WO2021255512A1 - Nouveaux dérivés de flavane substitués et leur procédé de préparation - Google Patents

Nouveaux dérivés de flavane substitués et leur procédé de préparation Download PDF

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WO2021255512A1
WO2021255512A1 PCT/IB2020/058487 IB2020058487W WO2021255512A1 WO 2021255512 A1 WO2021255512 A1 WO 2021255512A1 IB 2020058487 W IB2020058487 W IB 2020058487W WO 2021255512 A1 WO2021255512 A1 WO 2021255512A1
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formula
compound
phthalonitrile
flavan
nitrile
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PCT/IB2020/058487
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English (en)
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Srinivas Reddy MALE
Krishnamurthy Sridhar Madanapalli
Krishna Reddy Pingili
Venkata Reddy Buthukuri
Ramu Enishetty
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Azista Industries Private Limited
Benova Labs Private Limited
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Publication of WO2021255512A1 publication Critical patent/WO2021255512A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D311/00—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only hetero atom, condensed with other rings
    • C07D311/02—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only hetero atom, condensed with other rings ortho- or peri-condensed with carbocyclic rings or ring systems
    • C07D311/04—Benzo[b]pyrans, not hydrogenated in the carbocyclic ring
    • C07D311/58—Benzo[b]pyrans, not hydrogenated in the carbocyclic ring other than with oxygen or sulphur atoms in position 2 or 4
    • C07D311/60—Benzo[b]pyrans, not hydrogenated in the carbocyclic ring other than with oxygen or sulphur atoms in position 2 or 4 with aryl radicals attached in position 2
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D311/00—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only hetero atom, condensed with other rings
    • C07D311/96—Heterocyclic compounds containing six-membered rings having one oxygen atom as the only hetero atom, condensed with other rings spiro-condensed with carbocyclic rings or ring systems

Definitions

  • the present invention relates to novel substituted flavan derivatives of the Formula (I) Formula (I)
  • the present invention also relates to a process for the preparation of phthalonitrile or cyanate ester flavan derivatives.
  • the present invention also relates to use of novel substituted flavan derivatives to produce polymer composite materials. BACKGROUND OF THE INVENTION
  • Polymer matrix composite materials are widely used in a variety of technical fields, such as in the aerospace, automotive, marine, infrastructure, military, sports, and industrial fields. These lightweight materials exhibit excellent mechanical properties, high corrosion resistance, dimensional stability, and low assembly costs.
  • Phthalonitrile polymers or resins and their composites are considered as the material of choice for high performance applications due to their excellent thermal stability and mechanical properties, elevated glass transition temperatures, high chemical resistance and non- inflammability characteristics. Phthalonitrile resin matrix composites are known to retain a very high percentage ( ⁇ 80%) of their room temperature mechanical, electrical, and dielectric properties at temperatures of 300 to 350 C and are thus excellent candidate materials for aero engine components, missile and launch vehicle structures, submarine and aircraft interiors.
  • phthalonitrile resins have been described in literature. These resins are generally prepared by end capping bis phenols with phthalonitrile moieties. For examples resins have been prepared from bis phenol A, dihydroxy biphenyl, resorcinol etc. Dhanya et al., RSC Adv. 2016, 5, 91254–91261 discloses a synthesis of phthalonitrile resin bearing cyanate ester group.
  • the phthalonitrile monomer is a compound of the formula: wherein A is any divalent organic radical.
  • US 2003/0229198 Al discloses a process for the preparation of phthalonitrile monomer comprising the formula: wherein Ar is an independently selected divalent aromatic radical; and wherein n is an even integer greater than or equal to 2; comprising the step of reacting a 3- or 4- nitrophthalonitrile with a hydroxy-terminated aromatic ether oligomer.
  • Ar is an independently selected divalent aromatic radical
  • n is an even integer greater than or equal to 2
  • none of the prior art discloses the phthalonitrile or cyanate ester flavan derivatives.
  • the existing products can be used upto the maximum of temperature 350 °C. In view of the importance, there is a need for developing the compounds to explore extending the maximum use temperature.
