67405-20-3Relevant academic research and scientific papers
Metalated 1,3-azaphospholes: Synthesis of lithium-1,3-benzazaphospholides and reactivity towards organoelement and organometal halides
Surana, Anushka,Singh, Shreeyukta,Bansal, Raj Kumar,Peulecke, Normen,Spannenberg, Anke,Heinicke, Joachim
, p. 113 - 124 (2002)
Metalation of benzazaphospholes 1a-e with t-BuLi provided the ambident anions 1a-eLi in high selectivity. A crystal structure analysis of 1bLi 3THF reveals monomers and coordination of lithium at nitrogen. The tungsten pentacarbonyl
PC-N-Heterocycles: Synthesis of biaryl-type 1,3-benzazaphospholes with ortho-substituted phenyl or 2-heteroaryl groups
Aluri, Bhaskar Reddy,Niaz, Basit,Kindermann, Markus K.,Jones, Peter G.,Heinicke, Joachim
, p. 211 - 224 (2011/02/16)
A facile synthesis of functionally substituted 2-(hetero)aryl 1,3-benzazaphospholes via nickel- or palladium-catalyzed phosphonylation of N-acyl-2-bromoanilides 1a-k with triethyl phosphite is presented. Anilidophosphonates 2a-g with naphthoyl-, o-substituted phenyl, furoyl- or thenoyl groups allow direct reductive cyclization with LiAlH4 to benzazaphospholes 3. The reaction of the o-bromoderivative 2d proceeds with concomitant replacement of bromine by hydrogen, whereas the electron-withdrawing pyridyl group of 2h prevents the synthesis of 3h by this short route. An alternative synthesis of 2-pyridylbenzazaphosphole 3hvia anilidophosphonates succeeded starting from Fmoc-anilinophosphonate 2kvia selective cleavage of the N-protecting group, reduction of the resulting phosphonoaniline to phosphinoaniline and cyclization with pyridine-2-carboxaldehyde via a dihydrobenzazaphosphole 8. N-Substituted pyridylmethylbenzazaphosphole 9 was detected as a side product. The structure elucidation of the new compounds is based on multinuclear NMR data and X-ray crystal structure analyses of a phosphonoanilide, underlining the dominance of N-H...OP hydrogen bonds over N-H...OC type hydrogen bonds, of 3h and a supramolecular associate of 3b and its unprecedented air oxidation product 10.
1H-1,3-benzazaphospholes: The organometallic route and a new three-step synthesis with reductive ring closure
Bansal, Raj K.,Gupta, Neelima,Heinicke, Joachim,Nikonov, George N.,Saguitova, Farida,Sharma, Dinesh C.
, p. 264 - 269 (2007/10/03)
Primary and N-secondary 2-phosphanylanilines were synthesized via metallation of 2-bromoanilines, coupling with CIP(NMe2)2, alcoholysis and reduction with LiAlH4, and subsequently reacted with formimidoester hydrochloride to give 1,3-benzazaphospholes. For 1H-1,3-benzazaphospholes, a shorter alternative three-step synthesis was developed, based on N-acylation of 2-bromoaniline, NiCl2-catalyzed arylation of triethyl phosphite and a new reductive cyclization of amidophosphonic acid ester with excess LiAlH4.
