Patents by Inventor Apurba Bhattacharya
Apurba Bhattacharya has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 7534882Abstract: A method for aminating pyrrole derivatives via in situ generated chloramines and for preparing pyrrolotriazine compounds having the formula III,Type: GrantFiled: April 3, 2006Date of Patent: May 19, 2009Assignee: Bristol-Myers Squibb CompanyInventors: Apurba Bhattacharya, Nitinchandra Patel, John Anthony Grosso, Luca Parlanti
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Publication number: 20070249563Abstract: Processes for preparing fosphenytoin.Type: ApplicationFiled: April 20, 2007Publication date: October 25, 2007Inventors: Apurba Bhattacharya, Vijayabhaskar Bolugoddu, Pravinchandra Vankawala, Chandrasekhar Elati, Srinivas Gangula, Amarnath Lekkala, Ramakrishna Mallemula, Anitha Naredla, Ashok Sigala
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Publication number: 20070032657Abstract: A method of preparing an intermediate which is useful for the preparation of azaindole derivatives.Type: ApplicationFiled: July 25, 2006Publication date: February 8, 2007Inventors: Prashant Deshpande, John Grosso, Apurba Bhattacharya, Vikram Purohit
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Patent number: 7173152Abstract: The present invention provides a method for the reductive acetamidation of an aryl nitro compound by reacting a substituted acid with an aryl nitro compound and adding a catalytic amount of a base with the substituted acid and the aryl nitro compound to form an acetamidation aryl nitro compound. The acetamidation aryl nitro compound is then purified.Type: GrantFiled: August 19, 2005Date of Patent: February 6, 2007Assignee: The Texas A&M University SystemInventors: Apurba Bhattacharya, Victor Suarez
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Publication number: 20060229449Abstract: A method for aminating pyrrole derivatives via in situ generated chloramines and for preparing pyrrolotriazine compounds having the formula III,Type: ApplicationFiled: April 3, 2006Publication date: October 12, 2006Inventors: Apurba Bhattacharya, Nitinchandra Patel, John Grosso, Luca Parlanti
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Publication number: 20060052638Abstract: The present invention provides a method for the reductive acetamidation of an aryl nitro compound by reacting a substituted acid with an aryl nitro compound and adding a catalytic amount of a base with the substituted acid and the aryl nitro compound to form an acetamidation aryl nitro compound. The acetamidation aryl nitro compound is then purified.Type: ApplicationFiled: August 19, 2005Publication date: March 9, 2006Applicant: The Texas A&M University SystemInventors: Apurba Bhattacharya, Victor Suarez
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Patent number: 6969775Abstract: A process of producing organic compounds, such as acetaminophen, nitroalcohols and indoles, employs a catalyst system of an oxyethylene ether and a metal containing inorganic or organic reagent. The oxyethylene ether at least partially complexes the metal of the inorganic or organic reagent. As such, the reactions may be conducted neat. The processes are environmentally friendly and operationally simple.Type: GrantFiled: September 19, 2003Date of Patent: November 29, 2005Assignee: The Texas A&M University SystemInventors: Apurba Bhattacharya, Gaurang L. Parmar, Vikram C. Purohit, Nitin C. Patel
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Publication number: 20040138509Abstract: A process of producing organic compounds, such as acetaminophen, nitroalcohols and indoles, employs a catalyst system of an oxyethylene ether and a metal containing inorganic or organic reagent. The oxyethylene ether at least partially complexes the metal of the inorganic or organic reagent. As such, the reactions may be conducted neat. The processes are environmentally friendly and operationally simple.Type: ApplicationFiled: September 19, 2003Publication date: July 15, 2004Applicant: The Texas A&M University SystemInventors: Apurba Bhattacharya, Gaurang L. Parmar, Vikram C. Purohit, Nitin C. Patel
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Patent number: 6326509Abstract: An improved process is provided for synthesis of a halomethyl benzoic acid chloromethyl ester, a key intermediate for use in production of azole antifungal compounds and other pharmaceutical products.Type: GrantFiled: May 9, 2000Date of Patent: December 4, 2001Assignee: Bristol-Myers Squibb CompanyInventors: Wangying Yang, Xuebao Wang, Apurba Bhattacharya, Melissa Chau
