 hours
Into a 50-cc reactor (Parr Instrument Co.) were loaded 5.4 g (18.9 mmol) SF5OOSF5 and 2.5 g C6H5Br (15.9 mmol). The mixture was heated to 150° C. and held at temperature for about 4 hours. After the specified time, the reactor and contents were cooled and vented. The product was extracted into CH2Cl2 and separated by decantation. Analysis of the product by GC-MS revealed a normalized product distribution as follows:
Normalized Area % Results for Example 8.
C6H5Br 175126741 46.9% C6H4BrF (isomer i) 12731248 3.4% C6H4BrF (isomer ii) 5688453 1.5% C6H3FBrOSF5 (isomer a) 497408 0.1% C6H3FBrOSF5 (isomer b) 220192 0.1% C6H3FBrOSF5 (isomer c) 1007588 0.3% C6H4BrOSF5 (isomer 1) 15827801 4.2% C6H4BrOSF5 (isomer 2) 55554072 14.9% C6H4BrOSF5 (isomer 3) 28544473 7.6% C6H4Br2 43407648 11.6% C6H4Br2 16520858 4.4% C6H4OSF5)2 18031721 4.8% C6H4(OSF5)2 420381 0.1%
Comparative Example 9 Reaction of C6H5Br with SF5OOSF5 without solvent at 100° C. for 17 hours
Into a 50-cc reactor (Parr Instrument Co.) were loaded 6.4 g (22.4 mmol) SF5OOSF5 and 5.2 g C6H5Br (33.1 mmol). The mixture was heated to 100° C. and stirred at temperature for about 17 hours. After the specified time, analysis of the product by GC-MS revealed a normalized product distribution as follows:
Normalized Area % Results for Example 9.
C6H5Br 102914338 23.0% C6H4BrF (all isomers) 5668030 1.3% C6H3FBrOSF5 (all isomers) 11732015 2.6% C6H4BrOSF5 (all isomers) 289983915 64.7% C6H4Br2 (all isomers) 25008815 5.6% C6H4(OSF5)2 (all isomers) 12741470 2.8%
Comparative Example 10 Reaction of C6H5Br with SF5OOSF5 in CH2Cl2 solvent at 150° C. for 22 hours
Into a 50-cc reactor (Parr Instrument Co.) were loaded 4.8 g (16.8 mmol) SF5OOSF5, 2.8 g C6H5Br (17.8 mmol), and 20 mL CH2Cl2. The mixture was heated to 150° C. and stirred at temperature for about 22 hours. After the specified time, the reactor and contents were cooled and vented. The product was extracted into CH2Cl2 and separated by decantation. Analysis of the product by GC-MS revealed a normalized product distribution as follows:
Normalized Area % Results for Example 10.
C6H5Br 57955908 34.3% C6H4BrF (all isomers) 3899930 2.3% C6H4BrClOSF5 (all isomers) 20912871 12.4% C6H4BrOSF5 (all isomers) 7882943700 46.6% C6H4Br2 (all isomers) 3104083 1.8% C6H4(OSF5)2 (all isomers) 4452776 2.6%
Comparative Example 11 Reaction of C6H5Br with SF5OOSF5 in F-113 solvent at 125° C. for 14 hours
Part 1: Heating at 125° C. for 14 hours
Into a 50-cc reactor (Parr Instrument Co.) were loaded 18.6 g (65.0 mmol) SF5OOSF5, 10.4 g C6H5Br (66.2 mmol), and 30 mL F-113 solvent. The mixture was heated to 125° C. and stirred at temperature for about 14 hours. After the specified time, the reactor and contents were cooled and vented. Analysis of the product by GC-MS revealed a normalized product distribution given in the first column of the Table 5.
Part 2: Heating at 125° C. for additional 14 hours
The reactor and contents were reheated to 125° C. and maintained there for an additional 14 hours. After the specified time, the reactor and contents were cooled and vented. Analysis of the product by GC-MS revealed a normalized product distribution given in the second column of the Table 5.
Part 3: Heating at 150° C. for additional 15 hours
The reactor and contents were reheated to 150° C. and maintained there for an additional 15 hours. After the specified time, the reactor and contents were cooled and vented. Analysis of the product by GC-MS revealed a normalized product distribution given in the third column of the Table 5.
