67040-46-4Relevant articles and documents
Total syntheses of (±) and (-)-stemoamide
Jacobi, Peter A.,Lee, Kyungae
, p. 4295 - 4303 (2007/10/03)
(±)-Stemoamide (1) was prepared in seven steps beginning with y- chlorobutryl chloride (20) and succinimide (15), which were efficiently converted to the key alkyne oxazole 17 on a multigram scale. Intramolecular (Diels-Alder)-(retro-Diels-Alder) reaction of 17 then gave butenolide 12b directly upon aqueous workup. The remaining two stereocenters in 1 were established in a single step by a highly selective reduction of 12b (NaBH4/NiCl2), followed by equilibration to the thermodynamically favored natural configuration. In analogous fashion (-)-stemoamide (1) was prepared beginning with L-pyroglutamic acid (S-35).
Heterocyclic Prostaglandins. V. Synthesis of (12R,15S)-(-)-11-Deoxy-8-azaprostaglandin E1 and Related Compounds
Saijo, Shigeyoshi,Wada, Masao,Himizu, Jun-ichi,Ishida, Akihiko
, p. 1449 - 1458 (2007/10/02)
The synthesis of (12R,15S)-(-)-11-deoxy-8-azaprostaglandin E1 ((R)-1a) and three diastereomers ((R)-2a, (S)-1a, and (S)-2a) starting from optically active pyroglutamic acid ((R)-3 and (S)-3) is reported.Esterification of (R)-3 and NaBH4 reduction gave (R)-(-)-5-hydroxymethyl-2-pyrrolidinone ((R)-5).Ethoxyethylation of (R)-5 and N-alkylation with methyl 7-bromoheptanoate, followed by acid treatment, provided (R)-hydroxymethyl pyrrolidinone ((R)-8).The Collins oxidation of (R)-8 gave (R)-(-)-methyl 7-(5-formyl-2-oxo-1-pyrrolidine)heptanoate ((R)-9), which served as a key intermediate.The Wittig reaction of (R)-9 and dimethyl 2-oxoheptylphosphonate gave the (R)-enone ((R)-10a) which was converted to the (12R,15S)-enol ((R)-11a) and (12R,15R)-enol ((R)-12a) by NaBH4 reduction.Alkaline hydrolysis of (R)-11a and (R)-12a gave (R)-1a and (R)-2a in high yields.Similarly, the (S)-aldehyde ((S)-9) was prepared from (S)-3 and converted to the (12S,15S)-acid ((S)-1a) and (12S,15R)-acid ((S)-2a) by the same sequence of reactions used for the (R)-series.Some (12R,15S)-acid derivatives ((R)-1b-g) with a modified ω-chain were also synthesized.These analogs ((R)-1b-g) were also prepared from (R)-9 via synthetic sequences similar to that described above.Keywords - heterocyclic prostaglandin; (12R,15S)-(-)-11-deoxy-8-azaprostaglandin E1; (12R,15R)-(-)-11-deoxy-8-azaprostaglandin E1; (12S,15S)-(+)-11-deoxy-8-azaprostaglandin E1; (12S,15R)-(+)-11-deoxy-8-azaprostaglandin E1; (R)-(-)-methyl 7-(5-formyl-2-oxo-1-pyrrolidine)heptanoate; (S)-(+)-methyl 7-(5-formyl-2-oxo-1-pyrrolidine)heptanoate