  • the inventors of the present invention have investigated the influence of phthalonitrile on flavan group for extending the maximum use temperature beyond 400 °C by synthesizing new phthalonitrile flavan resin based on compounds having more than two phenolic hydroxyl groups which involves use of inexpensive raw material which are easily available or prepared from commercially available sources easily and simple synthetic procedure.
  • the melt viscosity of conventional phthalonitrile resins is very low in range 50 to 400 mPaS. The low melt viscosity of these resins creates problems in the fabrication of composites. Particularly it is very difficult to make controlled flow prepregs and zero bleed prepregs using these resins.
  • the current invention relates to preparation of novel phthalonitrile resins which are amorphous solids with a glass transition temperature of 60 to 85 C. When heated to 120 C, the resins become high viscosity liquids with a viscosity of ⁇ 50000 mPaS. The viscosity will decrease to about 10000 to 20000 mPaS at 180 C which is the curing temperature of the resin.
  • the novel phthalonitrile resins are prepared from trihydroxy flavan structures.
  • the trihydoxy flavans are prepared by condensation of ketones with resorcinol.
  • the ketones that can used include acetone, cyclopentanone, cyclohexanone, methyl ethyl ketone etc.
  • the flavans have a unique cycloaliphatic bridge between the aromatic rings of resorcinol.
  • the cycloaliphatic bridge provides a semi flexible link providing increased toughness to the cured resin without reducing the high temperature capabilities.
  • the phthalonitrile resins of this invention have excellent film forming characteristics. Controlled flow or zero bleed prepregs can be very easily manufactured by hot melt film transfer process using the phthalonitrile resins of this invention.
  • the resins of this invention do not need to be converted into prepolymers for the manufacture of prepregs.
  • the monomeric resin itself can be used along with a curing agent without the addition of any other modifiers greatly simplifying the process of making prepregs.
  • the phthalonitrile resins of this invention can be cured in the same manner as conventional phthalonitriles. They can be cured using aromatic diamines, phthalonitriles of amino phenols etc., as a curing agent agents at temperature of 180 to 200°C. The cured resin can be further post cured at 350 to 400°C to enhance the thermal stability of the cured resins.
  • the post cured resins will have glass transition temperature >400°C and decomposition temperature > 475°C.
  • cyanate esters are addition curable resins.
  • the -OCN groups in cyanate and -CN groups in phthalonitrile have similar mechanism of curing; it was of interest to investigate the cure behaviour of a resin possessing both the groups on the flavan based structure.
  • the present invention was also to carry out the preparation of cyanate ester (–OCN) and phthalonitrile groups linked on to the same positions and to examine the implications of these structural modifications on cure behaviour and thermal properties of the resultant resins.
  • cyanate ester monomers were prepared with free phenolic functional groups that gives provision for further chemical modifications if required i.e free phenolic groups to phthalonitrile groups.
  • OBJECTIVE OF THE INVENTION The main objective of the present invention is to provide novel substituted flavan derivatives Formula (I).
  • R is nitrile, nitrile substituted benzene which is further optionally substituted; and R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are independently selected from hydrogen, linear or branched C 1 -C 10 alkyl; R 2 and R 3 or R 4 and R 5 may be taken together with the carbon atom to which they are attached form an optionally substituted 3-7 membered ring containing 0-3 hetero atoms or groups independently selected from N, O, NH and CO.
  • Another objective of the present invention is to provide a process for the preparation of phthalonitrile or cyanate ester flavan derivatives.
  • Still another objective of the present invention is to provide the use of flavan derivatives to produce polymer composite materials which can be used in a variety of technical fields, such as in aerospace, automotive, marine, infrastructure, military, sports, and industrial fields.
  • the present invention relates to novel substituted flavan derivatives Formula (I).
  • R is nitrile, nitrile substituted benzene which is further optionally substituted; and R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are independently selected from hydrogen, linear or branched C 1 -C 10 alkyl; R 2 and R 3 or R 4 and R 5 may be taken together with the carbon atom to which they are attached form an optionally substituted 3-7 membered ring containing 0-3 hetero atoms or groups independently selected from N, O, NH and CO.
  • the present invention provides novel phthalonitrile flavan type compound of Formula (Ia).
  • Formula (Ia) In another aspect, the present invention provides novel phthalonitrile flavan type compound of Formula (Ib).
