Porphyrin-steroids

UPS results are also available for the amino acids and their methyl esters, peptides, porphyrins, steroids, vitamins, opiate narcotics, biogenic amines, tranquilizers, antipyretic and antiinflammatory agents, quinonoid molecules (which are important for electron... 

Regioselectively addressable functionalized templates (RAFT), oligovalent moieties with chemically distinct functional groups that can be selectively addressed in the preparation of template-associated synthetic proteins (TASP). RAFT are molecular scaffolds that comprise porphyrins, steroids, calixarenes, glycosides, and a variety of cyclic peptides and peptidomimetics. RAFT... 

J. COMBINATIONS OF PORPHYRIN AND OTHER HOSTS—PORPHYRIN-CALIXARENE, PORPHYRIN-CYCLODEXTRIN, PORPHYRIN-STEROIDS... 

Volume 19. Metabolism of amino acids, proteins, purines, and pyrimidines Volume 20. Metabolism of porphyrins, steroids, isoprenoids, flavonoids and fungal substances... 

Girgenti E, Ricoux R, Mahy JP (2004) Desi and synthesis of a Mn(III)-porphyrin steroid conjugate used as a new cleavable affinity label on the road to semi-synthetic catalytic antibodies. Tetrahedron 60 10049-10058... 

A major trend in organic synthesis, however, is the move towards complex systems. It may happen that one needs to combine a steroid and a sugar molecule, a porphyrin and a carotenoid, a penicillin and a peptide. Also the specialists in a field have developed reactions and concepts that may, with or without modifications, be applied in other fields. If one needs to protect an amino group in a steroid, it is advisable not only to search the steroid literature but also to look into publications on peptide synthesis. In the synthesis of corrin chromophores with chiral centres, special knowledge of steroid, porphyrin, and alkaloid chemistry has been very helpful (R.B. Woodward, 1967 A. Eschenmoser, 1970). 

Bonar-Law R. P., Mackay L. G., Walter C. J., Marvaud V., Sanders J. K. M. Towards Synthetic Enzymes Based on Porphyrins and Steroids Pure Appl. Chem. 1994 66 803-810... 

Recently, Breslow19 reported a regioselective and stereoselective hydroxylation of steroid substrates catalyzed by manganese porphyrin... 

The highly evolved catalyst 20 combines several features that have proved successful in simpler cases. The ionic sulfonate groups make the substrate sufficiently soluble for the reaction to be run in water. (The four hydrophilic cyclodextrins perform the same service for the catalyst.) The target reaction, the seledive oxidation of the steroid skeleton, goes back to the early days of enzyme models,1711 and the choice of porphyrin and of manganese as the metal cation are based on many years experience. The aryl groups are perfluorinated because an earlier version of the catalyst suffered self-oxidation. 

An example of side-chain fimctionalizahon is the attachment of tetraphenyl-porphyrin carboxylic acid to a fullerene bound steroid (214) via standard EDCl coupling with the hydroxy group of the steroid (Scheme 4.36) [230]. 

Structure 2 precisely adheres to the analytical constraints of Table I, but a wide variety of aliphatic alicyclic terpenoids, steroids, and porphyrins may serve as its precursors. The Harvey et al. (20) precursor model was favored... 

The sterols that were chosen as substrates contained two double bonds, one at various positions in the side chain and A5 in the steroid nucleus. Whereas the latter double bond was never touched in reactions with the Fe(III) porphyrin vesicle system 183 in the presence of PhIO, the side chain double bonds of desmosterol 186 and fucosterol 187 were epoxidized to 188 and 189 in 32% and 22% yield, respectively (Fig. 31). In contrast, stigmasterol 190 was not reactive, since the double bond cannot approach the reactive iron-oxo intermediate. 

Another approach to improved chemoselectivity utilizes sterically hindered alkenes, as reported by Konoike et al. (Scheme 3.25) [115]. Ursolic add 12, a steroid with a highly congested trisubstituted double bond, undergoes allylic hydroxylation at the C-ll position with MCPBA and tetrakis(pentafluorophenyl)porphyrin iron chloride [Fe(PFPP)Cl] as a catalyst to give a single diastereomer 13 in 91% yield. With sterically less encumbered systems only epoxidation was observed. 

Towards synthetic enzymes based on porphyrins and steroids, Pure Appl. Chem. 1994, 66, 803-810. 

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