Shuji Miura

Prostaglandin chemistry—V : Synthesis of new prostaglandin synthons; 4(R)-(+)- and 4(S)-(−)-t-butyldimethylsiloxycyclopent-2-en-1-one

Abstract Optically active prostaglandin intermediates, 4( R )-(+)- and 4( S )-(−)-hydroxycyclopent-2-en-1-one derivatives, were synthesized from 3( R ),5( R )-diacetoxycyclopent-1-ene, 3( R )-acetoxy-5( R )-hydroxycyclopent-1-ene and 3( S ),5( S )-dihydroxycyclopent-1-ene obtained by microbiological hydrolysis of 3,5-diacetoxycyclopent-1-ene. The absolute configurations of all these compounds were determined by the exciton chirality method and the induced CD method. The optical purities were determined by NMR measurements of the diastereomeric esters of a versatile optically pure acid, (+)-α-methoxy-α-trifluoromethylphenylacetic acid.

Prostaglandin chemistry—IV : Microbiological kinetic resolution and asymmetric hydrolysis of 3,5-diacetoxycyclopent-1-ene

Abstract A 1:1 mixture of cis- and trans-3,5-diacetoxycyclopent-1-ene (1) was asymmetrically hydrolysed by bakers yeast to give trans-3(R)-acetoxy-5(R)-hydroxycyclopent-1-ene (R-2a) and S-predominant 3,5-dihydroxycyclopent-1-ene (3) accompanied by trans-3(R),5(R)-diacetoxycyclopent-1-ene (R-1a). The optical activities on the products were found to be dependent on the difference of the enzymatic hydrolytic rate among cis-, trans(S,S)- and trans(R,R)-3,5-diacetoxycyclopent-1-ene. The asymmetric hydrolysis was also investigated on wheat germ lipase, citrus acetyl esterase, and the lipase prepared from Aspergillus niger.

Prostaglandin chemistry—VIII : Synthesis of optically active 7-oxoprostaglandins

Abstract Regiospecific α-acylation of β-alkenylated enolates generated by conjugate addition of lithium organocuprates to α,β-unsaturated ketones is described. Several new 7-oxoprostaglandin analogues, 7-oxoprostaglandin E 1 ( 18 ), 11-deoxy-7-oxoprostaglandin E 1 ( 23 ), and their 15-epi enantiomers 17 and 22 , were synthesized by conjugate addition-acylation method. From optically active 4( R ) -t - butyldimethylsiloxycyclopent - 2 - en - 1 - one ( R - 11 ), 7-oxoprostaglandin E 1 ( 18 ) was synthesized. Determination of the absolute configuration of 11-deoxy-7-oxoprostaglandin E 1 ( 23 ) and its 15-epi enantiomer ( 22 ) on the basis of CD study is described. Successful acylation of β-alkenylated lithium copper enolates with reactive acylating agents such as thiol esters and N-acyl imidazole as well as acyl halides is described.

Prostaglandin chemistry VI. Synthesis of 8-methoxycarbonylprostaglandins

Cyclopentenon (I) reagiert mit den Lithium-cupraten (II) nach anschliesender Umsetzung mit Chlorkohlensaureester (III) zu Mischungen der Substitutionsprodukte (IV) und (V), aus dem Tetrahydropyranyloxy-cyclopentenon (VI) entstehen die beiden Substitutionsprodukte (VII) und (VIII).