  • Formula (Ib) In another aspect, the present invention provides novel phthalonitrile flavan type compound of Formula (Ic). Formula (Ic) In another aspect, the present invention provides novel cyanate ester flavan derivative of Formula (Id). Formula (Id) In another aspect, the present invention provides a process for the preparation of novel substituted flavan derivatives of Formula (I).
  • R is nitrile, nitrile substituted benzene which is further optionally substituted; R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are as defined above; wherein the process comprises reaction of compound of Formula (II) Formula (II) wherein, R 1 , R 2 , R 3 , R 4 ,R 5 and R 6 are as defined above; with nitrobenzene dinitrile or halonitrile using a base in presence of suitable solvent to give compound of Formula (I).
  • the present invention provides a process for the preparation of novel substituted flavan derivatives.
  • the present invention provides the use of flavan derivatives of Formula (I) Formula (I) wherein, R is nitrile groups, substituted or unsubstituted benzene wherein the substitutions are nitrile groups; and R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are as defined above; to produce polymer composite materials which can be used in a variety of technical fields, such as in aerospace, automotive, marine, infrastructure, military, sports, and industrial fields.
  • Figure 1 FR-IR spectra of compound of Formula (Ia)
  • Figure 2 Proton NMR spectrum of compound of Formula (Ia)
  • Figure 3 Carbon NMR spectrum of compound of Formula (Ia)
  • Figure 4 Mass spectrum of compound of Formula (Ia)
  • Figure 5 DSC spectrum of compound of Formula (Ia)
  • Figure 6 FR-IR spectra of compound of Formula (Ic)
  • Figure 7 Proton NMR spectrum of compound of Formula (Ic)
  • Figure 8 Mass spectrum of compound of Formula (Ic)
  • Figure 9 DSC spectrum of compound of Formula (Ic) DETAILED DESCRIPTION OF THE INVENTION
  • the group “R” as used herein and is not limited to nitrile, nitrile substituted benzene which is further optionally substituted, specifically phthalonitrile.
  • substitutions on benzene group as used herein are not limited to nitrile groups.
  • the group “R” as used herein is specifically nitrile, phthalonitrile groups.
  • the “alkyl” group as used herein is same or different and independently represent unsubstituted or substituted groups selected from C 1 -C 10 alkyl such as methyl, ethyl, n-propyl and the like; the substituents include hydroxy, halogen such as fluorine, chlorine, bromine and the like; nitro, cyano or amino, (C 1 -C 6 ) alkyl, (C 1 -C 6 ) alkoxy, aryl or aroyl groups.
  • Substituents as used herein is selected from hydroxy, halogen such as fluorine, chlorine, bromine and the like; nitro, cyano or amino, (C 1 -C 6 ) alkyl, (C 1 -C 6 ) alkoxy, aryl or aroyl groups.
  • the present invention specifically provides compounds of Formula (I) selected from the group consisting of: phthalonitrile derivative of 2,4,4-trimethyl-7,2’,4’-trihydroxyflavan (Compound of Formula (Ia)); phthalonitrile derivative of 2',4',7-trihydroxy-2,3-propanoflavan-4- spirocyclopentane (Compound of Formula (Ib)); phthalonitrile derivative of 2,3-butano-2',4',7-trihydroxyflavan-4- spirocyclohexane (Compound of Formula (Ic)); and 2,4,4-trimethyl-7,2',4'-tricyanatoflavan (Compound of Formula (Id)).
  • the definition of “substituted flavan derivatives of Formula (I)” inherently includes all stereoisomers of the compound of Formula (I) either as pure stereoisomer or as a mixture of two or more stereomers.
  • the word stereoisomers includes enantiomers, diasteroisomers, racemates, cis isomers, trans isomers and mixture thereof.
  • stereoisomer is substantially free, i.e. associated with less than 50%, preferably less than 20%, more preferably less than 5%, in particularly less than 2% or 1% of the other isomers.
  • a compounds of formula (I) is for instance specified as (R)
  • the compound of Formula (I) is for instance specified as E
  • the compounds of Formula (I) is for instance specified as cis isomer, this means that the compound is free of the trans isomer.
