51233-80-8Relevant articles and documents
5-phenylpyrrolo-1,4-benzoxazine and 5-phenylpyrrolo-1,4-benzothiazine compounds, process and intermediates for their production and pharmaceutical compositions containing them
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, (2008/06/13)
Pharmacologically active compounds of formula I STR1 which can be substituted in the phenyl rings and in which R1 denotes hydrogen or lower alkyl, R2 denotes hydrogen or lower alkyl, Y denotes oxygen or sulfur n represents an integer from 1 to 3 Z represents a bond, a CO group or a CH= group, Q denotes nitrogen or the CH group and R7, if Q denotes nitrogen, represents an optionally substituted pyridyl or phenyl radical or, if Q denotes the CH group, represents the N-methyl-N-(4-oxo-3H-pyrimidin-2-yl)amino group, and their acid addition salts and processes and intermediates for their preparation.
ACYCLIC STEREOSELECTION-13; ARYL ESTERS: REAGENTS FOR THREO-ALDOLIZATION
Heathcock, Clayton H.,Pirrung, Michael C.,Montgomery, Stephen H.,Lampe, John
, p. 4087 - 4095 (2007/10/02)
Preformed Li enolates of hindered aryl esters condense with aldehydes to give predominantly threo aldols.The method has been explored with esters 3 (DMP propionate), 4 (BHT propionate), 5 (DBHA propionate).DMP propionate reacts with benzaldehyde and α-unbranched aliphatic aldehydes to give threo:erythro ratios of about 6.5:1.However, with α-branched aliphatic aldehydes, ester 3 gives only threo-aldols.BHT propionate and DBHA propionate give only threo-aldols with all aldehydes studied.The DMP aldols may be converted into β-hydroxy acids by simple hydrolysis with KOH in aqueous methanol.BHT aldols cannot be hydrolyzed without retroaldolization.However, these aldols can be reduced to diastereomerically pure 1,3-diols.The DBHA aldols can converted into β-hydroxy acids by a method involving oxidation with ceric ammonium nitrate (CAN) in aqueous acetonitrile.Threo-selectivity is also seen in the condensations of DMP butyrate (15), DBHA butyrate (16), DMP pentenoate (17), and BHT pentenoate (18).The approach has been utilized in a stereoselective synthesis of racemic methyl corynomycolate.