The S chmidt Reaction

Abstract

The reaction between equimolar quantities of hydrazoic acid and carbonyl compounds in the presence of a strong mineral acid has become known as the Schmidt reaction It offers a convenient method for the preparation of amines from acids. Aldehydes yield nitriles and formyl derivatives of amines, and ketones yield amides. With hydrazoic acid in large excess, aldehdyes and ketones yield substituted tetrazoles. The reaction of carbonyl compounds with hydrazoic acid was first reported by Karl Friedrich Schmidt in 1923.

Alternative Route to the Diisocyanate Building Block 1,4-Diisocyanato-4-methylpentane (DIMP)

“…All spectra are referenced to CDCl 3 or tetramethylsilane (TMS), and the data are given in parts per million (ppm). Anhydrous tetrahydrofuran (THF, 99%, inhibited with 250 ppm 2,6-di-tert-butyl-4-methylphenol), 2-(N-ethyl-anilino)ethanol (7, 99%), diisopropylamine (redistilled, 99.5%), sodium azide (NaN 3 , 99%), 1,2-dichloroethane (DCE, 99%), hexyllithium (2.3 M in hexanes), isobutyronitrile (99%), 1-bromo-3-chloropropane (99%), potassium cyanide (KCN, 97%), N,N-dimethylformamide (DMF, anhydrous, 99.8%), thionyl chloride (SOCl 2 , 99%), and zirconium (IV) tetra(acetylacetonate) [Zr(acac) 4 , 98%] were purchased from Sigma-Aldrich Chemical Co. (Milwaukee). All other solvents or reagents were obtained commercially and used as received.…”

Application of Vinyl Azides in Chemical Synthesis: A Recent Update

“…Therefore, it could be expected that vinyl azides potentially bear nucleophilic reactivity like enamines. The nucleophilic attack of enamines (the Stork-enamine reactions) onto electrophiles (E + ) provides iminium ions (Scheme a), whereas that of vinyl azides should afford iminodiazonium ions (Scheme b), which are the reactive intermediates observed in the Schmidt reactions (Scheme c). In the Schmidt reactions, 1,2-substituent migration of iminodiazonium ions with elimination of dinitrogen provides nitrilium ions, which are hydrolyzed to give amides.…”

Schmidt Reaction of ω-Azido Valeryl Chlorides Followed by Intermolecular Trapping of the Rearrangement Ions: Synthesis of Assoanine and Related Pyrrolophenanthridine Alkaloids

“…The Schmidt–Aubé reaction is involved with the rearrangement of alkyl azides with ketones or aldehydes (Scheme ), and it has been used as a powerful strategy for synthesis of various N -heterocycles. , The analogue reaction of alkyl azides with acyl chlorides was reported in our group, and it proceeded through the N -diazonium ion amide intermediate, which was different from the Schmidt–Aubé reaction . Rearrangement of the intermediate would produce isocyanate ion and N -acyliminium ion as the primary products.…”