  • the present invention also provides a process for the preparation of phthalonitrile flavan derivative of Formula (Ia)
  • the present invention also provides a process for the preparation of phthalonitrile flavan derivative of Formula (Ib) Formula (Ib) wherein the process comprising reaction of compound of Formula (IIb) Formula (IIb) with compound of Formula (III) Formula (III) using a base in presence of suitable solvent to give compound of Formula (Ib).
  • the present invention also provides a process for the preparation of phthalonitrile flavan derivative of Formula (Ic) Formula (Ic) wherein the process comprising reaction of compound of Formula (IIc) Formula (IIc) with compound of Formula (III) Formula (III) using a base in presence of suitable solvent to give compound of Formula (Ic).
  • the present invention provides a process for the preparation of cyanate ester flavan derivative of Formula (Id) Formula (Id) wherein the process comprising reaction of compound of Formula (IIa) Formula (IIa) with halonitrile using a base in presence of suitable solvent to give compound of Formula (Id).
  • the present invention provides a simple, economical and commercially feasible procedure for synthesis of phthalonitrile or cyanate ester flavan derivatives with commercially acceptable high temperature capabilities.
  • the present invention provides use of flavan derivatives to produce polymer composite materials which can be used in a variety of technical fields, such as in aerospace, automotive, marine, infrastructure, military, sports, and industrial fields.
  • the reactions of the present invention are carried out in the absence or presence of a solvent.
  • the reaction of phthalonitrilation as given in the present invention is carried out at a temperature in the range 30 °C to 40 °C.
  • the nitrilation reaction as given in the present invention is carried out at a temperature in the range -10 °C to 40 °C.
  • the purification as given in any of the reaction steps referred herein is carried out at a temperature in the range -10 °C to 60 °C.
  • solvent used in the present invention is selected from water or "alcohol solvents” such as methanol, ethanol, n-propanol, isopropanol, n-butanol and t-butanol and the like or "hydrocarbon solvents” such as benzene, toluene, xylene, heptane, hexane and cyclohexane and the like or "ketone solvents” such as acetone, ethyl methyl ketone, diethyl ketone, methyl tert-butyl ketone, isopropyl ketone and the like or "esters solvents” such as methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, and the like or "nitrile solvents” such as acetonitrile
  • base used in the present invention is selected from either inorganic base like alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide; alkali metal carbonates such as sodium carbonate, potassium carbonate, cesium carbonate and lithium carbonate; Alkali metal bicarbonates such as sodium bicarbonate and potassium bicarbonate; alkali metal alkoxides such as sodium methoxide, potassium methoxide, sodium tertiary butoxide, potassium tertiary butoxide or mixtures thereof; alkyl metals such as n-butyl lithium or silicon-based amides, such as sodium and potassium bis(trimethylsilyl)amide, Lithium hexamethyldisilazide, Sodium hexamethyldisilazide and potassium hexamethyldisilazide or organic bases such as LDA (lithium diisopropylamide), triethylamine, triethanolaminetributylamine, N-methylmorpholine,
  • LDA lithium
  • the synthesized phthalonitrile or cyanate ester flavan derivatives of Formula (1a) and Formula (1b) were characterized using FT-IR spectroscopy.
  • the curing study of synthesized compounds were studied by Differential Scanning Calorimetry (DSC).
  • the thermal stability of was analyzed using Thermo gravimetric Analyzer (TGA).
  • the current invention relates to preparation of novel phthalonitrile resins which are amorphous solids with a glass transition temperature of 60 to 85 C . When heated to 120 C the resins become high viscosity liquids with a viscosity of ⁇ 50000 mPaS. The viscosity will decrease to about 10000 to 20000 mPaS at 180 C which is the curing temperature of the resin.
  • the novel phthalonitrile resins are prepared from tri hydroxy flavan structures.
  • the trihydoxy flavans are prepared by condensation of ketones with resorcinol.
  • the ketones that can used include acetone, cyclopentanone, cyclohexanone, methyl ethyl ketone etc.
  • the resins are particularly suitable for production of zero bleed prepregs with carbon fibres, glass fibres or quartz fibres.
  • the prepregs can be used for the manufacture composite components for aeroengine components, structural components of missiles, airframe, launch vehicles and satellites which are required to function at high temperatures in the range 250°C to 350°C.
  • the resins can also be used for preparation of compression moulding compounds.