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Patent number: 5763608Abstract: The present invention provides a process for preparing a 5,6-dihydro-3H-pyrimidin-4-one derivatives which comprises the steps of (a) dehydrating a N-acyl beta amino acid in the presence of a dehydration agent and an organic solvent for a sufficient period of time and under suitable temperature and pressure conditions to form an oxazone (b) adding a carboxylic acid and a primary amine salt of a carboxylic acid to said oxazone to form a mixture, (c) distilling azeotropically said mixture for a suitable period of time and under suitable temperature and pressure conditions to substantially remove said dehydration agent and said organic solvent, and (d) heating the product of step (c) for a sufficient period of time and under suitable temperature and pressure conditions to form said pyrimidin derivatives.Type: GrantFiled: February 5, 1996Date of Patent: June 9, 1998Assignee: Hoechst Celanese CorporationInventors: Apurba Bhattacharya, Diane E. Allen
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Patent number: 5739330Abstract: The present invention provides a process for preparing a quinazolone which comprises the steps of (a) dehydrating a N-acyl beta amino acid in the presence of a dehydration agent and an organic solvent for a sufficient period of time and under suitable temperature and pressure conditions to form an oxazone (b) adding a carboxylic acid and a primary amine salt of a carboxylic acid to said oxazone to form a mixture, (c) distilling azeotropically said mixture for a suitable period of time and under suitable temperature and pressure conditions to substantially remove said dehydration agent and said organic solvent, and (d) heating the product of step (c) for a sufficient period of time and under suitable temperature and pressure conditions to form said quinazolone.Type: GrantFiled: February 5, 1996Date of Patent: April 14, 1998Assignee: Hoechst Celanese CorporationInventors: Apurba Bhattacharya, Diane E. Allen
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Patent number: 5508451Abstract: A process for preparing a dialkali metal cromoglycate which comprises (1) condensing a hydroxy substituted ketone with a condensing agent in the presence of a base material and an organic solvent; (2) subjecting the condensed material to ring-closure conditions, first in the presence of an alkali metal alkoxide and a suitable organic solvent, then followed by the addition of substantially dry mineral acid and a suitable organic solvent; and (3) hydrolyzing the ring-closed material in the presence of a base material and a suitable organic solvent to form said cromoglycate.Type: GrantFiled: July 7, 1994Date of Patent: April 16, 1996Assignee: Hoechst Celanese CorporationInventors: Apurba Bhattacharya, Boyd A. Keys
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Patent number: 5489712Abstract: The present invention provides a novel process for preparing cyclic ketones, such as indanones, which comprises the steps of (a) subjecting a substituted ketone to suitable methylenation conditions in the presence of a methylene transfer agent and an acylating agent for a sufficient period of time and under suitable conditions of temperature and pressure to form the corresponding alpha, beta unsaturated ketone, and (b) subjecting said unsaturated ketone to suitable cyclization conditions in the presence of a suitable acid or base for a sufficient period of time and under suitable conditions of temperature and pressure to form said cyclic ketones.Type: GrantFiled: November 4, 1994Date of Patent: February 6, 1996Assignee: Hoechst Celanese CorporationInventor: Apurba Bhattacharya
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Patent number: 5399707Abstract: A process is provided whereby S(+)-ibuprofen or R(-)-ibuprofen L-lysinate salt is produced by selective precipitation from a mixture containing enantiomers of ibuprofen and L-lysine. The quantity of L-lysine is not more than about a molar equivalent of the quantity of one of the enantiomers in the ibuprofen enantiomeric mixture. Upon precipitation of one ibuprofen enantiomer from the mixture, the overall precipitate and reaction mixture can be held for a sufficient period of time at a second temperature to allow the first precipitate to redissolve into the reaction mixture and the other ibuprofen enantiomer to precipitate out of the mixture in the salt form. Optically active ibuprofen is racemized by being heated at 100.degree. C. to 300.degree. C. in the substantial absence of other materials.Type: GrantFiled: June 10, 1994Date of Patent: March 21, 1995Assignee: Hoechst Celanese CorporationInventors: Apurba Bhattacharya, John R. Fritch, Carl D. Murphy, Larry D. Zeagler, Carina A. McAdams
