1.4- Diols furans, 2,3-dihydro

Enantioselective Hydrolysis of Racemic 1- 2, 3 -Dihydro Benzofb]Furan-4 -yl -1,2-Oxirane. Epoxide hydrolase catalyzes the enantioselective hydrolysis of an epoxide to the corresponding enantiomerically enriched diol and unreacted epoxide (22,23). The (5)-epoxide (12) is a key intermediate in the synthesis of a number of prospective drug candidates (24). The enantiospecific hydrolysis of the racemic 1- 2, 3 -dihydro benzo[b]furan-4 -yl -l,2-oxirane (13) to the corresponding (R)-diol (14) and unreacted -epoxide (12) (Fig. 4A) was demonstrated by Goswami et aL (25). Among cultures evaluated, two Aspergillus niger strains (SC 16310, SC 16311)... 

A number of instances can be cited from the literature wherein the isosteres had similar transformations. Bacterial dioxygenase-catalyzed ci5-dihydroxylation of the tetracyclic arene benzo[c]phenanthrene was found to occur exclusively at fjord region (cavity region) bonds. The isosteric compounds benzo[b]naphthol [l,2-d]furan and benzo[b]naphthol[l,2-d]thiophene were also similarly ci5-dihydroxylated at the fjord region bonds by bacterial dioxygenases (Boyd et al., 2001) (see Fig. 4.3). The isosteres 1,2-dihydronaphthalene, 2,3-dihydrobenzothiophene, and 2,3-dihydro-benzofuran gave similar corresponding diol products on incubation with Pseudomonas putida UV4. Microbes that possess the metabolic pathways to metabolize benzene, when substituted by... 

Synthesis of 2-ene-l,4-diols from boranes and furans via dihydro-1,2-oxaborins... 

The particular structural features of AICAR (Fig. 4.18, 2) that includes an aminoimidazole moiety as well as a ribofuranose residue are reflected in its mass spectrometric dissociation behavior as shown with its product ion mass spectrum (obtained after positive ESI and CID Fig. 4.19b). Numerous product ions originating from consecutive losses of water (-18 Da) and ammonia (-17 Da) were found at m/z 242,241,223,205, and 188, and most abundant fragment ions resulting from the aminoimidazole-carboxamide nucleus were observed at m/z 127 and 110. Assuming an initial protonation of the primary amino function, the neutral loss of the ribose residue (2-hydroxymethyl-2,3-dihydro-furan-3,4-diol, -132 Da) gives rise to the protonated 5-amino-imidazole-4-carboxamide m/z 127) that subsequently releases ammonia (-17 Da) to yield the cation of imidazole-4-carboxamide with m/z 110 (Scheme 4.11b). ... 

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