  • the flavans have a unique cycloaliphatic bridge between the aromatic rings of resorcinol.
  • the cycloaliphatic bridge provides a semi flexible link providing increased toughness to the cured resin without reducing the high temperature capabilities.
  • the phthalonitrile resins of this invention have excellent film forming characteristics. Controlled flow or zero bleed prepregs can be very easily manufactured by hot melt film transfer process using the phthalonitrile resins of this invention. Further, unlike the conventional phthalonitrile resins, the resins of this invention do not need to be converted into prepolymers for the manufacture of prepregs.
  • the monomeric resin itself can used along with a curing agent without the addition of any other modifiers greatly simplifying the process of making prepregs.
  • the phtalonitrile resins of this invention can be cured in the same manner as conventional phthalonitriles. They can be cured using aromatic diamines, phthalonitriles of amino phenols etc. Additionally, cyanate esters are addition curable resins.
  • the -OCN groups in cyanate and -CN groups in phthalonitrile havie similar mechanism of curing; it was of interest to investigate the cure behaviour of a resin possessing both the groups on the flavan based structure.
  • the present invention was also to evaluate the preparation of cyanate ester (–OCN) and phthalonitrile groups linked on to the same positions and to examine the implications of these structural modifications on cure behaviour and thermal properties of the resultant resins.
  • Example-2 Synthesis of phthalonitrile derivative of 2,4,4-trimethyl-7,2’,4’- trihydroxyflavan (Compound of Formula (Ia)): 2,4,4-Trimethyl-7,2’,4’-trihydroxyflavan (30.0 g, 0.1mol), 4-nitrophthalonitrile (52.5 g, 0.3mol) were dissolved in DMSO (300 ml) in a round bottom flask. Potassium carbonate (41.6g, 0.3mol) was added in four lots to the above mixture and stirred for 24 hours at room temperature. After completion of the reaction (monitored by TLC), reaction mass was poured slowly into water (750ml).
  • Example-3 Synthesis of phthalonitrile derivative of 2,4,4-trimethyl-7,2’,4’- trihydroxyflavan (Compound of Formula (Ia)): 2,4,4-Trimethyl-7,2’,4’-trihydroxyflavan (30.0 g, 0.1mol), 4-nitro phthalonitrile (52.5 g, 0.3mol) were dissolved in DMF (250 ml) in a round bottom flask. Potassium carbonate (41.6g, 0.3mol) was added in four lots to the above mixture and stirred for 24 hours at room temperature. After completion of the reaction (monitored by TLC), reaction mass was poured slowly into water (750ml).
  • Example-4 Synthesis of phthalonitrile derivative of 2,4,4-trimethyl-7,2’,4’- trihydroxyflavan (Compound of Formula (Ia)): 2,4,4-Trimethyl-7,2’,4’-trihydroxyflavan (30.0 g, 0.1mol), 4-nitro phthalonitrile (52.5 g, 0.3mol) were dissolved in NMP (300 ml) in a round bottom flask. Potassium carbonate (41.6g, 0.3mol) was added in four lots to the above mixture and stirred for 24 hours at room temperature.
  • Example-5 Synthesis of phthalonitrile derivative of 2,4,4-trimethyl-7,2’,4’- trihydroxyflavan (Compound of Formula (Ia)): 2,4,4-Trimethyl-7,2’,4’-trihydroxyflavan (30.0 g, 0.1mol), 4-nitrophthalonitrile (52.5 g, 0.3mol) were dissolved in DMSO (300 ml) in a round bottom flask. Sodium hydroxide (12 g, 0.3mol) was added in four lots to the above mixture and stirred for 24 hours at room temperature.
  • Example-6 Synthesis of 2' ,4' ,7-trihydroxy-2,3-propanoflavan-4-spirocyclo pentane (Compound of Formula (IIb)): Resorcinol (39.65 g, 360mmol), cyclopentanone (10.11 g, 120mmol) and distilled water (400 ml) taken in a four necked round bottom flask and stirred for few minutes to get clear solution.
