Synthesis and structural characterization of pincer type bicyclic diacyloxy- and diazaselenuranes

Abstract

Synthesis and structural characterization of a new class of pincer type bicyclic diacyloxy- and diazaselenuranes is reported. The reaction of dimethyl 2-bromo-5-tert-butylisophthalate (28) with sodium benzeneselenolate affords the corresponding monoselenide, dimethyl 5-tert-butyl-2-(phenylselanyl)isophthalate (29). Reduction of 29 with LiAlH(4) provides 5-tert-butyl-2-(phenylselanyl)-1,3-phenylene)dimethanol 31. Oxidation of 29 or its hydrolyzed derivative, 5-tert-butyl-2-(phenylselanyl)isophthalic acid (30), with H(2)O(2) results in the formation of bicyclic diacyloxyselenurane (25). The reaction of 30 with aniline using the DCC coupling reaction gives 5-tert-butyl-N(1),N(3)-diphenyl-2-(phenylselanyl)isophthalamide (38). Reaction of 38 with H(2)O(2) leads to the formation of the corresponding bicyclic diazaselenurane (27) via selenoxide intermediate 39. Compounds 25, 27, 29 and 31 were characterized by single crystal X-ray crystallography. The structural aspects of the pincer type bicyclic chalcogenuranes are investigated using experimental and computational studies and compared with the related systems.

Contrasting Reactivity of 2‐chloro‐1‐formyl‐3‐hydroxymethylenecyclohexene and its Schiff Bases towards Disodium Diselenide: Isolation of Selenospirocycles versus Azapentalenes

“…The downfield shift is also due to the contribution of Se(IV) species, i. e ., canonical structure ‘c’ in the overall molecule. Similar downfield shifts in 77 Se resonance have been observed for compounds having Se(IV) ,…”

Isolation and structures of some selenium and tellurium derivatives of 1, 4, 5, 8, 9, 12-hexabromododecahydrotriphenylene as co-crystals of triphenylene

“…In the present study we report our attempts to insert heteroatoms like selenium and tellurium at the peripheral positions of the triphenylene rings using nucleophilic substitution reaction without any substitution on the triphenylene rings. During the course of the present study, Shao and co-workers 10 have reported the insertion of sulfur and selenium heteroatoms at the peripheral positions of the triphenylene rings (16)(17). In this case they succeeded in incorporating sulfur and selenium by electrophilic substitution reaction using n-BuLi as reagent followed by chalcogen (S, Se) insertion.…”

“…The 77 Se NMR signal for 22 was observed at 462 ppm which is slightly more (∼50 ppm) downfield shifted as compared to that expected for monoselenides. 16 This value of 462 ppm is also downfield shifted as compared to bis(2formylphenyl)selenide (393 ppm). 17 For selenocyanate 23, the 77 Se NMR chemical shift was 411 ppm, which is close to the chemical shifts reported for the related RSe-C≡N derivatives.…”

Adaptive responses of sterically confined intramolecular chalcogen bonds

“…5 ), our understanding about adaptive behaviors of chalcogen bonding components (the sigma donors and the proximal Lewis base under steric confinement) was enhanced. 25 , 28 , 29 …”