Synthesis and molecular structure of 1,3-dihydro-1-hydroxy-3-methyl-1,2,3-benziodoxaphosphole 3-oxide

Phosphonylation of 2‐Amino‐ and 2‐Amido‐3‐bromopyridines and 2‐Amino‐3‐chloroquinoxalines with Triethyl Phosphite

“…[31] NMR spectra were measured at 25°C on a multinuclear FT-NMR spectrometer Bruker ARX300 or AVANCE300 at 300.1 ( 1 H), 75.5 ( 13 C), and 121.5 ( 31 P) MHz. The 1 H, 13 C and 31 P chemical shifts δ are given in ppm relative to Me 4 Si and H 3 PO 4 (85 %), respectively, as external standards. The assignments made correspond to position numbers in the pyridine or quinoxaline ring and in the N-substituents (denoted by additional Ј or i, o, m, p for phenyl).…”

“…The isomeric 3-acylamido-and 3-aminopyridine-2-phosphonates (δ = 11.3-12.3; 14.5 ppm) [18] absorb at markedly higher field, halfway to 2-aminoquinoxaline-3-phosphonates 7a,b, which by further electron release resonate in the range of δ = 9.4-9.8 ppm. The electronic effects are also reflected in the 13 C chemical shifts, which are strongly influenced by changes of the π-electron density. The most characteristic feature in the solution 1 H NMR spectra of 3 and 4 compared to 1 and 2 is the large downfield shift of the NH signals (∆δ = 1.9-2.8 ppm).…”

“…The Tavs procedure is more easy to perform, does neither need auxiliary ligands (triethyl phosphite itself acts as ligand [13] ) nor a base or solvent, and for thermally sufficiently stable aromatic compounds this reaction is thus an advantageous alternative. Optimization is reduced to screening for suitable transition metal precursors.…”

The Chemistry between Hypervalent Iodine(III) Reagents and Organophosphorus Compounds

“…[17] In 1978, Balthazor and co-workers reported the synthesis of ortho-phosphinato iodosoarene 14, obtained from the peracetic acid oxidation of iodoarene 13, and this could again be converted to the methoxy derivative 15 upon heating with methanol (Scheme 3 b). [18] Surprisingly, when the synthesis of the analogous chloride was attempted, it resulted in dichloride 16, and not the ortho-stabilized monochloride, analogous to 14 or 15 (Scheme 3 c). In 2005, Protasiewicz and co-workers prepared the ortho-phosphoryl-stabilized, monomeric iodosobenzene derivative 18 (Scheme 3 d); however, the product was found to disproportionate into 17 and 19 upon recrystallization.…”

Intramolecular Reversible Addition Reactions to the Other Groups

“…2-lodosobenzoic acid (56) [1l3-116], its amides (57) [115,117], esters (58) [114,116], and a mixed acetic acid anhydride (59) [116,118] only appear as cyclic isomers as do 2-iodosobenzenesulfonamide (60) [119], 2-iodosophenylmethylphosphinic acid (61) [120], 2-iodosophenylacetic acid (62) [121], 2-iodosophenyl phosphate (63) [122] and 2-iodoxybenzoic acid (64) [ 116]. Stable cyclic hydroxyiodinanes (65, R = Me, CF3) bearing a gemdimethyl or gem-trifluoromethyl group have been synthesized [123] as well as the exclusively cyclic chloroiodinane (66) [123,124].…”