  • Example-7 Synthesis of phthalonitrile derivative of 2' ,4' ,7-trihydroxy-2,3- propanoflavan-4-spirocyclo pentane (Compound of Formula (Ib)): 2' ,4' ,7-Trihydroxy-2,3-propanoflavan-4-spirocyclopentane (4g, 11.35mmol), 4-nitro phthalonitrile (5.9 g, 34mmol) were dissolved in DMSO (30 ml) in round bottom flask. Potassium carbonate (4.7g, 34mmol) was added in four lots to the above mixture and stirred for 24 hours at room temperature. After completion of the reaction, reaction mass was poured into water (250ml) while stirring.
  • Example-8 Synthesis of phthalonitrile derivative of 2' ,4' ,7-trihydroxy-2,3- propanoflavan-4-spirocyclo pentane (Compound of Formula (Ib)): 2' ,4' ,7-Trihydroxy-2,3-propanoflavan-4-spirocyclopentane (4g, 11.35mmol), 4-nitro phthalonitrile (5.9 g, 34mmol) were dissolved in DMF (30 ml) in round bottom flask.
  • Example-9 Alternative process for the synthesis of phthalonitrile derivative of 2' ,4' ,7-trihydroxy-2,3-propanoflavan-4-spirocyclopentane(Compound of Formula (Ib)): 2' ,4' ,7-Trihydroxy-2,3-propanoflavan-4-spirocyclopentane (4g, 11.35mmol), 4-nitro phthalonitrile (5.9 g, 34mmol) were dissolved in DMSO (30 ml) in round bottom flask, sodium hydroxide (0.14 g, 34mmol) was added in four lots to the above mixture and stirred for 24 hours at room temperature. After completion of the reaction, reaction mass was poured into water (250ml) while stirring.
  • Example-10 Synthesis of 2,3-Butano-2' ,4' ,7-trihydroxyflavan-4-spirocyclohexane (Compound of Formula (IIc)): Resorcinol (20.85 g, 189.37mmol), cyclohexanone (6 g, 61.13mmol) and distilled water (200ml) were taken in a double necked round bottom flask and stirred for few minutes to get clear solution.
  • Example-11 Synthesis of phthalonitrile derivative of 2, 3- butano-2' , 4' , 7- trihydroxy flavan -4-spirocyclo hexane (Compound of Formula (Ic)): 2,3-Butano-2' ,4' ,7-trihydroxyflavan-4-spirocyclohexane (4g, 10.51mmol), 4- nitrophthalonitrile (5.46 g, 31.53mmol) were dissolved in DMSO solvent (30ml) in a round bottom flask.
  • Potassium carbonate (4.56 g, 32.99mmol) was added in four lots to above mixture and stirred at room temperature for 24 hours. After completion of the reaction, pour the reaction mass into water (250ml) while stirring. Filtered the product and dried to get the title compound (6.5 g).
  • Example-12 Synthesis of phthalonitrile derivative of 2, 3- butano-2' ,4' ,7- trihydroxy flavan-4-spirocyclo hexane (Compound of Formula (Ic)): 2,3-Butano-2' ,4' ,7-trihydroxyflavan-4-spirocyclohexane (4g, 10.51mmol), 4- nitrophthalonitrile (5.46 g, 31.53mmol) were dissolved in DMF solvent (30ml) in a round bottom flask. Potassium carbonate (4.56 g, 32.99mmol) was added in four lots to above mixture and stirred at room temperature for 24 hours. After completion of the reaction, pour the reaction mass into water (250ml) while stirring.
  • Example-14 Synthesis of 2,4,4-trimethyl-7,2',4'-tricyanatoflavan (Compound of Formula (Id)) To the solution of 2,4,4-Trimethyl-7,2’,4’-trihydroxyflavan (30.0 g, 0.1mol), in 30 ml of methanol slowly add Potassium hydroxide (16.8 g, 0.3 mol), and cool the reaction mass to -15oC to -10oC. Slowly add cyanogen bromide (42 g, 0.4 mol) in methanol (60 ml) to the reaction mass over a period of 60 minutes. Maintain the reaction mass at the same temperature for 4-5 hrs.
