David Keith Donald

Synthesis and study of a non macrocyclic FK506 derivative

Abstract The affinity of a non macrocyclic analogue of FK506 for the immunophilin FKBP12 was determined The affinity of this analogue/FKBP12 complex for calcineurin was studied.

Synthesis and evaluation of dual domain macrocyclic FKBP12 ligands.

Abstract A number of dual domain, macrocyclic FKBP12 ligands were synthesised in which the FK506 effector domain was fused to simplified FKBP12 bindings domains. The resulting macrocyclic compounds possessed moderate binding affinities for FKBP12 but showed no activity in an assay for FKBP12 dependent calcineurin inhibition.

A synthesis of the C(1)-C(15) segment of tsukubaenolide (FK 506).

Abstract A synthesis of the C(1)-C(15) segment ( 4 ) of Tsukubaenolide ( 1 ) from Tri-O-acetyl-D-glucal and (S)-Pipecolinic acid methyl ester is described.

Synthetic FKBP12 ligands. Design and synthesis of pyranose replacements.

Abstract A number of FKBP12 ligands were designed and synthesised and their affinity for FKBP12 assessed. In these ligands the pyranose ring of FK506 was replaced by other more synthetically accessible groups. The preparation of suitable intermediates for the synthesis of “dual domain” inhibitors (compounds 6a–c, 15 and 22) is also described.

A synthesis of the C16-C23 segment of FK-506

Abstract A copper-catalysed migratory insertion reaction was used to construct the tri-substituted alkene of the C16-C23 segment 4 of the potent immunosuppressant FK-506 (Tsukubaenolide) (1).

C10 N-Acyl modified FK-506: A possible hybrid analogue of the transition state of peptidyl-prolyl cis-trans isomerization.

Abstract Three C-10 N-Acyl derivatives of FK-506 have been prepared. The reduced receptor binding of these analogues is not consistent with a direct overlap of FK-506 and a peptide substrate.

Studies relating to the immunosuppressive activity of FK506

Abstract Beckmann rearrangement of FK506 E-oxime gave amide 2 and the fragmentation product 4 . Compound 4 was also prepared by total synthesis.

The effect of Monocarboxylate Transporter (MCT1) inhibitor, AR-C117977 on accelerated rejection of cardiac grafts in pre-sensitised rats and concordant xenotransplantation

Previous studies have demonstrated the immunosuppressive properties of the monocarboxylate transporter MCT1 inhibitor, AR-C117977. The objective of this study was to evaluate the possible limitations in immunosuppressive efficacy of AR-C117977 in models of hyper acute rejection of cardiac transplants in pre-sensitised rats and in concordant cardiac xenotransplantation. Methods: A primary graft was given without treatment in order to induce sensitisation. At 10 days, a second cardiac transplant was performed, and doses of the test compound were given and compared to or combined with cyclosporin (CsA). Serum samples were retrieved for flow cytometry and measurements of antibody from the presensitised recipients before and after the second transplantation. Results: Survival was significantly prolonged with AR-C117977 in combination with CsA (median 12.5 days) compared with single treatment. AR-C117977 had a better effect on antibody formation and binding to B-cells than CsA, but a similar effect on T-cells. Acute rejection could not be prevented in any of the treatment groups in the xenotransplant model. Conclusion: A short course of the MCT1 inhibitor AR-C117977, in combination with CsA, prevented accelerated acute rejection in presensitised rats, but no longterm graft survival was achieved. Rejection in xenotransplantation was not prevented. Correspondence to: Clara Paul, Agneta Montgomery, Department of Surgery, Institution of Surgical Science, Malmö, Lund University, Sweden, Email: helenclarapaul@gmail.com

Recent Progress in Research on the Immunosuppressant FK-506

Publisher Summary This chapter discusses that FK-506 is produced by unidentified strain of Streptomyces which has subsequently been designated as Streptomyces tsukubaensis after its place of isolation—Tsukuba, Ibaraki Prefecture, Japan. The elucidation of the gross structure of FK-506 with its 23-membered macrolide ring harboring the unusual masked 1,2,3-tricarbonyl system has relied on extensive chemical, degradative, and spectroscopic studies. The determination of the relative configuration of the stereogenic centers however is not possible by NMR spectroscopy and has come instead from a single-crystal X-ray analysis. The absolute configuration of FK-506 is assigned, as acid hydrolysis results in the isolation of L-pipecolic acid. In deuteriochloroform 13C NMR spectrum of FK-506 shows a doubling of all peaks with a relative intensity of approximately 3:1. This ratio is highly solvent dependent. When FK-506 is dissolved in CD2Cl2 at low temperature, only one rotameric form is seen corresponding to that seen in the X-ray structure. As the temperature is raised, another set of signals appears and the calculated energy barrier to this process corresponds to that expected for amide bond rotation.