Normalized Area % Results for Example 11 Parts 1-3.
Example 11 Example 11 Example 11 Part 1 Part 2 Part 3 Normalized Normalized Normalized Product Area % Area % Area %
C6H5Br 50.3% 46.4% 29.4% C6H4BrF 2.4% 4.6% 7.4% (all isomers) C6H4BrFOSF5 0.9% 2.1% 2.1% (all isomers) C6H4BrOSF5 18.0% 19.8% 26.6% (all isomers) C6H4Br2 20.2% 20.0% 24.2% (all isomers) C6H3Br2F 3.9% 2.1% 1.6% C6H4(OSF5)2 4.3% 5.0% 8.7% (all isomers)
Summary of Comparative Examples 7-11.
Conversion of C6H5Br to Total Amount of Br-Ph- Example Number Products OSF5 (3 isomers) Obtained
7 76.2% 47.4% 8 53.1 % 26.7% 9 77.0 % 64.7% 10 65.7% 46.6% 11 70.6% 26.6%
The Examples showed that the method described in DE 10058472 A1 is far inferior to the method of the invention.
1. A process for preparing bromo-1-oxypentafluorosulfanylbenzene, the process comprising brominating pentafluorosulfanyloxybenzene with a bromination agent to provide the bromo-1-oxypentafluorosulfanylbenzene.
2. The process of claim 1, wherein the bromination agent is at least one member selected from the group consisting of 1,3-dibromo-5,5-dimethylhydantoin, N-bromosuccinimide, N-bromoacetamide and bromine.
3. The process of claim 1, wherein the brominating step comprises mixing the pentafluorosulfanyloxybenzene, the bromination agent and a catalyst in a non-polar organic solvent.
4. The process of claim 1, wherein the brominating comprises the sequential steps of: (a) adding the bromination agent to a vessel; (b) adding to the vessel a solution comprising the pentafluorosulfanyloxybenzene in a non-polar organic solvent; and (c) adding a catalyst to the vessel.
5. The process of claim 4, wherein the catalyst is triflic acid.
6. The process of claim 5, wherein the bromination agent is 1,3-dibromo-5,5-dimethylhydantoin or N-bromosuccinimide.
7. The process of claim 6, wherein the solvent is methylene chloride.
8. The process of claim 7, wherein a molar ratio of the pentafluorosulfanyloxybenzene to bromine of the bromination agent is from 1:2 to 2:1.
9. The process of claim 8, wherein the molar ratio is 1:1.05 to 1.05:1.
10. The process of claim 1, wherein the bromo-1-oxypentafluorosulfanylbenzene is provided in a product mixture comprising at least one of 4-bromo-1-oxypentafluorosulfanylbenzene and 2-bromo-1-oxypentafluorosulfanylbenzene.
11. The process of claim 10, wherein the product mixture comprises more 4-bromo-1-oxypentafluorosulfanylbenzene than 2-bromo-1-oxypentafluorosulfanylbenzene.
12. The process of claim 10, wherein the product mixture comprises at least 51 wt % 4-bromo-1-oxypentafluorosulfanylbenzene and 0 to 49 wt % 2-bromo-1-oxypentafluorosulfanylbenzene.
100 58 472 June 2001 DE
10058472 June 2001 DE
928412 June 1963 GB
J.R. Case, et al, “Preparation and Properties of Some Pentafluorosulphuroxyaryl . . . ,” J. Chem. Soc., 1962, pp. 2107-2110.
Patent Publication Number: 20080009653
Inventors: Robert George Syvret (Allentown, PA), Gauri Sankar Lal (Whitehall, PA)
Application Number: 11/484,226
Current U.S. Class: Sulfur Containing (568/18); Boron Containing (568/1); Sulfur Bonded Directly To A Ring (568/54); Halogen Containing (568/56); Sulfur, Oxygen, Halogen Or Group Ia Or Iia Light Metal Containing (568/6)
International Classification: C07C 315/00 (20060101); C07C 317/00 (20060101); C07C 319/00 (20060101); C07C 331/00 (20060101); C07C 381/00 (20060101);