New compounds from . X-ray crystal and molecular structures of olguine

Synthesis of gem-difluoromethylenated analogues of anamarine

“…The combined organic extracts were washed with 1 M HCl and brine, dried over anhydrous Na 2 SO 4 . Removal of all the solvent in vacuo gave a residue, which was purified by silica gel chromatography (petroleum ether:ethyl acetate = 20:1) to afford compound 13 (7.74 g, 92% yield) as a clear oil: 1 …”

“…Isolated from the flowers and leaves of a Peruvian Hyptis species by Valverde and co-workers in 1979 [1,2], (+)-anamarine 1 has a structure featuring R-configuration in the 5,6-dihydro-2H-pyran-2-one ring and L-gluco arrangement in the C6-side chain (Fig. 1).…”

Preparation of (4R,5S)-(5-methyl-2,2-dimethyl-1,3-dioxolane-4-ylmethyl)-phosphonium iodide. A synthetic approach to olguine: further model studies

“…Examples are the a,p-unsaturated &lactones olguine 1 and anamarine 2, which have been isolated from an unclassified Hyptis species (4,5), or asperlin 3, an antibiotic isolated from Aspergillus nidulans (6). The synthesis of these substances from carbohydrate precursors could be envisaged (7).…”

“…Compound 21 could be used as one of the fragments required in a Wittig condensation leading to olguine (4). The reaction of the epoxy-aldehydes 9 and 10 with the phosphonium salt 21 gave a Z and E mixture of the olefins [22][23][24][25] in good yield (90% and 79% respectively) (see Tables 2 and 3, Schemes 5 and 6), when the reaction was carried out in THFIHMPTA (6: 1).…”

On the absolute configuration determination by X-ray diffraction data

“…, (4) Gonzalez et al (1978b), (5) Gonzalez et al (1978c), (6) Fonseca et al (1979) Fayos et al (1979), (8) Alemany et al (1979a), (9) Alemany et al (1979b), (10) to be published To calculate the structure factors, F c ( -x e ), one can use more conveniently, the +x coordinates and just reverse the sign of f", the imaginary part of the scattering factors for the anomalous dispersors. In the same way, F c (+xj can be calculated from the -χ model.…”