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Tiruvettipuram K Thiruvengadam, Chou Hong Tann, Junning Lee, Timothy McAllister, Anantha Sudhakar: Process for the stereospecific synthesis of azetidinones. Schering Corporation, Paul A Thompson, Anita W Magatti, April 26, 1994: US05306817 (38 worldwide citation)

This invention provides an improved process for producing azetidinones. More particularly, this invention provides the steps of producing an trans-azetidinone represented by the formula ##STR1## from a carboxylic acid R.sup.2 -D-CH.sub.2 -COOH, an aldehyde R.sup.1 -A-CHO and an amine RNH.sub.2, by t ...


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Tiruvettipuram K Thiruvengadam, Chou Hong Tann, Timothy L McAllister: Process for the stereospecific synthesis of azetidinones. Schering Corporation, John H C Blasdale, Norman C Dulak, Anita W Magatti, October 1, 1996: US05561227 (31 worldwide citation)

This invention provides an improved process for producing azetidinones. More particularly, this invention provides the steps of producing an azetidinone represented by the formula I ##STR1## from a carboxylic acid R.sup.2 --D--CH.sub.2 COOH, an aldehyde R.sup.1 --A--CHO and an amine RNH.sub.2, by th ...


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Tiruvettipuram Kannapan Thiruvengadam, Timothy McAllister, Chou Hong Tann: Process for the synthesis of azetidinones. Schering Corporation, Anita W Magatti, March 17, 1998: US05728827 (31 worldwide citation)

This invention provides a process for preparing azetidinones useful as intermediates in the synthesis of penems and as hypocholesterolemic agents, particularly for azetidinones substituted in the C-3 and C-4 positions and optionally substituted at the ring nitrogen, comprising reacting a .beta.-(sub ...


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Tiruvettipuram K Thiruvengadam, Chou Hong Tann, Junning Lee, Timothy McAllister, Cesar Colon, Derek H R Barton, Ronald Breslow, Anantha Sudhakar: Process for the stereospecific synthesis of azetidinones. Schering Corporation, Paul A Thompson, July 25, 2000: US06093812 (28 worldwide citation)

This invention provides an improved process for producing azetidinones. More particularly, this invention provides the steps of producing an trans-azetidinone represented by the formula ##STR1## from a carboxylic acid R.sup.2 --D--CH.sub.2 COOH, an aldehyde R.sup.1 --A--CHO and an amine RNH.sub.2, b ...


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Xiaoyong Fu, Tiruvettipuram K Thiruvengadam, Chou Hong Tann, Cesar Colon: Process for preparing .DELTA.9,11 and 21-chloro corticosteroids. Schering Corporation, Anita W Magatti, April 1, 1997: US05616742 (19 worldwide citation)

Described is a process for the regioselective dehydration of 11-hydroxy steroids using PCl.sub.5, PCl.sub.3, POCl.sub.3 or either SO.sub.2 Cl.sub.2 and imidazole, or PPh.sub.3 and CCl.sub.4. The disclosed process selectively forms .DELTA..sup.9,11 steroids from either 11-.alpha.- or 11-.beta.-hydrox ...


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Daw Iong Albert Kwok, David J S Tsai, Chou Hong Tann, Xiaoyong Fu: Process for the preparation of 17-esters of 9 .alpha., 21-dihalo-pregnane-11 .beta., 17 .alpha.-diol-20-ones. Schering Corporation, Arthur Mann, Anita W Magatti, March 23, 1999: US05886200 (9 worldwide citation)

The invention provides an improved process for the preparation of 17-esters of 9.alpha.,21 -dihalo-pregnane-11.beta.,17.alpha.-diol-20-ones, and in particular for the preparation of 17-esters of anti-inflammatory steroids according to the following scheme: ##STR1## wherein RCO, R.sup.1, X, Y and the ...


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Xiaoyong Fu, Tiruvettipuram K Thiruvengadam, Chou Hong Tann, Junning Lee, Cesar Colon: Process for preparing delta 9,11 and 21-chloro corticosteroids. Schering Corporation, Paul A Thompson, March 26, 1996: US05502222 (7 worldwide citation)

Described is a process for the regioselective dehydration of 11-hydroxy steroids using PCl.sub.5, PCl.sub.3, POCl.sub.3 or either SO.sub. Cl.sub.2 and imidazole, or PPh.sub.3 and CCl.sub.4. The disclosed process selectively forms .increment..sup.9,11 steroids from either 11-.alpha.- or 11-.beta.-hyd ...


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Xiaoyong Fu, Tiruvettipuram K Thiruvengadam, Chou Hong Tann, Junning Lee, Cesar Colon: Process for preparing delta 9, 11 and 21-chlorocorticosteroids. Schering Corporation, Arthur Mann, Paul A Thompson, May 12, 1998: US05750745 (6 worldwide citation)

Described is a process for the regioselective dehydration of 11-hydroxy steroids using PCl.sub.5, PCl.sub.3, POCl.sub.3 or either SO.sub.2 Cl.sub.2 and imidazole, or PPh.sub.3 and CCl.sub.4. The disclosed process selectively forms .DELTA..sup.9,11 steroids from either 11-.alpha.- or 11-.beta.-hydrox ...