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Updated: Jul 15, 2026

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
Reactions of the HCN-tetramer with aldehydes
Klemens Koch1, W Bernd Schweizer, Albert Eschenmoser
1Laboratory of Organic Chemistry, Swiss Federal Institute of Technology ETH, Hönggerberg HCI, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich.
Abstract:
The HCN-tetramer, a 'classic' of the prebiotic chemistry of HCN, is shown to undergo a remarkable reaction with acetaldehyde in slightly basic or neutral aqueous solution at room temperature. The reaction consists in an aldolization-type C,C-bond formation, accompanied by a (presumably aldehyde-catalyzed) hydration of one of the two nitrile groups and the formation of two cyclic aminal-type groupings, each of the latter incorporating an additional molecule of the aldehyde. Should this so far unexplored type of chemistry of the HCN-tetramer prove to have some generality, the finding might add a new dimension to the potential etiological relevance of this HCN-oligomer.
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