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Patent number: 5380867Abstract: A process is provided whereby S(+)-ibuprofen or R(-)-ibuprofen L-lysinate salt is produced by selective precipitation from a mixture containing enantiomers of ibuprofen and L-lysine. The quantity of L-lysine is not more than about a molar equivalent of the quantity of one of the enantiomers in the ibuprofen enantiomeric mixture. Upon precipitation of one ibuprofen enantiomer from the mixture, the overall precipitate and reaction mixture can be held for a sufficient period of time at a second temperature to allow the first precipitate to redissolve into the reaction mixture and the other ibuprofen enantiomer to precipitate out of the mixture in the salt form. Optically active ibuprofen is racemized by being heated at 100.degree. C. to 300.degree. C. in the substantial absence of other materials.Type: GrantFiled: October 19, 1993Date of Patent: January 10, 1995Assignee: Hoechst Celanese CorporationInventors: Apurba Bhattacharya, John R. Fritch, Carl D. Murphy, Larry D. Zeagler, Carina A. McAdams
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Patent number: 5338859Abstract: The present invention provides a process for the production of calcium salts of hydantoic acids and which comprises the steps of reacting a hydantoin with a calcium base material such as calcium hydroxide in an aqueous medium at a sufficient temperature and for a sufficient period of time to form the calcium salt of the corresponding hydantoic acid and then separating the calcium salt of such acid from the reaction mass. This separation can include the further steps of cooling the reaction mass down to facilitate the precipitation of the acid/salt crystals and then separating the precipitate by means of filtering or centrifugating. These acids can then be subjected to a HNO.sub.2 -mediated decarbamoylation process followed by an optical resolution step to thus provide high yields of D-p-hydroxyphenylglycine which is a key synthetic immediate or building block for semi-synthetic penicillin and cephalosporins.Type: GrantFiled: February 12, 1993Date of Patent: August 16, 1994Assignee: Hoechst Celanese CorporationInventor: Apurba Bhattacharya
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Patent number: 5332834Abstract: There is disclosed and claimed a process whereby S(+)-ibuprofen L-lysinate salt is produced by selective precipitation from a mixture containing enantiomers of ibuprofen and L-lysine. The quantity of L-lysine is not more than about a molar equivalent of the quantity of S(+)-ibuprofen in the ibuprofen enantiomeric mixture. The mother liquors after separating the above salt are enriched in R-ibuprofen which is racemized by a novel thermal racemization process and may then be recycled.Type: GrantFiled: December 2, 1992Date of Patent: July 26, 1994Assignee: Hoechst Celanese CorporationInventors: Apurba Bhattacharya, John R. Fritch, Carl D. Murphy, Larry D. Zeagler, Carina Araullo-McAdams
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Patent number: 5304610Abstract: A unique polymer was synthesized via copolymerization of vinylpyridine and acetoxystyrene under radical-initiated conditions followed by acidic or basic hydrolysis of the acetoxy group to afford the corresponding hydroxy group. The built-in acid-base dual functionality (phenolic and pyridyl units) in this polymer backbone gives rise to its unique solubility properties over a wide pH range in both aqueous and non-aqueous media. Due to its amphoteric nature, this polymer finds application as an anti-stat, viscosity modifier, and/or ion-exchange resin.Type: GrantFiled: April 2, 1993Date of Patent: April 19, 1994Assignee: Hoechst Celanese CorporationInventors: Apurba Bhattacharya, Kenneth G. Davenport, Michael T. Sheehan, James R. Sounik
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Patent number: 5237061Abstract: A process for preparing compounds of the formula ##STR1## which comprises reacting an imidazolide of the formula ##STR2## with an amine of the formula NHR.sub.4 R.sub.5 in the presence of a Grignard reagent to form a compound of formula I or reacting an imidazolide of formula II with a compound of the formula R.sub.6 Mgx to form a compound of formula I.Type: GrantFiled: October 31, 1988Date of Patent: August 17, 1993Assignee: Merck & Co., Inc.Inventors: Apurba Bhattacharya, Ulf H. Dolling, Joseph S. Amato, John M. Williams
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Patent number: 5232995Abstract: A unique polymer was synthesized via copolymerization of vinylpyridine and acetoxystyrene under radical-initiated conditions followed by acidic or basic hydrolysis of the acetoxy group to afford the corresponding hydroxy group. The built-in acid-base dual functionality (phenolic and pyridyl units) in this polymer backbone gives rise to its unique solubility properties over a wide pH range in both aqueous and non-aqueous media. Due to its amphoteric nature, this polymer finds application as an anti-stat, viscosity modifier, and/or ion-exchange resin.Type: GrantFiled: January 12, 1993Date of Patent: August 3, 1993Assignee: Hoechst Celanese CorporationInventors: Apurba Bhattacharya, Kenneth G. Davenport, Michael T. Sheehan, James R. Sounik