As for aldehydes , the hydrogen atoms on the carbon adjacent ("α to") the carboxyl group in esters are sufficiently acidic to undergo deprotonation, which in turn leads to a variety of useful reactions. Deprotonation requires relatively strong bases, such as alkoxides . Deprotonation gives a nucleophilic enolate , which can further react, ., the Claisen condensation and its intramolecular equivalent, the Dieckmann condensation . This conversion is exploited in the malonic ester synthesis , wherein the diester of malonic acid reacts with an electrophile (., alkyl halide ), and is subsequently decarboxylated. Another variation is the Fráter–Seebach alkylation .
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Within developing countries, exports from Latin America and Africa have fallen, while those of the Near East and the Far East have increased. For sheepskins, Oceania remains the dominant exporting region.
The tendency for bovine hides and skins is that developing countries change from being a net exporter to being a net importer, reflecting an expansion in tanning capacity in most developing countries, especially in the Far East and in Latin America. Conversely, the role of developed countries has changed from that of a net importer to net exporter of cattle hides. Japan and Western Europe are still net importers.
The european tanneries import wet blue from a wide range of sources: the USA, Argentina, Brazil, South Africa, Australia, Russia and Eastern Europe.
This means that certain steps of the processes of integrated tanneries are transferred to other countries, particularly to third World countries. From the environmental point of view this development has two consequences. First, environmentally important steps are transferred to other countries, and secondly, particular agents, which are restricted or prohibited within the EC, might be applied and are consequently imported via the hides and skins into the EC. As regards sheepskins, developing countries became net importers in the mid-nineties. Conversely, the developed countries as a whole are net exporters; Europe again, though, remains a net importer.