Synthesis of macrolide prostaglandin analogs

Mass spectrometric fragmentation patterns for the syn and anti isomers of PGE2 and PGD2-methyloxime methyl esters and their analogs

A systematic study of the mass spectral fragmentation of the methyl ester-methyloxime-trimethylsilyl ether derivatives of D and E prostaglandins and selected omega-chain analogs is presented. Fragments from the omega-chain analogs are shifted the appropriate mass when compared with the parent PGD2 or PGE2. NMR data of the methyloxime methyl ester of PGE2 have permitted assignment of the syn and anti isomers (relative to the alpha chain) to the fast and slow eluting gas chromatographic peaks, respectively.

Temperature and field dependent 1H-NMR relaxation data as probes of prostaglandin motional parameters in aqueous media

Proton resonance correlation times (tau eff) for PGF2 alpha and a more rigid analog have been derived from the field-strength dependence of spin-lattice relaxation times ( T1D ) using 200 and 500 MHz observation. Those hydrogens showing tau eff less than the value calculated for whole molecule tumbling (which applies for H-5----H-15) also show a significantly greater temperature dependence for T1D at 500 MHz. Minor wagging may occur at the C-7 and C-10 methylenes , and gradually increasing segmental motion is observed toward both side chain termini. A current model for the aqueous geometry of PGF2 alpha is developed from this data and studies of relaxation rate changes upon specific deuteration.

Omega chain methylated analogs of PGF2 alpha and PGE2

Our previously published prostaglandin (PG) synthesis route, in which the omega-chain is added in the penultimate step, provides facile access to a wide variety of omega-chain variant PG analogs. Each series requires only the synthesis of the appropriate methylated acylphosphonate for the Emmons' condensation. The syntheses of analogs bearing the following methylation patterns are detailed: 15-Me; 17,17-(Me) 2; 17, 17, 20-(Me) 3; 18, 18, 20-(Me) 3; 15, 18, 18, 20-(Me) 4; and 15-OMe-18, 18, 20- (Me) 3. The well-known 16., 16-dimethyl prostaglandins have also been prepared by this sequence. The synthesis of 16, 16-tetramethylene-PG analogs is also described.

Molecular basis for prostaglandin potency. III. Tests of the significance of the "hairpin conformation" in biorecognition phenomena

Prostaglandin analogs of the PGF2 alpha, 15-epi-PGF2 alpha, and PGE2 type bearing the following methyl substitution patterns -- 15-Me, 16, 16-(Me)2, 17, 17-(Me)2, and 18, 18, 20-(Me)3 -- and analogs constrained to "hairpin" alignment [via 1, (omega-1)-olide formation] and to "non-hairpin" arrangements [via 1, 9- and 1, 15-olide formation] are compared in the following biological assays: contraction of uterine and gastro-intestinal smooth muscle strips, luteolytic antifertility potency in the hamster, binding affinity to two different PGF2 alpha-receptor preparations from bovine corpora lutea, binding to the PGE-specific receptors from rat kidney and liver, inhibition of ADP- induced aggregation of human platelet-rich-plasma, and the effect on rat blood blood pressure. The methylated prostaglandins were also concerted to the corresponding prostacyclins and examined as to action on the platelet and on rat blood pressure. All evidence points to topographically distinct receptors for F2 alpha-, E- and I2- type prostaglandins. Cross-reactivity is reduced in most of the analogs examined. Independent of the target organ or tissue, the receptors show common features based on the functional class of PG recognized. "Hairpin" alignment improves binding (and potency) only for the PGF2 alpha specific assays. PGE-specific binding and potency is disrupted to an increasing extent as the chain branching point is moved further from the 15-hydroxyl center. In contrast 16, 16-dimethylation is particularly disruptive for the PGI2/E1 platelet receptor interaction.