Fast Heck-Cassar-Sonogashira (HCS) Reactions in Green Solvents.

The replacement of toxic solvents with greener alternatives in Heck-Cassar-Sonogashira (HCS) cross-couplings was investigated. The fine-tuning of the HCS protocol allowed to achieve complete conversions and high speed under mild conditions. N-Hydroxyethylpyrrolidone (HEP) gave the best results. Moreover, the methodology was successfully applied to the synthesis of an intermediate of the anticancer drug Erlotinib, demonstrating the versatility of the new green protocol.

Blakeslea trispora genes for carotene biosynthesis.

We cloned the carB and carRA genes involved in beta-carotene biosynthesis from overproducing and wild-type strains of Blakeslea trispora. The carB gene has a length of 1,955 bp, including two introns of 141 and 68 bp, and encodes a protein of 66.4 kDa with phytoene dehydrogenase activity. The carRA gene contains 1,894 bp, with a single intron of 70 bp, and encodes a protein of 69.6 kDa with separate domains for lycopene cyclase and phytoene synthase. The estimated transcript sizes for carB and carRA were 1.8 and 1.9 kb, respectively. CarB from the beta-carotene-overproducing strain B. trispora F-744 had an S528R mutation and a TAG instead of a TAA stop codon. The overproducing strain also had a P143S mutation in CarRA. Both B. trispora genes could complement mutations in orthologous genes in Mucor circinelloides and could be used to construct transformed strains of M. circinelloides that produced higher levels of beta-carotene than did the nontransformed parent. The results show that these genes are conserved across the zygomycetes and that the B. trispora carB and carRA genes are functional and potentially useable to increase carotenoid production.

Biotechnological lycopene production by mated fermentation of Blakeslea trispora.

A semi-industrial process (800-l fermentor) for lycopene production by mated fermentation of Blakeslea trispora plus (+) and minus (-) strains has been developed. The culture medium was designed at the flask scale, using a program based on a genetic algorithm; and a fermentation process by means of this medium was developed. Fermentation involves separate vegetative phases for (+) and (-) strains and inoculation of the production medium with a mix of both together. Feeding with imidazole or pyridine, molecules known to inhibit lycopene cyclase enzymatic activity, enhanced lycopene accumulation. Different raw materials and physical parameters, including dissolved oxygen, stirring speed, air flow rate, temperature, and pH, were checked in the fermentor to get maximum lycopene production. Typical data for the fermentation process are presented and discussed. This technology can be easily scaled-up to an industrial application for the production of this carotenoid nowadays widely in demand.

Mass spectrometry of avermectins: structural determination of two new derivatives of Ivermectin B(1a).

Fragmentation pathways of Avermectins were studied by electron impact (EI), chemical ionisation (CI), electrospray ionisation (ESI) and by collision experiments. Structure characterisation was obtained using ESI combined with multi-stage (MS(n)) tandem mass spectrometry, analysis of homologues, and effects on fragment masses of H/D exchange. By these approaches the structures of two new derivatives of Avermectins were characterised.