An expeditious and practical synthetic process for phytosphingosine and tetrahydroxy-LCB from D-glutamic acid

A concise route to the highly-functionalized azetidine precursor: the enantioselective synthesis of penaresidin B

An efficient, high-yielding and scalable synthesis of penaresidin B is achieved, in which the highly functionalized azetidine precursor is constructed and stereoselectively from glycal.

Discovery of novel prostaglandin analogs of PGE2 as potent and selective EP2 and EP4 receptor agonists

Analogs of PGE(2) with introduction of diene groups at the omega-side chain have been synthesized and evaluated for their binding affinity for EP(2) and EP(4) receptors. An optimized analog (compound 9b) showed high potency and selectivity for the EP(4) receptor over other known receptors.

Synthesis of penaresidin derivatives and its biological activity

A series of stereoisomers for the azetidine ring of penaresidin B was synthesized and their cytotoxic and antimicrobial activities were evaluated. Among six synthetic isomers 1-6, isomers 4 and 5 showed relatively potent cytotoxic activity against A549 (lung) and HT29 (colon) tumor cells as well as antibacterial activity.

Discovery of highly selective EP4 receptor agonists that stimulate new bone formation and restore bone mass in ovariectomized rats

Heptanoic acid lactams, exemplified by 2, were identified as highly selective EP4 agonists via high throughput screening. Lead optimization led to the identification of lactams with a 30-fold increase in EP4 potency in vitro. Compounds demonstrated robust bone anabolic effects when administered in vivo in rat models of osteoporosis.

A general, efficient and stereospecific route to sphingosine, sphinganines, phytosphingosines and their analogs

Sphingosine, sphinganines and phytosphingosines and their analogs were synthesized by an aldol condensation between an iminoglycinate bearing a (+)-(1R,2R,5R)-2-hydroxy-3-pinanone group as chiral auxiliary and an appropriate aldehyde. All condensations proceeded with excellent enantioselectivity to generate the (2S,3R)-D-erythro structures in good yields.

Synthesis of 3'-deoxy-3'-difluoromethyl azanucleosides from trans-4-hydroxy-l-proline

[reaction: see text] Two strategies were tried to synthesize 3'-deoxy-3'-difluoromethyl azanucleosides. After the failure of the first route, the key intermediate 12 from trans-4-hydroxyproline 7 in 8 steps was stereoselectively prepared. The alcohol 12 was subjected to selective protection, oxidation, and difluoromethylenation to afford the fluorinated compound 18, whose hydrogenation was then systematically investigated. After a series of transformations of protecting groups, the resultant compounds 22 and 23 were oxidized to the desired lactams 24 and 25, which were successfully utilized to synthesize our target molecules, 3'-deoxy-3'-difluoromethyl azanucleosides 33, 34a, 34b, and 35.

New cerebrosides from Euphorbia peplis L.: antimicrobial activity evaluation

The less polar fraction of the methanolic extract from the plant Euphorbia peplis L. exhibited interesting antifungal and antitubercular activity. A complex mixture of four glucocerebrosides was responsible for this activity. Two new cerebrosides were isolated for the first time from Euphorbiaceae, 4 was assigned as 1-O-(beta-D-glucopyranosyl)-(2S,3S,4E,8E)-2N-[(2'R)-2'-hydroxy-hexadecanoyl]-4 (E), 8 (E)-octadecadiene-1,3-diol and 3 as the 1-O-(beta-D-glucopyranosyl)-(2S,3S,4R,8Z)-2N-[(2'R)-2'-hydroxytetracosanoyl]-8 (Z)-octadecene-1,3,4-triol. The structures were determined on the basis of chemical and spectroscopic evidences. Mass spectrometry of dimethyl disulfide derivatives was useful for the determination of the double-bond positions in the long-chain bases.

Preliminary biological assay on cerebroside mixture from Euphorbia nicaeensis All. Isolation and structure determination of five glucocerebrosides

Preliminary studies of in vitro cytostatic activity on less polar fraction of the MeOH extract of the plant Euphorbia nicaeensis All., carried out on KB cells, have evinced a relatively low ability of extract to inhibit cell growth. Successive, five glucocerebrosides were isolated from the cerebroside molecular species obtained from this extract using normal and reversed phase column 'flash-chromatography'. The structures of these cerebrosides were determined on the basis of chemical and spectroscopic evidences. Mass spectrometry of dimethyl disulfide derivatives was useful for the determination of the double-bond positions in the long-chain bases.

A facile synthesis of phytosphingosine from diisopropylidene-D-mannofuranose

In the present study, an efficient method with a high overall yield for preparing phytosphingosine and an analogue was developed. Starting with commercially available 2,3;5,6-di-O-isopropylidene-d-mannofuranose, a variety of lipid moieties were incorporated to obtain phytosphingosine and an analogue. Through an eight-step manipulation, phytosphingosine was obtained with an overall yield of 57%.

Discovery of a potent and selective agonist of the prostaglandin EP4 receptor

Analogues of PGE(2) wherein the hydroxycyclopentanone ring has been replaced by a lactam have been prepared and evaluated as ligands for the EP(4) receptor. An optimized compound (19a) shows high potency and agonist efficacy at the EP(4) receptor and is highly selective over the other seven known prostaglandin receptors.