90490-47-4Relevant academic research and scientific papers
Organphosphorus Compounds. XVIII. Synthesisi of 2-Phenyl-2,3-dihydro-1H-1,2-benzazaphosphole 2-Sulfide by Pyrolysis of (2-Aminobenzyl)phenyldithiophosphonic Acid
Collins, David J.,Drygala, Peter F.,Swan, John M.
, p. 2095 - 2110 (2007/10/02)
Reaction of 2-phthalimidobenzyl bromide (12b) with the dialkyl phenylphosphonites (13a-c) afforded the corresponding alkyl phosphinates (14a-c) which upon hydrazinolysis yielded the respective (2-aminobenzyl)phenylphosphinates (16a-c).Reduction of the phosphinates (16a) or (16b) with lithium aluminium hydride gave (2-aminobenzyl)phenylphosphine (15), characterized by its conversion into crystalline 2,3-diphenyl-1,2,3,4-tetrahydro-1,3-benzazaphosphorine (18). (2-Aminobenzyl)phenylphosphine (15) was heated with sulfur in benzene under reflux for 30 min to give 80percent of (2-aminobenzyl)phenyldithiophosphinic acid (20) which when heated between 100-200 deg in vacuum underwent elimination of hydrogen sulfide to yield 2-phenyl-2,3-dihydro-1H-1,2-benzazaphosphole 2-sulfide (22a).Several other new phosphorus compounds are described.An attempt to prepare a 1H-1,2-benzazaphosphole derivative by photolysis of methyl benzylphosphonic azide (7) was unsuccessful.
Organophosphorus Compounds. XIX. Synthesis of 2,3-Dihydro-1H-1,2-benzazaphosphole 2-Oxides, Variously Substituted on Nitrogen and Phosphorus, by N-P Cyclization of Zwitterionic Intermediates
Collins, David J.,Drygala, Peter F.,Swan, John M.
, p. 2517 - 2536 (2007/10/02)
2-Phenyl-2,3-dihydro-1H-1,2-benzazaphosphole 2-oxide (7a) was prepared by thermolysis of the corresponding zwitterionic amino phosphinic acid (4), or its hydrochloride salt (1).Thermolysis of methyl (2-aminobenzyl)phenylphosphinate (5a) was accompanied by intermolecu;ar O->N transmethylation to give, after cyclization, 1-methyl-2-phenyl-2,3-dihydro-1H-1,2-benzazaphosphole 2-oxide (9a); similarly, the ethyl ester (5b) gave the N-ethyl heterocycle (9b). Reaction of 2-phthalimidobenzyl bromide (13a) with diethyl methylphosphonite (14b) gave ethyl (2-phthalimidobenzyl)methylphosphinate 15a).Hydrolysis of (15a) afforded (2-aminobenzyl)-methylphosphinic acid (16), and thermolysis of this produced 2-methyl-2,3-dihydro-1H-1,2-benzazaphosphole 2-oxide (18a). 1-Methyl-2-methoxy-2,3-dihydro-1H-1,2-benzazaphosphole 2-oxide (24) was synthesized in an analogous manner. Base catalyzed N-alkylation of the benzazaphosphole derivatives (7a) and (18a) was readily achieved, and the interconversion of 2-oxides and 2-sulfides was accomplished by conventional methods.