  • Potassium hydroxide 16.8 g, 0.3 mol
  • cyanogen bromide 42 g, 0.4 mol
  • methanol 60 ml
  • Example-15 Synthesis of 2,4,4-trimethyl-7,2',4'-tricyanatoflavan (Compound of Formula (Id)) To the solution of 2,4,4-Trimethyl-7,2’,4’-trihydroxyflavan (30.0 g, 0.1mol), in 30 ml of methanol slowly add Sodium carbonate (42.4 g, 0.4 mol), and cool the reaction mass to -15oC to -10oC. Slowly add cyanogen bromide (42 g, 0.4 mol) in methanol (60 ml) to the reaction mass over a period of 60 minutes. Maintain the reaction mass at the same temperature for 4-5 hrs.
  • Example-16 Synthesis of of 2,4,4-trimethyl-7,2',4'-tricyanatoflavan (Compound of Formula (Id)) : To the solution of 2,4,4-Trimethyl-7,2’,4’-trihydroxyflavan (30.0 g, 0.1mol), in 30 ml of methanol slowly add triethylamine (40.4 g, 0.4 mol), and cool the reaction mass to - 15oC to -10oC. Slowly add cyanogen bromide (42 g, 0.4 mol) in methanol (60 ml) to the reaction mass over a period of 60 minutes. Maintain the reaction mass at the same temperature for 4-5 hrs.
  • Example-17 Synthesis of of 2,4,4-trimethyl-7,2',4'-tricyanato flavan (Compound of Formula (Id)) : To the solution of 2,4,4-Trimethyl-7,2’,4’-trihydroxyflavan (30.0 g, 0.1mol), in 30 ml of DMF slowly add Sodium hydroxide (12 g, 0.4 mol), and cool the reaction mass to - 15oC to -10oC. Slowly add cyanogen bromide (42 g, 0.4 mol) in DMF (60 ml) to the reaction mass over a period of 60 minutes. Maintain the reaction mass at the same temperature for 4-5 hrs.
  • Example-18 Synthesis of 2,4,4-trimethyl-7,2',4'-tricyanatoflavan (Compound of Formula (Id)) To the solution of 2,4,4-Trimethyl-7,2’,4’-trihydroxyflavan (30.0 g, 0.1mol), in 30 ml of methanol slowly add sodium hydroxide (12 g, 0.3 mol), Slowly add cyanogen bromide (42 g, 0.4 mol) in methanol (60 ml) to the reaction mass at the room temperature over a period of 60 minutes. Maintain the reaction mass at the same temperature for 4-5 hrs. After completion of the reaction (monitored by TLC), distill off methanol under vacuum and add 300 ml of water. Extract the product with MDC (3X100 ml) and wash the MDC layer with water (100 ml). Dry the MDC layer with sodium sulphate and distill-off solvent to get the title compound (28 g, 74.6% yield).
  • sodium hydroxide 12 g, 0.3 mol

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Abstract

La présente invention concerne de nouveaux dérivés de flavane substitués de formule (I). La présente invention concerne également un procédé de préparation de dérivés de phtalonitrile ou d'ester de cyanate flavane. La présente invention concerne également l'utilisation de nouveaux dérivés de flavane substitués pour produire des matériaux composites polymères.
PCT/IB2020/058487 2020-06-19 2020-09-12 Nouveaux dérivés de flavane substitués et leur procédé de préparation WO2021255512A1 (fr)

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Citations (1)

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Publication number Priority date Publication date Assignee Title
US3553244A (en) * 1963-02-16 1971-01-05 Bayer Ag Esters of cyanic acid

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3553244A (en) * 1963-02-16 1971-01-05 Bayer Ag Esters of cyanic acid

Non-Patent Citations (2)

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AUGUSTINE DHANYA, MATHEW DONA, NAIR C. P. REGHUNADHAN: "Phthalonitrile resin bearing cyanate ester groups: synthesis and characterization", RSC ADVANCES, vol. 5, no. 111, 26 October 2015 (2015-10-26), pages 91254 - 91261, XP055889694, DOI: 10.1039/C5RA18045G *
ISSAM A. MOHAMMED ET AL.: "Synthesis of 1,3-benzoxazines Based on 2,4,4-trimethyl-7,2’,4’-trihydroxy Flavan: Antibacterial, Anti-inflammatory, Cyclooxygenase-2 Inhibition and Molecular Modelling Studies", LETTERS IN DRUG DESIGN & DISCOVERY, vol. 16, no. 1, 2019, pages 58 - 65, DOI: 10.2174/1570180815666180420100922 *

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