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Triethyl orthoformate is used in Bodroux-Chichibabin aldehyde synthesis to prepare an aldehyde with one carbon higher by reacting with Grignard reagent. It is also used in the electrophilic formylation of activated aromatic species such as phenol.
Acid-catalyzed reaction with an arylamine gives the N-ethoxymethylene derivative (imidic ester); see, e.g.: Org. Synth. Coll., 4, 464 (1963); reduction (NaBH4) gives the monomethyl amine: Synthesis, 55 (1974).
Due to their intrinsic dehydrating property, orthoformates are convenient reagents for acetalization of carbonyl compounds, under acid catalysis, e.g. tosic acid: J. Am. Chem. Soc., 60, 1905 (1938); J. Org. Chem., 20, 1695 (1955), or acidic ion-exchange resin: Synthesis, 348 (1974). Selective catalysis with NBS has been found to give high yields of acetals under almost neutral conditions: Synlett, 1456 (1999).
In the presence of BF3 etherate, is a source of the diethoxycarbenium ion: Synth. Commun., 19, 2307 (1989), a selective alkylating agent and a useful intermediate for the diethoxymethylenation of ketones, to give protected ß-ketoaldehydes: J. Org. Chem., 46, 2557 (1981). For a similar reaction with enamines to give the same products, see: Chem. Lett., 1307 (1982); Bull. Chem. Soc. Jpn., 57, 1876 (1984).
Orthoformates have also found use in the electrophilic formylation of activated aromatic species, e.g.: phenols (in the presence of AlCl3): Chem. Ber., 96, 308 (1963); pyrrole derivatives (with TFA): Austral. J. Chem., 25, 1979 (1972).
For further reactions of alkyl orthoformates, see Trimethyl orthoformate, A13760.
Yar, M.; Shahzad, S.; Siddiqi, S. A.; Mahmood, N.; Rauf, A.; Anwar, M. S.; Chaudhry, A. A.; Rehman, I. Triethyl orthoformate mediated a novel crosslinking method for the preparation of hydrogels for tissue engineering applications: characterization and in vitro cytocompatibility analysis. Mater. Sci. Eng., C 2015, 56, 154-164.
Szczepankiewicz, W.; Kuźnik, N. Synthesis of 3-arylquinazolin-4(3H)-imines from 2-amino-N'-arylbenzamidines and triethyl orthoformate. Tetrahedron Lett. 2015, 56 (10), 1198-1199.
Dichiarazioni di rischio (UE): H226-H315-H319-H335
Flammable liquid and vapour. Causes skin irritation. Causes serious eye irritation. May cause respiratory irritation.
Dichiarazioni precauzionali: P210-P261-P303+P361+P353-P305+P351+P338-P405-P501a
Keep away from heat/sparks/open flames/hot surfaces. - No smoking. Avoid breathing dust/fume/gas/mist/vapours/spray. IF ON SKIN (or hair): Remove/Take off immediately all contaminated clothing. Rinse skin with water/shower. IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing. Store locked up. Dispose of contents/container in accordance with local/regional/national/international regulations.