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).

  • Patent number: 7534882
    Abstract: A method for aminating pyrrole derivatives via in situ generated chloramines and for preparing pyrrolotriazine compounds having the formula III,
    Type: Grant
    Filed: April 3, 2006
    Date of Patent: May 19, 2009
    Assignee: Bristol-Myers Squibb Company
    Inventors: Apurba Bhattacharya, Nitinchandra Patel, John Anthony Grosso, Luca Parlanti
  • Publication number: 20070249563
    Abstract: Processes for preparing fosphenytoin.
    Type: Application
    Filed: April 20, 2007
    Publication date: October 25, 2007
    Inventors: Apurba Bhattacharya, Vijayabhaskar Bolugoddu, Pravinchandra Vankawala, Chandrasekhar Elati, Srinivas Gangula, Amarnath Lekkala, Ramakrishna Mallemula, Anitha Naredla, Ashok Sigala
  • Publication number: 20070032657
    Abstract: A method of preparing an intermediate which is useful for the preparation of azaindole derivatives.
    Type: Application
    Filed: July 25, 2006
    Publication date: February 8, 2007
    Inventors: Prashant Deshpande, John Grosso, Apurba Bhattacharya, Vikram Purohit
  • Patent number: 7173152
    Abstract: 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: Grant
    Filed: August 19, 2005
    Date of Patent: February 6, 2007
    Assignee: The Texas A&M University System
    Inventors: Apurba Bhattacharya, Victor Suarez
  • Publication number: 20060229449
    Abstract: A method for aminating pyrrole derivatives via in situ generated chloramines and for preparing pyrrolotriazine compounds having the formula III,
    Type: Application
    Filed: April 3, 2006
    Publication date: October 12, 2006
    Inventors: Apurba Bhattacharya, Nitinchandra Patel, John Grosso, Luca Parlanti
  • Publication number: 20060052638
    Abstract: 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: Application
    Filed: August 19, 2005
    Publication date: March 9, 2006
    Applicant: The Texas A&M University System
    Inventors: Apurba Bhattacharya, Victor Suarez
  • Patent number: 6969775
    Abstract: 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: Grant
    Filed: September 19, 2003
    Date of Patent: November 29, 2005
    Assignee: The Texas A&M University System
    Inventors: Apurba Bhattacharya, Gaurang L. Parmar, Vikram C. Purohit, Nitin C. Patel
  • Publication number: 20040138509
    Abstract: 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: Application
    Filed: September 19, 2003
    Publication date: July 15, 2004
    Applicant: The Texas A&M University System
    Inventors: Apurba Bhattacharya, Gaurang L. Parmar, Vikram C. Purohit, Nitin C. Patel
  • Patent number: 6326509
    Abstract: 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: Grant
    Filed: May 9, 2000
    Date of Patent: December 4, 2001
    Assignee: Bristol-Myers Squibb Company
    Inventors: Wangying Yang, Xuebao Wang, Apurba Bhattacharya, Melissa Chau
  • Patent number: 5763608
    Abstract: 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: Grant
    Filed: February 5, 1996
    Date of Patent: June 9, 1998
    Assignee: Hoechst Celanese Corporation
    Inventors: Apurba Bhattacharya, Diane E. Allen
  • Patent number: 5739330
    Abstract: 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: Grant
    Filed: February 5, 1996
    Date of Patent: April 14, 1998
    Assignee: Hoechst Celanese Corporation
    Inventors: Apurba Bhattacharya, Diane E. Allen
  • Patent number: 5508451
    Abstract: 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: Grant
    Filed: July 7, 1994
    Date of Patent: April 16, 1996
    Assignee: Hoechst Celanese Corporation
    Inventors: Apurba Bhattacharya, Boyd A. Keys
  • Patent number: 5489712
    Abstract: 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: Grant
    Filed: November 4, 1994
    Date of Patent: February 6, 1996
    Assignee: Hoechst Celanese Corporation
    Inventor: Apurba Bhattacharya
  • Patent number: 5399707
    Abstract: 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: Grant
    Filed: June 10, 1994
    Date of Patent: March 21, 1995
    Assignee: Hoechst Celanese Corporation
    Inventors: Apurba Bhattacharya, John R. Fritch, Carl D. Murphy, Larry D. Zeagler, Carina A. McAdams
  • Patent number: 5380867
    Abstract: 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: Grant
    Filed: October 19, 1993
    Date of Patent: January 10, 1995
    Assignee: Hoechst Celanese Corporation
    Inventors: Apurba Bhattacharya, John R. Fritch, Carl D. Murphy, Larry D. Zeagler, Carina A. McAdams
  • Patent number: 5338859
    Abstract: 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: Grant
    Filed: February 12, 1993
    Date of Patent: August 16, 1994
    Assignee: Hoechst Celanese Corporation
    Inventor: Apurba Bhattacharya
  • Patent number: 5332834
    Abstract: 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: Grant
    Filed: December 2, 1992
    Date of Patent: July 26, 1994
    Assignee: Hoechst Celanese Corporation
    Inventors: Apurba Bhattacharya, John R. Fritch, Carl D. Murphy, Larry D. Zeagler, Carina Araullo-McAdams
  • Patent number: 5304610
    Abstract: 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: Grant
    Filed: April 2, 1993
    Date of Patent: April 19, 1994
    Assignee: Hoechst Celanese Corporation
    Inventors: Apurba Bhattacharya, Kenneth G. Davenport, Michael T. Sheehan, James R. Sounik
  • Patent number: 5237061
    Abstract: 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: Grant
    Filed: October 31, 1988
    Date of Patent: August 17, 1993
    Assignee: Merck & Co., Inc.
    Inventors: Apurba Bhattacharya, Ulf H. Dolling, Joseph S. Amato, John M. Williams
  • Patent number: 5232995
    Abstract: 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: Grant
    Filed: January 12, 1993
    Date of Patent: August 3, 1993
    Assignee: Hoechst Celanese Corporation
    Inventors: Apurba Bhattacharya, Kenneth G. Davenport, Michael T. Sheehan, James R. Sounik