A new conjugated addition of trialkyl phosphites and alkylidenephosphoranes to 3‐ω‐azideoacetyl coumarin synthesis of some 1,2,3,4‐triazaphospholes, triazoles, and azido‐coumarin derivatives

Abstract

A new and efficient conjugate addition of trimethyl and triethyl phosphites to 3-x-azidoacetylcoumarin (1) has been studied. The reaction proceeded smoothly at r.t. furnishing 1,2,3,4-triazaphosphole coumarin derivatives 4a,b in $75% yields. Linear substituted triazoles 10a,b were also obtained from the reactions of 1 with a-keto ylides, acetyl-and benzoylmethylene triphenylphosphoranes. Contrary to these results, Wittig reaction was occurred when 1 was allowed to react with a-alkoxycarbonylmethylene-and cyanomethylenetriphenylphosphoranes 7c-e as well as with methylidene-and benzylidenetriphenylphosphoranes 8a,b resulting in the formation of the corresponding olefins either as an intermediate 14b or as final products 11a-c.

Spiro- and substituted tetrahydrobenzo[b]thiophene-triazaphospholes and phosphoramidates as potent antineoplastic agents: synthesis, biological evaluation, and SAR studies

“…Compounds 4a-4c showed 31 P NMR chemical shifts around 12 ppm confirming the presence of N-P-C linkage in an azaphosphole nucleus [23,24]. In their EI mass spectra, 4a-4c showed the molecular ion peaks in addition to the expected fragmentations of the corresponding compound.…”

“…The latter step was provoked by the formation of the highly stable P=O bond [23]. Similar triazaphosphole ring was previously obtained from the reaction of trialkyl phosphites with 3-x-azidoacetyl coumarin [24]. Furthermore, 4H-isooxazol-4-ylphosphonate was formed via [1 ?…”

Synthesis of Novel Coumarin Derivatives Bearing Phosphor Ester Motifs and Evaluation of their Antioxidant Activities

“…H3PO4 (85%) was used as external reference on recording the 31 P NMR spectra. TMSi was used as internal standard in DMSO-d6 on recording 1 H and 13 C NMR spectra, while chemical shifts (δ) are given Egyptian Journal of Chemistry http://ejchem.journals.ekb.eg/ 1 H NMR (500 MHz, DMSO-d6): δ = 1.16 (dt, 3 JHH 5.3, 4 JPH 4.2 Hz, 3H, NCMe), 1.30 (dt, 3 JHH 6.8, 4 JPH 4.8 Hz, 6H, P(OCH2Me)2), 3.14 (dq, 3 2 JPC 13.7 Hz, NCH2Me), 19.9 (d, 3 JPC 8.4 Hz, POCH2Me), 14.7 (d, 3 JPC 7.9 Hz, NCH2Me) ppm; 31…”

“…The attention in coumarin derivative chemistry and the biological activities of these compounds has increased through the previous five decades. In follow up to our lab research plan that pointed to the utility of phosphorus reagents in pharmaceuticals synthesis [18][19][20][21][22][23][24][25][26][27][28][29], we expand the previous work on phosphor reagents and coumarins [30,31] to produce unprecedented coumarin derivatives of prospective biological activities, particularly as antioxidants. The methodology depends on the reaction of azidochromene carbaldehyde 1 and 4-azidocoumarin (16) with trialkyl phosphites 2a-c, dialkyl phosphites 7a-c, and hexaalkylphosphorus triamides 11a,b.…”

Investigations of the Chemistry of Alkyl Phosphites Toward Nitrogen-Containing Compounds: Efficient Approaches to α-Amino-, β-Amino-, and/or Enaminophosphonates

“…[180] Another Staudinger-type reaction consists of two steps/one-pot reaction, in which the phosphor-imidates 184 was synthesized from the reaction of phosphites with organic azides. Further hydrolysis, the phosphoramidates 184 were isolated (Scheme 80).…”