Alkyl diazotates. XI. Flexible and directed synthesis of azoxyalkanes

Traube's “Oxazomalonic Acid” is a 3-Hydroxysydnone Carboxylate with an E-ONNO Geometry This research was supported by the Airforce Office of Scientific Research and the National Institutes of Health.

“…In his seminal early investigations of the base‐mediated condensation of nitric oxide with organic acids,1–4 Wilhelm Traube prepared an adduct of diethylmalonate, which he formulated as “ON 2 C(CO 2 H) 2 ” and termed an “oxazomalonic acid” 3. As written, this derivative is formally a conjugated diazotate,5, 6 and in contrast with the low thermal stability of diazotates, Traube's disodium salt is stable to 343 °C. These observations and much of the organic chemistry of nitric oxide have received scant attention since then, but the discovery of the numerous roles of nitric oxide in biology has renewed interest in this once obscure chemistry 7.…”

Traubes „Oxazomalonsäure“ ist ein 3-Hydroxysydnoncarboxylat mit E-konfigurierter ONNO-Einheit Diese Arbeit wurde vom Airforce Office of Scientific Research und den National Institutes of Health unterstützt.

“…Während seiner bedeutenden frühen Untersuchungen1–4 der basenvermittelten Kondensation von Stickstoffmonoxid mit organischen Säuren stellte Wilhelm Traube ein Diethylmalonat‐Addukt her, für das er die Formel ON 2 C(CO 2 H) 2 angab und das er als „Oxazomalonsäure“ bezeichnete 3. Dieses Derivat wird formal als konjugiertes Diazotat beschrieben,5, 6 doch ist Traubes Dinatriumsalz – im Unterschied zu den üblicherweise thermisch nicht stabilen Diazotaten – bis 343 °C stabil. Diese Beobachtungen und ein Großteil der organischen Chemie von Stickstoffmonoxid haben lange Zeit nur wenig Aufmerksamkeit erhalten.…”

Adventures in Reactive Intermediate Chemistry: A Perspective and Retrospective

“…eq 14. 72 Yields of the unsymmetrical azoxyalkane range from 30% to 60%. In 95:5 ether/HMPA, the N-nitrosoamine is the major byproduct.…”

“…A useful sidelight on alkanediazotates is their utility in a general, stereospecific synthesis of azoxyalkanes. ,, Alkylation of, e.g., 1-phenylethanediazotate with Et 3 O + BF 4 – converts the diazotate’s O – to an ethoxide anion, nitrogen is expelled, and the [PhEtCH +– OEt] ion pair collapses to the ether product by frontside return with 70% net retention . Accompanying this process is the alkylation of the “middle” nitrogen of the NN–O – triad, yielding 46% of azoxyalkane 19 .…”

“…In fact, alkylation with R′I of alkanediazotates, derived from aminoalkanes via N -nitrosourethanes, constitutes a flexible, directed synthesis of azoxyalkanes that affords a single, structurally predictable product and accommodates chirality at both of the azoxyalkane’s α and α′ carbon atoms; cf. eq . Yields of the unsymmetrical azoxyalkane range from 30% to 60%.…”