Improved synthesis of dicyclohexylidene protected quebrachitol and its use in the synthesis of L-chiro-inositol derivatives.

A modified synthesis of 1L-1,2:3,4-di-O-cyclohexylidene-5-O-methyl-chiro-inositol has been accomplished that improves the overall procedure, yield, and environmental aspects of its formation. Several inositol analogues have been prepared from this intermediate for testing as biosynthetic inhibitors of glycosyl-phosphatidylinositol (GPI) anchor formation.

Synthesis of cyclic pyranopterin monophosphate, a biosynthetic intermediate in the molybdenum cofactor pathway.

Cyclic pyranopterin monophosphate (1), isolated from bacterial culture, has previously been shown to be effective in restoring normal function of molybdenum enzymes in molybdenum cofactor (MoCo)-deficient mice and human patients. Described here is a synthesis of 1 hydrobromide (1·HBr) employing in the key step a Viscontini reaction between 2,5,6-triamino-3,4-dihydropyrimidin-4-one dihydrochloride and D-galactose phenylhydrazone to give the pyranopterin (5aS,6R,7R,8R,9aR)-2-amino-6,7-dihydroxy-8-(hydroxymethyl)-3H,4H,5H,5aH,6H,7H,8H,9aH,10H-pyrano[3,2-g]pteridin-4-one (10) and establishing all four stereocenters found in 1. Compound 10, characterized spectroscopically and by X-ray crystallography, was transformed through a selectively protected tri-tert-butoxycarbonylamino intermediate into a highly crystalline tetracyclic phosphate ester (15). The latter underwent a Swern oxidation and then deprotection to give 1·HBr. Synthesized 1·HBr had in vitro efficacy comparable to that of 1 of bacterial origin as demonstrated by its enzymatic conversion into mature MoCo and subsequent reconstitution of MoCo-free human sulfite oxidase-molybdenum domain yielding a fully active enzyme. The described synthesis has the potential for scale up.

Cocrystallization and configurations of myo-inositol-1,2-L-camphor acetals in two crystal structures.

The inositol rings in (1S,2R,3R,4S,5S,6R,7S,8S,11S)-myo-inositol-1,2-camphor acetal {systematic name: (1R,2S,3S,4R,5S,6R)-5,6-[(1S,2S,4S)-1,7,7-trimethylbicyclo[2.2.1]heptane-2,2-diyldioxy]cyclohexane-1,2,3,4-tetrol}, C(16)H(26)O(6), and (1R,2S,3S,4R,5R,6S,7R/S,8S,11S)-myo-inositol-1,2-camphor acetal trihydrate {systematic name: (1S,2R,3R,4S,5R,6S)-5,6-[(1S,4S,6R/S)-1,7,7-trimethylbicyclo[2.2.1]heptane-2,2-diyldioxy]cyclohexane-1,2,3,4-tetrol trihydrate}, C(16)H(26)O(6).3H(2)O, adopt flattened chair conformations with the latter crystal containing two stereoisomers in a 0.684 (2):0.316 (2) ratio, similar to that found both in solution and by calculation. Both molecules pack in the crystals in similar two-dimensional layers, utilizing strong O-H...O hydrogen bonds, with the trihydrate cell expanded to incorporate the additional hydrogen-bonded water molecules.