A phosphoryl to spiro-bicyclophosphorane transformation via β-amidic proton elimination in phosphorylated hydrazides

5-Methyl-3,8-di-(2-amino-4-bromophenyl)-4,9-dioxa-1,2,6,7-tetraaza-5λ5-phosphaspiro[4.4]nona-2,7-diene

“…It was revealed that only the aromatic hydrazide group of 9 participated in the condensation with 10, while the primary aromatic amine group of 9 remained intact. Compounds possessing 4,9-dioxa-1,2,6,7-tetraaza-5λ 5 -phosphaspiro [4.4]nona-2,7-diene structure have been previously reported by Schmidpeter [10] and their synthesis has been more recently investigated by Gholivand [11] and Hua [12]. Similar condensations between aromatic dihydrazides and phosphonyl dichlorides were also published by Ali [13].…”

“…Thus, compound 8 seems not to be a candidate for selective anticancer treatment. reported by Schmidpeter [10] and their synthesis has been more recently investigated by Gholivand [11] and Hua [12]. Similar condensations between aromatic dihydrazides and phosphonyl dichlorides were also published by Ali [13].…”

Chiral Hypervalent, Pentacoordinated Phosphoranes

“…The alternative approach to synthesize bicyclic pentacoordinate spirophosphoranes proposed by Gholivand et al [106] is based on the condensation of simple hydrazides (i.e., benzhydrazide 123a and 4-pyridinecarboxylic acid hydrazide 123b) with phosphoryl reagents followed by a dehydrationcyclization rearrangement of the resulting phosphorylated hydrazides. Such spiro-bicyclophosphorane with a trigonal bipyramidal structure is formed if phosphoryl reagent contains at least two appropriate leaving groups such as chlorine atoms (in PhPOCl2 or POCl3).…”

“…The intermediate was finally converted into 121 by dehydration. Similarly, several pentacoordinate phosphoranes 122c-g were easily prepared in the reaction of benzhydrazide 123a or 4-pyridinecarboxylic acid hydrazide 123b with PhPOCl2, PhNHPOCl2 or POCl3 in the presence of triethylamine [106] (Scheme 52). …”

“…It was suggested that the reaction, proceeding according to an electron transfer mechanism, occurred via 128 with a cleavage of the P-P bond and indeed, 127 was isolated in low yield even with two equivalents of 126 (Scheme 53) [107]. Similarly, several pentacoordinate phosphoranes 122c-g were easily prepared in the reaction of benzhydrazide 123a or 4-pyridinecarboxylic acid hydrazide 123b with PhPOCl2, PhNHPOCl2 or POCl3 in the presence of triethylamine [106] (Scheme 52). …”