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A novel photo protective mycosporine was isolated from the lichenized ascomycete Collema cristatum. Biological activity was measured in terms of protection against UV-B induced membrane destruction and pyrimidine dimer formation in cultured human keratinocytes, and prevention of UV-B induced erythema. It was found that the pure isolated compound prevented UV-B induced cell destruction in a dose-dependent manner, that the compound partially prevented pyrimidine dimer formation and completely prevented UV-B induced erythema when applied to the skin prior to irradiation.

Discovery of naturally-occurring boron compounds, all ionophoric polyketide macrodiolide antibiotics with a single boron atom critical for activity, established at least one biochemical role of boron. This review focuses primarily on presence and distribution of boron-containing compounds in vascular plants, marine algal species, and microorganisms.

Hydroboration of 1-alkynylphosphonates can be controlled to place boron on either C1 or C2 of the triple bond by control of reaction conditions. Initial hydroboration occurs on C1 (kinetic product), which can be isomerized to place boron on C2 (thermodynamic product) by extended heating or by use of large amounts of catalyst. Suzuki reaction of the hydroboration products with aryliodides provides a regio- and stereospecific route to disubstituted vinylphosphonates

The Arbuzov reaction of 1-iodoalkylboronates and P(OMe)3 proceeds smoothly to give phosphonoboronates 2, in good yields. Essentially no alkene formation is observed, apparently because of prior complexation of the phosphite with boron as observed by 11B NMR. Selective hydrolysis of the methyl esters is possible by treatment of 2 with excess Me3SiBr followed by methanol to give 3. Treatment of 3 with 6N HCl leads to the free phosphonoboronic, 4a.

A novel cyclic undecapeptide, Schizotrin A, possessing moderately strong antimicrobial activity is the major active metabolite in the cultured cyanobacterium Schizotrix sp. (TAU strain IL-89-2). The gross structure of Schizotrin A ( 1 ) was determined mainly by homonuclear- and inverse-heteronuclear-2D-NMR techniques and HRFABMS.

[figure: see text] Hydroboration of vinyl phosphonates with pinacolborane (PBH) proceeds to give phosphonoboronates, 2. Surprisingly, such compounds have not been reported before. The reaction works well with terminal alkenylphosphonates. Internal alkenylphosphonates give complex mixtures. Hydroboration/Suzuki coupling of alkynylphosphonates, with PBH, in a one-pot procedure gives trisubstituted vinylphosphonates in good overall yields and provides a new synthesis of these compounds.

Hydroboration of vinyl phosphonates with pinacolborane (PBH) proceeds to give phosphonoboronates, 2. Surprisingly, such compounds have not been reported before. The reaction works well with terminal alkenylphosphonates. Internal alkenylphosphonates give complex mixtures. Hydroboration/Suzuki coupling of alkynylphosphonates, with PBH, in a one-pot procedure gives trisubstituted vinylphosphonates in good overall yields and provides a new synthesis of these compounds.

A series of novel phosphonoboronates consisting of PC1B, PCnB, PC(X)CnB, and PCC=CB derivatives were evaluated as MMP-2 inhibitors. Structure–activity relationships (SARs) data for the compounds were discovered and are discussed.

A novel photo protective mycosporine was isolated from the lichenized ascomycete Collema cristatum. Biological activity was measured in terms of protection against UV-B induced membrane destruction and pyrimidine dimer formation in cultured human keratinocytes, and prevention of UV-B induced erythema. It was found that the pure isolated compound prevented UV-B induced cell destruction in a dose-dependent manner, that the compound partially prevented pyrimidine dimer formation and completely prevented UV-B induced erythema when applied to the skin prior to irradiation.

A series of novel phosphonoboronates consisting of PC(1)B, PC(n)B, PC(X)C(n)B, and PCC=CB derivatives were evaluated as MMP-2 inhibitors. Structure-activity relationships (SARs) data for the compounds were discovered and are discussed.